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flask - empty form data when sending request from file with netcat

I have a remote server running a simple flask server on it. I use this server for debugging purposes of my MCU cellular interface.
from flask import Flask
from flask import request
app = Flask(__name__)
#app.route("/b61d39e9-94ca-49e2-96ba-bdc3325a8aeb", methods = ["POST"])
def root():
print(request.headers)
if(request.is_json):
content = request.get_json()
print (content)
print(request.form.get("uuid"))
return "OK"
if(__name__ == "__main__"):
app.run(host = "0.0.0.0", port = 65432, debug = True)
And I send this request using netcat and the command nc ... 65432 < Request.txt
POST /b61d39e9-94ca-49e2-96ba-bdc3325a8aeb HTTP/1.1
Host: ESP32-DevKit VE
Content-Type: multipart/form-data;boundary="data"
--data
Content-Disposition: form-data; name="uuid"
ff0dbd36-dc36-4df5-8196-324adf76ed3f
--data--
netcat is reporting error 200, so everything was fine, but the flask web server doesn´t output the value of the field uuid.
... - - [13/Aug/2022 09:21:21] "POST /b61d39e9-94ca-49e2-96ba-bdc3325a8aeb HTTP/1.1" 200 -
Host: ESP32-DevKit VE
Content-Type: multipart/form-data;boundary="data"
None
I can not figure out what kind of problem is here.

It appears you're missing Content-Length header. I was able to get uuid using your python code above and this request:
POST /b61d39e9-94ca-49e2-96ba-bdc3325a8aeb HTTP/1.1
Content-Type: multipart/form-data; boundary=--------------------------data
Content-Length: 135
----------------------------data
Content-Disposition: form-data; name="uuid"
ff0dbd36-dc36-4df5-8196-324adf76ed3f
----------------------------data--

Python. Cannot make a request to simple site api. Flask and requests

I am trying to create simple API for my site. I created the route with flask:
#api.route('/api/rate&message_id=<message_id>&performer=<performer_login>', methods=['POST'])
def api_rate_msg(message_id, performer_login):
print("RATE API ", message_id, ' ', performer_id)
return 400
print(...) function don't execute...
I use flask-socketio to communicate between client and server.
I send json from client and process it with:
#socket.on('rate')
def handle_rate(data):
print(data)
payload = {'message_id':data['message_id'], 'performer':data['performer']}
r = requests.post('/api/rate', params=payload)
print (r.status_code)
Note, that data variable is sending from client and is correct(I've checked it).
print(r.status_code) don't exec too...
Where I'm wrong? Please, sorry for my bad english :(
This api function must increase rate of message, which stored in mongodb, if interesting.

Don't put &message_id=<message_id>&performer=<performer_login> in your route string. Instead, get these arguments from request.args.
Try it:
from flask import request
...
#api.route('/api/rate', methods=['POST'])
def api_rate_msg():
print(request.args)
return ''
I've tested it with httpie:
$ http -v POST :5000/api/rate message_id==123 performer_login==foo
POST /api/rate?message_id=123&performer_login=foo HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:5000
User-Agent: HTTPie/0.9.8
HTTP/1.0 200 OK
Content-Length: 0
Content-Type: text/html; charset=utf-8
Date: Sun, 02 Apr 2017 13:54:40 GMT
Server: Werkzeug/0.11.11 Python/2.7.13
And from flask's log:
ImmutableMultiDict([('message_id', u'123'), ('performer_login', u'foo')])
127.0.0.1 - - [02/Apr/2017 22:54:40] "POST /api/rate?message_id=123&performer_login=foo HTTP/1.1" 200 -

Remove the below part from your api route
&message_id=<message_id>&performer=<performer_login
This is not required in POST request. It helps in GET requests. API call in request is not matching the route definition and therefore you have the current problem

HTTP post Json 400 Error

I am trying to post data to my server from my microcontroller. I need to send raw http data from my controller and this is what I am sending below:
POST /postpage HTTP/1.1
Host: https://example.com
Accept: */*
Content-Length: 18
Content-Type: application/json
{"cage":"abcdefg"}
My server requires JSON encoding and not form encoded request.
For the above request sent, I get an 400 error from the server, HTTP/1.1 400 Bad Request
However, when I try to reach the post to my server via a python script via my laptop, I am able to get a proper response.
import requests
url='https://example.com'
mycode = 'abcdefg'
def enter():
value = requests.post('url/postpage',
params={'cage': mycode})
print vars(value)
enter()
Can anyone please let me know where I could be going wrong in the raw http data I'm sending above ?

HTTP specifies the separator between headers as a single newline, and requires a double newline before the content:
POST /postpage HTTP/1.1
Host: https://example.com
Accept: */*
Content-Length: 18
Content-Type: application/json
{"cage":"abcdefg"}
If you don’t think you’ve got all of the request right, try seeing what was sent by Python:
response = ...
request = response.request # request is a PreparedRequest.
headers = request.headers
url = request.url
Read the docs for PreparedRequest for more information.
To pass a parameter, use this Python:
REQUEST = 'POST /postpage%s HTTP/1.1\r\nHost: example.com\r\nContent-Length: 0\r\nConnection: keep-alive\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nUser-Agent: python-requests/2.4.3 CPython/2.7.9 Linux/4.4.11-v7+\r\n\r\n';
query = ''
for k, v in params.items():
query += '&' + k + '=' + v # URL-encode here if you want.
if len(query): query = '?' + query[1:]
return REQUEST % query

How to do `PUT` on Amazon S3 using Python Requests

I am trying to upload a file to Amazon S3 with Python Requests (Python is v2.7.9 and requests is v2.7). Following the curl command which works perfectly:
curl --request PUT --upload-file img.png https://mybucket-dev.s3.amazonaws.com/6b89e187-26fa-11e5-a04f-a45e60d45b53?Signature=Ow%3D&Expires=1436595966&AWSAccessKeyId=AQ
But when I do same with requests, it fails. Here's what I have tried:
url = https://mybucket-dev.s3.amazonaws.com/6b89e187-26fa-11e5-a04f-a45e60d45b53?Signature=Ow%3D&Expires=1436595966&AWSAccessKeyId=AQ
requests.put(url, files={'file': base64_encoded_image})
requests.put(url, files={'upload_file': base64_encoded_image})
It fails with 403 and response I am getting is:
<Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message>
Then I ran curl in verbose mode:
* Hostname was NOT found in DNS cache
* Trying 54.231.168.134...
* Connected to mybucket-dev.s3.amazonaws.com (54.231.168.134) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
* Server certificate: *.s3.amazonaws.com
* Server certificate: VeriSign Class 3 Secure Server CA - G3
* Server certificate: VeriSign Class 3 Public Primary Certification Authority - G5
> PUT /6b89e187-26fa-11e5-a04f-a45e60d45b53?Signature=Ow%3D&Expires=1436595966&AWSAccessKeyId=AQ HTTP/1.1
> User-Agent: curl/7.37.1
> Host: mybucket-dev.s3.amazonaws.com
> Accept: */*
> Content-Length: 52369
> Expect: 100-continue
>
< HTTP/1.1 100 Continue
* We are completely uploaded and fine
< HTTP/1.1 200 OK
< x-amz-id-2: 5lLCQ3FVrTBg2vkyk44E+MecQJb2OGiloO0+2pKePtxPgZptKECNlUyYN43sl4LBNe9f8idh/cc=
< x-amz-request-id: 636A24D53DEB5215
< Date: Fri, 10 Jul 2015 12:04:44 GMT
< ETag: "5802130d4320b56a72afe720e2c323a7"
< Content-Length: 0
* Server AmazonS3 is not blacklisted
< Server: AmazonS3
<
* Connection #0 to host mybucket-dev.s3.amazonaws.com left intact
So then I added headers
headers = {'Content-Length': '52369', 'Host': 'mybucket-dev.s3.amazonaws.com', 'Expect': '100-continue', 'Accept': '*/*', 'User-Agent': 'curl/7.37.1'}
requests.put(url, files={'file': base64_encoded_image}, headers=headers)
I tried with different combinations of header, still it throws same error. Then I tried to send query parameters too:
payload={'Expires': '1436595966', 'AWSAccessKeyId': 'AQ', 'Signature': 'Ow%3D'}
requests.put(url, files={'file': base64_encoded_image}, headers=headers, data=payload)
It still fails and same error. I tried URL without query parameters and sending them as data=payload to requests, it fails with same error.

Engineers at requests helped me:
with open('img.png', 'rb') as data:
requests.put(url, data=data)

Acording to this documentation you have pass the files argument to post method also need send the key name for S3
import requests
url = 'https://s3.amazonaws.com/<some-bucket-name>'
data = { 'key': 'test/test.jpeg' }
files = { 'file': open('test.jpeg', 'rb') }
r = requests.post(url, data=data, files=files)
print "status %s" % r.status_code

Python requests - print entire http request (raw)?

While using the requests module, is there any way to print the raw HTTP request?
I don't want just the headers, I want the request line, headers, and content printout. Is it possible to see what ultimately is constructed from HTTP request?

Since v1.2.3 Requests added the PreparedRequest object. As per the documentation "it contains the exact bytes that will be sent to the server".
One can use this to pretty print a request, like so:
import requests
req = requests.Request('POST','http://stackoverflow.com',headers={'X-Custom':'Test'},data='a=1&b=2')
prepared = req.prepare()
def pretty_print_POST(req):
"""
At this point it is completely built and ready
to be fired; it is "prepared".
However pay attention at the formatting used in
this function because it is programmed to be pretty
printed and may differ from the actual request.
"""
print('{}\n{}\r\n{}\r\n\r\n{}'.format(
'-----------START-----------',
req.method + ' ' + req.url,
'\r\n'.join('{}: {}'.format(k, v) for k, v in req.headers.items()),
req.body,
))
pretty_print_POST(prepared)
which produces:
-----------START-----------
POST http://stackoverflow.com/
Content-Length: 7
X-Custom: Test
a=1&b=2
Then you can send the actual request with this:
s = requests.Session()
s.send(prepared)
These links are to the latest documentation available, so they might change in content:
Advanced - Prepared requests and API - Lower level classes

import requests
response = requests.post('http://httpbin.org/post', data={'key1': 'value1'})
print(response.request.url)
print(response.request.body)
print(response.request.headers)
Response objects have a .request property which is the PreparedRequest object that was sent.

An even better idea is to use the requests_toolbelt library, which can dump out both requests and responses as strings for you to print to the console. It handles all the tricky cases with files and encodings which the above solution does not handle well.
It's as easy as this:
import requests
from requests_toolbelt.utils import dump
resp = requests.get('https://httpbin.org/redirect/5')
data = dump.dump_all(resp)
print(data.decode('utf-8'))
Source: https://toolbelt.readthedocs.org/en/latest/dumputils.html
You can simply install it by typing:
pip install requests_toolbelt

Note: this answer is outdated. Newer versions of requests support getting the request content directly, as AntonioHerraizS's answer documents.
It's not possible to get the true raw content of the request out of requests, since it only deals with higher level objects, such as headers and method type. requests uses urllib3 to send requests, but urllib3 also doesn't deal with raw data - it uses httplib. Here's a representative stack trace of a request:
-> r= requests.get("http://google.com")
/usr/local/lib/python2.7/dist-packages/requests/api.py(55)get()
-> return request('get', url, **kwargs)
/usr/local/lib/python2.7/dist-packages/requests/api.py(44)request()
-> return session.request(method=method, url=url, **kwargs)
/usr/local/lib/python2.7/dist-packages/requests/sessions.py(382)request()
-> resp = self.send(prep, **send_kwargs)
/usr/local/lib/python2.7/dist-packages/requests/sessions.py(485)send()
-> r = adapter.send(request, **kwargs)
/usr/local/lib/python2.7/dist-packages/requests/adapters.py(324)send()
-> timeout=timeout
/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py(478)urlopen()
-> body=body, headers=headers)
/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py(285)_make_request()
-> conn.request(method, url, **httplib_request_kw)
/usr/lib/python2.7/httplib.py(958)request()
-> self._send_request(method, url, body, headers)
Inside the httplib machinery, we can see HTTPConnection._send_request indirectly uses HTTPConnection._send_output, which finally creates the raw request and body (if it exists), and uses HTTPConnection.send to send them separately. send finally reaches the socket.
Since there's no hooks for doing what you want, as a last resort you can monkey patch httplib to get the content. It's a fragile solution, and you may need to adapt it if httplib is changed. If you intend to distribute software using this solution, you may want to consider packaging httplib instead of using the system's, which is easy, since it's a pure python module.
Alas, without further ado, the solution:
import requests
import httplib
def patch_send():
old_send= httplib.HTTPConnection.send
def new_send( self, data ):
print data
return old_send(self, data) #return is not necessary, but never hurts, in case the library is changed
httplib.HTTPConnection.send= new_send
patch_send()
requests.get("http://www.python.org")
which yields the output:
GET / HTTP/1.1
Host: www.python.org
Accept-Encoding: gzip, deflate, compress
Accept: */*
User-Agent: python-requests/2.1.0 CPython/2.7.3 Linux/3.2.0-23-generic-pae

requests supports so called event hooks (as of 2.23 there's actually only response hook). The hook can be used on a request to print full request-response pair's data, including effective URL, headers and bodies, like:
import textwrap
import requests
def print_roundtrip(response, *args, **kwargs):
format_headers = lambda d: '\n'.join(f'{k}: {v}' for k, v in d.items())
print(textwrap.dedent('''
---------------- request ----------------
{req.method} {req.url}
{reqhdrs}
{req.body}
---------------- response ----------------
{res.status_code} {res.reason} {res.url}
{reshdrs}
{res.text}
''').format(
req=response.request,
res=response,
reqhdrs=format_headers(response.request.headers),
reshdrs=format_headers(response.headers),
))
requests.get('https://httpbin.org/', hooks={'response': print_roundtrip})
Running it prints:
---------------- request ----------------
GET https://httpbin.org/
User-Agent: python-requests/2.23.0
Accept-Encoding: gzip, deflate
Accept: */*
Connection: keep-alive
None
---------------- response ----------------
200 OK https://httpbin.org/
Date: Thu, 14 May 2020 17:16:13 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 9593
Connection: keep-alive
Server: gunicorn/19.9.0
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true
<!DOCTYPE html>
<html lang="en">
...
</html>
You may want to change res.text to res.content if the response is binary.

Here is a code, which makes the same, but with response headers:
import socket
def patch_requests():
old_readline = socket._fileobject.readline
if not hasattr(old_readline, 'patched'):
def new_readline(self, size=-1):
res = old_readline(self, size)
print res,
return res
new_readline.patched = True
socket._fileobject.readline = new_readline
patch_requests()
I spent a lot of time searching for this, so I'm leaving it here, if someone needs.

A fork of #AntonioHerraizS answer (HTTP version missing as stated in comments)
Use this code to get a string representing the raw HTTP packet without sending it:
import requests
def get_raw_request(request):
request = request.prepare() if isinstance(request, requests.Request) else request
headers = '\r\n'.join(f'{k}: {v}' for k, v in request.headers.items())
body = '' if request.body is None else request.body.decode() if isinstance(request.body, bytes) else request.body
return f'{request.method} {request.path_url} HTTP/1.1\r\n{headers}\r\n\r\n{body}'
headers = {'User-Agent': 'Test'}
request = requests.Request('POST', 'https://stackoverflow.com', headers=headers, json={"hello": "world"})
raw_request = get_raw_request(request)
print(raw_request)
Result:
POST / HTTP/1.1
User-Agent: Test
Content-Length: 18
Content-Type: application/json
{"hello": "world"}
💡 Can also print the request in the response object
r = requests.get('https://stackoverflow.com')
raw_request = get_raw_request(r.request)
print(raw_request)

I use the following function to format requests. It's like #AntonioHerraizS except it will pretty-print JSON objects in the body as well, and it labels all parts of the request.
format_json = functools.partial(json.dumps, indent=2, sort_keys=True)
indent = functools.partial(textwrap.indent, prefix=' ')
def format_prepared_request(req):
"""Pretty-format 'requests.PreparedRequest'
Example:
res = requests.post(...)
print(format_prepared_request(res.request))
req = requests.Request(...)
req = req.prepare()
print(format_prepared_request(res.request))
"""
headers = '\n'.join(f'{k}: {v}' for k, v in req.headers.items())
content_type = req.headers.get('Content-Type', '')
if 'application/json' in content_type:
try:
body = format_json(json.loads(req.body))
except json.JSONDecodeError:
body = req.body
else:
body = req.body
s = textwrap.dedent("""
REQUEST
=======
endpoint: {method} {url}
headers:
{headers}
body:
{body}
=======
""").strip()
s = s.format(
method=req.method,
url=req.url,
headers=indent(headers),
body=indent(body),
)
return s
And I have a similar function to format the response:
def format_response(resp):
"""Pretty-format 'requests.Response'"""
headers = '\n'.join(f'{k}: {v}' for k, v in resp.headers.items())
content_type = resp.headers.get('Content-Type', '')
if 'application/json' in content_type:
try:
body = format_json(resp.json())
except json.JSONDecodeError:
body = resp.text
else:
body = resp.text
s = textwrap.dedent("""
RESPONSE
========
status_code: {status_code}
headers:
{headers}
body:
{body}
========
""").strip()
s = s.format(
status_code=resp.status_code,
headers=indent(headers),
body=indent(body),
)
return s

test_print.py content:
import logging
import pytest
import requests
from requests_toolbelt.utils import dump
def print_raw_http(response):
data = dump.dump_all(response, request_prefix=b'', response_prefix=b'')
return '\n' * 2 + data.decode('utf-8')
#pytest.fixture
def logger():
log = logging.getLogger()
log.addHandler(logging.StreamHandler())
log.setLevel(logging.DEBUG)
return log
def test_print_response(logger):
session = requests.Session()
response = session.get('http://127.0.0.1:5000/')
assert response.status_code == 300, logger.warning(print_raw_http(response))
hello.py content:
from flask import Flask
app = Flask(__name__)
#app.route('/')
def hello_world():
return 'Hello, World!'
Run:
$ python -m flask hello.py
$ python -m pytest test_print.py
Stdout:
------------------------------ Captured log call ------------------------------
DEBUG urllib3.connectionpool:connectionpool.py:225 Starting new HTTP connection (1): 127.0.0.1:5000
DEBUG urllib3.connectionpool:connectionpool.py:437 http://127.0.0.1:5000 "GET / HTTP/1.1" 200 13
WARNING root:test_print_raw_response.py:25
GET / HTTP/1.1
Host: 127.0.0.1:5000
User-Agent: python-requests/2.23.0
Accept-Encoding: gzip, deflate
Accept: */*
Connection: keep-alive
HTTP/1.0 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 13
Server: Werkzeug/1.0.1 Python/3.6.8
Date: Thu, 24 Sep 2020 21:00:54 GMT
Hello, World!