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Django: ConnectionResetError: [Errno 54]

This logs, quite repeatedly, every time my app loads on my computer.
Exception happened during processing of request from ('127.0.0.1', 53597)
Traceback (most recent call last):
File "/usr/local/Cellar/python#3.8/3.8.6/Frameworks/Python.framework/Versions/3.8/lib/python3.8/socketserver.py", line 650, in process_request_thread
self.finish_request(request, client_address)
File "/usr/local/Cellar/python#3.8/3.8.6/Frameworks/Python.framework/Versions/3.8/lib/python3.8/socketserver.py", line 360, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/usr/local/Cellar/python#3.8/3.8.6/Frameworks/Python.framework/Versions/3.8/lib/python3.8/socketserver.py", line 720, in __init__
self.handle()
File "/usr/local/lib/python3.8/site-packages/django/core/servers/basehttp.py", line 174, in handle
self.handle_one_request()
File "/usr/local/lib/python3.8/site-packages/django/core/servers/basehttp.py", line 182, in handle_one_request
self.raw_requestline = self.rfile.readline(65537)
File "/usr/local/Cellar/python#3.8/3.8.6/Frameworks/Python.framework/Versions/3.8/lib/python3.8/socket.py", line 669, in readinto
return self._sock.recv_into(b)
ConnectionResetError: [Errno 54] Connection reset by peer
I realize that this has been posted on extensively over the years, but it seems to me that the consensus on the answer is that it could be one of a few things:
(a) Using a .png instead of an .ico in a favicon
(b) Misusing {% static %}
(c) Misusing event.preventDefault()
Unfortunately for me, none of those things have happened in the last few weeks in my teams commits. So I ask, are there other solutions I may be missing? This is a result of me recently merging with a master development branch.

As I mentioned over here, I had this issue show up while debugging POST DRF api endpoints.
The solution was to add SITE_URL to settings with my localhost and dev server port set, i.e.
SITE_URL = "http://localhost:4000"
Commonly this error is associated with a missing favicon file. But I'm not sure if this change gets around that issue or is due to something else.
For added context, I hit this error while using Pycharm's http request scratch file to debug and validate DRF (django rest framework) endpoints.
The format I was using was:
### Send POST request with json body
POST http://localhost:4000/api/admin/add_node/
Content-Type: application/json
Authorization: Basic admin password
{
"name": "node01",
"username": "username",
"password": "password"
}

Error when serving html with WSGI

I am trying to make an application that serves a simple HTML form to the user and then calls a function when the user submits the form. It uses wsgiref.simple_server to serve the HTML. The server is encountering an error and I can't understand why. The code is as follows:
#!/usr/bin/python3
from wsgiref.simple_server import make_server
from wsgiref.util import setup_testing_defaults
import webbrowser # open user's web browser to url when server is run
from sys import exc_info
from traceback import format_tb
# Easily serves an html form at path_to_index with style at path_to_style
# Calls on_submit when the form is submitted, passing a dictionary with key
# value pairs { "input name" : submitted_value }
class SimpleServer:
def __init__(self, port=8000, on_submit=None, index_path="./index.html", css_path="./style.css"):
self.port = port
self.on_submit = on_submit
self.index_path = index_path
self.css_path = css_path
# Forwards request to proper method, or returns 404 page
def wsgi_app(self, environ, start_response):
urls = [
(r"^$", self.index),
(r"404$", self.error_404),
(r"style.css$", self.css)
]
path = environ.get("PATH_INFO", "").lstrip("/")
# Call another application if they called a path defined in urls
for regex, application in urls:
match = re.search(regex, path)
# if the match was found, return that page
if match:
environ["myapp.url_args"] = match.groups()
return application(environ, start_response)
return error_404(environ, start_response)
# Gives the user a form to submit all their input. If the form has been
# submitted, it sends the ouput of self.on_submit(user_input)
def index(self, environ, start_response):
# user_input is a dictionary, with keys from the names of the fields
user_input = parse_qs(environ['QUERY_STRING'])
# return either the form or the calculations
index_html = open(self.index_path).read()
body = index_html if user_input == {} else calculate(user_input)
mime_type = "text/html" if user_input == {} else "text/plain"
# return the body of the message
status = "200 OK"
headers = [ ("Content-Type", mime_type),
("Content-Length", str(len(body))) ]
start_response(status, headers)
return [body.encode("utf-8")]
def start_form(self):
httpd = make_server('', self.port, ExceptionMiddleware(self.wsgi_app))
url = "http://localhost:" + str(self.port)
print("Visit " + url)
# webbrowser.open(url)
httpd.serve_forever()
if __name__ == "__main__":
server = SimpleServer()
server.start_form()
When I run it, I get the error
127.0.0.1 - - [16/Dec/2014 21:15:57] "GET / HTTP/1.1" 500 0
Traceback (most recent call last):
File "/usr/lib/python3.4/wsgiref/handlers.py", line 138, in run
self.finish_response()
File "/usr/lib/python3.4/wsgiref/handlers.py", line 180, in finish_response
self.write(data)
File "/usr/lib/python3.4/wsgiref/handlers.py", line 266, in write
"write() argument must be a bytes instance"
AssertionError: write() argument must be a bytes instance
127.0.0.1 - - [16/Dec/2014 21:15:57] "GET / HTTP/1.1" 500 59
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 49354)
Traceback (most recent call last):
File "/usr/lib/python3.4/wsgiref/handlers.py", line 138, in run
self.finish_response()
File "/usr/lib/python3.4/wsgiref/handlers.py", line 180, in finish_response
self.write(data)
File "/usr/lib/python3.4/wsgiref/handlers.py", line 266, in write
"write() argument must be a bytes instance"
AssertionError: write() argument must be a bytes instance
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3.4/wsgiref/handlers.py", line 141, in run
self.handle_error()
File "/usr/lib/python3.4/wsgiref/handlers.py", line 368, in handle_error
self.finish_response()
File "/usr/lib/python3.4/wsgiref/handlers.py", line 180, in finish_response
self.write(data)
File "/usr/lib/python3.4/wsgiref/handlers.py", line 274, in write
self.send_headers()
File "/usr/lib/python3.4/wsgiref/handlers.py", line 331, in send_headers
if not self.origin_server or self.client_is_modern():
File "/usr/lib/python3.4/wsgiref/handlers.py", line 344, in client_is_modern
return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
TypeError: 'NoneType' object is not subscriptable
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3.4/socketserver.py", line 305, in _handle_request_noblock
self.process_request(request, client_address)
File "/usr/lib/python3.4/socketserver.py", line 331, in process_request
self.finish_request(request, client_address)
File "/usr/lib/python3.4/socketserver.py", line 344, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/usr/lib/python3.4/socketserver.py", line 669, in __init__
self.handle()
File "/usr/lib/python3.4/wsgiref/simple_server.py", line 133, in handle
handler.run(self.server.get_app())
File "/usr/lib/python3.4/wsgiref/handlers.py", line 144, in run
self.close()
File "/usr/lib/python3.4/wsgiref/simple_server.py", line 35, in close
self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'
This output doesn't actually include the script I am running, which I am confused about. Any thoughts?

Just to register the solution for this issue, the problem is with len() function.
str(len(body))
It calculate the wrong size and when return the server Content-Length, then it wait more bytes that needed.
Thus, always send bytes using a buffer with UTF-8, follow example:
from io import StringIO
stdout = StringIO()
print("Hello world!", file=stdout)
start_response("200 OK", [('Content-Type', 'text/plain; charset=utf-8')])
return [stdout.getvalue().encode("utf-8")]

Looking at your code I don't see a direct reason for this error. However, I would strongly advise that unless you're trying to learn how wsgi works (or implement your own framework), you should use an existing micro-framework. WSGI is NOT meant to be used directly by applications. It provides a very thin interface between Python and a web server.
A nice and light framework is bottle.py -- I use it for all Python webapps. But there are many many others, look for "Non Full-Stack Frameworks" in https://wiki.python.org/moin/WebFrameworks.
A nice advantage of bottle is that it's a single file, which makes it easy to distribute with your server.

Broken pipe during stream

I have a project with Django I am working on where I want to stream some mp3 files.
I have this same issue:
Streaming mp3 files with django, read from a page with <audio>
Let me explain: I want stream an ogg with Django, and with an <audio> tag in my html page
I have a url like domain.tld/song/show/X/, where X is the id of my song.
I can stream with VLC (directly with the file path), I can stream during test, (I write what I receive and read it with VLC).
But when I open my browser and load my home page domain.tld where I have and <\audio\> balise with url domain.tld/song/show/1/, I get a big broken pipe, as if my client closed the connection.
I read on others post that some problems was resolved when they put server in production. So I push my app on server, use apache, with the django.wgsi like on djangoproject.com.
I am running python 2.7.3 on Debian 7 with Django version 1.5.
there my code:
Song/views.py
def playAudioFile(request, pk):
f = get_stream_song(pk)# return a pipe from pipes.Template
l = f.read() # the file is an ogg get by pydub.com
f.close()
size_read = 550000
sr = size_read
while sr == size_read:
print "rep"
r = l[:size_read]
l=l[size_read:]
sr = len(r)
yield r
time.sleep(0.1)
#url : ~/song/show/X/
##login_required
def show_song(request, pk):
return StreamingHttpResponse(playAudioFile(request, pk), mimetype='audio/ogg',)
In my HTML, I just have that:
<audio controls height="100" width="100" preload="auto">
<source src="/.../song/show/1/" type="audio/ogg">
<embed height="50" width="100" src="/.../song/show/1/">
</audio>
The error looks like:
Traceback (most recent call last):
File "/usr/lib/python2.7/wsgiref/handlers.py", line 86, in run
self.finish_response()
File "/usr/lib/python2.7/wsgiref/handlers.py", line 127, in finish_response
self.write(data)
File "/usr/lib/python2.7/wsgiref/handlers.py", line 215, in write
self._write(data)
File "/usr/lib/python2.7/socket.py", line 324, in write
self.flush()
File "/usr/lib/python2.7/socket.py", line 303, in flush
self._sock.sendall(view[write_offset:write_offset+buffer_size])
error: [Errno 104] Connection reset by peer
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 46392)
Traceback (most recent call last):
File "/usr/lib/python2.7/SocketServer.py", line 593, in process_request_thread
self.finish_request(request, client_address)
File "/usr/lib/python2.7/SocketServer.py", line 334, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/home/lumy/SPhoque/SonoPhoque/SoPhoque/local/lib/python2.7/site-packages/django/core/servers/basehttp.py", line 150, in __init__
super(WSGIRequestHandler, self).__init__(*args, **kwargs)
File "/usr/lib/python2.7/SocketServer.py", line 651, in __init__
self.finish()
File "/usr/lib/python2.7/SocketServer.py", line 704, in finish
self.wfile.flush()
File "/usr/lib/python2.7/socket.py", line 303, in flush
self._sock.sendall(view[write_offset:write_offset+buffer_size])
error: [Errno 32] Broken pipe
I got this twice each time I try to stream.
Edit 15h 29/05:
I did what rahan suggested:
Looking at Firebug and Firefox debugger:
The client does:
GET 1 200 OK localhost:8000 537.1KB 4.71s
Headers
Response Headersview source
Date Wed, 29 May 2013 13:08:54 GMT
Server WSGIServer/0.1 Python/2.7.3
Content-Type audio/ogg
Request Headersview source
Host localhost:8000
User-Agent Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20100101 Firefox/10.0.12 Iceweasel/10.0.12
Accept audio/webm,audio/ogg,audio/wav,audio/*;q=0.9,application/ogg;q=0.7,video/*;q=0.6,*/*;q=0.5
Accept-Language en-us,en;q=0.5
Connection keep-alive
Range bytes=0-
Referer http://localhost:8000/
and details say that the total size for all documents is 1 MB (526 KB from cache)

May be I am crossing your existing solution, i have a suggestion, for mp3 streaming use nginx/apache server, these days there is solution known as sendfile, for example in your case on django view
def send_file_header(server_type):
header = "X-Sendfile" if server_type == "apache" else "X-Accel-Redirect"
return header
#login_required
def show_song(request, pk):
res = HttpResponse()
path = "/path/to/secret/x.mp3"
response[send_file_header('nginx')] = path
response['Content-Type']= "application/octet-stream"
response['Content-Disposition'] = "attachment; filename=\"x.mp3\""
return response

Python BaseHTTPServer, how do I catch/trap "broken pipe" errors?

I build a short url translator engine in Python, and I'm seeing a TON of "broken pipe" errors, and I'm curious how to trap it best when using the BaseHTTPServer classes. This isn't the entire code, but gives you an idea of what I'm doing so far:
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
import memcache
class clientThread(BaseHTTPRequestHandler):
def do_GET(self):
content = None
http_code,response_txt,long_url = \
self.ag_trans_url(self.path,content,'GET')
self.http_output( http_code, response_txt, long_url )
return
def http_output(self,http_code,response_txt,long_url):
self.send_response(http_code)
self.send_header('Content-type','text/plain')
if long_url:
self.send_header('Location', long_url)
self.end_headers()
if response_txt:
self.wfile.write(response_txt)
return
def ag_trans_url(self, orig_short_url, post_action, getpost):
short_url = 'http://foo.co' + orig_short_url
# fetch it from memcache
long_url = mc.get(short_url)
# other magic happens to look it up from db if there was nothing
# in memcache, etc
return (302, None, log_url)
def populate_memcache()
# connect to db, do lots of mc.set() calls
def main():
populate_memcache()
try:
port = 8001
if len(sys.argv) > 1:
port = int(sys.argv[1])
server = HTTPServer(('',port), clientThread)
#server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
print '[',str(datetime.datetime.now()),'] short url processing has begun'
server.serve_forever()
except KeyboardInterrupt,SystemExit:
print '^C received, shutting down server'
server.socket.close()
The code itself works great, but started throwing errors almost immediately when in production:
Traceback (most recent call last):
File "/usr/lib/python2.5/SocketServer.py", line 222, in handle_request
self.process_request(request, client_address)
File "/usr/lib/python2.5/SocketServer.py", line 241, in process_request
self.finish_request(request, client_address)
File "/usr/lib/python2.5/SocketServer.py", line 254, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/usr/lib/python2.5/SocketServer.py", line 522, in __init__
self.handle()
File "/usr/lib/python2.5/BaseHTTPServer.py", line 316, in handle
self.handle_one_request()
File "/usr/lib/python2.5/BaseHTTPServer.py", line 310, in handle_one_request
method()
File "/opt/short_url_redirector/shorturl.py", line 38, in do_GET
self.http_output( http_code, response_txt, long_url )
File "/opt/short_url_redirector/shorturl.py", line 52, in http_output
self.send_response(http_code)
File "/usr/lib/python2.5/BaseHTTPServer.py", line 370, in send_response
self.send_header('Server', self.version_string())
File "/usr/lib/python2.5/BaseHTTPServer.py", line 376, in send_header
self.wfile.write("%s: %s\r\n" % (keyword, value))
File "/usr/lib/python2.5/socket.py", line 274, in write
self.flush()
File "/usr/lib/python2.5/socket.py", line 261, in flush
self._sock.sendall(buffer)
error: (32, 'Broken pipe')
The bulk of these errors seem to stem from having a problem calling the send_header() method where all I'm writing out is this:
self.send_header('Location', long_url)
So I'm curious where in my code to try to trap for this IO exception... do I write try/except calls around each of the self.send_header/self.end_headers/self.wfile.write calls? The other error I see from time to time is this one, but not sure which exception to watch to even catch this:
Traceback (most recent call last):
File "/usr/lib/python2.5/SocketServer.py", line 222, in handle_request
self.process_request(request, client_address)
File "/usr/lib/python2.5/SocketServer.py", line 241, in process_request
self.finish_request(request, client_address)
File "/usr/lib/python2.5/SocketServer.py", line 254, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/usr/lib/python2.5/SocketServer.py", line 522, in __init__
self.handle()
File "/usr/lib/python2.5/BaseHTTPServer.py", line 316, in handle
self.handle_one_request()
File "/usr/lib/python2.5/BaseHTTPServer.py", line 299, in handle_one_request
self.raw_requestline = self.rfile.readline()
File "/usr/lib/python2.5/socket.py", line 381, in readline
data = self._sock.recv(self._rbufsize)
error: (104, 'Connection reset by peer')

This appears to be a bug in SocketServer, see this link Python Bug: 14574
A fix (works for me in Python 2.7) is to override the SocketServer.StreamRequestHandler finish() method, something like this:
...
def finish(self,*args,**kw):
try:
if not self.wfile.closed:
self.wfile.flush()
self.wfile.close()
except socket.error:
pass
self.rfile.close()
#Don't call the base class finish() method as it does the above
#return SocketServer.StreamRequestHandler.finish(self)

The "broken pipe" exception means that your code tried to write to a socket/pipe which the other end has closed. If the other end is a web browser, the user could have stopped the request. You can ignore the traceback; it does not indicate a serious problem. If you want to suppress the message, you can put a try ... except block around all of the code in your http_output function, and log the exception if you like.
Additionally, if you want your HTTP server to process more than one request at a time, you need your server class to use one of the SocketServer.ForkingMixIn and SocketServer.ThreadingMixIn classes. Check the documentation of the SocketServer module for details.
Add: The "connection reset by peer" exception means that your code tried to read from a dead socket. If you want to suppress the traceback, you will need to extend the BaseHTTPServer class and override the handle_one_request method to add a try ... except block. You will need a new server class anyway, to implement the earlier suggestion about processing more than one request at a time.

In my application, the error didn't occur in finish(), it occurred in handle(). This fix catches the broken pipe errors:
class MyHTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
...
def handle(self):
try:
BaseHTTPServer.BaseHTTPRequestHandler.handle(self)
except socket.error:
pass

Pymongo AssertionError: ids don't match

I use:
MongoDB 1.6.5
Pymongo 1.9
Python 2.6.6
I have 3 types of daemons. 1st load data from web, 2nd analyze it and save result, and 3rd group result. All of them working with Mongodb.
At some time 3rd daemon throws many exceptions like this(mostly when there are big amount of data in DB):
Traceback (most recent call last):
File "/usr/local/lib/python2.6/dist-packages/gevent-0.13.1-py2.6-linux-x86_64.egg/gevent/greenlet.py", line 405, in run
result = self._run(*self.args, **self.kwargs)
File "/data/www/spider/daemon/scripts/mainconverter.py", line 72, in work
for item in res:
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/cursor.py", line 601, in next
if len(self.__data) or self._refresh():
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/cursor.py", line 564, in _refresh
self.__query_spec(), self.__fields))
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/cursor.py", line 521, in __send_message
**kwargs)
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/connection.py", line 743, in _send_message_with_response
return self.__send_and_receive(message, sock)
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/connection.py", line 724, in __send_and_receive
return self.__receive_message_on_socket(1, request_id, sock)
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/connection.py", line 714, in __receive_message_on_socket
struct.unpack("<i", header[8:12])[0])
AssertionError: ids don't match -561338340 0
<Greenlet at 0x2baa628: <bound method Worker.work of <scripts.mainconverter.Worker object at 0x2ba8450>>> failed with AssertionError
Can anyone tell what cause this exeption and how to fix this.
Thanks.

This is likely a threading problem related to how you are using worker threads with gevent coroutines. It seems like the pymongo connection object is reading a response for a request it didn't make.