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Replacing Python requests with tornado HTTPclient doesn't work with basic auth

There is a simple code on Python using requests module to make 1 get request with basic authorization. It works.
Then raised a need to rewrite this code to use tornado HTTP client. It doesn't work. Server returns 500 code. I tried HTTP client and AsyncHTTP client, both doesn't work.
Also I have other request, it need authorization token instead of basic auth and it works with Tornado AsyncHTTP client
Here is working and non-working examples with logs. Could you please help to find the reason of error? HTTP logs are quite similar, I don't see any substant difference. I tried to check non-working example without headers Connection and Content-Length, nothing changed.
I deleted from examples password, user name and host name, but I ckecked a lot of times they are identical in working and non-working examples.
Working example:
import requests
from requests.auth import HTTPBasicAuth
url = "http://myhost:81/oapi/GetDate/4rnm"
details_ = requests.get(url, headers={'x-app-id': "kav_test"}, timeout=30, auth=HTTPBasicAuth("user", "login"))
Log from working example:
DEBUG:urllib3.connectionpool:Starting new HTTP connection (1): myhost
send: b'GET /oapi/GetDate/4rnm HTTP/1.1\r\nHost: myhost:81\r\nUser-Agent: python-requests/2.18.4\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nConnection: keep-alive\r\nx-app-id: kav_test\r\nAuthorization: Basic foo==\r\n\r\n'
reply: 'HTTP/1.1 200 OK\r\n'
DEBUG:urllib3.connectionpool:myhost:81 "GET /oapi/GetDate/4rnm HTTP/1.1" 200 None
header: Transfer-Encoding header: Content-Type header: Server header: Access-Control-Allow-Origin header: Access-Control-Allow-Headers header: Access-Control-Allow-Credentials header: Access-Control-Allow-Methods header: Access-Control-Max-Age header: Set-Cookie header: Date {"date":"2021-01-01","hasErrors":false,"errors":[]}
non-working example:
from tornado import httpclient, ioloop
http_client_ = httpclient.AsyncHTTPClient()
...
url = "http://myhost:81/oapi/GetDate/4rnm"
response = await http_client_.fetch(url, method='GET', auth_username="user", auth_password="login", headers={'x-app-id': "test", "Connection": "keep-alive", "Content-Length": "0"}
Log from non-working example:
There is an error Host not found in the end, but I don't understand why, because on the top of log there is a connection with the the host.
DEBUG:asyncio:Using selector: SelectSelector
DEBUG:tornado.curl_httpclient:GET myhost:81/oapi/GetDate/4rnm (username: 'foo')
DEBUG:tornado.curl_httpclient:Trying myip...
DEBUG:tornado.curl_httpclient:TCP_NODELAY set
DEBUG:tornado.curl_httpclient:Connected to myhost (myip) port 81 (#0)
DEBUG:tornado.curl_httpclient:Server auth using Basic with user 'foo'
DEBUG:tornado.curl_httpclient:> GET /oapi/GetDate/4rnm HTTP/1.1
DEBUG:tornado.curl_httpclient:> Host: myhost:81
DEBUG:tornado.curl_httpclient:> Authorization: Basic foo==
DEBUG:tornado.curl_httpclient:> User-Agent: Mozilla/5.0 (compatible; pycurl)
DEBUG:tornado.curl_httpclient:> Accept: */*
DEBUG:tornado.curl_httpclient:> Accept-Encoding: gzip,deflate
DEBUG:tornado.curl_httpclient:> X-App-Id: kav_test
DEBUG:tornado.curl_httpclient:> Connection: keep-alive
DEBUG:tornado.curl_httpclient:> Content-Length: 0
DEBUG:tornado.curl_httpclient:>
Traceback (most recent call last):
DEBUG:tornado.curl_httpclient:< HTTP/1.1 500 Internal Server Error
DEBUG:tornado.curl_httpclient:< Transfer-Encoding: chunked
DEBUG:tornado.curl_httpclient:< Content-Type: application/json
tornado.httpclient.HTTPClientError: HTTP 500: Internal Server Error
DEBUG:tornado.curl_httpclient:< X-Error-Msg:
Host (myhost:81) not found.
(x-local://wtv/wtv_tools_web.xml, line 5689)
(x-local://wtv/wtv_tools_web.xml, line 6149)
(user_init(), wt\web\openapi.html, line 976)
(Authorize(), wt\web\openapi.html, line 896)
(wt\web\openapi.html, line 1079)

Flask-SocketIO socket fails to connect and continuously re-attempts

I have an app that's outputting a JSON through a socket which was working fine in the past, however recently the socket doesn't seem to be establishing and it continuously POST & GET's with the lines:
<user_ip>,<client_ip> - - [17/Jul/2018 12:48:17]"GET /socket.io/?EIO=3&transport=polling......HTTP/1.1" 200 221 0.000000
<user_ip>,<client_ip> - - [17/Jul/2018 12:48:17]"POST /socket.io/?EIO=3&transport=polling......HTTP/1.1" 200 243 0.517600
Additionally, when the WebSocket first tries, I can see from Chromes console the message:
WebSocket connection to ..... failed: Establishing a tunnel via proxy server failed.
I've also had a look through what I think is a similar issue based on socketIO-client but wasn't able to resolve my problem.
Can anyone help with overcoming this connection issue?
Included a full log on running the app below:
Server initialized for eventlet.
* Debugger is active!
* Debugger PIN: 129-744-633
(7616) wsgi starting up on http://0.0.0.0:6328
(7616) accepted (<client_ip>, 50548)
<user_ip>,<client_ip> - - [17/Jul/2018 13:18:23] "GET /<app_url> HTTP/1.1" 200 1664 0.015000
3602c46fa50247eb9d397fda82f3eae8: Sending packet OPEN data {'sid': '3602c46fa50247eb9d397fda82f3eae8', 'upgrades': ['websocket'], 'pingTimeout': 60000, 'pingInterval': 25000}
3602c46fa50247eb9d397fda82f3eae8: Sending packet MESSAGE data 0
<user_ip>,<client_ip> - - [17/Jul/2018 13:18:23] "GET /socket.io/?EIO=3&transport=polling&t=1531829903367-0 HTTP/1.1" 200 381 0.000000
(7616) accepted (<client_ip>, 50560)
3602c46fa50247eb9d397fda82f3eae8: Received packet MESSAGE data 0/testnamespace
3602c46fa50247eb9d397fda82f3eae8: Sending packet MESSAGE data 0/testnamespace
<user_ip>,<client_ip> - - [17/Jul/2018 13:18:23] "POST /socket.io/?EIO=3&transport=polling&t=1531829903377-1&sid=3602c46fa50247eb9d397fda82f3eae8 HTTP/1.1" 200 221 0.000000
<user_ip>,<client_ip> - - [17/Jul/2018 13:18:23] "GET /socket.io/?EIO=3&transport=polling&t=1531829903379-2&sid=3602c46fa50247eb9d397fda82f3eae8 HTTP/1.1" 200 226 0.000000
(7616) accepted (<client_ip>, 50562)
3602c46fa50247eb9d397fda82f3eae8: Received packet MESSAGE data 2/testnamespace,["event_1",{"data":"Web app connection successful."}]
3602c46fa50247eb9d397fda82f3eae8: Sending packet MESSAGE data 2/testnamespace,["client_event",{"json":[{"Date&Time":"........}]

Requests Library Force Use of HTTP/1.1 On HTTPS Proxy CONNECT

I am having a problem with a misbehaving HTTP Proxy server. I have no control over the proxy server, unfortunately -- it's an 'enterprise' product from IBM. The proxy server is part of a service virtualization solution being leveraged for software testing.
The fundamental issue (I think*) is that the proxy server sends back HTTP/1.0 responses. I can get it to work fine from SOAP UI ( A Java application) and curl from the command line, but Python refuses to connect. From what I can tell, Python is behaving correctly, and the other two are not, as the server expects HTTP/1.1 responses (it wants Host headers, at the very least, to route the service request to a given stub).
Is there a way to get Requests, or the underlying urllib3, or the even farther down http lib to always use http1.1, even if the other end appears to be using 1.0?
Here is a sample program (unfortunately, it requires you to have an IBM Ration Integration Tester installation with RTCP to really replicate) to reproduce the problem:
import http.client as http_client
http_client.HTTPConnection.debuglevel = 1
import logging
import requests
logging.basicConfig()
logging.getLogger().setLevel(logging.DEBUG)
requests_log = logging.getLogger("requests.packages.urllib3")
requests_log.setLevel(logging.DEBUG)
requests_log.propagate = True
requests.post("https://host:8443/axl",
headers={"soapAction": '"CUCM:DB ver=9.1 updateSipTrunk"'},
data='<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tns="http://www.cisco.com/AXL/API/9.1"><soapenv:Header/><soapenv:Body><tns:updateSipTrunk><name>PLACEHOLDER</name><newName>PLACEHOLDER</newName><destinations><destination><addressIpv4>10.10.1.5</addressIpv4><sortOrder>1</sortOrder></destination></destinations></tns:updateSipTrunk></soapenv:Body></soapenv:Envelope>',
verify=False)
(Proxy is configured via HTTPS_PROXY environment variable)
Debug output before the error, note the HTTP/1.0:
INFO:requests.packages.urllib3.connectionpool:Starting new HTTPS connection (1): host.com
send: b'CONNECT host.com:8443 HTTP/1.0\r\n'
send: b'\r\n'
header: Host: host.com:8443
header: Proxy-agent: Green Hat HTTPS Proxy/1.0
The exact error text that occurs in RHEL 6 is:
requests.exceptions.SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] sslv3 alert handshake failure (_ssl.c:646)
Even though the Host header is shown here, it does NOT show up on the wire. I confirmed this with a tcpdump:
14:03:14.315049 IP sourcehost.53214 > desthost.com: Flags [P.], seq 0:32, ack 1, win 115, options [nop,nop,TS val 2743933964 ecr 4116114841], length 32
0x0000: 0000 0c07 ac00 0050 56b5 4044 0800 4500 .......PV.#D..E.
0x0010: 0054 3404 4000 4006 2ca0 0af8 3f15 0afb .T4.#.#.,...?...
0x0020: 84f8 cfde 0c7f a4f8 280a 4ebd b425 8018 ........(.N..%..
0x0030: 0073 da46 0000 0101 080a a38d 1c0c f556 .s.F...........V
0x0040: XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX ..CONNECT.host
0x0050: XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX xx:8443.HTTP/1.0
0x0060: 0d0a
When I curl it with verbose, this is what the output looks like:
* About to connect() to proxy proxy-host.com port 3199 (#0)
* Trying 10.**.**.** ... connected
* Connected to proxy-host.com (10.**.**.**) port 3199 (#0)
* Establish HTTP proxy tunnel to host.com:8443
> CONNECT host.com:8443 HTTP/1.1
> Host: host.com:8443
> User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.19.1 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2
> Proxy-Connection: Keep-Alive
> soapAction: "CUCM:DB ver=9.1 updateSipTrunk"
>
< HTTP/1.0 200 OK
< Host: host.com:8443
< Proxy-agent: Green Hat HTTPS Proxy/1.0
<
* Proxy replied OK to CONNECT request
* Initializing NSS with certpath: sql:/etc/pki/nssdb
* CAfile: /path/to/store/ca-bundle.crt
CApath: none
* SSL connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
Truncated after this point. You can see the HTTP/1.0 response from the proxy after connecting. The curl's tcpdump also clearly shows the host header, as well as HTTP 1.1.
*I can't be entirely sure this is the fundamental issue, as I can't test it. I do see HTTP/1.0 responses, and can tell that my non-working Python code sends CONNECT HTTP/1.0 messages, while the working Java sends HTTP/1.1 messages, as does Curl. It's possible the problem is unrelated (although I find that unlikely) or that Python is misbehaving, and not Java/curl. I simply don't know enough to know for sure.
So, is there a way to force urllib3/requests to use HTTP v1.1 at all times?

httplib (which requests relies upon for HTTP(S) heavy lifting) always uses HTTP/1.0 with CONNECT:
Lib/httplib.py:788:
def _tunnel(self):
self.send("CONNECT %s:%d HTTP/1.0\r\n" % (self._tunnel_host,
self._tunnel_port))
for header, value in self._tunnel_headers.iteritems():
self.send("%s: %s\r\n" % (header, value))
self.send("\r\n")
<...>
So you can't "force" it to use "HTTP/1.1" here other than by editing the subroutine.
This MAY be the problem if the proxy doesn't support HTTP/1.0 - in particular, 1.0 does not require a Host: header, and indeed, as you can see by comparing your log output with the code above, httplib does not send it. While, in verity, a proxy may expect it regardless. But if this is the case, you should've gotten an error from the proxy or something in response to CONNECT -- unless the proxy is so borken that it substitutes some default (or garbage) for Host:, returns 200 anyway and tries to connect God-knows-where, at which point you're getting timeouts.
You can make httplib add the Host: header to CONNECT by adding it to _tunnel_headers (indirectly):
s=requests.Session()
proxy_url=os.environ['HTTPS_PROXY']
s.proxies["https"]=proxy_url
# have to specify proxy here because env variable is only detected by httplib code
#while we need to trigger requests' proxy logic that acts earlier
# "https" means any https host. Since a Session persists cookies,
#it's meaningless to make requests to multiple hosts through it anyway.
pm=s.get_adapter("https://").proxy_manager_for(proxy_url)
pm.proxy_headers['Host']="host.com"
del pm,proxy_url
<...>
s.get('https://host.com')

If you do not depend on the requests library you may find the following snippet useful:
import http.client
conn = http.client.HTTPSConnection("proxy.domain.lu", 8080)
conn.set_tunnel("www.domain.org", 443, headers={'User-Agent': 'curl/7.56.0'})
conn.request("GET", "/api")
response = conn.getresponse()
print( response.read() )

How to connect a client to a server through an HTTP proxy in Python?

I'm really new to coding using sockets.
I like the socket library, I get to understand a big part of what's happening in my program, so i you don't mind i would like to stick with it.
So as the title says, I have a socket based client and server and I would like to exchange content through an HTTP proxy(I'm using a Squid proxy). This little piece of code is supposed to bypass the proxy in my campus to simulate a chat over the campus network. This is totally legal since I asked the IT guys that work there.
Here's the deal, I am able to send a POST request through the proxy to my server which receives it and sends it back to client 1, but when I try to send more requests to the proxy none of them gets to the server so I think to my self the connection died but here's the thing, when I send messages from client 2 which is connected directly to the server, the server AND client 1 receive them.
import socket
from _thread import *
def sender(server,h):
b=input("<<--Send--")
b=h
server.send(b.encode())
PROXY_IP="127.0.0.1"
PROXY_PORT=3128
server=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
server.settimeout(0.05)
server.connect((PROXY_IP,PROXY_PORT))
header="""POST http://127.0.0.1:3001 HTTP/1.1\r\n
Host: 127.0.0.1:3001\r\n
Proxy-Connection: keep-alive\r\n
Content-Length: 5 \r\n\r\n
hello\r\n"""
server.send(header.encode())
while 1:
try:
start_new_thread(sender,(server,header))
a=server.recv(1024)
print("-->>{}".format(a.decode()))
except KeyboardInterrupt:
break
except:
pass
server.close()
I already tried the CONNECT method which works perfectly, but it's not allowed in my campus network proxy.
What am I doing wrong ?
Is there something I should know about how to re-send content through a proxy ?
Thank you for your time and please bear with me..
Here's what I get on the client that sends a request to the proxy:
~#Sent : POST http://127.0.0.1:3001 HTTP/1.1
Host: 127.0.0.1:3001
Proxy-Connection: keep-alive
Content-Length: 5
hello
#Received : HTTP/1.1 200 OK
Server: squid/3.5.19
Mime-Version: 1.0
Date: Mon, 10 Oct 2016 00:46:39 GMT
X-Transformed-From: HTTP/0.9
X-Cache: MISS from kali
X-Cache-Lookup: MISS from kali:3128
Transfer-Encoding: chunked
Via: 1.1 kali (squid/3.5.19)
Connection: keep-alive
#Received : B2
POST / HTTP/1.1
Content-Length: 5
Host: 127.0.0.1:3001
Via: 1.1 kali (squid/3.5.19)
X-Forwarded-For: 127.0.0.1
Cache-Control: max-age=259200
Connection: keep-alive
hello
#Sent : POST http://127.0.0.1:3001 HTTP/1.1
Host: 127.0.0.1:3001
Proxy-Connection: keep-alive
Content-Length: 5
hello
Nothing is received after this..

POST http://127.0.0.1:3001 HTTP/1.1\r\n
Host: 127.0.0.1:3001\r\n
Proxy-Connection: keep-alive\r\n
Content-Length: 5 \r\n\r\n
hello\r\n
The body of your HTTP response consists of 7 bytes not 5 as you've stated in your Content-length. The \r\n after the 5 byte still belong to the response body. Giving the wrong size might mixup request handling, i.e. the proxy is expecting a new request but is actually getting \r\n, i.e. the 2 bytes after your 5 bytes Content-length.
Apart from that both path and Host header must include the name of the target from the perspective of the proxy. Using 127.0.0.1. like in your example would mean that you try to access a server at the same host of the proxy, i.e. localhost from the view of the proxy. This is probably not what you've intended.
...
X-Transformed-From: HTTP/0.9
This header in the response of the proxy indicates that your server does not properly speak HTTP/1.x. Instead of sending HTTP header and body it just sends the payload back without any HTTP header, like done in the HTTP 0.9 protocol which was obsoleted 20 years ago. With HTTP 0.9 the response will always end only at the end of the TCP connection. This means that you cannot have multiple requests within the same TCP connection.
I'm really new to coding using sockets.
The problem is not caused by the wrong use of sockets but due the wrong implementation of the application protocol, i.e. the data send over the socket. If you really need to implement HTTP please study the standards, i.e. RFC 7230 and following. If you don't want to do this use existing and tested HTTP libraries instead of writing your own.

How do I debug a HTTP 502 error?

I have a Python Tornado server sitting behind a nginx frontend. Every now and then, but not every time, I get a 502 error. I look in the nginx access log and I see this:
127.0.0.1 - - [02/Jun/2010:18:04:02 -0400] "POST /a/question/updates HTTP/1.1" 502 173 "http://localhost/tagged/python" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3"
and in the error log:
2010/06/02 18:04:02 [error] 14033#0: *1700 connect() failed (111: Connection refused)
while connecting to upstream, client: 127.0.0.1, server: _,
request: "POST /a/question/updates HTTP/1.1",
upstream: "http://127.0.0.1:8888/a/question/updates", host: "localhost", referrer: "http://localhost/tagged/python"
I don't think any errors show up in the Tornado log. How would you go about debugging this? Is there something I can put in the Tornado or nginx configuration to help debug this?

The line from the error log is very informative in my opinion. It says the connection was refused by the upstream, it contains client IP, Nginx server config, request line, hostname, upstream URL and referrer.
It is pretty clear you must look at the upstream (or firewall) to find out the reason.
In case you'd like to look at how Nginx processes the request, why it chooses specific server and location sections -- there is a beautiful "debug" mode. (Note, your Nginx binary must be built with debugging symbols included). Then:
error_log /path/to/your/error.log debug;
will turn on debugging for all the requests. Debugging information in the error log requires some time to get used to interpret it, but it's worth the efforts.
Do not use this "as is" for high traffic sites! It generates a lot of information and your error log will grow very fast. If you need to debug requests in the production, use debug_connection directive:
events {
debug_connection 1.2.3.4;
}
It turns debugging on for the specific client IP address only.