Flask - How do I read the raw body in a POST request when the content type is "application/x-www-form-urlencoded"

Question

Turns out that Flask sets request.data to an empty string if the content type of the request is application/x-www-form-urlencoded. Since I'm using a JSON body request, I just want to parse the json or force Flask to parse it and return request.json.

This is needed because changing the AJAX content type forces an HTTP OPTION request, which complicates the back-end.

How do I make Flask return the raw data in the request object?

Ghee

Yep flask.request.data.decode("utf-8") blank, but I thought it was a client side problem. Thanks for confirming flask is doing this! Wow omg 10 years later! this conversation really saved my biscuit today ! I was puzzled for a few hours. – Staid

Answer 1

You can get the post data via request.form.keys()[0] if content type is application/x-www-form-urlencoded.

request.form is a multidict, whose keys contain the parsed post data.

Excaudate

It seems this was also the way to get the data our of a post to bottle. Just change request.form.keys()[0] to list(request.forms.keys())[0]. Thanks for finally solving hours of debugging! – Lozenge

Why does it work? It seems it should be just the first key of the dictionary parsed from the body, but it somehow returns the entire body? – Shorn

Can someone please explain why the data is put into the form keys? – Carinacarinate

This does not give you all of the post data if the data contains = and & characters. – Hawkinson

@Emil it should be form not forms. – Hasen

Even though this works, I don't think it should be the accepted answer. The other two answers below offer much better approaches to code legibility and maintainability. – Ides

2023. This is straight up wrong. The [0] doesn't reference to anything and gives to you a runtime error because form.keys() are in key: value pairs. param1=value1&param2=value2 returns ImmutableMultiDict([('key1', 'value1'), ('key2', 'value2')]) – Doughnut

I would use form.keys and go from there to get the data you need. get_data() returns a byte stream, only useful if you're dealing with binary data.` – Doughnut

Answer 2

Use request.get_data() to get the POST data. This works independent of whether the data has content type application/x-www-form-urlencoded or application/octet-stream.

Hawkinson

This doesn't seem to be the case. With the requests I'm getting, if I use get_data() I get an empty bytes(), but with the accepted answer's method (looking at the form keys) I get a bunch of data. – Forsooth

Yup me too, nothing in get_data(), but it seems ridiculous to do it as in the accepted answer. – Bruni

Answer 3

If you want get the JSON when request is 'Content-Type': 'application/x-www-form-urlencoded' you need "force" conversion to json like de code below:

from flask import Flask, request
import os


app = Flask(__name__)


@app.route("/my-endpoint", methods = ['POST'])
def myEndpoint():

    requestJson = request.get_json(force=True)

    //TODO: do something....

    return requestJson


if __name__ == "__main__":
    port = int(os.environ.get('PORT', 5000))
    app.run(host='0.0.0.0', port=port, debug=True, use_reloader=True)

Colloquium

Probably it is outdated now so it's not working – Braga

Answer 4

main.py

import json

from flask import Flask, request

app = Flask(__name__)


@app.route('/', methods=['POST'])
def index():
    mimetype = request.mimetype
    if mimetype == 'application/x-www-form-urlencoded':
        form = json.loads(next(iter(request.form.keys())))
    elif mimetype == 'multipart/form-data':
        form = dict(request.form)
    elif mimetype == 'application/json':
        form = request.json
    else:
        form = request.data.decode()
    print(mimetype, form, type(form))
    return form


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

Test

curl -X POST http://127.0.0.1:5000/ --data "{\"a\":1, \"b\":2}"

curl -X POST http://127.0.0.1:5000/ -F a=1 -F b=2

curl -X POST -H "Content-type: application/json" http://127.0.0.1:5000/ --data "{\"a\":1, \"b\":2}"

Result

application/x-www-form-urlencoded {'a': 1, 'b': 2} <class 'dict'>
multipart/form-data {'a': '1', 'b': '2'} <class 'dict'>
application/json {'a': 1, 'b': 2} <class 'dict'>

Fain

Answer 5

You can get it that way:

@app.route("/path-to-the-post-endpoint", methods=["POST"])
def handle_post_request():
    data = request.form.to_dict()
    data['some_key_1'] = "Some Value 1"
    data['some_key_2'] = "Some Value 2"
    # ...etc.

    # DO SOMETHING HERE

    return [], 200

Krebs

My post request Content-Type was application/x-www-form-urlencoded and I want to convert it to a dictionary. This worked for me request.form.to_dict() – Maynardmayne

Answer 6

try this:

f = request.form

   output = []

   user_data = {}

   user_data['email'] = f['email']

   user_data['password'] = f['password']

   user_data['key'] = f['key']

   output.append(user_data)

Homicide

Answer 7

request.values will obtain both args and post, proiritizing args per Python docs

request.json will handle a JSON payload.

Doughnut