# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>

# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import contextlib

import struct

import sys

import threading

from .i18n import _

from . import (

    encoding,

    error,

    hook,

    pycompat,

    util,

    wireproto,

    wireprototypes,

)

stringio = util.stringio

urlerr = util.urlerr

urlreq = util.urlreq

HTTP_OK = 200

HGTYPE = 'application/mercurial-0.1'

HGTYPE2 = 'application/mercurial-0.2'

HGERRTYPE = 'application/hg-error'

FRAMINGTYPE = b'application/mercurial-exp-framing-0001'

HTTPV2 = wireprototypes.HTTPV2

SSHV1 = wireprototypes.SSHV1

SSHV2 = wireprototypes.SSHV2

def decodevaluefromheaders(req, headerprefix):

    """Decode a long value from multiple HTTP request headers.

    Returns the value as a bytes, not a str.

    """

    chunks = []

    i = 1

    while True:

        v = req.headers.get(b'%s-%d' % (headerprefix, i))

        if v is None:

            break

        chunks.append(pycompat.bytesurl(v))

        i += 1

    return ''.join(chunks)

class httpv1protocolhandler(wireprototypes.baseprotocolhandler):

    def __init__(self, req, ui, checkperm):

        self._req = req

        self._ui = ui

        self._checkperm = checkperm

    @property

    def name(self):

        return 'http-v1'

    def getargs(self, args):

        knownargs = self._args()

        data = {}

        keys = args.split()

        for k in keys:

            if k == '*':

                star = {}

                for key in knownargs.keys():

                    if key != 'cmd' and key not in keys:

                        star[key] = knownargs[key][0]

                data['*'] = star

            else:

                data[k] = knownargs[k][0]

        return [data[k] for k in keys]

    def _args(self):

        args = self._req.qsparams.asdictoflists()

        postlen = int(self._req.headers.get(b'X-HgArgs-Post', 0))

        if postlen:

            args.update(urlreq.parseqs(

                self._req.bodyfh.read(postlen), keep_blank_values=True))

            return args

        argvalue = decodevaluefromheaders(self._req, b'X-HgArg')

        args.update(urlreq.parseqs(argvalue, keep_blank_values=True))

        return args

    def forwardpayload(self, fp):

        # Existing clients *always* send Content-Length.

        length = int(self._req.headers[b'Content-Length'])

        # If httppostargs is used, we need to read Content-Length

        # minus the amount that was consumed by args.

        length -= int(self._req.headers.get(b'X-HgArgs-Post', 0))

        for s in util.filechunkiter(self._req.bodyfh, limit=length):

            fp.write(s)

    @contextlib.contextmanager

    def mayberedirectstdio(self):

        oldout = self._ui.fout

        olderr = self._ui.ferr

        out = util.stringio()

        try:

            self._ui.fout = out

            self._ui.ferr = out

            yield out

        finally:

            self._ui.fout = oldout

            self._ui.ferr = olderr

    def client(self):

        return 'remote:%s:%s:%s' % (

            self._req.urlscheme,

            urlreq.quote(self._req.remotehost or ''),

            urlreq.quote(self._req.remoteuser or ''))

    def addcapabilities(self, repo, caps):

        caps.append('httpheader=%d' %

                    repo.ui.configint('server', 'maxhttpheaderlen'))

        if repo.ui.configbool('experimental', 'httppostargs'):

            caps.append('httppostargs')

        # FUTURE advertise 0.2rx once support is implemented

        # FUTURE advertise minrx and mintx after consulting config option

        caps.append('httpmediatype=0.1rx,0.1tx,0.2tx')

        compengines = wireproto.supportedcompengines(repo.ui, util.SERVERROLE)

        if compengines:

            comptypes = ','.join(urlreq.quote(e.wireprotosupport().name)

                                 for e in compengines)

            caps.append('compression=%s' % comptypes)

        return caps

    def checkperm(self, perm):

        return self._checkperm(perm)

# This method exists mostly so that extensions like remotefilelog can

# disable a kludgey legacy method only over http. As of early 2018,

# there are no other known users, so with any luck we can discard this

# hook if remotefilelog becomes a first-party extension.

def iscmd(cmd):

    return cmd in wireproto.commands

def handlewsgirequest(rctx, req, res, checkperm):

    """Possibly process a wire protocol request.

    If the current request is a wire protocol request, the request is

    processed by this function.

    ``req`` is a ``parsedrequest`` instance.

    ``res`` is a ``wsgiresponse`` instance.

    Returns a bool indicating if the request was serviced. If set, the caller

    should stop processing the request, as a response has already been issued.

    """

    # Avoid cycle involving hg module.

    from .hgweb import common as hgwebcommon

    repo = rctx.repo

    # HTTP version 1 wire protocol requests are denoted by a "cmd" query

    # string parameter. If it isn't present, this isn't a wire protocol

    # request.

    if 'cmd' not in req.qsparams:

        return False

    cmd = req.qsparams['cmd']

    # The "cmd" request parameter is used by both the wire protocol and hgweb.

    # While not all wire protocol commands are available for all transports,

    # if we see a "cmd" value that resembles a known wire protocol command, we

    # route it to a protocol handler. This is better than routing possible

    # wire protocol requests to hgweb because it prevents hgweb from using

    # known wire protocol commands and it is less confusing for machine

    # clients.

    if not iscmd(cmd):

        return False

    # The "cmd" query string argument is only valid on the root path of the

    # repo. e.g. ``/?cmd=foo``, ``/repo?cmd=foo``. URL paths within the repo

    # like ``/blah?cmd=foo`` are not allowed. So don't recognize the request

    # in this case. We send an HTTP 404 for backwards compatibility reasons.

    if req.dispatchpath:

        res.status = hgwebcommon.statusmessage(404)

        res.headers['Content-Type'] = HGTYPE

        # TODO This is not a good response to issue for this request. This

        # is mostly for BC for now.

        res.setbodybytes('0\n%s\n' % b'Not Found')

        return True

    proto = httpv1protocolhandler(req, repo.ui,

                                  lambda perm: checkperm(rctx, req, perm))

    # The permissions checker should be the only thing that can raise an

    # ErrorResponse. It is kind of a layer violation to catch an hgweb

    # exception here. So consider refactoring into a exception type that

    # is associated with the wire protocol.

    try:

        _callhttp(repo, req, res, proto, cmd)

    except hgwebcommon.ErrorResponse as e:

        for k, v in e.headers:

            res.headers[k] = v

        res.status = hgwebcommon.statusmessage(e.code, pycompat.bytestr(e))

        # TODO This response body assumes the failed command was

        # "unbundle." That assumption is not always valid.

        res.setbodybytes('0\n%s\n' % pycompat.bytestr(e))

    return True

def handlewsgiapirequest(rctx, req, res, checkperm):

    """Handle requests to /api/*."""

    assert req.dispatchparts[0] == b'api'

    repo = rctx.repo

    # This whole URL space is experimental for now. But we want to

    # reserve the URL space. So, 404 all URLs if the feature isn't enabled.

    if not repo.ui.configbool('experimental', 'web.apiserver'):

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('Experimental API server endpoint not enabled'))

        return

    # The URL space is /api/<protocol>/*. The structure of URLs under varies

    # by <protocol>.

    # Registered APIs are made available via config options of the name of

    # the protocol.

    availableapis = set()

    for k, v in API_HANDLERS.items():

        section, option = v['config']

        if repo.ui.configbool(section, option):

            availableapis.add(k)

    # Requests to /api/ list available APIs.

    if req.dispatchparts == [b'api']:

        res.status = b'200 OK'

        res.headers[b'Content-Type'] = b'text/plain'

        lines = [_('APIs can be accessed at /api/<name>, where <name> can be '

                   'one of the following:\n')]

        if availableapis:

            lines.extend(sorted(availableapis))

        else:

            lines.append(_('(no available APIs)\n'))

        res.setbodybytes(b'\n'.join(lines))

        return

    proto = req.dispatchparts[1]

    if proto not in API_HANDLERS:

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('Unknown API: %s\nKnown APIs: %s') % (

            proto, b', '.join(sorted(availableapis))))

        return

    if proto not in availableapis:

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('API %s not enabled\n') % proto)

        return

    API_HANDLERS[proto]['handler'](rctx, req, res, checkperm,

                                   req.dispatchparts[2:])

def _handlehttpv2request(rctx, req, res, checkperm, urlparts):

    from .hgweb import common as hgwebcommon

    # URL space looks like: <permissions>/<command>, where <permission> can

    # be ``ro`` or ``rw`` to signal read-only or read-write, respectively.

    # Root URL does nothing meaningful... yet.

    if not urlparts:

        res.status = b'200 OK'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('HTTP version 2 API handler'))

        return

    if len(urlparts) == 1:

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('do not know how to process %s\n') %

                         req.dispatchpath)

        return

    permission, command = urlparts[0:2]

    if permission not in (b'ro', b'rw'):

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('unknown permission: %s') % permission)

        return

    if req.method != 'POST':

        res.status = b'405 Method Not Allowed'

        res.headers[b'Allow'] = b'POST'

        res.setbodybytes(_('commands require POST requests'))

        return

    # At some point we'll want to use our own API instead of recycling the

    # behavior of version 1 of the wire protocol...

    # TODO return reasonable responses - not responses that overload the

    # HTTP status line message for error reporting.

    try:

        checkperm(rctx, req, 'pull' if permission == b'ro' else 'push')

    except hgwebcommon.ErrorResponse as e:

        res.status = hgwebcommon.statusmessage(e.code, pycompat.bytestr(e))

        for k, v in e.headers:

            res.headers[k] = v

        res.setbodybytes('permission denied')

        return

    if command not in wireproto.commands:

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('unknown wire protocol command: %s\n') % command)

        return

    repo = rctx.repo

    ui = repo.ui

    proto = httpv2protocolhandler(req, ui)

    if not wireproto.commands.commandavailable(command, proto):

        res.status = b'404 Not Found'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('invalid wire protocol command: %s') % command)

        return

    if req.headers.get(b'Accept') != FRAMINGTYPE:

        res.status = b'406 Not Acceptable'

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('client MUST specify Accept header with value: %s\n')

                           % FRAMINGTYPE)

        return

        res.status = b'415 Unsupported Media Type'

        # TODO we should send a response with appropriate media type,

        # since client does Accept it.

        res.headers[b'Content-Type'] = b'text/plain'

        res.setbodybytes(_('client MUST send Content-Type header with '

                           'value: %s\n') % FRAMINGTYPE)

        return

    # We don't do anything meaningful yet.

    res.status = b'200 OK'

    res.headers[b'Content-Type'] = b'text/plain'

    res.setbodybytes(b'/'.join(urlparts) + b'\n')

# Maps API name to metadata so custom API can be registered.

API_HANDLERS = {

    HTTPV2: {

        'config': ('experimental', 'web.api.http-v2'),

        'handler': _handlehttpv2request,

    },

}

class httpv2protocolhandler(wireprototypes.baseprotocolhandler):

    def __init__(self, req, ui):

        self._req = req

        self._ui = ui

    @property

    def name(self):

        return HTTPV2

    def getargs(self, args):

        raise NotImplementedError

    def forwardpayload(self, fp):

        raise NotImplementedError

    @contextlib.contextmanager

    def mayberedirectstdio(self):

        raise NotImplementedError

    def client(self):

        raise NotImplementedError

    def addcapabilities(self, repo, caps):

        raise NotImplementedError

    def checkperm(self, perm):

        raise NotImplementedError

def _httpresponsetype(ui, req, prefer_uncompressed):

    """Determine the appropriate response type and compression settings.

    Returns a tuple of (mediatype, compengine, engineopts).

    """

    # Determine the response media type and compression engine based

    # on the request parameters.

    protocaps = decodevaluefromheaders(req, 'X-HgProto').split(' ')

    if '0.2' in protocaps:

        # All clients are expected to support uncompressed data.

        if prefer_uncompressed:

            return HGTYPE2, util._noopengine(), {}

        # Default as defined by wire protocol spec.

        compformats = ['zlib', 'none']

        for cap in protocaps:

            if cap.startswith('comp='):

                compformats = cap[5:].split(',')

                break

        # Now find an agreed upon compression format.

        for engine in wireproto.supportedcompengines(ui, util.SERVERROLE):

            if engine.wireprotosupport().name in compformats:

                opts = {}

                level = ui.configint('server', '%slevel' % engine.name())

                if level is not None:

                    opts['level'] = level

                return HGTYPE2, engine, opts

        # No mutually supported compression format. Fall back to the

        # legacy protocol.

    # Don't allow untrusted settings because disabling compression or

    # setting a very high compression level could lead to flooding

    # the server's network or CPU.

    opts = {'level': ui.configint('server', 'zliblevel')}

    return HGTYPE, util.compengines['zlib'], opts

def _callhttp(repo, req, res, proto, cmd):

    # Avoid cycle involving hg module.

    from .hgweb import common as hgwebcommon