# hgweb/request.py - An http request from either CGI or the standalone server.

#

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

# Copyright 2005, 2006 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 wsgiref.headers as wsgiheaders

#import wsgiref.validate

from ..thirdparty import (

    attr,

)

from .. import (

    error,

    pycompat,

    util,

)

class multidict(object):

    """A dict like object that can store multiple values for a key.

    Used to store parsed request parameters.

    This is inspired by WebOb's class of the same name.

    """

    def __init__(self):

        # Stores (key, value) 2-tuples. This isn't the most efficient. But we

        # don't rely on parameters that much, so it shouldn't be a perf issue.

        # we can always add dict for fast lookups.

        self._items = []

    def __getitem__(self, key):

        """Returns the last set value for a key."""

        for k, v in reversed(self._items):

            if k == key:

                return v

        raise KeyError(key)

    def __setitem__(self, key, value):

        """Replace a values for a key with a new value."""

        try:

            del self[key]

        except KeyError:

            pass

        self._items.append((key, value))

    def __delitem__(self, key):

        """Delete all values for a key."""

        oldlen = len(self._items)

        self._items[:] = [(k, v) for k, v in self._items if k != key]

        if oldlen == len(self._items):

            raise KeyError(key)

    def __contains__(self, key):

        return any(k == key for k, v in self._items)

    def __len__(self):

        return len(self._items)

    def get(self, key, default=None):

        try:

            return self.__getitem__(key)

        except KeyError:

            return default

    def add(self, key, value):

        """Add a new value for a key. Does not replace existing values."""

        self._items.append((key, value))

    def getall(self, key):

        """Obtains all values for a key."""

        return [v for k, v in self._items if k == key]

    def getone(self, key):

        """Obtain a single value for a key.

        Raises KeyError if key not defined or it has multiple values set.

        """

        vals = self.getall(key)

        if not vals:

            raise KeyError(key)

        if len(vals) > 1:

            raise KeyError('multiple values for %r' % key)

        return vals[0]

    def asdictoflists(self):

        d = {}

        for k, v in self._items:

            if k in d:

                d[k].append(v)

            else:

                d[k] = [v]

        return d

@attr.s(frozen=True)

class parsedrequest(object):

    """Represents a parsed WSGI request.

    Contains both parsed parameters as well as a handle on the input stream.

    """

    # Request method.

    method = attr.ib()

    # Full URL for this request.

    url = attr.ib()

    # URL without any path components. Just <proto>://<host><port>.

    baseurl = attr.ib()

    # Advertised URL. Like ``url`` and ``baseurl`` but uses SERVER_NAME instead

    # of HTTP: Host header for hostname. This is likely what clients used.

    advertisedurl = attr.ib()

    advertisedbaseurl = attr.ib()

    # URL scheme (part before ``://``). e.g. ``http`` or ``https``.

    urlscheme = attr.ib()

    # Value of REMOTE_USER, if set, or None.

    remoteuser = attr.ib()

    # Value of REMOTE_HOST, if set, or None.

    remotehost = attr.ib()

    # Relative WSGI application path. If defined, will begin with a

    # ``/``.

    apppath = attr.ib()

    # List of path parts to be used for dispatch.

    dispatchparts = attr.ib()

    # URL path component (no query string) used for dispatch. Can be

    # ``None`` to signal no path component given to the request, an

    # empty string to signal a request to the application's root URL,

    # or a string not beginning with ``/`` containing the requested

    # path under the application.

    dispatchpath = attr.ib()

    # The name of the repository being accessed.

    reponame = attr.ib()

    # Raw query string (part after "?" in URL).

    querystring = attr.ib()

    # multidict of query string parameters.

    qsparams = attr.ib()

    # wsgiref.headers.Headers instance. Operates like a dict with case

    # insensitive keys.

    headers = attr.ib()

    # Request body input stream.

    bodyfh = attr.ib()

    # WSGI environment dict, unmodified.

    rawenv = attr.ib()

    """Parse URL components from environment variables.

    WSGI defines request attributes via environment variables. This function

    parses the environment variables into a data structure.

    If ``reponame`` is defined, the leading path components matching that

    string are effectively shifted from ``PATH_INFO`` to ``SCRIPT_NAME``.

    This simulates the world view of a WSGI application that processes

    requests from the base URL of a repo.

    If ``altbaseurl`` (typically comes from ``web.baseurl`` config option)

    is defined, it is used - instead of the WSGI environment variables - for

    constructing URL components up to and including the WSGI application path.

    For example, if the current WSGI application is at ``/repo`` and a request

    is made to ``/rev/@`` with this argument set to

    ``http://myserver:9000/prefix``, the URL and path components will resolve as

    if the request were to ``http://myserver:9000/prefix/rev/@``. In other

    words, ``wsgi.url_scheme``, ``SERVER_NAME``, ``SERVER_PORT``, and

    ``SCRIPT_NAME`` are all effectively replaced by components from this URL.

    """

    # PEP 3333 defines the WSGI spec and is a useful reference for this code.

    # We first validate that the incoming object conforms with the WSGI spec.

    # We only want to be dealing with spec-conforming WSGI implementations.

    # TODO enable this once we fix internal violations.

    #wsgiref.validate.check_environ(env)

    # PEP-0333 states that environment keys and values are native strings

    # (bytes on Python 2 and str on Python 3). The code points for the Unicode

    # strings on Python 3 must be between \00000-\000FF. We deal with bytes

    # in Mercurial, so mass convert string keys and values to bytes.

    if pycompat.ispy3:

        env = {k.encode('latin-1'): v for k, v in env.iteritems()}

        env = {k: v.encode('latin-1') if isinstance(v, str) else v

               for k, v in env.iteritems()}

    if altbaseurl:

        altbaseurl = util.url(altbaseurl)

    # https://www.python.org/dev/peps/pep-0333/#environ-variables defines

    # the environment variables.

    # https://www.python.org/dev/peps/pep-0333/#url-reconstruction defines

    # how URLs are reconstructed.

    fullurl = env['wsgi.url_scheme'] + '://'

    if altbaseurl and altbaseurl.scheme:

        advertisedfullurl = altbaseurl.scheme + '://'

    else:

        advertisedfullurl = fullurl

    def addport(s, port):

        if s.startswith('https://'):

            if port != '443':

                s += ':' + port

        else:

            if port != '80':

                s += ':' + port

        return s

    if env.get('HTTP_HOST'):

        fullurl += env['HTTP_HOST']

    else:

        fullurl += env['SERVER_NAME']

        fullurl = addport(fullurl, env['SERVER_PORT'])

    if altbaseurl and altbaseurl.host:

        advertisedfullurl += altbaseurl.host

        if altbaseurl.port:

            port = altbaseurl.port

        elif altbaseurl.scheme == 'http' and not altbaseurl.port:

            port = '80'

        elif altbaseurl.scheme == 'https' and not altbaseurl.port:

            port = '443'

        else:

            port = env['SERVER_PORT']

        advertisedfullurl = addport(advertisedfullurl, port)

    else:

        advertisedfullurl += env['SERVER_NAME']

        advertisedfullurl = addport(advertisedfullurl, env['SERVER_PORT'])

    baseurl = fullurl

    advertisedbaseurl = advertisedfullurl

    fullurl += util.urlreq.quote(env.get('SCRIPT_NAME', ''))

    fullurl += util.urlreq.quote(env.get('PATH_INFO', ''))

    if altbaseurl:

        path = altbaseurl.path or ''

        if path and not path.startswith('/'):

            path = '/' + path

        advertisedfullurl += util.urlreq.quote(path)

    else:

        advertisedfullurl += util.urlreq.quote(env.get('SCRIPT_NAME', ''))

    advertisedfullurl += util.urlreq.quote(env.get('PATH_INFO', ''))

    if env.get('QUERY_STRING'):

        fullurl += '?' + env['QUERY_STRING']

        advertisedfullurl += '?' + env['QUERY_STRING']

    # If ``reponame`` is defined, that must be a prefix on PATH_INFO

    # that represents the repository being dispatched to. When computing

    # the dispatch info, we ignore these leading path components.

    if altbaseurl:

        apppath = altbaseurl.path or ''

        if apppath and not apppath.startswith('/'):

            apppath = '/' + apppath

    else:

        apppath = env.get('SCRIPT_NAME', '')

    if reponame:

        repoprefix = '/' + reponame.strip('/')

        if not env.get('PATH_INFO'):

            raise error.ProgrammingError('reponame requires PATH_INFO')

        if not env['PATH_INFO'].startswith(repoprefix):

            raise error.ProgrammingError('PATH_INFO does not begin with repo '

                                         'name: %s (%s)' % (env['PATH_INFO'],

                                                            reponame))

        dispatchpath = env['PATH_INFO'][len(repoprefix):]

        if dispatchpath and not dispatchpath.startswith('/'):

            raise error.ProgrammingError('reponame prefix of PATH_INFO does '

                                         'not end at path delimiter: %s (%s)' %

                                         (env['PATH_INFO'], reponame))

        apppath = apppath.rstrip('/') + repoprefix

        dispatchparts = dispatchpath.strip('/').split('/')

        dispatchpath = '/'.join(dispatchparts)

    elif 'PATH_INFO' in env:

        if env['PATH_INFO'].strip('/'):

            dispatchparts = env['PATH_INFO'].strip('/').split('/')

            dispatchpath = '/'.join(dispatchparts)

        else:

            dispatchparts = []

            dispatchpath = ''

    else:

        dispatchparts = []

        dispatchpath = None

    querystring = env.get('QUERY_STRING', '')

    # We store as a list so we have ordering information. We also store as

    # a dict to facilitate fast lookup.

    qsparams = multidict()

    for k, v in util.urlreq.parseqsl(querystring, keep_blank_values=True):

        qsparams.add(k, v)

    # HTTP_* keys contain HTTP request headers. The Headers structure should

    # perform case normalization for us. We just rewrite underscore to dash

    # so keys match what likely went over the wire.

    headers = []

    for k, v in env.iteritems():

        if k.startswith('HTTP_'):

            headers.append((k[len('HTTP_'):].replace('_', '-'), v))

    headers = wsgiheaders.Headers(headers)

    # This is kind of a lie because the HTTP header wasn't explicitly

    # sent. But for all intents and purposes it should be OK to lie about

    # this, since a consumer will either either value to determine how many

    # bytes are available to read.

    if 'CONTENT_LENGTH' in env and 'HTTP_CONTENT_LENGTH' not in env:

        headers['Content-Length'] = env['CONTENT_LENGTH']

    return parsedrequest(method=env['REQUEST_METHOD'],

                         url=fullurl, baseurl=baseurl,

                         advertisedurl=advertisedfullurl,

                         advertisedbaseurl=advertisedbaseurl,

                         urlscheme=env['wsgi.url_scheme'],

                         remoteuser=env.get('REMOTE_USER'),

                         remotehost=env.get('REMOTE_HOST'),

                         apppath=apppath,

                         dispatchparts=dispatchparts, dispatchpath=dispatchpath,

                         reponame=reponame,

                         querystring=querystring,

                         qsparams=qsparams,

                         headers=headers,

                         bodyfh=bodyfh,

                         rawenv=env)

class offsettrackingwriter(object):

    """A file object like object that is append only and tracks write count.

    Instances are bound to a callable. This callable is called with data

    whenever a ``write()`` is attempted.

    Instances track the amount of written data so they can answer ``tell()``

    requests.

    The intent of this class is to wrap the ``write()`` function returned by

    a WSGI ``start_response()`` function. Since ``write()`` is a callable and

    not a file object, it doesn't implement other file object methods.

    """

    def __init__(self, writefn):

        self._write = writefn

        self._offset = 0

    def write(self, s):

        res = self._write(s)

        # Some Python objects don't report the number of bytes written.

        if res is None:

            self._offset += len(s)

        else:

            self._offset += res

    def flush(self):

        pass

    def tell(self):

        return self._offset

class wsgiresponse(object):

    """Represents a response to a WSGI request.

    A response consists of a status line, headers, and a body.

    Consumers must populate the ``status`` and ``headers`` fields and

    make a call to a ``setbody*()`` method before the response can be

    issued.

    When it is time to start sending the response over the wire,

    ``sendresponse()`` is called. It handles emitting the header portion

    of the response message. It then yields chunks of body data to be

    written to the peer. Typically, the WSGI application itself calls

    and returns the value from ``sendresponse()``.

    """

    def __init__(self, req, startresponse):

        """Create an empty response tied to a specific request.

        ``req`` is a ``parsedrequest``. ``startresponse`` is the

        ``start_response`` function passed to the WSGI application.

        """

        self._req = req

        self._startresponse = startresponse

        self.status = None

        self.headers = wsgiheaders.Headers([])

        self._bodybytes = None

        self._bodygen = None

        self._bodywillwrite = False

        self._started = False

        self._bodywritefn = None

    def _verifybody(self):

        if (self._bodybytes is not None or self._bodygen is not None

            or self._bodywillwrite):

            raise error.ProgrammingError('cannot define body multiple times')

    def setbodybytes(self, b):

        """Define the response body as static bytes.

        The empty string signals that there is no response body.

        """

        self._verifybody()

        self._bodybytes = b

        self.headers['Content-Length'] = '%d' % len(b)

    def setbodygen(self, gen):

        """Define the response body as a generator of bytes."""

        self._verifybody()

        self._bodygen = gen

    def setbodywillwrite(self):

        """Signal an intent to use write() to emit the response body.

        **This is the least preferred way to send a body.**

        It is preferred for WSGI applications to emit a generator of chunks

        constituting the response body. However, some consumers can't emit

        data this way. So, WSGI provides a way to obtain a ``write(data)``

        function that can be used to synchronously perform an unbuffered

        write.

        Calling this function signals an intent to produce the body in this

        manner.

        """

        self._verifybody()

        self._bodywillwrite = True

    def sendresponse(self):

        """Send the generated response to the client.

        Before this is called, ``status`` must be set and one of

        ``setbodybytes()`` or ``setbodygen()`` must be called.

        Calling this method multiple times is not allowed.

        """

        if self._started:

            raise error.ProgrammingError('sendresponse() called multiple times')

        self._started = True

        if not self.status:

            raise error.ProgrammingError('status line not defined')

        if (self._bodybytes is None and self._bodygen is None

            and not self._bodywillwrite):

            raise error.ProgrammingError('response body not defined')

        # RFC 7232 Section 4.1 states that a 304 MUST generate one of

        # {Cache-Control, Content-Location, Date, ETag, Expires, Vary}

        # and SHOULD NOT generate other headers unless they could be used

        # to guide cache updates. Furthermore, RFC 7230 Section 3.3.2

        # states that no response body can be issued. Content-Length can

        # be sent. But if it is present, it should be the size of the response

        # that wasn't transferred.

        if self.status.startswith('304 '):

            # setbodybytes('') will set C-L to 0. This doesn't conform with the

            # spec. So remove it.

            if self.headers.get('Content-Length') == '0':

                del self.headers['Content-Length']

            # Strictly speaking, this is too strict. But until it causes

            # problems, let's be strict.

            badheaders = {k for k in self.headers.keys()

                          if k.lower() not in ('date', 'etag', 'expires',

                                               'cache-control',

                                               'content-location',

                                               'vary')}

            if badheaders: