Hotfix for #27: avoid slash before .html in GitHub compatibility redirects

Reviewed-on: https://codeberg.org/Codeberg/pages-server/pulls/23

handler.go

@@ -25,8 +25,8 @@ func handler(ctx *fasthttp.RequestCtx) {
 	// Force new default from specification (since November 2020) - see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy#strict-origin-when-cross-origin
 	ctx.Response.Header.Set("Referrer-Policy", "strict-origin-when-cross-origin")
 
-	// Enable caching, but require revalidation to reduce confusion
+	// Enable browser caching for up to 10 minutes
-	ctx.Response.Header.Set("Cache-Control", "must-revalidate")
+	ctx.Response.Header.Set("Cache-Control", "public, max-age=600")
 
 	trimmedHost := TrimHostPort(ctx.Request.Host())
 
@@ -418,7 +418,7 @@ func upstream(ctx *fasthttp.RequestCtx, targetOwner string, targetRepo string, t
 	var res *fasthttp.Response
 	var cachedResponse fileResponse
 	var err error
-	if cachedValue, ok := fileResponseCache.Get(uri + "?timestamp=" + strconv.FormatInt(options.BranchTimestamp.Unix(), 10)); ok {
+	if cachedValue, ok := fileResponseCache.Get(uri + "?timestamp=" + strconv.FormatInt(options.BranchTimestamp.Unix(), 10)); ok && len(cachedValue.(fileResponse).body) > 0 {
 		cachedResponse = cachedValue.(fileResponse)
 	} else {
 		req = fasthttp.AcquireRequest()
@@ -444,6 +444,15 @@ func upstream(ctx *fasthttp.RequestCtx, targetOwner string, targetRepo string, t
 					return true
 				}
 			}
+			// compatibility fix for GitHub Pages (/example → /example.html)
+			optionsForIndexPages.AppendTrailingSlash = false
+			optionsForIndexPages.RedirectIfExists = strings.TrimSuffix(string(ctx.Request.URI().Path()), "/") + ".html"
+			if upstream(ctx, targetOwner, targetRepo, targetBranch, targetPath + ".html", &optionsForIndexPages) {
+				_ = fileResponseCache.Set(uri+"?timestamp="+strconv.FormatInt(options.BranchTimestamp.Unix(), 10), fileResponse{
+					exists: false,
+				}, FileCacheTimeout)
+				return true
+			}
 		}
 		ctx.Response.SetStatusCode(fasthttp.StatusNotFound)
 		if res != nil {
@@ -460,12 +469,20 @@ func upstream(ctx *fasthttp.RequestCtx, targetOwner string, targetRepo string, t
 		return true
 	}
 
-	// Append trailing slash if missing (for index files)
+	// Append trailing slash if missing (for index files), and redirect to fix filenames in general
 	// options.AppendTrailingSlash is only true when looking for index pages
 	if options.AppendTrailingSlash && !bytes.HasSuffix(ctx.Request.URI().Path(), []byte{'/'}) {
 		ctx.Redirect(string(ctx.Request.URI().Path())+"/", fasthttp.StatusTemporaryRedirect)
 		return true
 	}
+	if bytes.HasSuffix(ctx.Request.URI().Path(), []byte("/index.html")) {
+		ctx.Redirect(strings.TrimSuffix(string(ctx.Request.URI().Path()), "index.html"), fasthttp.StatusTemporaryRedirect)
+		return true
+	}
+	if options.RedirectIfExists != "" {
+		ctx.Redirect(options.RedirectIfExists, fasthttp.StatusTemporaryRedirect)
+		return true
+	}
 	s.Step("error handling")
 
 	// Set the MIME type
@@ -504,7 +521,7 @@ func upstream(ctx *fasthttp.RequestCtx, targetOwner string, targetRepo string, t
 	}
 	s.Step("response")
 
-	if res != nil {
+	if res != nil && ctx.Err() == nil {
 		cachedResponse.exists = true
 		cachedResponse.mimeType = mimeType
 		cachedResponse.body = cacheBodyWriter.Bytes()
@@ -520,5 +537,6 @@ type upstreamOptions struct {
 	ForbiddenMimeTypes  map[string]struct{}
 	TryIndexPages       bool
 	AppendTrailingSlash bool
+	RedirectIfExists    string
 	BranchTimestamp     time.Time
 }