Add file size failsafe

main.go

@@ -20,6 +20,7 @@ import (
 )
 
 const TIMEOUT_NS time.Duration = time.Duration(60_000_000_000)
+const MAX_FILE_SIZE int64 = 512 * 1024
 
 var (
 	hosts     tofu.KnownHosts
@@ -158,23 +159,33 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	limitedBody := io.LimitedReader{
+		R: resp.Body,
+		N: MAX_FILE_SIZE,
+	}
 	defer resp.Body.Close()
 
 	mime, _, _ := strings.Cut(resp.Meta, ";")
 	if mime == "application/rss+xml" || mime == "application/rss" ||
 		mime == "application/atom+xml" || mime == "application/atom" ||
 		mime == "application/xml" || mime == "text/xml" {
-		out, err := io.ReadAll(resp.Body)
+		out, err := io.ReadAll(&limitedBody)
 		if err != nil {
 			log.Fatal(err)
 		}
+		if limitedBody.N <= 0 {
+			log.Fatalf("up to %d bytes read from the body", MAX_FILE_SIZE)
+		}
 		fmt.Print(string(out))
 	} else if mime == "text/gemini" {
 		aw := AtomWriter{
 			Title: "",
 			Items: nil,
 		}
-		gemini.ParseLines(resp.Body, aw.Handle)
+		gemini.ParseLines(&limitedBody, aw.Handle)
+		if limitedBody.N <= 0 {
+			log.Fatalf("up to %d bytes read from the body", MAX_FILE_SIZE)
+		}
 		sort.Sort(ByTime(aw.Items))
 		feed := Feed{
 			XMLNS: "http://www.w3.org/2005/Atom",