Python Requests: Post JSON and file in single request

Question

I need to do a API call to upload a file along with a JSON string with details about the file.

I am trying to use the python requests lib to do this:

import requests  info = {     'var1' : 'this',     'var2'  : 'that', }  data = json.dumps({     'token' : auth_token,     'info'  : info, })  headers = {'Content-type': 'multipart/form-data'}  files = {'document': open('file_name.pdf', 'rb')}  r = requests.post(url, files=files, data=data, headers=headers) 

This throws the following error:

    raise ValueError("Data must not be a string.")  ValueError: Data must not be a string 

If I remove the 'files' from the request, it works.
If I remove the 'data' from the request, it works.
If I do not encode data as JSON it works.

For this reason I think the error is to do with sending JSON data and files in the same request.

Any ideas on how to get this working?

Answer 1

Don't encode using json.

import requests  info = {     'var1' : 'this',     'var2'  : 'that', }  data = {     'token' : auth_token,     'info'  : info, }  headers = {'Content-type': 'multipart/form-data'}  files = {'document': open('file_name.pdf', 'rb')}  r = requests.post(url, files=files, data=data, headers=headers) 

Note that this may not necessarily be what you want, as it will become another form-data section.

Answer 2

See this thread How to send JSON as part of multipart POST-request

Do not set the Content-type header yourself, leave that to pyrequests to generate

def send_request():     payload = {"param_1": "value_1", "param_2": "value_2"}     files = {         'json': (None, json.dumps(payload), 'application/json'),         'file': (os.path.basename(file), open(file, 'rb'), 'application/octet-stream')     }      r = requests.post(url, files=files)     print(r.content)