improve & refactor & return specific error pages

server/upstream/upstream.go

@@ -2,6 +2,7 @@ package upstream
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"strings"
@@ -56,23 +57,25 @@ type Options struct {
 func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client) (final bool) {
 	log := log.With().Strs("upstream", []string{o.TargetOwner, o.TargetRepo, o.TargetBranch, o.TargetPath}).Logger()
 
+	if o.TargetOwner == "" || o.TargetRepo == "" {
+		html.ReturnErrorPage(ctx, "either repo owner or name info is missing", http.StatusBadRequest)
+		return true
+	}
+
 	// Check if the branch exists and when it was modified
 	if o.BranchTimestamp.IsZero() {
 		branch := GetBranchTimestamp(giteaClient, o.TargetOwner, o.TargetRepo, o.TargetBranch)
 
-		if branch == nil {
-			html.ReturnErrorPage(ctx, "", http.StatusFailedDependency)
+		if branch == nil || branch.Branch == "" {
+			html.ReturnErrorPage(ctx,
+				fmt.Sprintf("could not get timestamp of branch '%s'", o.TargetBranch),
+				http.StatusFailedDependency)
 			return true
 		}
 		o.TargetBranch = branch.Branch
 		o.BranchTimestamp = branch.Timestamp
 	}
 
-	if o.TargetOwner == "" || o.TargetRepo == "" || o.TargetBranch == "" {
-		html.ReturnErrorPage(ctx, "", http.StatusBadRequest)
-		return true
-	}
-
 	// Check if the browser has a cached version
 	if ifModifiedSince, err := time.Parse(time.RFC1123, string(ctx.Response().Header.Get(headerIfModifiedSince))); err == nil {
 		if !ifModifiedSince.Before(o.BranchTimestamp) {
@@ -127,7 +130,7 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client) (fin
 	}
 	if res != nil && (err != nil || res.StatusCode != http.StatusOK) {
 		log.Printf("Couldn't fetch contents (status code %d): %v\n", res.StatusCode, err)
-		html.ReturnErrorPage(ctx, "", http.StatusInternalServerError)
+		html.ReturnErrorPage(ctx, fmt.Sprintf("%v", err), http.StatusInternalServerError)
 		return true
 	}