Fix /api/v3/projects routing error

Non-special API requests were getting special treatment, which
resulted in 500 errors. This change avoids the special treatment and
adds tests that assert that regular API requests should be left alone
by gitlab-workhorse.

main.go

@@ -52,7 +52,7 @@ const gitProjectPattern = `^/[^/]+/[^/]+\.git/`
 const apiPattern = `^/api/`
 
 // A project ID in an API request is either a number or two strings 'namespace/project'
-const projectsAPIPattern = `^/api/v3/projects/(\d+)|([^/]+/[^/]+)/`
+const projectsAPIPattern = `^/api/v3/projects/((\d+)|([^/]+/[^/]+))/`
 
 const ciAPIPattern = `^/ci/api/`
 

main_test.go

@@ -273,6 +273,37 @@ func TestDownloadCacheCreate(t *testing.T) {
 	}
 }
 
+func TestRegularProjectsAPI(t *testing.T) {
+	apiResponse := "API RESPONSE"
+	ts := testAuthServer(nil, 200, apiResponse)
+	defer ts.Close()
+	ws := startWorkhorseServer(ts.URL)
+	defer ws.Close()
+
+	for _, resource := range []string{
+		"/api/v3/projects/123/repository/not/special",
+		"/api/v3/projects/foo/bar/repository/not/special",
+		"/api/v3/projects/123/not/special",
+		"/api/v3/projects/foo/bar/not/special",
+	} {
+		resp, err := http.Get(ws.URL + resource)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer resp.Body.Close()
+		buf := &bytes.Buffer{}
+		if _, err := io.Copy(buf, resp.Body); err != nil {
+			t.Error(err)
+		}
+		if buf.String() != apiResponse {
+			t.Errorf("GET %q: Expected %q, got %q", resource, apiResponse, buf.String())
+		}
+		if resp.StatusCode != 200 {
+			t.Errorf("GET %q: expected 200, got %d", resource, resp.StatusCode)
+		}
+	}
+}
+
 func TestAllowedXSendfileDownload(t *testing.T) {
 	contentFilename := "my-content"
 	prepareDownloadDir(t)