add u1db code (not as submodule)

1 files changed, 218 insertions, 0 deletions

diff --git a/u1db/remote/http_client.py b/u1db/remote/http_client.py
new file mode 100644
index 00000000..decddda3
--- /dev/null
+++ b/u1db/remote/http_client.py
@@ -0,0 +1,218 @@
+# Copyright 2011-2012 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Base class to make requests to a remote HTTP server."""
+
+import httplib
+from oauth import oauth
+try:
+    import simplejson as json
+except ImportError:
+    import json  # noqa
+import socket
+import ssl
+import sys
+import urlparse
+import urllib
+
+from time import sleep
+from u1db import (
+    errors,
+    )
+from u1db.remote import (
+    http_errors,
+    )
+
+from u1db.remote.ssl_match_hostname import (  # noqa
+    CertificateError,
+    match_hostname,
+    )
+
+# Ubuntu/debian
+# XXX other...
+CA_CERTS = "/etc/ssl/certs/ca-certificates.crt"
+
+
+def _encode_query_parameter(value):
+    """Encode query parameter."""
+    if isinstance(value, bool):
+        if value:
+            value = 'true'
+        else:
+            value = 'false'
+    return unicode(value).encode('utf-8')
+
+
+class _VerifiedHTTPSConnection(httplib.HTTPSConnection):
+    """HTTPSConnection verifying server side certificates."""
+    # derived from httplib.py
+
+    def connect(self):
+        "Connect to a host on a given (SSL) port."
+
+        sock = socket.create_connection((self.host, self.port),
+                                        self.timeout, self.source_address)
+        if self._tunnel_host:
+            self.sock = sock
+            self._tunnel()
+        if sys.platform.startswith('linux'):
+            cert_opts = {
+                'cert_reqs': ssl.CERT_REQUIRED,
+                'ca_certs': CA_CERTS
+                }
+        else:
+            # XXX no cert verification implemented elsewhere for now
+            cert_opts = {}
+        self.sock = ssl.wrap_socket(sock, self.key_file, self.cert_file,
+                                    ssl_version=ssl.PROTOCOL_SSLv3,
+                                    **cert_opts
+                                    )
+        if cert_opts:
+            match_hostname(self.sock.getpeercert(), self.host)
+
+
+class HTTPClientBase(object):
+    """Base class to make requests to a remote HTTP server."""
+
+    # by default use HMAC-SHA1 OAuth signature method to not disclose
+    # tokens
+    # NB: given that the content bodies are not covered by the
+    # signatures though, to achieve security (against man-in-the-middle
+    # attacks for example) one would need HTTPS
+    oauth_signature_method = oauth.OAuthSignatureMethod_HMAC_SHA1()
+
+    # Will use these delays to retry on 503 befor finally giving up. The final
+    # 0 is there to not wait after the final try fails.
+    _delays = (1, 1, 2, 4, 0)
+
+    def __init__(self, url, creds=None):
+        self._url = urlparse.urlsplit(url)
+        self._conn = None
+        self._creds = {}
+        if creds is not None:
+            if len(creds) != 1:
+                raise errors.UnknownAuthMethod()
+            auth_meth, credentials = creds.items()[0]
+            try:
+                set_creds = getattr(self, 'set_%s_credentials' % auth_meth)
+            except AttributeError:
+                raise errors.UnknownAuthMethod(auth_meth)
+            set_creds(**credentials)
+
+    def set_oauth_credentials(self, consumer_key, consumer_secret,
+                              token_key, token_secret):
+        self._creds = {'oauth': (
+            oauth.OAuthConsumer(consumer_key, consumer_secret),
+            oauth.OAuthToken(token_key, token_secret))}
+
+    def _ensure_connection(self):
+        if self._conn is not None:
+            return
+        if self._url.scheme == 'https':
+            connClass = _VerifiedHTTPSConnection
+        else:
+            connClass = httplib.HTTPConnection
+        self._conn = connClass(self._url.hostname, self._url.port)
+
+    def close(self):
+        if self._conn:
+            self._conn.close()
+            self._conn = None
+
+    # xxx retry mechanism?
+
+    def _error(self, respdic):
+        descr = respdic.get("error")
+        exc_cls = errors.wire_description_to_exc.get(descr)
+        if exc_cls is not None:
+            message = respdic.get("message")
+            raise exc_cls(message)
+
+    def _response(self):
+        resp = self._conn.getresponse()
+        body = resp.read()
+        headers = dict(resp.getheaders())
+        if resp.status in (200, 201):
+            return body, headers
+        elif resp.status in http_errors.ERROR_STATUSES:
+            try:
+                respdic = json.loads(body)
+            except ValueError:
+                pass
+            else:
+                self._error(respdic)
+        # special case
+        if resp.status == 503:
+            raise errors.Unavailable(body, headers)
+        raise errors.HTTPError(resp.status, body, headers)
+
+    def _sign_request(self, method, url_query, params):
+        if 'oauth' in self._creds:
+            consumer, token = self._creds['oauth']
+            full_url = "%s://%s%s" % (self._url.scheme, self._url.netloc,
+                                      url_query)
+            oauth_req = oauth.OAuthRequest.from_consumer_and_token(
+                consumer, token,
+                http_method=method,
+                parameters=params,
+                http_url=full_url
+                )
+            oauth_req.sign_request(
+                self.oauth_signature_method, consumer, token)
+            # Authorization: OAuth ...
+            return oauth_req.to_header().items()
+        else:
+            return []
+
+    def _request(self, method, url_parts, params=None, body=None,
+                                                       content_type=None):
+        self._ensure_connection()
+        unquoted_url = url_query = self._url.path
+        if url_parts:
+            if not url_query.endswith('/'):
+                url_query += '/'
+                unquoted_url = url_query
+            url_query += '/'.join(urllib.quote(part, safe='')
+                                  for part in url_parts)
+            # oauth performs its own quoting
+            unquoted_url += '/'.join(url_parts)
+        encoded_params = {}
+        if params:
+            for key, value in params.items():
+                key = unicode(key).encode('utf-8')
+                encoded_params[key] = _encode_query_parameter(value)
+            url_query += ('?' + urllib.urlencode(encoded_params))
+        if body is not None and not isinstance(body, basestring):
+            body = json.dumps(body)
+            content_type = 'application/json'
+        headers = {}
+        if content_type:
+            headers['content-type'] = content_type
+        headers.update(
+            self._sign_request(method, unquoted_url, encoded_params))
+        for delay in self._delays:
+            try:
+                self._conn.request(method, url_query, body, headers)
+                return self._response()
+            except errors.Unavailable, e:
+                sleep(delay)
+        raise e
+
+    def _request_json(self, method, url_parts, params=None, body=None,
+                                                            content_type=None):
+        res, headers = self._request(method, url_parts, params, body,
+                                     content_type)
+        return json.loads(res), headers