refactor: move initial URL parsing into function 'convertToURL'

1 files changed, 20 insertions, 9 deletions

diff --git a/main.go b/main.go
index 4cb3d0d..3582ed5 100644
--- a/main.go
+++ b/main.go
@@ -46,14 +46,7 @@ func main() {
 		log.Fatalf("Invalid -depth argument: %d", *maxDepth)
 	}
 
-	// Add "https://" scheme prefix if missing. It looks like we
-	// have to do this before the parsing step, not after.
-	if !strings.HasPrefix(*startRawURL, "http://") && !strings.HasPrefix(*startRawURL, "https://") {
-		*startRawURL = "https://" + *startRawURL
-		fmt.Printf("start url: %s\n", *startRawURL)
-	}
-
-	startURL, err := url.Parse(*startRawURL)
+	startURL, err := convertToURL(*startRawURL)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -61,10 +54,28 @@ func main() {
 	// Our web crawlers use concurrency: check if any goroutines
 	// have leaked.
 	getLeakProfile(func() {
-		classic(*startURL, *maxConcurrency, *maxURLs, *maxDepth)
+		classic(startURL, *maxConcurrency, *maxURLs, *maxDepth)
 	})
 }
 
+// convertToURL parses the given rawURL into a [url.URL]. If the
+// rawURL is missing a scheme, "https://" is prepended before parsing.
+//
+// Return the parsed URL, along with any error.
+func convertToURL(rawURL string) (url.URL, error) {
+	if !strings.HasPrefix(rawURL, "http://") && !strings.HasPrefix(rawURL, "https://") {
+		rawURL = "https://" + rawURL
+		fmt.Printf("start url: %s\n", rawURL)
+	}
+
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return url.URL{}, fmt.Errorf("can't parse %s: %w", rawURL, err)
+	}
+
+	return *u, nil
+}
+
 // getLeakProfile runs a leaky program snippet, extracts the goroutine leak profile,
 // and writes it to stdout.
 func getLeakProfile(leakySnippet func()) {