spin up a simple web server that prints post data to console - python

I've found a number of simple web servers in python that will spin up a quick server and respond to requests simply. What I need is a server that won't just print the IP address, timestamp, method, and response code of each request (127.0.0.1 - - [28/Aug/2017 10:42:11] "POST / HTTP/1.1" 200 -), but also, if a POST request, I need it to print out the POST data.
So for example, if I send a POST request with {"foo":"bar"} in the body of the message, I want the server to print 127.0.0.1 - - [28/Aug/2017 10:42:11] "POST / HTTP/1.1" 200 - {"foo":"bar"} to the console before responding.
I'm not sure how to modify any of the linked options above to do this. If there's another simple option, that would work as well.

To just print out whatever JSON gets sent to a server, build yourself a basic catch-all endpoint and just print the JSON from it. In flask, this looks like the following:
import logging
from flask import Flask, request
app = Flask(__name__)
#app.route('/', methods=['POST', 'GET'], defaults={'path': ''})
#app.route('/<path:path>', methods=['POST', 'GET'])
def index(path):
print("HTTP {} to URL /{} received JSON {}".format(request.method, path, request.get_json()))
return "True"
Here's my calls to the server:
In [15]: requests.post('http://localhost:5000/', json={'a': 1})
Out[15]: <Response [200]>
In [16]: requests.post('http://localhost:5000/some/endpoint', json={'a': 1})
Out[16]: <Response [200]>
In [17]: requests.get('http://localhost:5000/', json={'a': 1})
Out[17]: <Response [200]>
Here's the server output:
In [7]: app.run(host='0.0.0.0')
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
HTTP POST to URL / received JSON {'a': 1}
127.0.0.1 - - [28/Aug/2017 11:57:49] "POST / HTTP/1.1" 200 -
HTTP POST to URL /some/endpoint received JSON {'a': 1}
127.0.0.1 - - [28/Aug/2017 11:57:51] "POST /some/endpoint HTTP/1.1" 200 -
HTTP GET to URL / received JSON {'a': 1}
127.0.0.1 - - [28/Aug/2017 11:57:55] "GET / HTTP/1.1" 200 -
Original Answer
A simple decorator should do the trick:
from flask import Flask, request
app = Flask(__name__)
def print_if_post(*args, **kwargs):
def inner_decorator(f):
def inner(*args, **kwargs):
if request.method == 'POST':
json = request.get_json()
print("JSON Data: {}".format(json))
return f(*args, **kwargs)
return app.route(*args, **kwargs)(inner)
return inner_decorator
This decorator will function exactly like app.route, but will print any JSON data sent to its endpoint:
#print_if_post('/', methods=['POST', 'GET'])
def index():
return "True"
Called with the following code:
In [4]: requests.get('http://localhost:5000/')
Out[4]: <Response [200]>
In [5]: requests.post('http://localhost:5000/', json={'a': 1})
Out[5]: <Response [200]>
Server outputs:
In [2]: app.run(host='0.0.0.0')
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
127.0.0.1 - - [28/Aug/2017 11:03:11] "GET / HTTP/1.1" 200 -
JSON Data: {'a': 1}
127.0.0.1 - - [28/Aug/2017 11:03:23] "POST / HTTP/1.1" 200 -

Related

Flask 405 error with valid route when not accessing request data

I'm getting a 405 error when I don't actually use a request body for successive identical requests.
Example:
app = Flask(__name__)
CORS(app)
#app.route("/login", methods=["POST"])
def login():
return jsonify({'success': True})
Request body is pretty simple:
{'username': 'foo', 'password': 'bar'}
Flutter code generating request:
http.Response response = await http.post(
Uri.parse("http://127.0.0.1:5000/login"),
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
'username': username,
'password': username,
}),
);
Term output:
127.0.0.1 - - [10/May/2022 05:37:36] "OPTIONS /login HTTP/1.1" 200 -
127.0.0.1 - - [10/May/2022 05:37:36] "POST /login HTTP/1.1" 200 -
127.0.0.1 - - [10/May/2022 05:37:41] "{"username":"foo","password":"bar"}POST /login HTTP/1.1" 405 -
127.0.0.1 - - [10/May/2022 05:37:55] "{"username":"foo","password":"bar"}OPTIONS /login HTTP/1.1" 405 -
This is greatly simplified, but is enough to produce the expected error.
However, this Flask code does not generate the same error:
#app.route("/login", methods=["POST"])
def login():
print(request.json['username'])
return jsonify({'success': True})
And term output:
127.0.0.1 - - [10/May/2022 05:58:54] "POST /login HTTP/1.1" 200 -
127.0.0.1 - - [10/May/2022 06:08:16] "OPTIONS /login HTTP/1.1" 200 -
foo
127.0.0.1 - - [10/May/2022 06:08:16] "POST /login HTTP/1.1" 200 -
foo
127.0.0.1 - - [10/May/2022 06:08:16] "POST /login HTTP/1.1" 200 -
foo
I realize this is a stupid scenario, because when wouldn't you actually use the data? I just ran into this while tinkering and lost an hour figuring out why it was throwing the error.
My question is: Why does it throw a 405 error and what is the actual difference? Does the data persist between requests if you don't access it? Is this intended functionality, and is there documentation that covers this?
This was fixed in Werkzeug 2.1.2: https://github.com/pallets/werkzeug/issues/2397

Cherrypy logingg POST body

I'am using default cherrypy logger.
I have log every access request to my server. For GET request i have full info, like
127.0.0.1 - - [06/Jul/2021:16:10:28] "GET /test/?contract_id=228322 HTTP/1.0" 200 33
But for POST request i can't log query params or body.
127.0.0.1 - - [06/Jul/2021:13:21:03] "POST /test HTTP/1.0" 201 169
So how can i log POST query's body?
You can create tool like
def response_logging():
cherrypy.log.access_log.info(
'[{time}] {ip} "{user_agent}" {request_line} "{query_params}" "{body}" "{status}" {response}'.format(
time=datetime.now().strftime("%d/%m/%Y:%H:%M:%S"),
ip=cherrypy.request.remote.ip,
user_agent=cherrypy.request.headers["User-Agent"],
request_line=cherrypy.request.request_line,
query_params=cherrypy.request.body.request_params or "",
body=cherrypy.request.json if hasattr(cherrypy.request, "json") else "",
status=cherrypy.response.status,
response=cherrypy.response.body
)
)
cherrypy.tools.response_logging = cherrypy.Tool('on_end_request', response_logging)
print(cherrypy.request.params) # Prints params on querystring
print(cherrypy.request.headers) # Prints received headers on request
print(cherrypy.request.body) # Prints Body received

Why does my python HttpServer dump all received requests on close?

I have the following request handler:
class MyHandler(BaseHTTPRequestHandler):
def do_POST(self) -> None:
if self.path == "/myRoute":
self.handle_route()
def handle_route(self):
print("Handling /myRoute")
received_bytes = self.rfile.read(int(self.headers['Content-Length']))
data = json.loads(received_bytes.decode('utf8').replace("'", '"'))
logger.info(json.dumps(data, indent=4, sort_keys=True))
self.send_response(200)
self.send_header("Content-Type", "application/json")
self.end_headers()
self.wfile.write(bytes("{\"Success\":true,\"Exception\":\"\"}", "utf-8"))
I am successfully handling POSTs to the route /myRoute. However, when I close after the following usage:
my_server = server.HTTPServer(("localhost", 8080), MyHandler)
my_thread = threading.Thread(target=my_server.serve_forever)
my_thread.daemon = True
my_thread.start()
# do some work
my_server.server_close()
I see a "dump" of all the POSTs received. This makes me think I am not properly flushing my response(s) back to the client:
127.0.0.1 - - [04/Aug/2020 12:01:58] "POST /myRoute HTTP/1.1" 200 -
127.0.0.1 - - [04/Aug/2020 12:02:35] "POST /myRoute HTTP/1.1" 200 -
127.0.0.1 - - [04/Aug/2020 12:03:11] "POST /myRoute HTTP/1.1" 200 -
.
.
.
What makes me think this even more is that it is the same number of requests I received during the execution of my application.
Am I properly sending my responses back to the client?
To fix this, I simply overrided the BaseHttpRequestHandler.log_message() to do nothing:
def log_message(self, format: str, *args: Any) -> None:
"""
Override of BaseHTTPRequestHandler to skip logging of messages.
Parameters
----------
format: str
The str format.
args: Any
The values to log.
"""
Then I only logged what I was interested in via the typical logger = logging.getLogger(__name__) in my route handling methods.

Send a request with Django view using Python-Requests

I'm trying to create a simple microservice structure on my Django projecjt: so when a certain Django view is called, this view will send a JSON post request to a Flask microservice containing some user's data; the Flask microservice should receive the request, take that user's data and send back to Django some additional data using Requests again, so that my Django view can receive that data and perform some operations, such as showing it to the user.
Right now i'm just sending some dummy data, to test if this whole system ( Django > request to Flask > Flask > Request to Django) works, but i'm having some problems.
To debug my code, i'm trying to just print the received data. Here is my view:
def myView(request):
mydict = {}
# The request is sent to my external Python script..
req = requests.post('http://127.0.0.1:5000/', json={"one": 1}) # Some dummy data
# .. Once the external script sends back a request with data, this should handle it
if request.method == 'POST':
# The data is inside this variable
data = request.POST
for key in data.items():
if float(key[1]) > 0:
mydict.update({key[0]: key[1]})
print(mydict) #FIRST PRINT STATEMENT
print(mydict) #SECOND PRINT STATEMENT
response = HttpResponse(get_token(request))
return JsonResponse(mydict) #RETURNS "{}"
And here is how my Flask app sends data (once it receives the POST request from the Django view) using the Python-Requests library:
#app.route("/", methods=["GET","POST"])
def test():
# After the request from the VIEW is received, a request containing some random json data
# is sent to Django
url = 'http://127.0.0.1:8000/myView/'
client = requests.session()
# We need to get the CSRF token, in order for the request to be taken by Django
csrftoken = requests.get(url).cookies['csrftoken']
data = {"two": 2}
header = {'X-CSRFToken': csrftoken}
cookies = {'csrftoken': csrftoken}
resp = requests.post(url, data=data, headers=header, cookies=cookies)
# Let's seend the request to Django
return f"Test!"
Here is what's wrong with my code:
METHOD: POST
{'two': 2}
[10/Jan/2020 10:41:37] "POST /myView/ HTTP/1.1" 200 320
{}
[10/Jan/2020 10:41:37] "GET /myView/ HTTP/1.1" 200 2
Here is what's wrong:
Why does the first print statement return the correct data and why doesn't the second print? And why does return JsonResponse return an empty dictionary?
I tried to add print('METHOD: ', request.method) in the first lines of the view, here is what happened:
METHOD: GET
METHOD: GET
[10/Jan/2020 10:46:22] "GET /myView/ HTTP/1.1" 200 2
METHOD: POST
[10/Jan/2020 10:46:26] "POST /myView/ HTTP/1.1" 200 320
[10/Jan/2020 10:46:26] "GET /myView/ HTTP/1.1" 200 2
You're flask view can be simplified to just return the required data
#app.route("/", methods=["GET","POST"])
def test():
return {"two": 2}
Then you can use the data in the Django view after you have made the request to flask
response = requests.post('http://127.0.0.1:5000/', json={"one": 1})
print(response.json()) # This should contain the returned data

Why does Flask redirect to "GET /? HTTP/1.1"

I'm writing a simple Flask application in which I want to send some data from the front-end to the Flask app, have it perform some operations, and return new data to the front-end for display. I have made similar applications before, and by returning the POST response object, instead of render_template(), I'm able to simply return the data and do what I want with it on the front-end. However, this time I'm having problems.
I make a POST request from the Jquery in the front-end. Everything seems to work fine, I can see the data being returned in the browser console, except the page reloads before I can display the new data. It reloads to http://xxx.x.x.x:5000/?.
I can see the get request for /? in the Flask console. I'd like to know why it is doing this, and how I can get it to stop.
(I've found this difficult to research because most search engines will silently ignore any question marks in a query.)
Flask app:
import json
from flask import Flask, Response, render_template, request
from src.simple_lookup import analogy_lookup
app = Flask(__name__)
app.config['DEBUG'] = True
#app.route('/')
def hello_world():
return render_template('index.html', results=['a', 'b'])
#app.route('/get_words_simple', methods=['POST'])
def get_words_simple():
print('request.form:', request.form.keys)
data = analogy_lookup(request.form['keyword'], request.form['base'], request.form['goal'])
resp = Response(json.dumps(data), status=200, mimetype='application/json')
print('data:', data)
print('resp:', resp)
return resp
if __name__ == "__main__":
app.run()
Jquery:
$.post('get_words_simple?', data, function(json, status) {
console.log('response:', json);
if (json.hasOwnProperty('error')) {
$('.results').append('<p>' + json.error);
return;
}
var words = json.words;
$.each(words, function(i, text) {
var p = $("<p>");
p.append(text);
$('.results').append(p);
});
});
Flask console:
127.0.0.1 - - [27/Dec/2018 11:12:21] "GET / HTTP/1.1" 200 -
127.0.0.1 - - [27/Dec/2018 11:12:21] "GET /static/js/main.js HTTP/1.1" 200 -
request.form: <bound method MultiDict.keys of ImmutableMultiDict([('keyword', ''), ('base', ''), ('goal', '')])>
127.0.0.1 - - [27/Dec/2018 11:12:23] "GET /? HTTP/1.1" 200 -
127.0.0.1 - - [27/Dec/2018 11:12:23] "GET /static/js/main.js HTTP/1.1" 200 -
data: ['obtuvo', 'takata', 'stadshypotek', 'kriwet', 'shafiee', 'martorell', 'collum', '29,400', 'muteesa', 'patzek']
resp: <Response 111 bytes [200 OK]>
127.0.0.1 - - [27/Dec/2018 11:12:23] "POST /get_words_simple? HTTP/1.1" 200 -
Problem was that Bootstrap overrides type="submit" button functionality if it's in a form group. So my Jquery was doing everything right, but something about the html of the button was screwing everything up and trying to make a post request in a different way

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