[Solution included] This client isn't compatible with the Hetzner storage box WebDAV server

[oddmario]

trafficstars

Hello,

I tried using your WebDAV client to access my Hetzner storage box through their WebDAV server (pretty sure they use Apache as their WebDAV server)

First off, I noticed how their WebDAV differs than most of the WebDAV servers I have used before:

• Most of the WebDAV servers always respond in XML no matter what's the request method used
• Hetzner's WebDAV server (Apache I think?) responds in HTML unless the request method is a proper WebDAV verb (PROPFIND, etc).

So what's the issue?

If we perform a Readdir (for example) query on the Hetzner WebDAV server like that:

data, err := webdav.Readdir("/asset1", false)
if err != nil {
    fmt.Println(err)
}

the internal HTTP client of go-webdav will send the request with the URL https://uXXXX.your-storagebox.de/asset1 and the method PROPFIND, but then the server will respond with HTTP status code 302 and a Location: https://uXXXX.your-storagebox.de/asset1/ header. This really shouldn't be an issue since the Golang HTTP client follows any redirects by default (I actually couldn't debug what I have just stated without disabling the automatic redirections following first). However the request made after the redirect loses its request method (PROPFIND) and always gets changed to a GET request, and here all the issues start (since as I said in the start, the Hetzner WebDAV server will respond with HTML if the request method isn't one of the WebDAV request verbs)

I don't really know why the HTTP client doesn't follow the redirections with the same request method of the original request, but I managed to solve it by creating my own Transport like that:

type webdavTransport struct {
	username string
	password string
}

func (t *webdavTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	req.SetBasicAuth(t.username, t.password)

	var resp *http.Response
	var err error

	resp, err = http.DefaultTransport.RoundTrip(req)

	if err == nil {
		if resp.StatusCode == 301 || resp.StatusCode == 302 {
			newURL, _ := resp.Location()

			reqNew, _ := http.NewRequest(req.Method, newURL.String(), req.Body)
			reqNew.Header = req.Header

			respNew, errNew := http.DefaultTransport.RoundTrip(reqNew)

			resp = respNew
			err = errNew
		}
	}

	return resp, err
}

func FixedWebdavClientWithAuth(url, username, password string) (*webdav.Client, error) {
	client := &http.Client{
		Transport: &webdavTransport{
			username: username,
			password: password,
		},
                // Disable any redirections following since we'll manually handle this in the transport's RoundTripper
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			return http.ErrUseLastResponse
		},
	}

	return webdav.NewClient(client, url)
}

now using

webdav, err := FixedWebdavClientWithAuth("https://uXXXX.your-storagebox.de", "[redacted]", "[redacted]")

if err != nil {
    fmt.Println("unable to access")
}

data, err := webdav.Readdir("/asset1", false)
if err != nil {
    fmt.Println(err)
    fmt.Println("unable to access")
}

fmt.Println(data)

solves the issue and data gets printed successfully with no issues

[emersion]

See https://cs.opensource.google/go/go/+/refs/tags/go1.21.0:src/net/http/client.go;l=518;drc=97df9c0b051b6c06bff7ec7e61522e7bbef40c91

[jech]

In other words, the server should be replying with 307 instead of 302.