attempt to get module name from proxy

download/proxy.go

@@ -15,6 +15,7 @@ import (
 const (
 	proxyLatestURL = "https://proxy.golang.org/%s/@latest"
 	proxyZipURL    = "https://proxy.golang.org/%s/@v/%s.zip"
+	proxyModURL    = "https://proxy.golang.org/%s/@v/%s.mod"
 	reposDir       = "_repos/src"
 )
 
@@ -22,8 +23,46 @@ type moduleVersion struct {
 	Version string
 }
 
-// ProxyDownload downloads a package from proxy.golang.org
-func ProxyDownload(path string) (string, error) {
+// ModuleName gets the name of a module from the proxy
+func ModuleName(path string) (string, error) {
+	lowerPath := strings.ToLower(path)
+
+	ver, err := LatestVersion(path)
+	if err != nil {
+		return "", err
+	}
+
+	u := fmt.Sprintf(proxyModURL, lowerPath, ver)
+	resp, err := http.Get(u)
+	if err != nil {
+		return "", err
+	}
+
+	defer resp.Body.Close()
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("could not get latest module version from %s: %s", u, string(b))
+	}
+
+	sp := strings.Split(string(b), "\n")
+	if len(sp) == 0 {
+		return "", fmt.Errorf("empty go.mod")
+	}
+
+	mn := strings.Fields(sp[0])
+	if len(mn) != 2 {
+		return "", fmt.Errorf("invalid go.mod: %s", mn)
+	}
+
+	return mn[1], nil
+}
+
+// LatestVersion gets the latest module version from the proxy
+func LatestVersion(path string) (string, error) {
 	lowerPath := strings.ToLower(path)
 	u := fmt.Sprintf(proxyLatestURL, lowerPath)
 	resp, err := http.Get(u)
@@ -45,7 +84,19 @@ func ProxyDownload(path string) (string, error) {
 		return "", err
 	}
 
-	resp, err = http.Get(fmt.Sprintf(proxyZipURL, lowerPath, mv.Version))
+	return mv.Version, nil
+}
+
+// ProxyDownload downloads a package from proxy.golang.org
+func ProxyDownload(path string) (string, error) {
+	lowerPath := strings.ToLower(path)
+
+	ver, err := LatestVersion(path)
+	if err != nil {
+		return "", err
+	}
+
+	resp, err := http.Get(fmt.Sprintf(proxyZipURL, lowerPath, ver))
 	if err != nil {
 		return "", err
 	}
@@ -55,7 +106,7 @@ func ProxyDownload(path string) (string, error) {
 		return "", fmt.Errorf("status %d", resp.StatusCode)
 	}
 
-	zipPath := filepath.Join(reposDir, filepath.Base(path)+"@"+mv.Version+".zip")
+	zipPath := filepath.Join(reposDir, filepath.Base(path)+"@"+ver+".zip")
 	out, err := os.Create(zipPath)
 	if err != nil {
 		return "", err
@@ -85,10 +136,10 @@ func ProxyDownload(path string) (string, error) {
 		return "", err
 	}
 
-	err = os.Rename(filepath.Join(reposDir, lowerPath+"@"+mv.Version), filepath.Join(reposDir, lowerPath))
+	err = os.Rename(filepath.Join(reposDir, lowerPath+"@"+ver), filepath.Join(reposDir, lowerPath))
 	if err != nil {
 		return "", err
 	}
 
-	return mv.Version, nil
+	return ver, nil
 }

handlers/check.go

@@ -28,6 +28,15 @@ func CheckHandler(w http.ResponseWriter, r *http.Request, db *badger.DB) {
 		return
 	}
 
+	moduleName, err := download.ModuleName(repo)
+	if err != nil {
+		log.Println("ERROR: could not get module name:", err)
+	}
+
+	if moduleName != "" {
+		repo = moduleName
+	}
+
 	log.Printf("Checking repo %q...", repo)
 
 	forceRefresh := r.Method != "GET" // if this is a GET request, try to fetch from cached version in badger first