Slow writes for large response body for HTTPS connection

[nav-agarwal]

I'm submitting a ...

• bug report
• feature request
• question about the decisions made in the repository

Describe the bug. What is the current behavior?

Performance Bug
Slow writes observed(<2MB/permin) in case of large response body(around 300MB) when using HTTPS connection

What is the motivation / use case for changing the behavior?
Poor download performance for HTTPS connection on local server

To Reproduce

Steps to reproduce the behavior:

1. Setup HTTPS cherrypy server

import cherrypy
class Root(object):
   @cherrypy.expose
   def index(self):
       cherrypy.log("Inside index")
       buff = "a" * 1024 * 1024 * 300
       return buff

if __name__ == '__main__':
   config = {
           'server.ssl_certificate': 'cert.pem',
           'server.ssl_private_key': 'privkey.pem',
           'server.ssl_module' : 'pyopenssl',
   }
   cherrypy.config.update(config)
   cherrypy.quickstart(Root())

2. Make requests

import requests
r = requests.post("https://localhost:8080", verify=False)

Expected behavior
On HTTP connection same requests finishes within seconds

Details
Root Cause:Bug is due to following code in write function of makefile. This function is used for HTTPS connection writes only:
data = data[bytes_sent:]
Here we are copying almost complete buffer after every socket write. In python. slices leads to copy of remaining buffere as strings are immutable.
Possible fix:
Do chunking in small buffers by matining idx till which write has happened

Environment

• Cheroot version: 6.5.2
• CherryPy version: 17.4.0
• Python version: 2.7.13
• OS: Ubuntu 14.04.5 LTS
• Browser: -

Additional context
Performance Bug

[webknjaz]

Hey @nav-agarwal,

Thanks for reporting this! I assume you've made a typo in requests code (you wrote http), am I right?

P.S. Your explanation makes a lot of sense. Would you be interested in submitting that as a PR?

[webknjaz]

@nav-agarwal try out #134

Also, have you tried Python 3 version? It should be better optimized.

[nav-agarwal]

@webknjaz :

1. I have corrected http to https in my request code
2. I will try to test it with python3 and upload results in couple of days, but my gut feeling is that it will have same problems.

[webknjaz]

@nav-agarwal are you happy with the latest fix? #137

[nav-agarwal]

@webknjaz : Fix is working fine. Thanks for the quick fix