Add raw blob endpoint to get objects by SHA ID (#5334)

* Add raw blob endpoint

This should make it possible to download raw blobs directly from
/:repo/:username/raw/blob/:sha1 URLs.

* fix: Make it work

* As an SHA-ID is no path getRefNameFromPath can't be used to verify
file specifying parameter
* added relevant change in go-gitea/git #132

Signed-off-by: Berengar W. Lehr <Berengar.Lehr@kompetenztest.de>

* Update Gopkg.lock

Can't update all vendors due to errors

Signed-off-by: Berengar W. Lehr <Berengar.Lehr@kompetenztest.de>

* style: Add Gitea copyright header

* feat: Added integration test for /repo/u/r/raw/blob

* fix: correct year in copyright header

modules/context/repo.go

@@ -484,6 +484,8 @@ const (
 	RepoRefTag
 	// RepoRefCommit commit
 	RepoRefCommit
+	// RepoRefBlob blob
+	RepoRefBlob
 )
 
 // RepoRef handles repository reference names when the ref name is not
@@ -519,6 +521,9 @@ func getRefName(ctx *Context, pathType RepoRefType) string {
 		if refName := getRefName(ctx, RepoRefCommit); len(refName) > 0 {
 			return refName
 		}
+		if refName := getRefName(ctx, RepoRefBlob); len(refName) > 0 {
+			return refName
+		}
 		ctx.Repo.TreePath = path
 		return ctx.Repo.Repository.DefaultBranch
 	case RepoRefBranch:
@@ -531,6 +536,12 @@ func getRefName(ctx *Context, pathType RepoRefType) string {
 			ctx.Repo.TreePath = strings.Join(parts[1:], "/")
 			return parts[0]
 		}
+	case RepoRefBlob:
+		_, err := ctx.Repo.GitRepo.GetBlob(path)
+		if err != nil {
+			return ""
+		}
+		return path
 	default:
 		log.Error(4, "Unrecognized path type: %v", path)
 	}