Fix attachment download bug (#27486) (#27570)

Backport #27486 by @lunny

Fix #27204

This PR allows `/<username>/<reponame>/attachments/<uuid>` access with
personal access token and also changed attachments API download url to
it so it can be download correctly.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/auth/auth.go

 }
 
 var (
-	gitRawReleasePathRe = regexp.MustCompile(`^/[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+/(?:(?:git-(?:(?:upload)|(?:receive))-pack$)|(?:info/refs$)|(?:HEAD$)|(?:objects/)|(?:raw/)|(?:releases/download/))`)
-	lfsPathRe           = regexp.MustCompile(`^/[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+/info/lfs/`)
+	gitRawOrAttachPathRe = regexp.MustCompile(`^/[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+/(?:(?:git-(?:(?:upload)|(?:receive))-pack$)|(?:info/refs$)|(?:HEAD$)|(?:objects/)|(?:raw/)|(?:releases/download/)|(?:attachments/))`)
+	lfsPathRe            = regexp.MustCompile(`^/[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+/info/lfs/`)
 )
 
-func isGitRawReleaseOrLFSPath(req *http.Request) bool {
-	if gitRawReleasePathRe.MatchString(req.URL.Path) {
+func isGitRawOrAttachPath(req *http.Request) bool {
+	return gitRawOrAttachPathRe.MatchString(req.URL.Path)
+}
+
+func isGitRawOrAttachOrLFSPath(req *http.Request) bool {
+	if isGitRawOrAttachPath(req) {
 		return true
 	}
 	if setting.LFS.StartServer {

services/auth/auth_test.go

 			"/owner/repo/releases/download/tag/repo.tar.gz",
 			true,
 		},
+		{
+			"/owner/repo/attachments/6d92a9ee-5d8b-4993-97c9-6181bdaa8955",
+			true,
+		},
 	}
 	lfsTests := []string{
 		"/owner/repo/info/lfs/",
 		t.Run(tt.path, func(t *testing.T) {
 			req, _ := http.NewRequest("POST", "http://localhost"+tt.path, nil)
 			setting.LFS.StartServer = false
-			if got := isGitRawReleaseOrLFSPath(req); got != tt.want {
+			if got := isGitRawOrAttachOrLFSPath(req); got != tt.want {
 				t.Errorf("isGitOrLFSPath() = %v, want %v", got, tt.want)
 			}
 			setting.LFS.StartServer = true
-			if got := isGitRawReleaseOrLFSPath(req); got != tt.want {
+			if got := isGitRawOrAttachOrLFSPath(req); got != tt.want {
 				t.Errorf("isGitOrLFSPath() = %v, want %v", got, tt.want)
 			}
 		})
 		t.Run(tt, func(t *testing.T) {
 			req, _ := http.NewRequest("POST", tt, nil)
 			setting.LFS.StartServer = false
-			if got := isGitRawReleaseOrLFSPath(req); got != setting.LFS.StartServer {
-				t.Errorf("isGitOrLFSPath(%q) = %v, want %v, %v", tt, got, setting.LFS.StartServer, gitRawReleasePathRe.MatchString(tt))
+			if got := isGitRawOrAttachOrLFSPath(req); got != setting.LFS.StartServer {
+				t.Errorf("isGitOrLFSPath(%q) = %v, want %v, %v", tt, got, setting.LFS.StartServer, gitRawOrAttachPathRe.MatchString(tt))
 			}
 			setting.LFS.StartServer = true
-			if got := isGitRawReleaseOrLFSPath(req); got != setting.LFS.StartServer {
+			if got := isGitRawOrAttachOrLFSPath(req); got != setting.LFS.StartServer {
 				t.Errorf("isGitOrLFSPath(%q) = %v, want %v", tt, got, setting.LFS.StartServer)
 			}
 		})

services/auth/basic.go

 // Returns nil if header is empty or validation fails.
 func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
 	// Basic authentication should only fire on API, Download or on Git or LFSPaths
-	if !middleware.IsAPIPath(req) && !isContainerPath(req) && !isAttachmentDownload(req) && !isGitRawReleaseOrLFSPath(req) {
+	if !middleware.IsAPIPath(req) && !isContainerPath(req) && !isAttachmentDownload(req) && !isGitRawOrAttachOrLFSPath(req) {
 		return nil, nil
 	}
 

services/auth/oauth2.go

 func (o *OAuth2) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
 	// These paths are not API paths, but we still want to check for tokens because they maybe in the API returned URLs
 	if !middleware.IsAPIPath(req) && !isAttachmentDownload(req) && !isAuthenticatedTokenRequest(req) &&
-		!gitRawReleasePathRe.MatchString(req.URL.Path) {
+		!isGitRawOrAttachPath(req) {
 		return nil, nil
 	}
 

services/auth/reverseproxy.go

 	}
 
 	// Make sure requests to API paths, attachment downloads, git and LFS do not create a new session
-	if !middleware.IsAPIPath(req) && !isAttachmentDownload(req) && !isGitRawReleaseOrLFSPath(req) {
+	if !middleware.IsAPIPath(req) && !isAttachmentDownload(req) && !isGitRawOrAttachOrLFSPath(req) {
 		if sess != nil && (sess.Get("uid") == nil || sess.Get("uid").(int64) != user.ID) {
 			handleSignIn(w, req, sess, user)
 		}

services/convert/attachment.go

 package convert
 
 import (
-	"strconv"
-
 	repo_model "code.gitea.io/gitea/models/repo"
-	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 )
 
 }
 
 func APIAssetDownloadURL(repo *repo_model.Repository, attach *repo_model.Attachment) string {
-	if attach.CustomDownloadURL != "" {
-		return attach.CustomDownloadURL
-	}
-
-	// /repos/{owner}/{repo}/releases/{id}/assets/{attachment_id}
-	return setting.AppURL + "api/repos/" + repo.FullName() + "/releases/" + strconv.FormatInt(attach.ReleaseID, 10) + "/assets/" + strconv.FormatInt(attach.ID, 10)
+	return attach.DownloadURL()
 }
 
 // ToAttachment converts models.Attachment to api.Attachment for API usage