how download file with oauth2

[Daniele F.1]

Hi all, I'm switching my Dropbox app from oauth1 to oauth2. I've an issue when I try to download a file.

I use this code:

var r = Call("https://content.dropboxapi.com/2/files/download", access_token, "{\"path\":\"" + metaPath + "\"}");

private string Call(string endpoint, string access_token, string json) {
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(endpoint);
request.ContentType = "application/json";
request.Headers.Add("Authorization", "Bearer " + access_token);
request.Method = "POST";
Stream requestStream = request.GetRequestStream();
requestStream.Write(Encoding.UTF8.GetBytes(json), 0, json.Length);
requestStream.Close();
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string txtResponse = reader.ReadToEnd();
return txtResponse;
}

The "Call" function works well whit *list_folder* endpoint. But I get a 400 http error (invalid request) with *download* endopint. Any tips? It's the right way?

Thanks!

[Steve M.]

Sorry for the confusion here... we're still missing some overview documentation that may have made this clearer.

For "content-style" endpoints like upload and download, the JSON is passed in the "Dropbox-Api-Arg" header, not in the body of the request. Take a look at the example curl requests in the documentation to get the hang of this.

So you'll want something like this (completely untested):

private string CallContent(string endpoint, string access_token, string json) {
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(endpoint);
    request.Headers.Add("Authorization", "Bearer " + access_token);
    request.Headers.Add("Dropbox-API-Arg", json);
    request.Method = "POST";
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    Stream dataStream = response.GetResponseStream();
    StreamReader reader = new StreamReader(dataStream);
    string txtResponse = reader.ReadToEnd();
    return txtResponse;
}

[Steve M.]

As another tip, I'd say you should always read the body of the HTTP response when you get an error. The body of the 400 from the API will generally tell you exactly what's wrong with the request.