view tests/dumbhttp.py @ 23409:dc4d2cd3aa3e stable

hgweb: send proper HTTP response after uncaught exception

This patch fixes a bug where hgweb would send an incomplete HTTP
response.

If an uncaught exception is raised when hgweb is processing a request,
hgweb attempts to send a generic error response and log that exception.

The server defaults to chunked transfer coding. If an uncaught exception
occurred, it was sending the error response string / chunk properly.
However, RFC 7230 Section 4.1 mandates a 0 size last chunk be sent to
indicate end of the entity body. hgweb was failing to send this last
chunk. As a result, properly written HTTP clients would assume more data
was coming and they would likely time out waiting for another chunk to
arrive.

Mercurial's own test harness was paving over the improper HTTP behavior
by not attempting to read the response body if the status code was 500.
This incorrect workaround was added in ba6577a19656 and has been removed
with this patch.

#!/usr/bin/env python

"""
Small and dumb HTTP server for use in tests.
"""

from optparse import OptionParser
import BaseHTTPServer, SimpleHTTPServer, os, signal, subprocess, sys


def run(server_class=BaseHTTPServer.HTTPServer,
        handler_class=SimpleHTTPServer.SimpleHTTPRequestHandler,
        server_address=('localhost', 8000)):
    httpd = server_class(server_address, handler_class)
    httpd.serve_forever()


if __name__ == '__main__':
    parser = OptionParser()
    parser.add_option('-p', '--port', dest='port', type='int', default=8000,
        help='TCP port to listen on', metavar='PORT')
    parser.add_option('-H', '--host', dest='host', default='localhost',
        help='hostname or IP to listen on', metavar='HOST')
    parser.add_option('--pid', dest='pid',
        help='file name where the PID of the server is stored')
    parser.add_option('-f', '--foreground', dest='foreground',
        action='store_true',
        help='do not start the HTTP server in the background')

    (options, args) = parser.parse_args()

    signal.signal(signal.SIGTERM, lambda x, y: sys.exit(0))

    if options.foreground and options.pid:
        parser.error("options --pid and --foreground are mutually exclusive")

    if options.foreground:
        run(server_address=(options.host, options.port))
    else:
        # This doesn't attempt to cleanly detach the process, as it's not
        # meant to be a long-lived, independent process. As a consequence,
        # it's still part of the same process group, and keeps any file
        # descriptors it might have inherited besided stdin/stdout/stderr.
        # Trying to do things cleanly is more complicated, requires
        # OS-dependent code, and is not worth the effort.
        proc = subprocess.Popen([sys.executable, __file__, '-f',
            '-H', options.host, '-p', str(options.port)],
            stdin=open(os.devnull, 'r'),
            stdout=open(os.devnull, 'w'),
            stderr=subprocess.STDOUT)
        if options.pid:
            fp = file(options.pid, 'wb')
            fp.write(str(proc.pid) + '\n')
            fp.close()