PYTHON-1579 Update URI parser to adhere to new connection string spec (#755)

Author: juliusgeo

.evergreen/config.yml

@@ -523,7 +523,7 @@ functions:
         silent: true
         script: |
           cat <<'EOF' > "${PROJECT_DIRECTORY}/prepare_mongodb_aws.sh"
-            alias urlencode='${python3_binary} -c "import sys, urllib.parse as ulp; sys.stdout.write(ulp.quote_plus(sys.argv[1]))"'
+            alias urlencode='${python3_binary} -c "import sys, urllib.parse as ulp; sys.stdout.write(ulp.quote(sys.argv[1]))"'
             USER=$(urlencode ${iam_auth_ecs_account})
             PASS=$(urlencode ${iam_auth_ecs_secret_access_key})
             MONGODB_URI="mongodb://$USER:$PASS@localhost"
@@ -554,7 +554,7 @@ functions:
         script: |
           # DO NOT ECHO WITH XTRACE (which PREPARE_SHELL does)
           cat <<'EOF' > "${PROJECT_DIRECTORY}/prepare_mongodb_aws.sh"
-            alias urlencode='${python3_binary} -c "import sys, urllib.parse as ulp; sys.stdout.write(ulp.quote_plus(sys.argv[1]))"'
+            alias urlencode='${python3_binary} -c "import sys, urllib.parse as ulp; sys.stdout.write(ulp.quote(sys.argv[1]))"'
             alias jsonkey='${python3_binary} -c "import json,sys;sys.stdout.write(json.load(sys.stdin)[sys.argv[1]])" < ${DRIVERS_TOOLS}/.evergreen/auth_aws/creds.json'
             USER=$(jsonkey AccessKeyId)
             USER=$(urlencode $USER)

doc/changelog.rst

@@ -160,8 +160,19 @@ Breaking Changes in 4.0
   are passed to the server as-is rather than the previous behavior which
   substituted in a projection of ``{"_id": 1}``. This means that an empty
   projection will now return the entire document, not just the ``"_id"`` field.
-- ``MongoClient()`` now raises a :exc:`~pymongo.errors.ConfigurationError`
+- :class:`~pymongo.mongo_client.MongoClient` now raises a :exc:`~pymongo.errors.ConfigurationError`
   when more than one URI is passed into the ``hosts`` argument.
+- :class:`~pymongo.mongo_client.MongoClient`` now raises an
+  :exc:`~pymongo.errors.InvalidURI` exception
+  when it encounters unescaped percent signs in username and password when
+  parsing MongoDB URIs.
+- :class:`~pymongo.mongo_client.MongoClient` now uses
+  :py::func:`urllib.parse.unquote` rather than
+  :py:func:`urllib.parse.unquote_plus`,
+  meaning that plus signs ("+") are no longer converted to spaces (" "). This
+  means that if you were previously quoting your login information using
+  quote_plus, you must now switch to quote. Additionally, be aware that this
+  change only occurs when parsing login information from the URI.
 
 Notable improvements
 ....................

doc/examples/authentication.rst

@@ -11,14 +11,14 @@ Percent-Escaping Username and Password
 --------------------------------------
 
 Username and password must be percent-escaped with
-:meth:`urllib.parse.quote_plus`, to be used in a MongoDB URI. For example::
+:py:func:`urllib.parse.quote`, to be used in a MongoDB URI. For example::
 
   >>> from pymongo import MongoClient
   >>> import urllib.parse
-  >>> username = urllib.parse.quote_plus('user')
+  >>> username = urllib.parse.quote('user')
   >>> username
   'user'
-  >>> password = urllib.parse.quote_plus('pass/word')
+  >>> password = urllib.parse.quote('pass/word')
   >>> password
   'pass%2Fword'
   >>> MongoClient('mongodb://%s:%[email protected]' % (username, password))

doc/migrate-to-pymongo4.rst

@@ -190,9 +190,26 @@ now you must create a new instance.
 MongoClient raises exception when given more than one URI
 .........................................................
 
-``MongoClient()`` now raises a :exc:`~pymongo.errors.ConfigurationError`
+:class:`~pymongo.mongo_client.MongoClient` now raises a :exc:`~pymongo.errors.ConfigurationError`
 when more than one URI is passed into the ``hosts`` argument.
 
+MongoClient raises exception when given unescaped percent sign in login info
+............................................................................
+
+:class:`~pymongo.mongo_client.MongoClient` now raises an
+:exc:`~pymongo.errors.InvalidURI` exception
+when it encounters unescaped percent signs in username and password.
+
+MongoClient uses `unquote` rather than `unquote_plus` for login info
+....................................................................
+
+:class:`~pymongo.mongo_client.MongoClient` now uses
+:py:func:`urllib.parse.unquote` rather than
+:py:func:`urllib.parse.unquote_plus`, meaning that space characters are no
+longer converted to plus signs. This means that if you were previously
+quoting your login information using :py:func:`urllib.parse.quote_plus`, you
+must now switch to :py:func:`urllib.parse.quote`.
+
 Database
 --------
 

pymongo/auth.py

@@ -319,9 +319,6 @@ def _authenticate_gssapi(credentials, sock_info):
 
         if password is not None:
             if _USE_PRINCIPAL:
-                # Note that, though we use unquote_plus for unquoting URI
-                # options, we use quote here. Microsoft's UrlUnescape (used
-                # by WinKerberos) doesn't support +.
                 principal = ":".join((quote(username), quote(password)))
                 result, ctx = kerberos.authGSSClientInit(
                     service, principal, gssflags=kerberos.GSS_C_MUTUAL_FLAG)

pymongo/mongo_client.py

@@ -329,7 +329,7 @@ def __init__(
             a Unicode-related error occurs during BSON decoding that would
             otherwise raise :exc:`UnicodeDecodeError`. Valid options include
             'strict', 'replace', and 'ignore'. Defaults to 'strict'.
-          - ``srvServiceName`: (string) The SRV service name to use for
+          - `srvServiceName`: (string) The SRV service name to use for
             "mongodb+srv://" URIs. Defaults to "mongodb". Use it like so::
 
                 MongoClient("mongodb+srv://example.com/?srvServiceName=customname")

pymongo/uri_parser.py

@@ -18,7 +18,7 @@
 import warnings
 import sys
 
-from urllib.parse import unquote_plus
+from urllib.parse import unquote, unquote_plus
 
 from pymongo.common import (
     SRV_SERVICE_NAME,
@@ -35,25 +35,44 @@
 DEFAULT_PORT = 27017
 
 
+def _unquoted_percent(s):
+    """Check for unescaped percent signs.
+
+    :Paramaters:
+        - `s`: A string. `s` can have things like '%25', '%2525',
+           and '%E2%85%A8' but cannot have unquoted percent like '%foo'.
+    """
+    for i in range(len(s)):
+        if s[i] == '%':
+            sub = s[i:i+3]
+            # If unquoting yields the same string this means there was an
+            # unquoted %.
+            if unquote(sub) == sub:
+                return True
+    return False
+
 def parse_userinfo(userinfo):
     """Validates the format of user information in a MongoDB URI.
-    Reserved characters like ':', '/', '+' and '@' must be escaped
-    following RFC 3986.
+    Reserved characters that are gen-delimiters (":", "/", "?", "#", "[",
+    "]", "@") as per RFC 3986 must be escaped.
 
     Returns a 2-tuple containing the unescaped username followed
     by the unescaped password.
 
     :Paramaters:
         - `userinfo`: A string of the form <username>:<password>
     """
-    if '@' in userinfo or userinfo.count(':') > 1:
+    if ('@' in userinfo or userinfo.count(':') > 1 or
+            _unquoted_percent(userinfo)):
         raise InvalidURI("Username and password must be escaped according to "
-                         "RFC 3986, use urllib.parse.quote_plus")
+                         "RFC 3986, use urllib.parse.quote")
+
     user, _, passwd = userinfo.partition(":")
     # No password is expected with GSSAPI authentication.
     if not user:
         raise InvalidURI("The empty string is not valid username.")
-    return unquote_plus(user), unquote_plus(passwd)
+
+    return unquote(user), unquote(passwd)
 
 
 def parse_ipv6_literal_host(entity, default_port):
@@ -408,6 +427,12 @@ def parse_uri(uri, default_port=DEFAULT_PORT, validate=True, warn=False,
           wait for a response from the DNS server.
         - 'srv_service_name` (optional): A custom SRV service name
 
+    .. versionchanged:: 4.0
+       To better follow RFC 3986, unquoted percent signs ("%") are no longer
+       supported and plus signs ("+") are no longer decoded into spaces (" ")
+       when decoding username and password. To avoid these issues, use
+       :py:func:`urllib.parse.quote` when building the URI.
+
     .. versionchanged:: 3.9
         Added the ``normalize`` parameter.
 

test/connection_string/test/invalid-uris.json

@@ -189,15 +189,6 @@
       "auth": null,
       "options": null
     },
-    {
-      "description": "Username with password containing an unescaped colon",
-      "uri": "mongodb://alice:foo:[email protected]",
-      "valid": false,
-      "warning": null,
-      "hosts": null,
-      "auth": null,
-      "options": null
-    },
     {
       "description": "Username containing an unescaped at-sign",
       "uri": "mongodb://alice@@127.0.0.1",
@@ -251,6 +242,51 @@
       "hosts": null,
       "auth": null,
       "options": null
+    },
+    {
+      "description": "mongodb+srv with multiple service names",
+      "uri": "mongodb+srv://test5.test.mongodb.com,test6.test.mongodb.com",
+      "valid": false,
+      "warning": null,
+      "hosts": null,
+      "auth": null,
+      "options": null
+    },
+    {
+      "description": "mongodb+srv with port number",
+      "uri": "mongodb+srv://test7.test.mongodb.com:27018",
+      "valid": false,
+      "warning": null,
+      "hosts": null,
+      "auth": null,
+      "options": null
+    },
+    {
+      "description": "Username with password containing an unescaped percent sign",
+      "uri": "mongodb://alice%foo:[email protected]",
+      "valid": false,
+      "warning": null,
+      "hosts": null,
+      "auth": null,
+      "options": null
+    },
+    {
+      "description": "Username with password containing an unescaped percent sign and an escaped one",
+      "uri": "mongodb://user%20%:password@localhost",
+      "valid": false,
+      "warning": null,
+      "hosts": null,
+      "auth": null,
+      "options": null
+    },
+    {
+      "description": "Username with password containing an unescaped percent sign (non hex digit)",
+      "uri": "mongodb://user%w:password@localhost",
+      "valid": false,
+      "warning": null,
+      "hosts": null,
+      "auth": null,
+      "options": null
     }
   ]
 }

test/connection_string/test/valid-auth.json

@@ -240,6 +240,27 @@
         "authmechanism": "MONGODB-CR"
       }
     },
+    {
+      "description": "Subdelimiters in user/pass don't need escaping (MONGODB-CR)",
+      "uri": "mongodb://!$&'()*+,;=:!$&'()*+,;[email protected]/admin?authMechanism=MONGODB-CR",
+      "valid": true,
+      "warning": false,
+      "hosts": [
+        {
+          "type": "ipv4",
+          "host": "127.0.0.1",
+          "port": null
+        }
+      ],
+      "auth": {
+        "username": "!$&'()*+,;=",
+        "password": "!$&'()*+,;=",
+        "db": "admin"
+      },
+      "options": {
+        "authmechanism": "MONGODB-CR"
+      }
+    },
     {
       "description": "Escaped username (MONGODB-X509)",
       "uri": "mongodb://CN%3DmyName%2COU%3DmyOrgUnit%2CO%3DmyOrg%2CL%3DmyLocality%2CST%3DmyState%2CC%3DmyCountry@localhost/?authMechanism=MONGODB-X509",

test/connection_string/test/valid-host_identifiers.json

@@ -132,18 +132,18 @@
     },
     {
       "description": "UTF-8 hosts",
-      "uri": "mongodb://b\u00fccher.example.com,uml\u00e4ut.example.com/",
+      "uri": "mongodb://bücher.example.com,umläut.example.com/",
       "valid": true,
       "warning": false,
       "hosts": [
         {
           "type": "hostname",
-          "host": "b\u00fccher.example.com",
+          "host": "bücher.example.com",
           "port": null
         },
         {
           "type": "hostname",
-          "host": "uml\u00e4ut.example.com",
+          "host": "umläut.example.com",
           "port": null
         }
       ],