Lots of features, first version that reliably crawls Geminispace.

- [x] Concurrent downloading with workers
- [x] Concurrent connection limit per host
- [x] URL Blacklist
- [x] Save image/* and text/* files
- [x] Configuration via environment variables
- [x] Storing snapshots in PostgreSQL
- [x] Proper response header & body UTF-8 and format validation
.

.

gemini/gemini_url.go

@@ -0,0 +1,57 @@
+package gemini
+
+import (
+	"encoding/json"
+	"fmt"
+	"gemini-grc/logging"
+)
+
+type GeminiUrl struct {
+	Protocol string `json:"protocol,omitempty"`
+	Hostname string `json:"hostname,omitempty"`
+	Port     int    `json:"port,omitempty"`
+	Path     string `json:"path,omitempty"`
+	Descr    string `json:"descr,omitempty"`
+	Full     string `json:"full,omitempty"`
+}
+
+func (g *GeminiUrl) Scan(value interface{}) error {
+	if value == nil {
+		// Clear the fields in the current GeminiUrl object (not the pointer itself)
+		*g = GeminiUrl{}
+		return nil
+	}
+	b, ok := value.(string)
+	if !ok {
+		return fmt.Errorf("failed to scan GeminiUrl: expected string, got %T", value)
+	}
+	parsedUrl, err := ParseUrl(b, "")
+	if err != nil {
+		return err
+	}
+	*g = *parsedUrl
+	return nil
+}
+
+func (u GeminiUrl) 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)
+	}
+	return string(jsonData)
+}
+
+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)
+	}
+	return geminiUrl
+}