mercurial/hgweb/request.py

http server: support persistent connections.

only "hg serve" affected yet.  http server running cgi script will not
use persistent connections.  support for fastcgi will help that.

clients that support keepalive can use one tcp connection for all
commands during clone and pull.  this makes latency of binary search
during pull much lower over wan.

if server does not know content-length, it will force connection to
close at end.  right fix is to use chunked transfer-encoding but this is
easier and does not hurt performance. only command that is affected is
"changegroup" which is always last command during a pull.

# hgweb/request.py - An http request from either CGI or the standalone server.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from mercurial.demandload import demandload
demandload(globals(), "socket sys cgi os errno")
from mercurial.i18n import gettext as _

class hgrequest(object):
    def __init__(self, inp=None, out=None, env=None):
        self.inp = inp or sys.stdin
        self.out = out or sys.stdout
        self.env = env or os.environ
        self.form = cgi.parse(self.inp, self.env, keep_blank_values=1)
        self.will_close = True

    def write(self, *things):
        for thing in things:
            if hasattr(thing, "__iter__"):
                for part in thing:
                    self.write(part)
            else:
                try:
                    self.out.write(str(thing))
                except socket.error, inst:
                    if inst[0] != errno.ECONNRESET:
                        raise

    def done(self):
        if self.will_close:
            self.inp.close()
            self.out.close()
        else:
            self.out.flush()

    def header(self, headers=[('Content-type','text/html')]):
        for header in headers:
            self.out.write("%s: %s\r\n" % header)
        self.out.write("\r\n")

    def httphdr(self, type, filename=None, length=0):

        headers = [('Content-type', type)]
        if filename:
            headers.append(('Content-disposition', 'attachment; filename=%s' %
                            filename))
        # we do not yet support http 1.1 chunked transfer, so we have
        # to force connection to close if content-length not known
        if length:
            headers.append(('Content-length', str(length)))
            self.will_close = False
        else:
            headers.append(('Connection', 'close'))
            self.will_close = True
        self.header(headers)