Update README

.gitignore

@@ -1,6 +1,8 @@
 .idea
+.goroot
 **/.#*
 **/*~
+/.go
 /cmd
 /db/initdb.sql
 /db/*sh

Makefile

@@ -5,6 +5,15 @@ export PATH := $(PATH)
 
 all: fmt lint test
 
+.PHONY: debug
+debug:
+	@echo "PATH: $(PATH)"
+	@echo "GOPATH: $(shell go env GOPATH)"
+	@which go
+	@which gofumpt
+	@which gci
+	@which golangci-lint
+
 # Test
 test:
 	go test -v ./...

README.md

@@ -2,6 +2,8 @@
 
 A Gemini crawler.
 
+URLs to visit as well as data from visited URLs are stored into "snapshots" in the database.
+
 ## Done
 - [x] Concurrent downloading with workers
 - [x] Concurrent connection limit per host
@@ -10,22 +12,16 @@ A Gemini crawler.
 - [x] Configuration via environment variables
 - [x] Storing snapshots in PostgreSQL
 - [x] Proper response header & body UTF-8 and format validation
-- [x] Follow robots.txt
+- [x] Follow robots.txt, see gemini://geminiprotocol.net/docs/companion/robots.gmi
+- [x] Handle redirects (3X status codes)
 
 ## TODO
-- [ ] Take into account gemini://geminiprotocol.net/docs/companion/robots.gmi
-- [ ] Proper handling of all response codes
-  - [ ] Handle 3X redirects properly
-- [ ] Handle URLs that need presentation of a TLS cert, like astrobotany
-  + [ ] Probably have a common "grc" cert for all?
-- [ ] Proper input and response validations:
-  + [ ] When making a request, the URI MUST NOT exceed 1024 bytes
-- [ ] Subscriptions to gemini pages? gemini://geminiprotocol.net/docs/companion/
+- [ ] Better URL normalization
+- [ ] Provide a TLS cert for sites that require it, like Astrobotany
 
 ## TODO for later
-- [ ] Add other protocols
-  + [ ] Gopher
-  + [ ] Scroll gemini://auragem.letz.dev/devlog/20240316.gmi
-  + [ ] Spartan
-  + [ ] Nex
-  + [ ] SuperTXT https://supertxt.net/00-intro.html
+- [ ] Gopher
+- [ ] Scroll gemini://auragem.letz.dev/devlog/20240316.gmi
+- [ ] Spartan
+- [ ] Nex
+- [ ] SuperTXT https://supertxt.net/00-intro.html

blacklist.txt

@@ -0,0 +1,2 @@
+gemi.dev
+mastogem.picasoft.net

config/config.go

@@ -8,83 +8,149 @@ import (
 	"github.com/rs/zerolog"
 )
 
+// Environment variable names.
+const (
+	EnvLogLevel               = "LOG_LEVEL"
+	EnvNumWorkers             = "NUM_OF_WORKERS"
+	EnvWorkerBatchSize        = "WORKER_BATCH_SIZE"
+	EnvMaxResponseSize        = "MAX_RESPONSE_SIZE"
+	EnvResponseTimeout        = "RESPONSE_TIMEOUT"
+	EnvPanicOnUnexpectedError = "PANIC_ON_UNEXPECTED_ERROR"
+	EnvBlacklistPath          = "BLACKLIST_PATH"
+	EnvDryRun                 = "DRY_RUN"
+)
+
+// Config holds the application configuration loaded from environment variables.
 type Config struct {
-	LogLevel        zerolog.Level
-	rootPath        string
-	MaxResponseSize int
-	NumOfWorkers    int
-	ResponseTimeout int
-	WorkerBatchSize int
+	LogLevel               zerolog.Level // Logging level (debug, info, warn, error)
+	MaxResponseSize        int           // Maximum size of response in bytes
+	NumOfWorkers           int           // Number of concurrent workers
+	ResponseTimeout        int           // Timeout for responses in seconds
+	WorkerBatchSize        int           // Batch size for worker processing
+	PanicOnUnexpectedError bool          // Panic on unexpected errors when visiting a URL
+	BlacklistPath          string        // File that has blacklisted strings of "host:port"
+	DryRun                 bool          // If false, don't write to disk
 }
 
-var CONFIG Config
+var CONFIG Config //nolint:gochecknoglobals
 
-func GetConfig() *Config {
-	var config Config
-	for _, envVar := range []string{
-		"LOG_LEVEL",
-		"ROOT_PATH",
-		"NUM_OF_WORKERS",
-		"WORKER_BATCH_SIZE",
-		"MAX_RESPONSE_SIZE",
-		"RESPONSE_TIMEOUT",
-	} {
-		if env, ok := os.LookupEnv(envVar); !ok {
-			fmt.Fprintf(os.Stderr, "Missing env var %s\n", envVar)
-			os.Exit(1)
-		} else {
-			switch envVar {
-			case "LOG_LEVEL":
-				{
-					logLevel, err := zerolog.ParseLevel(env)
+// parsePositiveInt parses and validates positive integer values.
+func parsePositiveInt(param, value string) (int, error) {
+	val, err := strconv.Atoi(value)
 	if err != nil {
-						fmt.Fprintf(os.Stderr, "Invalid LOG_LEVEL value\n")
-						os.Exit(1)
-					}
-					config.LogLevel = logLevel
-				}
-			case "ROOT_PATH":
-				{
-					config.rootPath = env
-				}
-			case "NUM_OF_WORKERS":
-				{
-					if numOfWorkers, err := strconv.Atoi(env); err != nil {
-						fmt.Fprintf(os.Stderr, "Invalid NUM_OF_WORKERS value\n")
-						os.Exit(1)
-					} else {
-						config.NumOfWorkers = numOfWorkers
+		return 0, ValidationError{
+			Param:  param,
+			Value:  value,
+			Reason: "must be a valid integer",
 		}
 	}
-			case "WORKER_BATCH_SIZE":
-				{
-					if workerBatchSize, err := strconv.Atoi(env); err != nil {
-						fmt.Fprintf(os.Stderr, "Invalid WORKER_BATCH_SIZE value\n")
-						os.Exit(1)
-					} else {
-						config.WorkerBatchSize = workerBatchSize
+	if val <= 0 {
+		return 0, ValidationError{
+			Param:  param,
+			Value:  value,
+			Reason: "must be positive",
 		}
 	}
-			case "MAX_RESPONSE_SIZE":
-				{
-					if maxResponseSize, err := strconv.Atoi(env); err != nil {
-						fmt.Fprintf(os.Stderr, "Invalid MAX_RESPONSE_SIZE value\n")
-						os.Exit(1)
-					} else {
-						config.MaxResponseSize = maxResponseSize
-					}
-				}
-			case "RESPONSE_TIMEOUT":
-				{
-					if val, err := strconv.Atoi(env); err != nil {
-						fmt.Fprintf(os.Stderr, "Invalid RESPONSE_TIMEOUT value\n")
-						os.Exit(1)
-					} else {
-						config.ResponseTimeout = val
-					}
-				}
-			}
-		}
-	}
-	return &config
+	return val, nil
+}
+
+func parseBool(param, value string) (bool, error) {
+	val, err := strconv.ParseBool(value)
+	if err != nil {
+		return false, ValidationError{
+			Param:  param,
+			Value:  value,
+			Reason: "cannot be converted to boolean",
+		}
+	}
+	return val, nil
+}
+
+// GetConfig loads and validates configuration from environment variables
+func GetConfig() *Config {
+	config := &Config{}
+
+	// Map of environment variables to their parsing functions
+	parsers := map[string]func(string) error{
+		EnvLogLevel: func(v string) error {
+			level, err := zerolog.ParseLevel(v)
+			if err != nil {
+				return ValidationError{
+					Param:  EnvLogLevel,
+					Value:  v,
+					Reason: "must be one of: debug, info, warn, error",
+				}
+			}
+			config.LogLevel = level
+			return nil
+		},
+		EnvNumWorkers: func(v string) error {
+			val, err := parsePositiveInt(EnvNumWorkers, v)
+			if err != nil {
+				return err
+			}
+			config.NumOfWorkers = val
+			return nil
+		},
+		EnvWorkerBatchSize: func(v string) error {
+			val, err := parsePositiveInt(EnvWorkerBatchSize, v)
+			if err != nil {
+				return err
+			}
+			config.WorkerBatchSize = val
+			return nil
+		},
+		EnvMaxResponseSize: func(v string) error {
+			val, err := parsePositiveInt(EnvMaxResponseSize, v)
+			if err != nil {
+				return err
+			}
+			config.MaxResponseSize = val
+			return nil
+		},
+		EnvResponseTimeout: func(v string) error {
+			val, err := parsePositiveInt(EnvResponseTimeout, v)
+			if err != nil {
+				return err
+			}
+			config.ResponseTimeout = val
+			return nil
+		},
+		EnvPanicOnUnexpectedError: func(v string) error {
+			val, err := parseBool(EnvPanicOnUnexpectedError, v)
+			if err != nil {
+				return err
+			}
+			config.PanicOnUnexpectedError = val
+			return nil
+		},
+		EnvBlacklistPath: func(v string) error {
+			config.BlacklistPath = v
+			return nil
+		},
+		EnvDryRun: func(v string) error {
+			val, err := parseBool(EnvDryRun, v)
+			if err != nil {
+				return err
+			}
+			config.DryRun = val
+			return nil
+		},
+	}
+
+	// Process each environment variable
+	for envVar, parser := range parsers {
+		value, ok := os.LookupEnv(envVar)
+		if !ok {
+			fmt.Fprintf(os.Stderr, "Missing required environment variable: %s\n", envVar)
+			os.Exit(1)
+		}
+
+		if err := parser(value); err != nil {
+			fmt.Fprintf(os.Stderr, "Configuration error: %v\n", err)
+			os.Exit(1)
+		}
+	}
+
+	return config
 }

config/errors.go

@@ -0,0 +1,14 @@
+package config
+
+import "fmt"
+
+// ValidationError represents a config validation error
+type ValidationError struct {
+	Param  string
+	Value  string
+	Reason string
+}
+
+func (e ValidationError) Error() string {
+	return fmt.Sprintf("invalid value '%s' for %s: %s", e.Value, e.Param, e.Reason)
+}

db/delete_robots_hosts.sql

@@ -0,0 +1,7 @@
+delete FROM snapshots
+WHERE host IN (
+    SELECT DISTINCT host
+    FROM snapshots
+    WHERE error LIKE 'robots.txt%'
+)
+AND url LIKE 'gemini://' || host || '/%';

db/error_stats.sql

@@ -0,0 +1,5 @@
+SELECT error, count(error) as count
+FROM snapshots
+GROUP BY error
+ORDER BY count DESC
+LIMIT 20;

db/fix-url-ports.sql

@@ -0,0 +1,22 @@
+-- Here's an SQL script that will find and remove snapshots without port numbers
+-- when there exists a duplicate with the default port 1965.
+
+-- Before running this DELETE though, you might want to
+-- verify the matches first with this SELECT:
+WITH duplicates AS (
+    SELECT s1.id as id_without_port, s2.id as id_with_port, s1.url as url_without_port, s2.url as url_with_port
+    FROM snapshots s1
+             JOIN snapshots s2
+                  ON s2.url = s1.url || ':1965'
+)
+SELECT * FROM duplicates;
+
+-- Now delete them for real:
+WITH duplicates AS (
+    SELECT s1.id as id_without_port, s2.id as id_with_port, s1.url as url_without_port, s2.url as url_with_port
+    FROM snapshots s1
+             JOIN snapshots s2
+                  ON s2.url = s1.url || ':1965'
+)
+DELETE FROM snapshots
+WHERE id IN (SELECT id_without_port FROM duplicates);

db/host_stats_visited.sql

@@ -0,0 +1,7 @@
+SELECT host, COUNT(*) AS row_count
+FROM snapshots
+WHERE response_code IS NOT NULL
+   AND error IS NULL
+GROUP BY host
+ORDER BY row_count DESC
+LIMIT 10;

db/initdb.sql

@@ -20,7 +20,7 @@ DROP TABLE IF EXISTS snapshots;
 CREATE TABLE snapshots (
     id SERIAL PRIMARY KEY,
     uid TEXT NOT NULL UNIQUE,
-    url TEXT NOT NULL,
+    url TEXT NOT NULL UNIQUE,
     host TEXT NOT NULL,
     timestamp TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
     mimetype TEXT,
@@ -42,7 +42,10 @@ CREATE INDEX idx_lang ON snapshots (lang);
 CREATE INDEX idx_response_code ON snapshots (response_code);
 CREATE INDEX idx_error ON snapshots (error);
 CREATE INDEX idx_host ON snapshots (host);
+CREATE INDEX unique_uid_url ON snapshots (uid, url);
+
 CREATE INDEX idx_snapshots_unprocessed_no_data ON snapshots (host)
 WHERE response_code IS NULL AND error IS NULL
 INCLUDE (id, uid, url, timestamp, mimetype, gemtext, links, lang);
+
 CREATE INDEX idx_response_code_error_nulls ON snapshots (response_code, error) WHERE response_code IS NULL AND error IS NULL;

db/migrate2_unique_urls.sql

@@ -0,0 +1,18 @@
+-- Step 1: Delete duplicate entries, keeping the last one based on timestamp
+-- Use a CTE to mark duplicates and delete them efficiently
+WITH ranked_snapshots AS (
+    SELECT 
+        id,
+        url,
+        ROW_NUMBER() OVER(PARTITION BY url ORDER BY timestamp DESC) AS row_num
+    FROM 
+        snapshots
+)
+DELETE FROM snapshots
+USING ranked_snapshots
+WHERE snapshots.id = ranked_snapshots.id
+AND ranked_snapshots.row_num > 1;
+
+-- Step 2: Add a unique constraint on the url column to prevent future duplicates
+ALTER TABLE snapshots
+ADD CONSTRAINT unique_url UNIQUE (url);

db/migration_3/migrate3_url_port.go

@@ -2,44 +2,56 @@ package main
 
 import (
 	"fmt"
-	"gemini-grc/gemini"
 	"os"
 
+	"gemini-grc/gemini"
 	_ "github.com/jackc/pgx/v5/stdlib" // PGX driver for PostgreSQL
 	"github.com/jmoiron/sqlx"
 )
 
+// MANUALLY SET TO TRUE WHEN MIGRATION HAS BEEN APPLIED
 func checkIfDone() bool { return true }
 
+func MustSelect(tx *sqlx.Tx, dest interface{}, query string, args ...interface{}) {
+	if err := tx.Select(dest, query, args...); err != nil {
+		panic(err)
+	}
+}
+
 // Populates the `host` field
 func main() {
-	db := connectToDB()
-
 	if checkIfDone() {
 		fmt.Println("Migration already applied")
 		return
 	}
 
-	count := 0
+	db := connectToDB()
+	defer db.Close()
+
+	batchSize := 1000
 	for {
 		// Start the transaction
-		tx, err := db.Beginx()
-		if err != nil {
-			fmt.Println(err)
-			return
-		}
-
-		query := `
-        SELECT * FROM snapshots
-        WHERE host IS NULL
-        LIMIT 5000
-    `
+		tx := db.MustBegin()
+		query := `SELECT * FROM snapshots WHERE url NOT LIKE '%1965%' LIMIT $1`
 		var snapshots []gemini.Snapshot
-		err = tx.Select(&snapshots, query)
+		MustSelect(tx, &snapshots, query, batchSize)
 		if len(snapshots) == 0 {
-			fmt.Println("Done!")
-			return
+			fmt.Println("No snapshots remaining, done")
+			break
 		}
+		for i, s := range snapshots {
+			_, err := gemini.ParseURL(s.URL.String(), "")
+			if err != nil {
+				panic(fmt.Sprintf("Error parsing URL. ID %d URL %s\n", s.ID, s.URL))
+			}
+			fmt.Printf("Saving %d %d %s\n", i+1, s.ID, s.URL)
+			err = gemini.UpsertSnapshot(0, tx, &s)
+			if err != nil {
+				panic(fmt.Sprintf("Error saving %s: %s", s.URL, err))
+			}
+			tx.MustExec(`DELETE FROM snapshots WHERE id=$1`, s.ID)
+		}
+		err := tx.Commit()
 		if err != nil {
 			fmt.Println(err)
 			err := tx.Rollback()
@@ -47,31 +59,7 @@ func main() {
 				panic(err)
 			}
 		}
-		for _, s := range snapshots {
-			s.Host = s.URL.Hostname
-			fmt.Println(count, s.UID, s.URL.Hostname)
-			err := gemini.SaveSnapshotToDB(tx, &s)
-			if err != nil {
-				fmt.Println(err)
-				err := tx.Rollback()
-				if err != nil {
-					panic(err)
 	}
-			}
-			count += 1
-		}
-
-		err = tx.Commit()
-		if err != nil {
-			fmt.Println(err)
-			err := tx.Rollback()
-			if err != nil {
-				panic(err)
-			}
-		}
-
-	}
-
 }
 
 func connectToDB() *sqlx.DB {

db/populateDB.go

@@ -1,9 +1,9 @@
 package main
 
 import (
-	"gemini-grc/uid"
 	"time"
 
+	"gemini-grc/uid"
 	"github.com/jmoiron/sqlx"
 )
 

db/url_port_stats.sql

@@ -0,0 +1,5 @@
+SELECT
+    COUNT(*) AS "All",
+    COUNT(CASE WHEN URL ~ '://[^:]+:[0-9]+' THEN 1 END) AS "With port",
+    COUNT(CASE WHEN URL !~ '://[^:]+:[0-9]+' THEN 1 END) AS "Without port"
+FROM snapshots;

debug.sh

@@ -1,14 +1,16 @@
 #!/bin/sh
 set -eu
 
+# Max response size 10MiB
 MAX_RESPONSE_SIZE=10485760 \
-LOG_LEVEL=info \
+LOG_LEVEL=debug \
 ROOT_PATH=./snaps \
 RESPONSE_TIMEOUT=10 \
-NUM_OF_WORKERS=5 \
+NUM_OF_WORKERS=1 \
+WORKER_BATCH_SIZE=1 \
 PG_DATABASE=gemini \
 PG_HOST=127.0.0.1 \
 PG_PORT=5433 \
 PG_USER=gemini \
 PG_PASSWORD=gemini \
-go run ./migrate1_host.go
+dlv debug

error_urls.txt

@@ -1,3 +1,6 @@
+// 31 redirect
+gemini://gemini.circumlunar.space
+
 // body with null byte
 gemini://kennedy.gemi.dev/archive/cached?url=gemini://spam.works/mirrors/textfiles/fun/consult.how&t=638427244900000000&raw=False
 

gemini/blacklist.go

@@ -0,0 +1,51 @@
+package gemini
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"gemini-grc/config"
+	"gemini-grc/logging"
+)
+
+var Blacklist *[]string //nolint:gochecknoglobals
+
+func LoadBlacklist() {
+	if Blacklist == nil {
+		data, err := os.ReadFile(config.CONFIG.BlacklistPath)
+
+		if err != nil {
+			Blacklist = &[]string{}
+			logging.LogWarn("Could not load Blacklist file: %v", err)
+			return
+		}
+		lines := strings.Split(string(data), "\n")
+
+		// Ignore lines starting with '#' (comments)
+		filteredLines := func() []string {
+			out := make([]string, 0, len(lines))
+			for _, line := range lines {
+				if !strings.HasPrefix(line, "#") {
+					out = append(out, line)
+				}
+			}
+			return out
+		}()
+
+		if len(lines) > 0 {
+			Blacklist = &filteredLines
+			logging.LogInfo("Blacklist has %d entries", len(*Blacklist))
+		}
+	}
+}
+
+func IsBlacklisted(url URL) bool {
+	hostWithPort := fmt.Sprintf("%s:%d", url.Hostname, url.Port)
+	for _, v := range *Blacklist {
+		if v == url.Hostname || v == hostWithPort {
+			return true
+		}
+	}
+	return false
+}

gemini/connectionPool.go

@@ -4,11 +4,11 @@ import (
 	"gemini-grc/logging"
 )
 
-var IpPool IpAddressPool = IpAddressPool{IPs: make(map[string]int)}
+var IpPool = IpAddressPool{IPs: make(map[string]int)}
 
-func AddIPsToPool(IPs []string) {
+func AddIPsToPool(ips []string) {
 	IpPool.Lock.Lock()
-	for _, ip := range IPs {
+	for _, ip := range ips {
 		logging.LogDebug("Adding %s to pool", ip)
 		IpPool.IPs[ip]++
 	}

gemini/errors.go

@@ -0,0 +1,101 @@
+package gemini
+
+import (
+	"errors"
+	"fmt"
+)
+
+type GeminiError struct {
+	Msg    string
+	Code   int
+	Header string
+}
+
+func (e *GeminiError) Error() string {
+	return fmt.Sprintf("%s: %s", e.Msg, e.Header)
+}
+
+func NewErrGeminiStatusCode(code int, header string) error {
+	var msg string
+	switch {
+	case code >= 10 && code < 20:
+		msg = "needs input"
+	case code >= 30 && code < 40:
+		msg = "redirect"
+	case code >= 40 && code < 50:
+		msg = "bad request"
+	case code >= 50 && code < 60:
+		msg = "server error"
+	case code >= 60 && code < 70:
+		msg = "TLS error"
+	default:
+		msg = "unexpected status code"
+	}
+	return &GeminiError{
+		Msg:    msg,
+		Code:   code,
+		Header: header,
+	}
+}
+
+var (
+	ErrGeminiRobotsParse      = errors.New("gemini robots.txt parse error")
+	ErrGeminiRobotsDisallowed = errors.New("gemini robots.txt disallowed")
+	ErrGeminiResponseHeader   = errors.New("gemini response header error")
+	ErrGeminiLinkLineParse    = errors.New("gemini link line parse error")
+
+	ErrURLParse  = errors.New("URL parse error")
+	ErrURLDecode = errors.New("URL decode error")
+	ErrUTF8Parse = errors.New("UTF-8 parse error")
+	ErrTextParse = errors.New("text parse error")
+
+	ErrNetwork                        = errors.New("network error")
+	ErrNetworkDNS                     = errors.New("network DNS error")
+	ErrNetworkTLS                     = errors.New("network TLS error")
+	ErrNetworkSetConnectionDeadline   = errors.New("network error - cannot set connection deadline")
+	ErrNetworkCannotWrite             = errors.New("network error - cannot write")
+	ErrNetworkResponseSizeExceededMax = errors.New("network error - response size exceeded maximum size")
+
+	ErrDatabase = errors.New("database error")
+)
+
+// We could have used a map for speed, but
+// we would lose ability to check wrapped
+// errors via errors.Is().
+
+var errGemini *GeminiError
+
+var knownErrors = []error{ //nolint:gochecknoglobals
+	errGemini,
+	ErrGeminiLinkLineParse,
+	ErrGeminiRobotsParse,
+	ErrGeminiRobotsDisallowed,
+	ErrGeminiResponseHeader,
+
+	ErrURLParse,
+	ErrURLDecode,
+	ErrUTF8Parse,
+	ErrTextParse,
+
+	ErrNetwork,
+	ErrNetworkDNS,
+	ErrNetworkTLS,
+	ErrNetworkSetConnectionDeadline,
+	ErrNetworkCannotWrite,
+	ErrNetworkResponseSizeExceededMax,
+
+	ErrDatabase,
+}
+
+func IsKnownError(err error) bool {
+	for _, known := range knownErrors {
+		if errors.Is(err, known) {
+			return true
+		}
+	}
+	// Check for wrapped errors as well
+	if errors.As(err, new(*GeminiError)) {
+		return true
+	}
+	return false
+}

gemini/errors_test.go

@@ -0,0 +1,24 @@
+package gemini
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+)
+
+func TestErrGemini(t *testing.T) {
+	t.Parallel()
+	err := NewErrGeminiStatusCode(50, "50 server error")
+	if !errors.As(err, new(*GeminiError)) {
+		t.Errorf("TestErrGemini fail")
+	}
+}
+
+func TestErrGeminiWrapped(t *testing.T) {
+	t.Parallel()
+	err := NewErrGeminiStatusCode(50, "50 server error")
+	errWrapped := fmt.Errorf("%w wrapped", err)
+	if !errors.As(errWrapped, new(*GeminiError)) {
+		t.Errorf("TestErrGeminiWrapped fail")
+	}
+}

gemini/files.go

@@ -2,12 +2,13 @@ package gemini
 
 import (
 	"fmt"
-	"gemini-grc/logging"
 	"net/url"
 	"os"
 	"path"
 	"path/filepath"
 	"strings"
+
+	"gemini-grc/logging"
 )
 
 // sanitizePath encodes invalid filesystem characters using URL encoding.
@@ -77,7 +78,7 @@ func SaveToFile(rootPath string, s *Snapshot, done chan struct{}) {
 
 	finalPath, err := calcFilePath(parentPath, urlPath)
 	if err != nil {
-		logging.LogError("Error saving %s: %w", s.URL, err)
+		logging.LogError("GeminiError saving %s: %w", s.URL, err)
 		return
 	}
 	// Ensure the directory exists
@@ -87,12 +88,12 @@ func SaveToFile(rootPath string, s *Snapshot, done chan struct{}) {
 		return
 	}
 	if s.MimeType.Valid && s.MimeType.String == "text/gemini" {
-		err = os.WriteFile(finalPath, (*s).Data.V, 0666)
+		err = os.WriteFile(finalPath, (*s).Data.V, 0o666)
 	} else {
-		err = os.WriteFile(finalPath, []byte((*s).GemText.String), 0666)
+		err = os.WriteFile(finalPath, []byte((*s).GemText.String), 0o666)
 	}
 	if err != nil {
-		logging.LogError("Error saving %s: %w", s.URL.Full, err)
+		logging.LogError("GeminiError saving %s: %w", s.URL.Full, err)
 	}
 	close(done)
 }

gemini/gemini.go

@@ -1,76 +1,37 @@
 package gemini
 
 import (
-	"errors"
 	"fmt"
-	"gemini-grc/logging"
 	"net/url"
 	"regexp"
 	"strconv"
+
+	"gemini-grc/logging"
 )
 
-func checkGeminiStatusCode(code int) error {
-	switch {
-	case code == 20:
-		return nil
-	case code >= 10 && code < 20:
-		return fmt.Errorf("gemini response %d needs data input", code)
-	case code >= 30 && code < 40:
-		return fmt.Errorf("gemini response %d redirect", code)
-	case code >= 40 && code < 50:
-		return fmt.Errorf("gemini response %d server error", code)
-	case code >= 50 && code < 60:
-		return fmt.Errorf("gemini response %d server permanent error", code)
-	case code >= 60 && code < 70:
-		return fmt.Errorf("gemini response %d certificate error", code)
-	default:
-		return fmt.Errorf("unexpected/unhandled Gemini response %d", code)
-	}
-}
-
-func ProcessGemini(snapshot *Snapshot) *Snapshot {
+func GetPageLinks(currentURL URL, gemtext string) LinkList {
 	// Grab link lines
-	linkLines := ExtractLinkLines(snapshot.GemText.String)
-	logging.LogDebug("[%s] Found %d links", snapshot.URL.String(), len(linkLines))
-
+	linkLines := ExtractLinkLines(gemtext)
+	if len(linkLines) == 0 {
+		return nil
+	}
+	var linkURLs LinkList
 	// Normalize URLs in links, and store them in snapshot
 	for _, line := range linkLines {
-		normalizedLink, descr, err := NormalizeLink(line, snapshot.URL.String())
+		normalizedLink, descr, err := NormalizeLink(line, currentURL.String())
 		if err != nil {
 			logging.LogDebug("Cannot normalize URL in line '%s': %v", line, err)
 			continue
 		}
-		geminiUrl, err := ParseUrl(normalizedLink, descr)
+		geminiUrl, err := ParseURL(normalizedLink, descr)
 		if err != nil {
 			logging.LogDebug("Cannot parse URL in link '%s': %v", line, err)
 			continue
 		}
-		if snapshot.Links == nil {
-			snapshot.Links = &LinkList{*geminiUrl}
-		} else {
-			*snapshot.Links = append(*snapshot.Links, *geminiUrl)
+		logging.LogDebug(geminiUrl.String())
+		linkURLs = append(linkURLs, *geminiUrl)
 	}
-	}
-	return snapshot
-}
-
-func ParseUrl(input string, descr string) (*GeminiUrl, error) {
-	u, err := url.Parse(input)
-	if err != nil {
-		return nil, fmt.Errorf("error parsing URL %s: %w", input, err)
-	}
-	protocol := u.Scheme
-	hostname := u.Hostname()
-	strPort := u.Port()
-	path := u.Path
-	if strPort == "" {
-		strPort = "1965"
-	}
-	port, err := strconv.Atoi(strPort)
-	if err != nil {
-		return nil, fmt.Errorf("error parsing URL %s: %w", input, err)
-	}
-	return &GeminiUrl{Protocol: protocol, Hostname: hostname, Port: port, Path: path, Descr: descr, Full: u.String()}, nil
+	return linkURLs
 }
 
 // ExtractLinkLines takes a Gemtext document as a string and returns all lines that are link lines
@@ -87,11 +48,11 @@ func ExtractLinkLines(gemtext string) []string {
 // NormalizeLink takes a single link line and the current URL,
 // return the URL converted to an absolute URL
 // and its description.
-func NormalizeLink(linkLine string, currentURL string) (link string, descr string, err error) {
+func NormalizeLink(linkLine string, currentURL string) (string, string, error) {
 	// Parse the current URL
 	baseURL, err := url.Parse(currentURL)
 	if err != nil {
-		return "", "", fmt.Errorf("invalid current URL: %v", err)
+		return "", "", fmt.Errorf("%w: %w", ErrURLParse, err)
 	}
 
 	// Regular expression to extract the URL part from a link line
@@ -101,13 +62,13 @@ func NormalizeLink(linkLine string, currentURL string) (link string, descr strin
 	matches := re.FindStringSubmatch(linkLine)
 	if len(matches) == 0 {
 		// If the line doesn't match the expected format, return it unchanged
-		return "", "", fmt.Errorf("not a link line: %v", linkLine)
+		return "", "", fmt.Errorf("%w for link line %s", ErrGeminiLinkLineParse, linkLine)
 	}
 
 	originalURLStr := matches[1]
 	_, err = url.QueryUnescape(originalURLStr)
 	if err != nil {
-		return "", "", fmt.Errorf("error decoding URL: %w", err)
+		return "", "", fmt.Errorf("%w: %w", ErrURLDecode, err)
 	}
 
 	restOfLine := ""
@@ -119,7 +80,7 @@ func NormalizeLink(linkLine string, currentURL string) (link string, descr strin
 	parsedURL, err := url.Parse(originalURLStr)
 	if err != nil {
 		// If URL parsing fails, return an error
-		return "", "", fmt.Errorf("invalid URL '%s': %v", originalURLStr, err)
+		return "", "", fmt.Errorf("%w: %w", ErrURLParse, err)
 	}
 
 	// Resolve relative URLs against the base URL
@@ -151,14 +112,33 @@ func ParseFirstTwoDigits(input string) (int, error) {
 	// Find the first match in the string
 	matches := re.FindStringSubmatch(input)
 	if len(matches) == 0 {
-		return 0, errors.New("no digits found at the beginning of the string")
+		return 0, fmt.Errorf("%w", ErrGeminiResponseHeader)
 	}
 
 	// Parse the captured match as an integer
 	snapshot, err := strconv.Atoi(matches[1])
 	if err != nil {
-		return 0, fmt.Errorf("failed to convert matched digits to int: %v", err)
+		return 0, fmt.Errorf("%w: %w", ErrTextParse, err)
 	}
 
 	return snapshot, nil
 }
+
+// extractRedirectTarget returns the redirection
+// URL by parsing the header (or error message)
+func extractRedirectTarget(currentURL URL, input string) (*URL, error) {
+	// \d+ - matches one or more digits
+	// \s+ - matches one or more whitespace
+	// ([^\r]+) - captures everything until it hits a \r (or end of string)
+	pattern := `\d+\s+([^\r]+)`
+	re := regexp.MustCompile(pattern)
+	matches := re.FindStringSubmatch(input)
+	if len(matches) < 2 {
+		return nil, fmt.Errorf("%w: Cannot find redirect target from header %s", ErrGeminiResponseHeader, input)
+	}
+	newURL, err := DeriveAbsoluteURL(currentURL, matches[1])
+	if err != nil {
+		return nil, fmt.Errorf("%w: Cannot find redirect target from header: %w", ErrGeminiResponseHeader, err)
+	}
+	return newURL, nil
+}

gemini/gemini_test.go

@@ -0,0 +1,47 @@
+package gemini
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestExtractRedirectTargetFullURL(t *testing.T) {
+	t.Parallel()
+	currentURL, _ := ParseURL("gemini://smol.gr", "")
+	input := "redirect: 31 gemini://target.gr"
+	result, err := extractRedirectTarget(*currentURL, input)
+	if err != nil || (result.String() != "gemini://target.gr:1965") {
+		t.Errorf("fail: %s", result)
+	}
+}
+
+func TestExtractRedirectTargetRelativeURL(t *testing.T) {
+	t.Parallel()
+	currentURL, _ := ParseURL("gemini://smol.gr", "")
+	input := "redirect: 31 /a/b"
+	result, err := extractRedirectTarget(*currentURL, input)
+	if err != nil || (result.String() != "gemini://smol.gr:1965/a/b") {
+		t.Errorf("fail: %s", result)
+	}
+}
+
+func TestExtractRedirectTargetRelativeURL2(t *testing.T) {
+	t.Parallel()
+	currentURL, _ := ParseURL("gemini://nox.im:1965", "")
+	input := "redirect: 31 ./"
+	result, err := extractRedirectTarget(*currentURL, input)
+	if err != nil || (result.String() != "gemini://nox.im:1965/") {
+		t.Errorf("fail: %s", result)
+	}
+}
+
+func TestExtractRedirectTargetWrong(t *testing.T) {
+	t.Parallel()
+	currentURL, _ := ParseURL("gemini://smol.gr", "")
+	input := "redirect: 31 fsdsdf"
+	result, err := extractRedirectTarget(*currentURL, input)
+	fmt.Println(err)
+	if result != nil || err == nil {
+		t.Errorf("fail: result should be nil, err is %s", err)
+	}
+}

gemini/gemini_url.go

@@ -1,12 +1,16 @@
 package gemini
 
 import (
-	"encoding/json"
+	"database/sql/driver"
 	"fmt"
 	"gemini-grc/logging"
+	"net/url"
+	"path"
+	"strconv"
+	"strings"
 )
 
-type GeminiUrl struct {
+type URL struct {
 	Protocol string `json:"protocol,omitempty"`
 	Hostname string `json:"hostname,omitempty"`
 	Port     int    `json:"port,omitempty"`
@@ -15,43 +19,79 @@ type GeminiUrl struct {
 	Full     string `json:"full,omitempty"`
 }
 
-func (g *GeminiUrl) Scan(value interface{}) error {
+func (u *URL) Scan(value interface{}) error {
 	if value == nil {
 		// Clear the fields in the current GeminiUrl object (not the pointer itself)
-		*g = GeminiUrl{}
+		*u = URL{}
 		return nil
 	}
 	b, ok := value.(string)
 	if !ok {
 		return fmt.Errorf("failed to scan GeminiUrl: expected string, got %T", value)
 	}
-	parsedUrl, err := ParseUrl(b, "")
+	parsedURL, err := ParseURL(b, "")
 	if err != nil {
 		return err
 	}
-	*g = *parsedUrl
+	*u = *parsedURL
 	return nil
 }
 
-func (u GeminiUrl) String() string {
+func (u URL) String() string {
 	return u.Full
-	//	return fmt.Sprintf("%s://%s:%d%s", u.Protocol, u.Hostname, u.Port, u.Path)
 }
 
-func GeminiUrltoJSON(g GeminiUrl) string {
-	// Serialize the Person struct to JSON
-	jsonData, err := json.Marshal(g)
-	if err != nil {
-		logging.LogError("Error serializing to JSON: %w", err)
+func (u URL) StringNoDefaultPort() string {
+	if u.Port == 1965 {
+		return fmt.Sprintf("%s://%s%s", u.Protocol, u.Hostname, u.Path)
 	}
-	return string(jsonData)
+	return u.Full
 }
 
-func GeminiUrlFromJSON(input string) GeminiUrl {
-	var geminiUrl GeminiUrl
-	err := json.Unmarshal([]byte(input), &geminiUrl)
-	if err != nil {
-		logging.LogError("Error deserializing from JSON: %w", err)
+func (u URL) Value() (driver.Value, error) {
+	if u.Full == "" {
+		return nil, nil
 	}
-	return geminiUrl
+	return u.Full, nil
+}
+
+func ParseURL(input string, descr string) (*URL, error) {
+	u, err := url.Parse(input)
+	if err != nil {
+		return nil, fmt.Errorf("%w: Input %s GeminiError %w", ErrURLParse, input, err)
+	}
+	protocol := u.Scheme
+	hostname := u.Hostname()
+	strPort := u.Port()
+	path := u.Path
+	if strPort == "" {
+		strPort = "1965"
+	}
+	port, err := strconv.Atoi(strPort)
+	if err != nil {
+		return nil, fmt.Errorf("%w: Input %s GeminiError %w", ErrURLParse, input, err)
+	}
+	full := fmt.Sprintf("%s://%s:%d%s", protocol, hostname, port, path)
+	return &URL{Protocol: protocol, Hostname: hostname, Port: port, Path: path, Descr: descr, Full: full}, nil
+}
+
+func DeriveAbsoluteURL(currentURL URL, input string) (*URL, error) {
+	logging.LogDebug("Calculating redirect URL. Current %s header string %s", currentURL, input)
+	// If URL is absolute, return just it
+	if strings.Contains(input, "://") {
+		return ParseURL(input, "")
+	}
+	// input is a path. Clean it and construct
+	// new path
+	var newPath string
+	// Handle weird cases found in the wild
+	if strings.HasPrefix(input, "/") {
+		newPath = path.Clean(input)
+	} else if input == "./" || input == "." {
+		newPath = path.Join(currentURL.Path, "/")
+	} else {
+		newPath = path.Join(currentURL.Path, path.Clean(input))
+	}
+	strURL := fmt.Sprintf("%s://%s:%d%s", currentURL.Protocol, currentURL.Hostname, currentURL.Port, newPath)
+	return ParseURL(strURL, "")
 }

gemini/gemini_url_test.go

@@ -0,0 +1,103 @@
+package gemini
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseURL(t *testing.T) {
+	t.Parallel()
+	input := "gemini://caolan.uk/cgi-bin/weather.py/wxfcs/3162"
+	parsed, err := ParseURL(input, "")
+	value, _ := parsed.Value()
+	if err != nil || !(value == "gemini://caolan.uk:1965/cgi-bin/weather.py/wxfcs/3162") {
+		t.Errorf("fail: %s", parsed)
+	}
+}
+
+func TestDeriveAbsoluteURL_abs_url_input(t *testing.T) {
+	t.Parallel()
+	currentURL := URL{
+		Protocol: "gemini",
+		Hostname: "smol.gr",
+		Port:     1965,
+		Path:     "/a/b",
+		Descr:    "Nothing",
+		Full:     "gemini://smol.gr:1965/a/b",
+	}
+	input := "gemini://a.b/c"
+	output, err := DeriveAbsoluteURL(currentURL, input)
+	if err != nil {
+		t.Errorf("fail: %v", err)
+	}
+	expected := &URL{
+		Protocol: "gemini",
+		Hostname: "a.b",
+		Port:     1965,
+		Path:     "/c",
+		Descr:    "",
+		Full:     "gemini://a.b:1965/c",
+	}
+	pass := reflect.DeepEqual(output, expected)
+	if !pass {
+		t.Errorf("fail: %#v != %#v", output, expected)
+	}
+}
+
+func TestDeriveAbsoluteURL_abs_path_input(t *testing.T) {
+	t.Parallel()
+	currentURL := URL{
+		Protocol: "gemini",
+		Hostname: "smol.gr",
+		Port:     1965,
+		Path:     "/a/b",
+		Descr:    "Nothing",
+		Full:     "gemini://smol.gr:1965/a/b",
+	}
+	input := "/c"
+	output, err := DeriveAbsoluteURL(currentURL, input)
+	if err != nil {
+		t.Errorf("fail: %v", err)
+	}
+	expected := &URL{
+		Protocol: "gemini",
+		Hostname: "smol.gr",
+		Port:     1965,
+		Path:     "/c",
+		Descr:    "",
+		Full:     "gemini://smol.gr:1965/c",
+	}
+	pass := reflect.DeepEqual(output, expected)
+	if !pass {
+		t.Errorf("fail: %#v != %#v", output, expected)
+	}
+}
+
+func TestDeriveAbsoluteURL_rel_path_input(t *testing.T) {
+	t.Parallel()
+	currentURL := URL{
+		Protocol: "gemini",
+		Hostname: "smol.gr",
+		Port:     1965,
+		Path:     "/a/b",
+		Descr:    "Nothing",
+		Full:     "gemini://smol.gr:1965/a/b",
+	}
+	input := "c/d"
+	output, err := DeriveAbsoluteURL(currentURL, input)
+	if err != nil {
+		t.Errorf("fail: %v", err)
+	}
+	expected := &URL{
+		Protocol: "gemini",
+		Hostname: "smol.gr",
+		Port:     1965,
+		Path:     "/a/b/c/d",
+		Descr:    "",
+		Full:     "gemini://smol.gr:1965/a/b/c/d",
+	}
+	pass := reflect.DeepEqual(output, expected)
+	if !pass {
+		t.Errorf("fail: %#v != %#v", output, expected)
+	}
+}

gemini/network.go

@@ -2,21 +2,26 @@ package gemini
 
 import (
 	"crypto/tls"
+	"errors"
 	"fmt"
-	"gemini-grc/config"
+	"gemini-grc/logging"
 	"io"
 	"net"
-	go_url "net/url"
+	gourl "net/url"
 	"regexp"
 	"slices"
 	"strconv"
+	"strings"
 	"time"
 
+	"gemini-grc/config"
+
 	"github.com/guregu/null/v5"
 )
 
-type GeminiPageData struct {
+type PageData struct {
 	ResponseCode   int
+	ResponseHeader string
 	MimeType       string
 	Lang           string
 	GemText        string
@@ -31,7 +36,7 @@ type GeminiPageData struct {
 func getHostIPAddresses(hostname string) ([]string, error) {
 	addrs, err := net.LookupHost(hostname)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("%w:%w", ErrNetworkDNS, err)
 	}
 	IpPool.Lock.RLock()
 	defer func() {
@@ -41,12 +46,12 @@ func getHostIPAddresses(hostname string) ([]string, error) {
 }
 
 func ConnectAndGetData(url string) ([]byte, error) {
-	parsedUrl, err := go_url.Parse(url)
+	parsedURL, err := gourl.Parse(url)
 	if err != nil {
-		return nil, fmt.Errorf("Could not parse URL, error %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrURLParse, err)
 	}
-	hostname := parsedUrl.Hostname()
-	port := parsedUrl.Port()
+	hostname := parsedURL.Hostname()
+	port := parsedURL.Port()
 	if port == "" {
 		port = "1965"
 	}
@@ -54,38 +59,37 @@ func ConnectAndGetData(url string) ([]byte, error) {
 	// Establish the underlying TCP connection.
 	dialer := &net.Dialer{
 		Timeout: time.Duration(config.CONFIG.ResponseTimeout) * time.Second,
-		KeepAlive: 10 * time.Second,
 	}
 	conn, err := dialer.Dial("tcp", host)
 	if err != nil {
-		return nil, fmt.Errorf("TCP connection failed: %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrNetwork, err)
 	}
 	// Make sure we always close the connection.
 	defer func() {
 		// No need to handle error:
-		// Connection will timeout eventually if still open somehow.
-		conn.Close()
+		// Connection will time out eventually if still open somehow.
+		_ = conn.Close()
 	}()
 
 	// Set read and write timeouts on the TCP connection.
 	err = conn.SetReadDeadline(time.Now().Add(time.Duration(config.CONFIG.ResponseTimeout) * time.Second))
 	if err != nil {
-		return nil, fmt.Errorf("Error setting connection deadline: %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrNetworkSetConnectionDeadline, err)
 	}
 	err = conn.SetWriteDeadline(time.Now().Add(time.Duration(config.CONFIG.ResponseTimeout) * time.Second))
 	if err != nil {
-		return nil, fmt.Errorf("Error setting connection deadline: %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrNetworkSetConnectionDeadline, err)
 	}
 
 	// Perform the TLS handshake
 	tlsConfig := &tls.Config{
-		InsecureSkipVerify: true,                 // Accept all TLS certs, even if insecure.
-		ServerName:         parsedUrl.Hostname(), // SNI should not include port
+		InsecureSkipVerify: true,                 //nolint:gosec    // Accept all TLS certs, even if insecure.
+		ServerName:         parsedURL.Hostname(), // SNI should not include port
 		// MinVersion:         tls.VersionTLS12, // Use a minimum TLS version. Warning breaks a lot of sites.
 	}
 	tlsConn := tls.Client(conn, tlsConfig)
 	if err := tlsConn.Handshake(); err != nil {
-		return nil, fmt.Errorf("TLS handshake error: %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrNetworkTLS, err)
 	}
 
 	// We read `buf`-sized chunks and add data to `data`.
@@ -93,9 +97,13 @@ func ConnectAndGetData(url string) ([]byte, error) {
 	var data []byte
 
 	// Send Gemini request to trigger server response.
-	_, err = tlsConn.Write([]byte(fmt.Sprintf("%s\r\n", url)))
+	// Fix for stupid server bug:
+	// Some servers return 'Header: 53 No proxying to other hosts or ports!'
+	// when the port is 1965 and is still specified explicitely in the URL.
+	_url, _ := ParseURL(url, "")
+	_, err = tlsConn.Write([]byte(fmt.Sprintf("%s\r\n", _url.StringNoDefaultPort())))
 	if err != nil {
-		return nil, fmt.Errorf("Error sending network request: %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrNetworkCannotWrite, err)
 	}
 	// Read response bytes in len(buf) byte chunks
 	for {
@@ -104,68 +112,83 @@ func ConnectAndGetData(url string) ([]byte, error) {
 			data = append(data, buf[:n]...)
 		}
 		if len(data) > config.CONFIG.MaxResponseSize {
-			data = []byte{}
-			return nil, fmt.Errorf("Response size exceeded maximum of %d bytes", config.CONFIG.MaxResponseSize)
+			return nil, fmt.Errorf("%w: %v", ErrNetworkResponseSizeExceededMax, config.CONFIG.MaxResponseSize)
 		}
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break
-			} else {
-				return nil, fmt.Errorf("Network error: %s", err)
 			}
+			return nil, fmt.Errorf("%w: %w", ErrNetwork, err)
 		}
 	}
 	return data, nil
 }
 
-// Connect to given URL, using the Gemini protocol.
-// Mutate given Snapshot with the data or the error.
-func Visit(s *Snapshot) {
-	data, err := ConnectAndGetData(s.URL.String())
+// Visit given URL, using the Gemini protocol.
+// Mutates given Snapshot with the data.
+// In case of error, we store the error string
+// inside snapshot and return the error.
+func Visit(s *Snapshot) (err error) {
+	// Don't forget to also store error
+	// response code (if we have one)
+	defer func() {
 		if err != nil {
 			s.Error = null.StringFrom(err.Error())
-		return
+			if errors.As(err, new(*GeminiError)) {
+				s.ResponseCode = null.IntFrom(int64(err.(*GeminiError).Code))
+			}
+		}
+	}()
+	data, err := ConnectAndGetData(s.URL.String())
+	if err != nil {
+		return err
 	}
 	pageData, err := processData(data)
 	if err != nil {
-		s.Error = null.StringFrom(err.Error())
-		return
+		return err
 	}
+	//marshalled, _ := json.MarshalIndent(pageData, "", "  ")
+	//fmt.Printf("%s\n", marshalled)
+	s.Header = null.StringFrom(pageData.ResponseHeader)
 	s.ResponseCode = null.IntFrom(int64(pageData.ResponseCode))
 	s.MimeType = null.StringFrom(pageData.MimeType)
 	s.Lang = null.StringFrom(pageData.Lang)
 	if pageData.GemText != "" {
-		s.GemText = null.StringFrom(string(pageData.GemText))
+		s.GemText = null.StringFrom(pageData.GemText)
 	}
 	if pageData.Data != nil {
 		s.Data = null.ValueFrom(pageData.Data)
 	}
+	return nil
 }
 
-// Update given snapshot with the
-// Gemini header data: response code,
-// mime type and lang (optional)
-func processData(data []byte) (*GeminiPageData, error) {
-	headers, body, err := getHeadersAndData(data)
+// processData returne results from
+// parsing Gemini header data:
+// Code, mime type and lang (optional)
+// Returns error if header was invalid
+func processData(data []byte) (*PageData, error) {
+	header, body, err := getHeadersAndData(data)
 	if err != nil {
 		return nil, err
 	}
-	code, mimeType, lang := getMimeTypeAndLang(headers)
-	geminiError := checkGeminiStatusCode(code)
-	if geminiError != nil {
-		return nil, geminiError
+	code, mimeType, lang := getMimeTypeAndLang(header)
+	logging.LogDebug("Header: %s", strings.TrimSpace(header))
+	if code != 20 {
+		return nil, NewErrGeminiStatusCode(code, header)
 	}
-	pageData := GeminiPageData{
+
+	pageData := PageData{
 		ResponseCode:   code,
+		ResponseHeader: header,
 		MimeType:       mimeType,
 		Lang:           lang,
 	}
 	// If we've got a Gemini document, populate
 	// `GemText` field, otherwise raw data goes to `Data`.
 	if mimeType == "text/gemini" {
-		validBody, err := EnsureValidUTF8(body)
+		validBody, err := BytesToValidUTF8(body)
 		if err != nil {
-			return nil, fmt.Errorf("UTF-8 error: %w", err)
+			return nil, fmt.Errorf("%w: %w", ErrUTF8Parse, err)
 		}
 		pageData.GemText = validBody
 	} else {
@@ -178,14 +201,14 @@ func processData(data []byte) (*GeminiPageData, error) {
 // basically the first line of the response
 // and should contain the response code,
 // mimeType and language.
-func getHeadersAndData(data []byte) (firstLine string, rest []byte, err error) {
+func getHeadersAndData(data []byte) (string, []byte, error) {
 	firstLineEnds := slices.Index(data, '\n')
 	if firstLineEnds == -1 {
-		return "", nil, fmt.Errorf("Could not parse response header")
+		return "", nil, ErrGeminiResponseHeader
 	}
-	firstLine = string(data[:firstLineEnds])
-	rest = data[firstLineEnds+1:]
-	return string(firstLine), rest, nil
+	firstLine := string(data[:firstLineEnds])
+	rest := data[firstLineEnds+1:]
+	return firstLine, rest, nil
 }
 
 // Parses code, mime type and language
@@ -194,12 +217,12 @@ func getHeadersAndData(data []byte) (firstLine string, rest []byte, err error) {
 // `20 text/gemini lang=en` (code, mimetype, lang)
 // `20 text/gemini` (code, mimetype)
 // `31 gemini://redirected.to/other/site` (code)
-func getMimeTypeAndLang(headers string) (code int, mimeType string, lang string) {
-	// Regex that parses code, mimetype & lang
-	re := regexp.MustCompile(`^(\d+)\s+([a-zA-Z0-9/\-+]+)(?:[;\s]+(lang=([a-zA-Z0-9-]+)))?\s*$`)
+func getMimeTypeAndLang(headers string) (int, string, string) {
+	// Regex that parses code, mimetype & optional charset/lang parameters
+	re := regexp.MustCompile(`^(\d+)\s+([a-zA-Z0-9/\-+]+)(?:[;\s]+(?:(?:charset|lang)=([a-zA-Z0-9-]+)))?\s*$`)
 	matches := re.FindStringSubmatch(headers)
 	if matches == nil || len(matches) <= 1 {
-		// Try to get code at least.
+		// Try to get code at least
 		re := regexp.MustCompile(`^(\d+)\s+`)
 		matches := re.FindStringSubmatch(headers)
 		if matches == nil || len(matches) <= 1 {
@@ -215,7 +238,7 @@ func getMimeTypeAndLang(headers string) (code int, mimeType string, lang string)
 	if err != nil {
 		return 0, "", ""
 	}
-	mimeType = matches[2]
-	lang = matches[4]
-	return code, mimeType, lang
+	mimeType := matches[2]
+	param := matches[3] // This will capture either charset or lang value
+	return code, mimeType, param
 }

gemini/network_test.go

@@ -6,6 +6,7 @@ import (
 
 // Test for input: `20 text/gemini`
 func TestGetMimeTypeAndLang1(t *testing.T) {
+	t.Parallel()
 	code, mimeType, lang := getMimeTypeAndLang("20 text/gemini")
 	if code != 20 || mimeType != "text/gemini" || lang != "" {
 		t.Errorf("Expected (20, 'text/gemini', ''), got (%d, '%s', '%s')", code, mimeType, lang)
@@ -13,13 +14,39 @@ func TestGetMimeTypeAndLang1(t *testing.T) {
 }
 
 func TestGetMimeTypeAndLang11(t *testing.T) {
+	t.Parallel()
 	code, mimeType, lang := getMimeTypeAndLang("20 text/gemini\n")
 	if code != 20 || mimeType != "text/gemini" || lang != "" {
 		t.Errorf("Expected (20, 'text/gemini', ''), got (%d, '%s', '%s')", code, mimeType, lang)
 	}
 }
 
+func TestGetMimeTypeAndLang12(t *testing.T) {
+	t.Parallel()
+	code, mimeType, lang := getMimeTypeAndLang("20 text/plain; charset=utf-8")
+	if code != 20 || mimeType != "text/plain" || lang != "utf-8" {
+		t.Errorf("Expected (20, 'text/plain', ''), got (%d, '%s', '%s')", code, mimeType, lang)
+	}
+}
+
+func TestGetMimeTypeAndLang13(t *testing.T) {
+	t.Parallel()
+	code, mimeType, lang := getMimeTypeAndLang("20 text/gemini; charset=utf-8")
+	if code != 20 || mimeType != "text/gemini" || lang != "utf-8" {
+		t.Errorf("Expected (20, 'text/plain', ''), got (%d, '%s', '%s')", code, mimeType, lang)
+	}
+}
+
 func TestGetTypeAndLang2(t *testing.T) {
+	t.Parallel()
+	code, mimeType, lang := getMimeTypeAndLang("20 text/gemini charset=en")
+	if code != 20 || mimeType != "text/gemini" || lang != "en" {
+		t.Errorf("Expected (20, 'text/gemini', 'en'), got (%d, '%s', '%s')", code, mimeType, lang)
+	}
+}
+
+func TestGetTypeAndLang21(t *testing.T) {
+	t.Parallel()
 	code, mimeType, lang := getMimeTypeAndLang("20 text/gemini lang=en")
 	if code != 20 || mimeType != "text/gemini" || lang != "en" {
 		t.Errorf("Expected (20, 'text/gemini', 'en'), got (%d, '%s', '%s')", code, mimeType, lang)
@@ -27,6 +54,7 @@ func TestGetTypeAndLang2(t *testing.T) {
 }
 
 func TestGetMimeTypeAndLang3(t *testing.T) {
+	t.Parallel()
 	code, mimeType, lang := getMimeTypeAndLang("31 gemini://redirect.to/page")
 	if code != 31 || mimeType != "" || lang != "" {
 		t.Errorf("Expected (20, '', ''), got (%d, '%s', '%s')", code, mimeType, lang)
@@ -34,6 +62,7 @@ func TestGetMimeTypeAndLang3(t *testing.T) {
 }
 
 func TestGetMimeTypeAndLang4(t *testing.T) {
+	t.Parallel()
 	code, mimeType, lang := getMimeTypeAndLang("aaafdasdasd")
 	if code != 0 || mimeType != "" || lang != "" {
 		t.Errorf("Expected (0, '', ''), got (%d, '%s', '%s')", code, mimeType, lang)
@@ -41,6 +70,7 @@ func TestGetMimeTypeAndLang4(t *testing.T) {
 }
 
 func TestGetMimeTypeAndLang5(t *testing.T) {
+	t.Parallel()
 	code, mimeType, lang := getMimeTypeAndLang("")
 	if code != 0 || mimeType != "" || lang != "" {
 		t.Errorf("Expected (0, '', ''), got (%d, '%s', '%s')", code, mimeType, lang)

gemini/persistence.go

@@ -1,10 +1,13 @@
 package gemini
 
 import (
+	"encoding/json"
 	"fmt"
-	"gemini-grc/logging"
+	"gemini-grc/config"
 	"os"
 
+	"gemini-grc/logging"
+
 	_ "github.com/jackc/pgx/v5/stdlib" // PGX driver for PostgreSQL
 	"github.com/jmoiron/sqlx"
 )
@@ -33,11 +36,41 @@ func ConnectToDB() *sqlx.DB {
 	return db
 }
 
-func SaveSnapshotToDB(tx *sqlx.Tx, s *Snapshot) error {
+func SaveSnapshotIfNew(tx *sqlx.Tx, s *Snapshot) error {
+	marshalled, err := json.MarshalIndent(s, "", "  ")
+	if err != nil {
+		panic(fmt.Sprintf("JSON serialization error for %v", s))
+	}
+	if config.CONFIG.DryRun {
+		logging.LogDebug("Would insert (if new) snapshot %s", marshalled)
+		return nil
+	}
 	query := `
-        INSERT INTO snapshots (uid, url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
-        VALUES (:uid, :url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
-        ON CONFLICT (uid) DO UPDATE SET
+        INSERT INTO snapshots (url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
+        VALUES (:url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
+        ON CONFLICT (url) DO NOTHING
+    `
+	_, err = tx.NamedExec(query, s)
+	if err != nil {
+		return fmt.Errorf("[%s] GeminiError inserting snapshot: %w", s.URL, err)
+	}
+	return nil
+}
+
+func UpsertSnapshot(id int, tx *sqlx.Tx, s *Snapshot) error {
+	marshalled, err := json.MarshalIndent(s, "", "  ")
+	if err != nil {
+		panic(fmt.Sprintf("JSON serialization error for %v", s))
+	}
+	if config.CONFIG.DryRun {
+		logging.LogDebug("[%d] Would upsert snapshot %s", id, marshalled)
+		return nil
+	}
+
+	query := `
+INSERT INTO snapshots (url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
+        VALUES (:url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
+        ON CONFLICT (url) DO UPDATE SET
             url = EXCLUDED.url,
             host = EXCLUDED.host,
             timestamp = EXCLUDED.timestamp,
@@ -47,24 +80,30 @@ func SaveSnapshotToDB(tx *sqlx.Tx, s *Snapshot) error {
             links = EXCLUDED.links,
             lang = EXCLUDED.lang,
             response_code = EXCLUDED.response_code,
-            error = EXCLUDED.error
-    `
-	_, err := tx.NamedExec(query, s)
+            error = EXCLUDED.error`
+	_, err = tx.NamedExec(query, s)
+	//if err != nil {
+	//	logging.LogError("[%s] GeminiError upserting snapshot: %w", s.URL, err)
+	//	panic("This shouldn't happen")
+	//}
 	if err != nil {
-		logging.LogError("[%s] [%s] Error upserting snapshot: %w", s.URL, s.MimeType.String, err)
-		return fmt.Errorf("DB error: %w", err) // Return the error instead of panicking
+		return fmt.Errorf("[%s] GeminiError upserting snapshot: %w", s.URL, err)
 	}
 	return nil
 }
 
 func SaveLinksToDBinBatches(tx *sqlx.Tx, snapshots []*Snapshot) error {
+	if config.CONFIG.DryRun {
+		return nil
+	}
+
 	// Approximately 5,957 rows maximum (65535/11 parameters), use 5000 to be safe
 	const batchSize = 5000
 
 	query := `
-        INSERT INTO snapshots (uid, url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
-        VALUES (:uid, :url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
-        ON CONFLICT (uid) DO NOTHING
+        INSERT INTO snapshots (url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
+        VALUES (:url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
+        ON CONFLICT (url) DO NOTHING
     `
 
 	for i := 0; i < len(snapshots); i += batchSize {
@@ -77,7 +116,7 @@ func SaveLinksToDBinBatches(tx *sqlx.Tx, snapshots []*Snapshot) error {
 
 		_, err := tx.NamedExec(query, batch)
 		if err != nil {
-			logging.LogError("Error batch inserting snapshots: %w", err)
+			logging.LogError("GeminiError batch inserting snapshots: %w", err)
 			return fmt.Errorf("DB error: %w", err)
 		}
 	}
@@ -86,14 +125,17 @@ func SaveLinksToDBinBatches(tx *sqlx.Tx, snapshots []*Snapshot) error {
 }
 
 func SaveLinksToDB(tx *sqlx.Tx, snapshots []*Snapshot) error {
+	if config.CONFIG.DryRun {
+		return nil
+	}
 	query := `
-        INSERT INTO snapshots (uid, url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
-        VALUES (:uid, :url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
-        ON CONFLICT (uid) DO NOTHING
+        INSERT INTO snapshots (url, host, timestamp, mimetype, data, gemtext, links, lang, response_code, error)
+        VALUES (:url, :host, :timestamp, :mimetype, :data, :gemtext, :links, :lang, :response_code, :error)
+        ON CONFLICT (url) DO NOTHING
     `
 	_, err := tx.NamedExec(query, snapshots)
 	if err != nil {
-		logging.LogError("Error batch inserting snapshots: %w", err)
+		logging.LogError("GeminiError batch inserting snapshots: %w", err)
 		return fmt.Errorf("DB error: %w", err)
 	}
 	return nil

gemini/processing.go

@@ -2,33 +2,58 @@ package gemini
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"unicode/utf8"
 
 	"golang.org/x/text/encoding/charmap"
+	"golang.org/x/text/encoding/japanese"
+	"golang.org/x/text/encoding/korean"
 	"golang.org/x/text/transform"
 )
 
+var (
+	ErrInputTooLarge  = errors.New("input too large")
+	ErrUTF8Conversion = errors.New("UTF-8 conversion error")
+)
+
 func BytesToValidUTF8(input []byte) (string, error) {
+	if len(input) == 0 {
+		return "", nil
+	}
+	const maxSize = 10 * 1024 * 1024 // 10MB
+	if len(input) > maxSize {
+		return "", fmt.Errorf("%w: %d bytes (max %d)", ErrInputTooLarge, len(input), maxSize)
+	}
 	// Remove NULL byte 0x00 (ReplaceAll accepts slices)
 	inputNoNull := bytes.ReplaceAll(input, []byte{byte(0)}, []byte{})
-	isValidUTF8 := utf8.Valid(inputNoNull)
-	if isValidUTF8 {
+	if utf8.Valid(inputNoNull) {
 		return string(inputNoNull), nil
 	}
 	encodings := []transform.Transformer{
-		charmap.ISO8859_1.NewDecoder(),   // First try ISO8859-1
-		charmap.Windows1252.NewDecoder(), // Then try Windows-1252, etc
-		// TODO: Try more encodings?
+		charmap.ISO8859_1.NewDecoder(),
+		charmap.ISO8859_7.NewDecoder(),
+		charmap.Windows1250.NewDecoder(), // Central European
+		charmap.Windows1251.NewDecoder(), // Cyrillic
+		charmap.Windows1252.NewDecoder(),
+		charmap.Windows1256.NewDecoder(), // Arabic
+		japanese.EUCJP.NewDecoder(),      // Japanese
+		korean.EUCKR.NewDecoder(),        // Korean
 	}
 	// First successful conversion wins.
+	var lastErr error
 	for _, encoding := range encodings {
 		reader := transform.NewReader(bytes.NewReader(inputNoNull), encoding)
 		result, err := io.ReadAll(reader)
-		if err == nil {
+		if err != nil {
+			lastErr = err
+			continue
+		}
+		if utf8.Valid(result) {
 			return string(result), nil
 		}
 	}
-	return "", fmt.Errorf("UTF-8 error: %w", err)
+
+	return "", fmt.Errorf("%w (tried %d encodings): %w", ErrUTF8Conversion, len(encodings), lastErr)
 }

gemini/processing_test.go

@@ -4,6 +4,7 @@ import "testing"
 
 // Make sure NULL bytes are removed
 func TestEnsureValidUTF8(t *testing.T) {
+	t.Parallel()
 	// Create a string with a null byte
 	strWithNull := "Hello" + string('\x00') + "world"
 	result, _ := BytesToValidUTF8([]byte(strWithNull))

gemini/robotmatch.go

@@ -2,16 +2,18 @@ package gemini
 
 import (
 	"fmt"
-	"gemini-grc/logging"
 	"strings"
 	"sync"
+
+	"gemini-grc/logging"
 )
 
-// key: "host:port" (string)
-// value:
-// empty []string if no robots data, or
-// list of URL prefixes ([]string) in robots
-var RobotsCache sync.Map
+// RobotsCache is a map of blocked URLs
+// key: URL
+// value: []string list of disallowed URLs
+// If a key has no blocked URLs, an empty
+// list is stored for caching.
+var RobotsCache sync.Map //nolint:gochecknoglobals
 
 func populateBlacklist(key string) (entries []string) {
 	// We either store an empty list when
@@ -40,44 +42,41 @@ func populateBlacklist(key string) (entries []string) {
 	// According to spec, the first is correct,
 	// however let's be lenient
 	var data string
-	if robotsData.MimeType == "text/plain" {
+	switch {
+	case robotsData.MimeType == "text/plain":
 		data = string(robotsData.Data)
-	} else if robotsData.MimeType == "text/gemini" {
+	case robotsData.MimeType == "text/gemini":
 		data = robotsData.GemText
-	} else {
+	default:
 		return []string{}
 	}
-	entries = ParseRobotsTxt(string(data), key)
+	entries = ParseRobotsTxt(data, key)
 	return entries
 }
 
-// Check if the snapshot URL matches
+// RobotMatch checks if the snapshot URL matches
 // a robots.txt allow rule.
-func RobotMatch(s *Snapshot) bool {
-	logging.LogDebug("Checking robots.txt cache for %s", s.URL.String())
-	key := fmt.Sprintf("%s:%d", s.Host, s.URL.Port)
-	v, ok := RobotsCache.Load(key)
+func RobotMatch(url URL) bool {
+	key := strings.ToLower(fmt.Sprintf("%s:%d", url.Hostname, url.Port))
+	logging.LogDebug("Checking robots.txt cache for %s", key)
+	var disallowedURLs []string
+	cacheEntries, ok := RobotsCache.Load(key)
 	if !ok {
 		// First time check, populate robot cache
-		logging.LogDebug("No robots.txt entry, populating cache for %s", s.URL.String())
-		disallowedURLs := populateBlacklist(key)
-		for _, url := range disallowedURLs {
-			if strings.HasPrefix(s.URL.String(), url) {
-				logging.LogDebug("robots.txt match: %s %s", s.URL.String(), url)
-				return true
-			}
-		}
+		disallowedURLs = populateBlacklist(key)
+		logging.LogDebug("Added to robots.txt cache: %v => %v", key, disallowedURLs)
 	} else {
-		if len(v.([]string)) == 0 {
-			logging.LogDebug("No robots.txt or no rules, allowed")
-			return false
+		disallowedURLs, _ = cacheEntries.([]string)
 	}
-		for _, url := range v.([]string) {
-			if strings.HasPrefix(s.URL.String(), url) {
-				logging.LogDebug("robots.txt match: %s %s", s.URL.String(), url)
+	return isURLblocked(disallowedURLs, url.Full)
+}
+
+func isURLblocked(disallowedURLs []string, input string) bool {
+	for _, url := range disallowedURLs {
+		if strings.HasPrefix(strings.ToLower(input), url) {
+			logging.LogDebug("robots.txt match: %s matches %s", input, url)
 			return true
 		}
 	}
-	}
 	return false
 }

gemini/robots.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 )
 
-// Takes robots.txt content and a host, and
+// ParseRobotsTxt takes robots.txt content and a host, and
 // returns a list of full URLs that shouldn't
 // be visited.
 // TODO Also take into account the user agent?

gemini/robots_test.go

@@ -6,6 +6,7 @@ import (
 )
 
 func TestParseRobotsTxt(t *testing.T) {
+	t.Parallel()
 	input := `User-agent: *
 Disallow: /cgi-bin/wp.cgi/view
 Disallow: /cgi-bin/wp.cgi/media
@@ -26,6 +27,7 @@ Disallow: /admin/`
 }
 
 func TestParseRobotsTxtEmpty(t *testing.T) {
+	t.Parallel()
 	input := ``
 
 	result := ParseRobotsTxt(input, "example.com")
@@ -34,3 +36,20 @@ func TestParseRobotsTxtEmpty(t *testing.T) {
 		t.Errorf("ParseRobotsTxt() = %v, want empty []string", result)
 	}
 }
+
+func TestIsURLblocked(t *testing.T) {
+	t.Parallel()
+	disallowedURLs := []string{
+		"gemini://example.com/cgi-bin/wp.cgi/view",
+		"gemini://example.com/cgi-bin/wp.cgi/media",
+		"gemini://example.com/admin/",
+	}
+	url := "gemini://example.com/admin/index.html"
+	if !isURLblocked(disallowedURLs, url) {
+		t.Errorf("Expected %s to be blocked", url)
+	}
+	url = "gemini://example1.com/admin/index.html"
+	if isURLblocked(disallowedURLs, url) {
+		t.Errorf("expected %s to not be blocked", url)
+	}
+}

gemini/snapshot.go

@@ -4,15 +4,13 @@ import (
 	"database/sql/driver"
 	"encoding/json"
 	"fmt"
-	"gemini-grc/logging"
-	"strings"
 
 	"github.com/guregu/null/v5"
 )
 
-type LinkList []GeminiUrl
+type LinkList []URL
 
-func (l LinkList) Value() (driver.Value, error) {
+func (l *LinkList) Value() (driver.Value, error) {
 	return json.Marshal(l)
 }
 
@@ -30,45 +28,16 @@ func (l *LinkList) Scan(value interface{}) error {
 
 type Snapshot struct {
 	ID int `db:"id" json:"id,omitempty"`
-	UID          string             `db:"uid" json:"uid,omitempty"`
-	URL          GeminiUrl          `db:"url" json:"url,omitempty"`
+	//UID          string             `db:"uid" json:"uid,omitempty"`
+	URL          URL                  `db:"url" json:"url,omitempty"`
 	Host         string               `db:"host" json:"host,omitempty"`
 	Timestamp    null.Time            `db:"timestamp" json:"timestamp,omitempty"`
 	MimeType     null.String          `db:"mimetype" json:"mimetype,omitempty"`
 	Data         null.Value[[]byte]   `db:"data" json:"data,omitempty"`       // For non text/gemini files.
 	GemText      null.String          `db:"gemtext" json:"gemtext,omitempty"` // For text/gemini files.
-	Links        *LinkList          `db:"links" json:"links,omitempty"`
+	Header       null.String          `db:"header" json:"header,omitempty"`   // Response header.
+	Links        null.Value[LinkList] `db:"links" json:"links,omitempty"`
 	Lang         null.String          `db:"lang" json:"lang,omitempty"`
 	ResponseCode null.Int             `db:"response_code" json:"code,omitempty"` // Gemini response status code.
 	Error        null.String          `db:"error" json:"error,omitempty"`        // On network errors only
 }
-
-func SnapshotToJSON(g Snapshot) string {
-	// Serialize the Person struct to JSON
-	jsonData, err := json.MarshalIndent(g, "", "\t")
-	if err != nil {
-		logging.LogError("Error serializing to JSON: %w", err)
-	}
-	return string(jsonData)
-}
-
-func SnapshotFromJSON(input string) Snapshot {
-	var snapshot Snapshot
-	err := json.Unmarshal([]byte(input), &snapshot)
-	if err != nil {
-		logging.LogError("Error deserializing from JSON: %w", err)
-	}
-	return snapshot
-}
-
-func ShouldPersistSnapshot(result *Snapshot) bool {
-	if !result.MimeType.Valid {
-		return false
-	}
-	if result.MimeType.String == "text/gemini" ||
-		strings.HasPrefix(result.MimeType.String, "image/") ||
-		strings.HasPrefix(result.MimeType.String, "text/") {
-		return true
-	}
-	return false
-}

gemini/worker.go

@@ -1,36 +1,38 @@
 package gemini
 
 import (
+	"errors"
 	"fmt"
-	"gemini-grc/config"
-	"gemini-grc/logging"
-	"gemini-grc/uid"
-	"gemini-grc/util"
 	"strings"
 	"time"
 
+	"gemini-grc/config"
+	"gemini-grc/logging"
+	"gemini-grc/util"
+
 	"github.com/guregu/null/v5"
 	"github.com/jmoiron/sqlx"
 )
 
 func SpawnWorkers(numOfWorkers int, db *sqlx.DB) {
 	logging.LogInfo("Spawning %d workers", numOfWorkers)
-	for i := 0; i < numOfWorkers; i++ {
+	for i := range numOfWorkers {
 		go func(i int) {
 			for {
-				runWorker(i, db)
+				RunWorker(i, db, nil)
 			}
 		}(i)
 	}
 }
 
-func runWorker(id int, db *sqlx.DB) {
-	// Start the DB transaction
+func RunWorker(id int, db *sqlx.DB, url *string) {
+	// Each worker runs within a DB transaction.
 	tx, err := db.Beginx()
 	if err != nil {
 		logging.LogError("Failed to begin transaction: %w", err)
 	}
 
+	// Commit/rollback at the end
 	defer func() {
 		err = tx.Commit()
 		if err != nil {
@@ -42,66 +44,97 @@ func runWorker(id int, db *sqlx.DB) {
 		}
 	}()
 
-	snapshots, err := GetRandomSnapshotsDistinctHosts(tx)
+	var snapshots []Snapshot
 
+	// If not given a specific URL,
+	// get some random ones to visit from DB.
+	if url == nil {
+		snapshots, err = GetRandomSnapshotsDistinctHosts(tx)
 		if err != nil {
-		logging.LogError("[%d] Error retrieving snapshot: %w", id, err)
-		time.Sleep(10 * time.Second)
-		return
+			logging.LogError("[%d] GeminiError retrieving snapshot: %w", id, err)
+			panic("This should never happen")
 		} else if len(snapshots) == 0 {
-		logging.LogInfo("[%d] No remaining snapshots to visit.", id)
+			logging.LogInfo("[%d] No snapshots to visit.", id)
 			time.Sleep(1 * time.Minute)
 			return
 		}
+	} else {
+		snapshotURL, err := ParseURL(*url, "")
+		if err != nil {
+			logging.LogError("Invalid URL given: " + *url)
+			return
+
+		}
+		snapshots = []Snapshot{{
+			//UID:       uid.UID(),
+			URL:       *snapshotURL,
+			Host:      snapshotURL.Hostname,
+			Timestamp: null.TimeFrom(time.Now()),
+		}}
+	}
+
+	// Start visiting URLs.
 	total := len(snapshots)
 	for i, s := range snapshots {
-		logging.LogInfo("[%d] Starting %d/%d %s", id, i+1, total, s.URL)
+		logging.LogInfo("[%d] Starting %d/%d %s", id, i+1, total, s.URL.String())
+		// We differentiate between errors:
+		// Unexpected errors are the ones returned from the following function.
+		// If an error is unexpected (which should never happen) we panic.
+		// Expected errors are stored as strings within the snapshot,
+		// so that they can also be stored in DB.
 		err = workOnSnapshot(id, tx, &s)
 		if err != nil {
-			logging.LogError("[%d] [%s] Unexpected Error %w", id, s.URL, err)
+			logging.LogError("[%d] [%s] Unexpected GeminiError %w", id, s.URL.String(), err)
 			util.PrintStackAndPanic(err)
 		}
 		if s.Error.Valid {
-			logging.LogWarn("[%d] [%s] Worker Error: %v", id, s.URL, s.Error.String)
+			logging.LogWarn("[%d] Error: %v", id, s.Error.String)
 		}
-		logging.LogDebug("[%d] Done %d/%d.", id, i, total)
+		logging.LogDebug("[%d] Done %d/%d.", id, i+1, total)
 	}
 	logging.LogInfo("[%d] Worker done.", id)
 }
 
+// workOnSnapshot visits a URL and stores the result.
+// errors should be returned only if they are unexpected.
 func workOnSnapshot(id int, tx *sqlx.Tx, s *Snapshot) (err error) {
+	if IsBlacklisted(s.URL) {
+		logging.LogInfo("[%d] URL matches Blacklist, ignoring %s", id, s.URL.String())
+		return nil
+	}
+
 	// If URL matches a robots.txt disallow line,
 	// add it as an error so next time it won't be
 	// crawled.
-	if RobotMatch(s) {
-		s.Error = null.StringFrom("robots.txt disallow match")
-		err = SaveSnapshotToDB(tx, s)
+	if RobotMatch(s.URL) {
+		s.Error = null.StringFrom(ErrGeminiRobotsDisallowed.Error())
+		err = UpsertSnapshot(id, tx, s)
 		if err != nil {
-			return fmt.Errorf("[%d] DB Error: %w", id, err)
+			return fmt.Errorf("[%d] %w", id, err)
 		}
 		return nil
 	}
 
+	// Resolve IP address via DNS
 	IPs, err := getHostIPAddresses(s.Host)
 	if err != nil {
-		s.Error = null.StringFrom("DNS Resolve error")
-		err = SaveSnapshotToDB(tx, s)
+		s.Error = null.StringFrom(err.Error())
+		err = UpsertSnapshot(id, tx, s)
 		if err != nil {
-			return fmt.Errorf("[%d] DB Error: %w", id, err)
+			return fmt.Errorf("[%d] %w", id, err)
 		}
 		return nil
 	}
 
-	// If the host's ip is in the connections pool,
-	// stop and add the url in the queue later.
+	// If the host's ip is in the connections pool we stop
 	IpPool.Lock.RLock()
-	logging.LogDebug("[%d] [%s] Checking pool for IP", id, s.URL)
+	logging.LogDebug("[%d] [%s] Checking pool for IP", id, s.URL.String())
 	for _, ip := range IPs {
 		_, ok := IpPool.IPs[ip]
 		if ok {
-			logging.LogDebug("[%d] Another worker is visiting this host: %s", id, s.URL)
+			logging.LogDebug("[%d] Another worker is visiting this host: %s", id, s.URL.String())
 			IpPool.Lock.RUnlock()
-			time.Sleep(1 * time.Second) // Avoid flood-retrying when few URLs remain
+			time.Sleep(1 * time.Second) // Avoid flood-retrying
 			return nil
 		}
 	}
@@ -109,72 +142,114 @@ func workOnSnapshot(id int, tx *sqlx.Tx, s *Snapshot) (err error) {
 
 	AddIPsToPool(IPs)
 
-	url := s.URL.String()
-	logging.LogDebug("[%d] Dialing %s", id, url)
-	Visit(s)
-	logging.LogDebug("[%d] Finished dialing.", id)
-
-	go func() {
+	// After finishing, remove the host IPs from
+	// the connections pool, with a small delay
+	// to avoid potentially hitting the same IP quickly.
+	defer func() {
 		time.Sleep(5 * time.Second)
 		RemoveIPsFromPool(IPs)
 	}()
 
-	if s.MimeType.Valid && s.MimeType.String == "text/gemini" {
-		logging.LogDebug("[%d] [%s] Processing", id, url)
-		s = ProcessGemini(s)
-	}
-	logging.LogDebug("[%d] Saving", id)
-	err = SaveSnapshotToDB(tx, s)
+	url := s.URL.String()
+	logging.LogDebug("[%d] Dialing %s", id, url)
+
+	err = Visit(s)
 	if err != nil {
-		return fmt.Errorf("[%d] DB Error: %w", id, err)
+		if !IsKnownError(err) {
+			logging.LogError("[%d] Unknown error visiting %s: %w", id, url, err)
+			return err
+		}
+		// Check if error is redirection, and handle it
+		s.Error = null.StringFrom(err.Error())
+		if errors.As(err, new(*GeminiError)) &&
+			err.(*GeminiError).Msg == "redirect" {
+			err = handleRedirection(id, tx, s)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	logging.LogInfo("[%d] Done, response code %d.", id, s.ResponseCode.ValueOrZero())
+
+	// If this is a gemini page, parse possible links inside
+	if !s.Error.Valid && s.MimeType.Valid && s.MimeType.String == "text/gemini" {
+		links := GetPageLinks(s.URL, s.GemText.String)
+		logging.LogDebug("[%d] Found %d links", id, len(links))
+		if len(links) > 0 {
+			s.Links = null.ValueFrom(links)
+		}
+	} else {
+		logging.LogDebug("[%d] Not looking for page links", id)
 	}
 
-	// Store links in batch
-	if s.Links != nil {
-		var batchSnapshots []*Snapshot
-		timestamp := null.TimeFrom(time.Now())
+	err = UpsertSnapshot(id, tx, s)
+	if err != nil {
+		return err
+	}
 
-		for _, link := range *s.Links {
-			if shouldPersistURL(tx, link) {
+	err = storeLinks(tx, s)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func storeLinks(tx *sqlx.Tx, s *Snapshot) error {
+	if s.Links.Valid {
+		var batchSnapshots []*Snapshot
+		for _, link := range s.Links.ValueOrZero() {
+			if shouldPersistURL(link) {
 				newSnapshot := &Snapshot{
-					UID:       uid.UID(),
+					//UID:       uid.UID(),
 					URL:       link,
 					Host:      link.Hostname,
-					Timestamp: timestamp,
+					Timestamp: null.TimeFrom(time.Now()),
 				}
 				batchSnapshots = append(batchSnapshots, newSnapshot)
 			}
 		}
 
 		if len(batchSnapshots) > 0 {
-			logging.LogDebug("[%d] Batch saving %d links", id, len(batchSnapshots))
-			err = SaveLinksToDBinBatches(tx, batchSnapshots)
+			err := SaveLinksToDBinBatches(tx, batchSnapshots)
 			if err != nil {
-				return fmt.Errorf("[%d] DB Error: %w", id, err)
+				return err
 			}
 		}
 	}
 	return nil
 }
 
-// Should we save the given URL for crawling?
-func shouldPersistURL(tx *sqlx.Tx, u GeminiUrl) bool {
-	if !strings.HasPrefix(u.String(), "gemini://") {
-		return false
-	}
-	query := `SELECT EXISTS(SELECT 1 FROM snapshots WHERE URL=$1)`
-	var exists bool
-	err := tx.Get(&exists, query, u.String())
+// shouldPersistURL returns true if we
+// should save the URL in the DB.
+// Only gemini:// urls are saved.
+func shouldPersistURL(u URL) bool {
+	return strings.HasPrefix(u.String(), "gemini://")
+}
+
+func handleRedirection(id int, tx *sqlx.Tx, s *Snapshot) error {
+	newURL, err := extractRedirectTarget(s.URL, s.Error.ValueOrZero())
 	if err != nil {
-		fmt.Println("Error executing query:", err)
-		return false
+		return err
 	}
-	return !exists
+	logging.LogDebug("[%d] Page redirects to %s", id, newURL)
+	// Insert fresh snapshot with new URL
+	snapshot := &Snapshot{
+		//UID:       uid.UID(),
+		URL:       *newURL,
+		Host:      newURL.Hostname,
+		Timestamp: null.TimeFrom(time.Now()),
+	}
+	logging.LogDebug("[%d] Saving empty snapshot for %s", id, snapshot.URL.String())
+	err = SaveSnapshotIfNew(tx, snapshot)
+	if err != nil {
+		return err
+	}
+	return nil
 }
 
 func GetRandomSnapshotsDistinctHosts(tx *sqlx.Tx) ([]Snapshot, error) {
 	// Old, unoptimized query
-	//
+
 	// query := `
 	//     SELECT DISTINCT ON (host) *
 	//     FROM snapshots
@@ -184,20 +259,28 @@ func GetRandomSnapshotsDistinctHosts(tx *sqlx.Tx) ([]Snapshot, error) {
 	//     LIMIT $1
 	// `
 	query := `
-        WITH RankedSnapshots AS (
-            SELECT id, uid, url, host, timestamp, mimetype, data, gemtext,
-                   links, lang, response_code, error,
-                   ROW_NUMBER() OVER (PARTITION BY host ORDER BY RANDOM()) as rn
+	    SELECT *
 	    FROM snapshots
 	    WHERE response_code IS NULL
 	      AND error IS NULL
-        )
-        SELECT id, uid, url, host, timestamp, mimetype, data, gemtext,
-               links, lang, response_code, error
-        FROM RankedSnapshots
-        WHERE rn = 1
+	    ORDER BY RANDOM()
 	    LIMIT $1
 	`
+	//query := `
+	//    WITH RankedSnapshots AS (
+	//        SELECT id, url, host, timestamp, mimetype, data, gemtext,
+	//               links, lang, response_code, error,
+	//               ROW_NUMBER() OVER (PARTITION BY host ORDER BY RANDOM()) as rn
+	//        FROM snapshots
+	//        WHERE response_code IS NULL
+	//          AND error IS NULL
+	//    )
+	//    SELECT id, url, host, timestamp, mimetype, data, gemtext,
+	//           links, lang, response_code, error
+	//    FROM RankedSnapshots
+	//    WHERE rn = 1
+	//    LIMIT $1
+	//`
 	var snapshots []Snapshot
 	err := tx.Select(&snapshots, query, config.CONFIG.WorkerBatchSize)
 	if err != nil {
@@ -205,3 +288,18 @@ func GetRandomSnapshotsDistinctHosts(tx *sqlx.Tx) ([]Snapshot, error) {
 	}
 	return snapshots, nil
 }
+
+func GetSnapshotFromURL(tx *sqlx.Tx, url string) ([]Snapshot, error) {
+	query := `
+	SELECT *
+	FROM snapshots
+	WHERE url=$1
+	LIMIT 1
+	`
+	var snapshots []Snapshot
+	err := tx.Select(&snapshots, query, url)
+	if err != nil {
+		return nil, err
+	}
+	return snapshots, nil
+}

go.mod

@@ -8,16 +8,22 @@ require (
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/matoous/go-nanoid/v2 v2.1.0
 	github.com/rs/zerolog v1.33.0
+	github.com/stretchr/testify v1.9.0
 	golang.org/x/text v0.19.0
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/rogpeppe/go-internal v1.13.1 // indirect
 	golang.org/x/crypto v0.27.0 // indirect
 	golang.org/x/sync v0.8.0 // indirect
 	golang.org/x/sys v0.25.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,6 +1,7 @@
 filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
 filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -19,6 +20,10 @@ github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo
 github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
 github.com/jmoiron/sqlx v1.4.0 h1:1PLqN7S1UYp5t4SrVVnt4nUVNemrDAtxlulVe+Qgm3o=
 github.com/jmoiron/sqlx v1.4.0/go.mod h1:ZrZ7UsYB/weZdl2Bxg6jCRO9c3YHl8r3ahlKmRT4JLY=
+github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
+github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/matoous/go-nanoid/v2 v2.1.0 h1:P64+dmq21hhWdtvZfEAofnvJULaRR1Yib0+PnU669bE=
@@ -34,6 +39,8 @@ github.com/mattn/go-sqlite3 v1.14.22/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxU
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
+github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
 github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
 github.com/rs/zerolog v1.33.0 h1:1cU2KZkvPxNyfgEmhHAz/1A9Bz+llsdYzklWFzgp0r8=
 github.com/rs/zerolog v1.33.0/go.mod h1:/7mN4D5sKwJLZQ2b/znpjC3/GQWY/xaDXUM0kKWRHss=
@@ -54,6 +61,8 @@ golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
 golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

http/http.go

@@ -0,0 +1,52 @@
+package http
+
+import (
+	"fmt"
+	"gemini-grc/logging"
+	_ "gemini-grc/logging"
+	"net/http"
+	"time"
+)
+
+func CreateServer(listenAddr string) *http.Server {
+	mux := http.NewServeMux()
+	mux.HandleFunc("GET /ping", wrapForError(getPing))
+
+	server := &http.Server{
+		Addr:              listenAddr,
+		Handler:           mux,
+		ReadHeaderTimeout: 10 * time.Second,
+	}
+
+	go func() {
+		// Start the server. Blocking call.
+		logging.LogInfo("HTTP server listening on %s", listenAddr)
+		if err := server.ListenAndServe(); err != nil {
+			panic(fmt.Sprintf("Server failed to start: %s", err))
+		}
+	}()
+	return server
+}
+
+func wrapForError(f func(http.ResponseWriter, *http.Request) error) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		err := f(w, r)
+		if err != nil {
+			code := http.StatusInternalServerError
+			logging.LogWarn("Error while handling request: %d %s", code, err)
+			http.Error(w, http.StatusText(code), code)
+		}
+	}
+}
+
+func getPing(w http.ResponseWriter, r *http.Request) error {
+	method := r.Method
+	url := r.URL.String()
+	path := r.URL.Path
+	response := fmt.Sprintf("Pong %s %s %s", method, url, path)
+	_, err := w.Write([]byte(response))
+	if err != nil {
+		return fmt.Errorf("failed to write response: %w", err)
+	}
+	return nil
+}

main.go

@@ -3,15 +3,14 @@ package main
 import (
 	"gemini-grc/config"
 	"gemini-grc/gemini"
+	"gemini-grc/http"
 	"gemini-grc/logging"
+	"github.com/jmoiron/sqlx"
+	"github.com/rs/zerolog"
+	zlog "github.com/rs/zerolog/log"
 	"os"
 	"os/signal"
 	"syscall"
-
-	"github.com/jmoiron/sqlx"
-
-	"github.com/rs/zerolog"
-	zlog "github.com/rs/zerolog/log"
 )
 
 func main() {
@@ -27,9 +26,10 @@ func main() {
 
 func runApp() error {
 	logging.LogInfo("Starting up. Press Ctrl+C to exit")
-	sigs := make(chan os.Signal, 1)
-	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
 
+	server := http.CreateServer("localhost:8899")
 	db := gemini.ConnectToDB()
 
 	// !!! DANGER !!!
@@ -44,13 +44,20 @@ func runApp() error {
 		}
 	}(db)
 
-	// if len(os.Args) > 1 {
-	// 	url := os.Args[1]
-	// }
-	// os.Exit(1)
+	gemini.LoadBlacklist()
+	// If there's an argument, assume it's a URL
+	// to visit and ignore database state.
+	if len(os.Args) > 1 {
+		url := os.Args[1]
+		go gemini.RunWorker(0, db, &url)
+	} else {
 		go gemini.SpawnWorkers(config.CONFIG.NumOfWorkers, db)
+	}
 
-	<-sigs
+	<-signals
+	if err := server.Close(); err != nil {
+		logging.LogError("GeminiError during server shutdown: %s", err)
+	}
 	logging.LogInfo("Received SIGINT or SIGTERM signal, exiting")
 	return nil
 }

uid/uid.go

@@ -1,14 +1,14 @@
 package uid
 
 import (
-	nanoid "github.com/jaevor/go-nanoid"
+	nanoid "github.com/matoous/go-nanoid/v2"
 )
 
 func UID() string {
-	// Missing o,O and l
-	uid, err := nanoid.CustomASCII("abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ0123456789", 20)
+	// No 'o','O' and 'l'
+	id, err := nanoid.Generate("abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ0123456789", 20)
 	if err != nil {
 		panic(err)
 	}
-	return uid()
+	return id
 }