Flask not getting any data from jQuery request data

Question

I\'ve a handler for a URL,

@app.route(\"/\", methods=[\'POST\'])
@crossdomain(origin=\'*\')
def hello():
    ss=str(request.data)
    print ss
    return ss
         


        

Answer 1

interesting, as it turns out you can only use request.data if the data was posted with a mimetype that flask can't handle, otherwise its an empty string "" I think, the docs weren't very clear, I did some tests and that seems to be the case, you can take a look at the console output the flask generates when you run my tests.

Incoming Request Data

data
  Contains the incoming request data as string in case it came with a mimetype Flask does not handle.

taken from http://flask.pocoo.org/docs/api/

but since we are doing a standard POST using json flask can handle this quite well as such you can access the data from the standard request.form this ss=str(request.form) should do the trick as I've tested it.

As a side note @crossdomain(origin='*') this seems dangerous, theres a reason why we don't allow cross site ajax requests, though Im sure you have your reasons.

this is the complete code I used for testing:

from flask import Flask
app = Flask(__name__)

from datetime import timedelta
from flask import make_response, request, current_app
from functools import update_wrapper


def crossdomain(origin=None, methods=None, headers=None,
                max_age=21600, attach_to_all=True,
                automatic_options=True):
    if methods is not None:
        methods = ', '.join(sorted(x.upper() for x in methods))
    if headers is not None and not isinstance(headers, basestring):
        headers = ', '.join(x.upper() for x in headers)
    if not isinstance(origin, basestring):
        origin = ', '.join(origin)
    if isinstance(max_age, timedelta):
        max_age = max_age.total_seconds()

    def get_methods():
        if methods is not None:
            return methods

        options_resp = current_app.make_default_options_response()
        return options_resp.headers['allow']

    def decorator(f):
        def wrapped_function(*args, **kwargs):
            if automatic_options and request.method == 'OPTIONS':
                resp = current_app.make_default_options_response()
            else:
                resp = make_response(f(*args, **kwargs))
            if not attach_to_all and request.method != 'OPTIONS':
                return resp

            h = resp.headers

            h['Access-Control-Allow-Origin'] = origin
            h['Access-Control-Allow-Methods'] = get_methods()
            h['Access-Control-Max-Age'] = str(max_age)
            if headers is not None:
                h['Access-Control-Allow-Headers'] = headers
            return resp

        f.provide_automatic_options = False
        return update_wrapper(wrapped_function, f)
    return decorator



@app.route("/", methods=['POST'])
@crossdomain(origin='*')
def hello():
    ss=str(request.form)

    print 'ss: ' + ss + ' request.data: ' + str(request.data)
    return ss


@app.route("/test/")
def t():
    return """



"""

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

output:

$ python test.py 
 * Running on http://127.0.0.1:5000/
127.0.0.1 - - [07/Aug/2012 02:45:28] "GET /test/ HTTP/1.1" 200 -
ss: ImmutableMultiDict([('adasdasd', u'')]) request.data: 
127.0.0.1 - - [07/Aug/2012 02:45:28] "POST / HTTP/1.1" 200 -
ss: ImmutableMultiDict([]) request.data: sync call
127.0.0.1 - - [07/Aug/2012 02:45:28] "POST / HTTP/1.1" 200 -
127.0.0.1 - - [07/Aug/2012 02:45:29] "GET /favicon.ico HTTP/1.1" 404 -

and my system:

$ python --version
Python 2.6.1

$ python -c 'import flask; print flask.__version__;'
0.8

$ uname -a
Darwin 10.8.0 Darwin Kernel Version 10.8.0: Tue Jun  7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386 i386

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