OkHttp upload multiple files with names to Python Flask server

Question

At Server end I use Python flask:

from flask import Flask, request
app = Flask(__name__)

@app.route("/upload", methods=["POST"])
def upload():
    print request.files
    print request.form
    return "200 ok"

if __name__ == '__main__':
    app.run(port=5000)

Java test code block:

public void test_Upload() throws Exception{
        MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");
        MediaType MEDIA_TYPE_XO = MediaType.parse("image/png");
        RequestBody requestBody = new MultipartBuilder()
                .type(MultipartBuilder.FORM)
                .addPart(
                        Headers.of("Content-Disposition", "form-data; name=\"title\""),
                        RequestBody.create(null, "Square Logo"))
                .addPart(
                        Headers.of("Content-Disposition", "form-data; name=\"image\""),
                        RequestBody.create(MEDIA_TYPE_PNG, new File("/Users/lollipop/Downloads/ic_launch.png")))
                .addPart(
                        Headers.of("Content-Disposition", "form-data; name=\"google\""),
                        RequestBody.create(MEDIA_TYPE_XO, new File("/Users/lollipop/Downloads/google-logo.png")))
                .build();
        Request request = new Request.Builder()
                .url("http://localhost:5000/upload")
                .post(requestBody)
                .build();
        Response resp = httpClient.newCall(request).execute();
        System.out.println(resp.body().string());
    }

And I run the test. server end cannot read the file from request.forms

output on server:

ImmutableMultiDict([])
ImmutableMultiDict([('image', u'5 ...many data ... fffd'), ('google', u'5i\u ...many data ... fffd'),('title', u'Square Logo')])

Why my files upload to request.form not in request.files. And all binary file data is parsed to unicode string.

Next, I test in Python requests. follows codes:

resp = requests.post("http://localhost:5000/upload",
                         files={
                             "image": open("/Users/lollipop/Downloads/ic_launch.png", "rb"),
                             "title": open("/Users/lollipop/Downloads/ic_launch.png", "rb"),
                             "google": open("/Users/lollipop/Downloads/google-logo.png", "rb")
                         })

And the server end output is reversed:

ImmutableMultiDict([('image', <FileStorage: u'ic_launch.png' (None)>), ('google', <FileStorage: u'google-logo.png' (None)>), ('title', <FileStorage: u'ic_launch.png' (None)>)])
ImmutableMultiDict([])

the upload files are in request.files not in request.form, this is my expected result.

So. how can I use OkHttp to upload files to flask server, and use request.files to retrive.

Update

the request is Flask requst.

from flask import request

the requests is a Python http client library.

Answer 1

This bug is not to Flask. I get misguided by this answer

At the OkHttp recipe in the documents. Described the post a file use the following code

public static final MediaType MEDIA_TYPE_MARKDOWN
      = MediaType.parse("text/x-markdown; charset=utf-8");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    File file = new File("README.md");

    Request request = new Request.Builder()
        .url("https://api.github.com/markdown/raw")
        .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, file))
        .build();

    Response response = client.newCall(request).execute();
    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

    System.out.println(response.body().string());
  }

Actually, this manner is not error, it post a file you don't need to provide a filename and other form data. But this is not a usual usage.

We often need to upload a file with specified name and some key-value form data. We even need to upload more than one file.

 RequestBody requestBody = new MultipartBuilder()
                .type(MultipartBuilder.FORM)
                .addFormDataPart("username", username)
                .addFormDataPart("password", password)
                .addFormDataPart("avatar", "avatar.png", RequestBody.create(MEDIA_TYPE_PNG, sourceFile))
                .addFormDataPart("introduce_image", "introduce_image.png", RequestBody.create(MEDIA_TYPE_PNG, sourceFile))
                .build();