view mercurial/hgweb/wsgicgi.py @ 2874:4ec58b157265

refactor text diff/patch code.

rename commands.dodiff to patch.diff.
rename commands.doexport to patch.export.
move some functions from commands to new mercurial.cmdutil module.
turn list of diff options into mdiff.diffopts class.

patch.diff and patch.export now has clean api for call from 3rd party
python code.

# hgweb/wsgicgi.py - CGI->WSGI translator
#
# Copyright 2006 Eric Hopper <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
#
# This was originally copied from the public domain code at
# http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side

import os, sys

def launch(application):

    environ = dict(os.environ.items())
    environ['wsgi.input']        = sys.stdin
    environ['wsgi.errors']       = sys.stderr
    environ['wsgi.version']      = (1,0)
    environ['wsgi.multithread']  = False
    environ['wsgi.multiprocess'] = True
    environ['wsgi.run_once']    = True

    if environ.get('HTTPS','off') in ('on','1'):
        environ['wsgi.url_scheme'] = 'https'
    else:
        environ['wsgi.url_scheme'] = 'http'

    headers_set = []
    headers_sent = []
    out = sys.stdout

    def write(data):
        if not headers_set:
             raise AssertionError("write() before start_response()")

        elif not headers_sent:
             # Before the first output, send the stored headers
             status, response_headers = headers_sent[:] = headers_set
             out.write('Status: %s\r\n' % status)
             for header in response_headers:
                 out.write('%s: %s\r\n' % header)
             out.write('\r\n')

        out.write(data)
        out.flush()

    def start_response(status,response_headers,exc_info=None):
        if exc_info:
            try:
                if headers_sent:
                    # Re-raise original exception if headers sent
                    raise exc_info[0], exc_info[1], exc_info[2]
            finally:
                exc_info = None     # avoid dangling circular ref
        elif headers_set:
            raise AssertionError("Headers already set!")

        headers_set[:] = [status,response_headers]
        return write

    result = application(environ, start_response)
    try:
        for data in result:
            if data:    # don't send headers until body appears
                write(data)
        if not headers_sent:
            write('')   # send headers now if body was empty
    finally:
        if hasattr(result,'close'):
            result.close()