Initial commit

server/server.go

@@ -0,0 +1,124 @@
+package server
+
+import (
+	"crypto/tls"
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"gemserve/common"
+	"gemserve/config"
+	"gemserve/errors"
+	"gemserve/logging"
+	"github.com/gabriel-vasile/mimetype"
+)
+
+type ServerConfig interface {
+	DirIndexingEnabled() bool
+	RootPath() string
+}
+
+func GenerateResponse(conn *tls.Conn, connId string, input string) ([]byte, error) {
+	trimmedInput := strings.TrimSpace(input)
+	// url will have a cleaned and normalized path after this
+	url, err := common.ParseURL(trimmedInput, "", true)
+	if err != nil {
+		return nil, errors.NewConnectionError(fmt.Errorf("failed to parse URL: %w", err))
+	}
+	logging.LogDebug("%s %s normalized URL path: %s", connId, conn.RemoteAddr(), url.Path)
+	serverRootPath := config.CONFIG.RootPath
+	localPath, err := calculateLocalPath(url.Path, serverRootPath)
+	if err != nil {
+		return nil, errors.NewConnectionError(err)
+	}
+	logging.LogDebug("%s %s request file path: %s", connId, conn.RemoteAddr(), localPath)
+
+	// Get file/directory information
+	info, err := os.Stat(localPath)
+	if errors.Is(err, os.ErrNotExist) || errors.Is(err, os.ErrPermission) {
+		return []byte("51 not found\r\n"), nil
+	} else if err != nil {
+		return nil, errors.NewConnectionError(fmt.Errorf("%s %s failed to access path: %w", connId, conn.RemoteAddr(), err))
+	}
+
+	// Handle directory.
+	if info.IsDir() {
+		return generateResponseDir(conn, connId, url, localPath)
+	}
+	return generateResponseFile(conn, connId, url, localPath)
+}
+
+func generateResponseFile(conn *tls.Conn, connId string, url *common.URL, localPath string) ([]byte, error) {
+	data, err := os.ReadFile(localPath)
+	if errors.Is(err, os.ErrNotExist) || errors.Is(err, os.ErrPermission) {
+		return []byte("51 not found\r\n"), nil
+	} else if err != nil {
+		return nil, errors.NewConnectionError(fmt.Errorf("%s %s failed to read file: %w", connId, conn.RemoteAddr(), err))
+	}
+
+	var mimeType string
+	if path.Ext(localPath) == ".gmi" {
+		mimeType = "text/gemini"
+	} else {
+		mimeType = mimetype.Detect(data).String()
+	}
+	headerBytes := []byte(fmt.Sprintf("20 %s\r\n", mimeType))
+	response := append(headerBytes, data...)
+	return response, nil
+}
+
+func generateResponseDir(conn *tls.Conn, connId string, url *common.URL, localPath string) (output []byte, err error) {
+	entries, err := os.ReadDir(localPath)
+	if err != nil {
+		return nil, errors.NewConnectionError(fmt.Errorf("%s %s failed to read directory: %w", connId, conn.RemoteAddr(), err))
+	}
+
+	if config.CONFIG.DirIndexingEnabled {
+		var contents []string
+		contents = append(contents, "Directory index:\n\n")
+		contents = append(contents, "=> ../\n")
+		for _, entry := range entries {
+			if entry.IsDir() {
+				contents = append(contents, fmt.Sprintf("=> %s/\n", entry.Name()))
+			} else {
+				contents = append(contents, fmt.Sprintf("=> %s\n", entry.Name()))
+			}
+		}
+		data := []byte(strings.Join(contents, ""))
+		headerBytes := []byte("20 text/gemini;\r\n")
+		response := append(headerBytes, data...)
+		return response, nil
+	} else {
+		filePath := path.Join(localPath, "index.gmi")
+		return generateResponseFile(conn, connId, url, filePath)
+
+	}
+}
+
+func calculateLocalPath(input string, basePath string) (string, error) {
+	// Check for invalid characters early
+	if strings.ContainsAny(input, "\\") {
+		return "", errors.NewError(fmt.Errorf("invalid characters in path: %s", input))
+	}
+
+	// If IsLocal(path) returns true, then Join(base, path)
+	// will always produce a path contained within base and
+	// Clean(path) will always produce an unrooted path with
+	// no ".." path elements.
+	filePath := input
+	filePath = strings.TrimPrefix(filePath, "/")
+	if filePath == "" {
+		filePath = "."
+	}
+	filePath = strings.TrimSuffix(filePath, "/")
+
+	localPath, err := filepath.Localize(filePath)
+	if err != nil || !filepath.IsLocal(localPath) {
+		return "", errors.NewError(fmt.Errorf("could not construct local path from %s: %s", input, err))
+	}
+
+	filePath = path.Join(basePath, localPath)
+	return filePath, nil
+}