fix hard-coded timeout and error panic in API archive download endpoint (#20925)

* fix hard-coded timeout and error panic in API archive download endpoint

This commit updates the `GET /api/v1/repos/{owner}/{repo}/archive/{archive}`
endpoint which prior to this PR had a couple of issues.

1. The endpoint had a hard-coded 20s timeout for the archiver to complete after
   which a 500 (Internal Server Error) was returned to client. For a scripted
   API client there was no clear way of telling that the operation timed out and
   that it should retry.

2. Whenever the timeout _did occur_, the code used to panic. This was caused by
   the API endpoint "delegating" to the same call path as the web, which uses a
   slightly different way of reporting errors (HTML rather than JSON for
   example).

   More specifically, `api/v1/repo/file.go#GetArchive` just called through to
   `web/repo/repo.go#Download`, which expects the `Context` to have a `Render`
   field set, but which is `nil` for API calls. Hence, a `nil` pointer error.

The code addresses (1) by dropping the hard-coded timeout. Instead, any
timeout/cancelation on the incoming `Context` is used.

The code addresses (2) by updating the API endpoint to use a separate call path
for the API-triggered archive download. This avoids producing HTML-errors on
errors (it now produces JSON errors).

Signed-off-by: Peter Gardfjäll <peter.gardfjall.work@gmail.com>

2 files changed, 4 insertions, 5 deletions

diff --git a/models/repo.go b/models/repo.go
index 35af6c1ef4..f2676a5696 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -218,8 +218,7 @@ func DeleteRepository(doer *user_model.User, uid, repoID int64) error {
 
 	archivePaths := make([]string, 0, len(archives))
 	for _, v := range archives {
-		p, _ := v.RelativePath()
-		archivePaths = append(archivePaths, p)
+		archivePaths = append(archivePaths, v.RelativePath())
 	}
 
 	if _, err := db.DeleteByBean(ctx, &repo_model.RepoArchiver{RepoID: repoID}); err != nil {
diff --git a/models/repo/archiver.go b/models/repo/archiver.go
index fd07d8554d..003911943f 100644
--- a/models/repo/archiver.go
+++ b/models/repo/archiver.go
@@ -39,9 +39,9 @@ func init() {
 	db.RegisterModel(new(RepoArchiver))
 }
 
-// RelativePath returns relative path
-func (archiver *RepoArchiver) RelativePath() (string, error) {
-	return fmt.Sprintf("%d/%s/%s.%s", archiver.RepoID, archiver.CommitID[:2], archiver.CommitID, archiver.Type.String()), nil
+// RelativePath returns the archive path relative to the archive storage root.
+func (archiver *RepoArchiver) RelativePath() string {
+	return fmt.Sprintf("%d/%s/%s.%s", archiver.RepoID, archiver.CommitID[:2], archiver.CommitID, archiver.Type.String())
 }
 
 var delRepoArchiver = new(RepoArchiver)