~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""http/https transport using pycurl"""

# TODO: test reporting of http errors

# TODO: Transport option to control caching of particular requests; broadly we

# would want to offer "caching allowed" or "must revalidate", depending on

# whether we expect a particular file will be modified after it's committed.

# It's probably safer to just always revalidate.  mbp 20060321

import os

from StringIO import StringIO

import bzrlib

from bzrlib.errors import (TransportNotPossible, NoSuchFile,

                           TransportError, ConnectionError,

                           DependencyNotPresent)

from bzrlib.trace import mutter

from bzrlib.transport import register_urlparse_netloc_protocol

from bzrlib.transport.http import HttpTransportBase, extract_auth, HttpServer

try:

    import pycurl

except ImportError, e:

    mutter("failed to import pycurl: %s", e)

    raise DependencyNotPresent('pycurl', e)

try:

    # see if we can actually initialize PyCurl - sometimes it will load but

    # fail to start up due to this bug:

    #  

    #   32. (At least on Windows) If libcurl is built with c-ares and there's

    #   no DNS server configured in the system, the ares_init() call fails and

    #   thus curl_easy_init() fails as well. This causes weird effects for

    #   people who use numerical IP addresses only.

    #

    # reported by Alexander Belchenko, 2006-04-26

    pycurl.Curl()

except pycurl.error, e:

    mutter("failed to initialize pycurl: %s", e)

    raise DependencyNotPresent('pycurl', e)

register_urlparse_netloc_protocol('http+pycurl')

class PyCurlTransport(HttpTransportBase):

    """http client transport using pycurl

    PyCurl is a Python binding to the C "curl" multiprotocol client.

    This transport can be significantly faster than the builtin Python client. 

    Advantages include: DNS caching, connection keepalive, and ability to 

    set headers to allow caching.

    """

    def __init__(self, base):

        super(PyCurlTransport, self).__init__(base)

        mutter('using pycurl %s' % pycurl.version)

    def should_cache(self):

        """Return True if the data pulled across should be cached locally.

        """

        return True

    def has(self, relpath):

        curl = pycurl.Curl()

        abspath = self._real_abspath(relpath)

        curl.setopt(pycurl.URL, abspath)

        curl.setopt(pycurl.FOLLOWLOCATION, 1) # follow redirect responses

        self._set_curl_options(curl)

        # don't want the body - ie just do a HEAD request

        curl.setopt(pycurl.NOBODY, 1)

        self._curl_perform(curl)

        code = curl.getinfo(pycurl.HTTP_CODE)

        if code == 404: # not found

            return False

        elif code in (200, 302): # "ok", "found"

            return True

        elif code == 0:

            self._raise_curl_connection_error(curl)

        else:

            self._raise_curl_http_error(curl)

    def _get(self, relpath, ranges):

        curl = pycurl.Curl()

        abspath = self._real_abspath(relpath)

        sio = StringIO()

        curl.setopt(pycurl.URL, abspath)

        self._set_curl_options(curl)

        curl.setopt(pycurl.WRITEFUNCTION, sio.write)

        curl.setopt(pycurl.NOBODY, 0)

        if ranges is not None:

            assert len(ranges) == 1

            # multiple ranges not supported yet because we can't decode the

            # response

            curl.setopt(pycurl.RANGE, '%d-%d' % ranges[0])

        self._curl_perform(curl)

        code = curl.getinfo(pycurl.HTTP_CODE)

        if code == 404:

            raise NoSuchFile(abspath)

        elif code == 200:

            sio.seek(0)

            return code, sio

        elif code == 206 and (ranges is not None):

            sio.seek(0)

            return code, sio

        elif code == 0:

            self._raise_curl_connection_error(curl)

        else:

            self._raise_curl_http_error(curl)

    def _raise_curl_connection_error(self, curl):

        curl_errno = curl.getinfo(pycurl.OS_ERRNO)

        url = curl.getinfo(pycurl.EFFECTIVE_URL)

        raise ConnectionError('curl connection error (%s) on %s'

                              % (os.strerror(curl_errno), url))

    def _raise_curl_http_error(self, curl):

        code = curl.getinfo(pycurl.HTTP_CODE)

        url = curl.getinfo(pycurl.EFFECTIVE_URL)

        raise TransportError('http error %d probing for %s' %

                             (code, url))

    def _set_curl_options(self, curl):

        """Set options for all requests"""

        # There's no way in http/1.0 to say "must revalidate"; we don't want

        # to force it to always retrieve.  so just turn off the default Pragma

        # provided by Curl.

        headers = ['Cache-control: max-age=0',

                   'Pragma: no-cache']

        ## curl.setopt(pycurl.VERBOSE, 1)

        # TODO: maybe include a summary of the pycurl version

        ua_str = 'bzr/%s (pycurl)' % (bzrlib.__version__)

        curl.setopt(pycurl.USERAGENT, ua_str)

        curl.setopt(pycurl.HTTPHEADER, headers)

        curl.setopt(pycurl.FOLLOWLOCATION, 1) # follow redirect responses

    def _curl_perform(self, curl):

        """Perform curl operation and translate exceptions."""

        try:

            curl.perform()

        except pycurl.error, e:

            # XXX: There seem to be no symbolic constants for these values.

            if e[0] == 6:

                # couldn't resolve host

                raise NoSuchFile(curl.getinfo(pycurl.EFFECTIVE_URL), e)

class HttpServer_PyCurl(HttpServer):

    """Subclass of HttpServer that gives http+pycurl urls.

    This is for use in testing: connections to this server will always go

    through pycurl where possible.

    """

    # urls returned by this server should require the pycurl client impl

    _url_protocol = 'http+pycurl'

def get_test_permutations():

    """Return the permutations to be used in testing."""

    return [(PyCurlTransport, HttpServer_PyCurl),

            ]