help: add internals.extensions topic
I think it's better to include the API overview in core as we now have the
internals section in our help system.
Retrieved from the wiki, and formatted as reST. Several wiki links are
removed since they are invalid in the help. The sections about example
extension are removed at all as they seemed too verbose.
https://www.mercurial-scm.org/wiki/WritingExtensions
Tests if hgweb can run without touching sys.stdin, as is required
by the WSGI standard and strictly implemented by mod_wsgi.
$ hg init repo
$ cd repo
$ echo foo > bar
$ hg add bar
$ hg commit -m "test"
$ cat > request.py <<EOF
> from __future__ import absolute_import
> import os
> import sys
> from mercurial import (
> dispatch,
> encoding,
> hg,
> pycompat,
> ui as uimod,
> util,
> )
> ui = uimod.ui
> from mercurial.hgweb import hgweb_mod
> stringio = util.stringio
>
> class FileLike(object):
> def __init__(self, real):
> self.real = real
> def fileno(self):
> print >> sys.__stdout__, 'FILENO'
> return self.real.fileno()
> def read(self):
> print >> sys.__stdout__, 'READ'
> return self.real.read()
> def readline(self):
> print >> sys.__stdout__, 'READLINE'
> return self.real.readline()
>
> sys.stdin = FileLike(sys.stdin)
> errors = stringio()
> input = stringio()
> output = stringio()
>
> def startrsp(status, headers):
> print('---- STATUS')
> print(status)
> print('---- HEADERS')
> print([i for i in headers if i[0] != 'ETag'])
> print('---- DATA')
> return output.write
>
> env = {
> 'wsgi.version': (1, 0),
> 'wsgi.url_scheme': 'http',
> 'wsgi.errors': errors,
> 'wsgi.input': input,
> 'wsgi.multithread': False,
> 'wsgi.multiprocess': False,
> 'wsgi.run_once': False,
> 'REQUEST_METHOD': 'GET',
> 'SCRIPT_NAME': '',
> 'PATH_INFO': '',
> 'QUERY_STRING': '',
> 'SERVER_NAME': '$LOCALIP',
> 'SERVER_PORT': os.environ['HGPORT'],
> 'SERVER_PROTOCOL': 'HTTP/1.0'
> }
>
> i = hgweb_mod.hgweb(b'.')
> for c in i(env, startrsp):
> pass
> sys.stdout.flush()
> pycompat.stdout.write(b'---- ERRORS\n')
> pycompat.stdout.write(b'%s\n' % errors.getvalue())
> print('---- OS.ENVIRON wsgi variables')
> print(sorted([x for x in os.environ if x.startswith('wsgi')]))
> print('---- request.ENVIRON wsgi variables')
> with i._obtainrepo() as repo:
> print(sorted([encoding.strfromlocal(x) for x in repo.ui.environ
> if x.startswith(b'wsgi')]))
> EOF
$ "$PYTHON" request.py
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'text/html; charset=ascii')]
---- DATA
---- ERRORS
---- OS.ENVIRON wsgi variables
[]
---- request.ENVIRON wsgi variables
['wsgi.errors', 'wsgi.input', 'wsgi.multiprocess', 'wsgi.multithread', 'wsgi.run_once', 'wsgi.url_scheme', 'wsgi.version']
$ cd ..