Better error handling, many fixes all around

gemini/gemini.go

@@ -9,14 +9,16 @@ import (
 	"gemini-grc/logging"
 )
 
-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
@@ -26,13 +28,10 @@ func ProcessGemini(snapshot *Snapshot) *Snapshot {
 			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
+	return linkURLs
 }
 
 // ExtractLinkLines takes a Gemtext document as a string and returns all lines that are link lines
@@ -124,3 +123,22 @@ func ParseFirstTwoDigits(input string) (int, error) {
 
 	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
+}