We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Relax record id validation
Do we really need to ensure that posted record ids match a uuid regex?

We can generate a uuid when a record without id is posted, and leave the usage of uuid in our official clients.
But is there any reason to use a different regex that collection and bucket names?

edit: The usecase is the Web sync extension chrome.storage.sync: since any key is accepted, it takes the md5 of the key to "generate" UUIDs. Instead we could let the client push any key as record id.
- Related #140 


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `kinto/views/records.py`
Content:
```
1 import copy
2 
3 import jsonschema
4 from kinto.core import resource
5 from kinto.core.errors import raise_invalid
6 from jsonschema import exceptions as jsonschema_exceptions
7 from pyramid.security import Authenticated
8 from pyramid.settings import asbool
9 
10 from kinto.views import object_exists_or_404
11 
12 
13 class RecordSchema(resource.ResourceSchema):
14     class Options:
15         preserve_unknown = True
16 
17 
18 _parent_path = '/buckets/{{bucket_id}}/collections/{{collection_id}}'
19 
20 
21 @resource.register(name='record',
22                    collection_path=_parent_path + '/records',
23                    record_path=_parent_path + '/records/{{id}}')
24 class Record(resource.ShareableResource):
25 
26     mapping = RecordSchema()
27     schema_field = 'schema'
28 
29     def __init__(self, *args, **kwargs):
30         super(Record, self).__init__(*args, **kwargs)
31 
32         # Check if already fetched before (in batch).
33         collections = self.request.bound_data.setdefault('collections', {})
34         collection_uri = self.get_parent_id(self.request)
35         if collection_uri not in collections:
36             # Unknown yet, fetch from storage.
37             collection_parent_id = '/buckets/%s' % self.bucket_id
38             collection = object_exists_or_404(self.request,
39                                               collection_id='collection',
40                                               parent_id=collection_parent_id,
41                                               object_id=self.collection_id)
42             collections[collection_uri] = collection
43 
44         self._collection = collections[collection_uri]
45 
46     def get_parent_id(self, request):
47         self.bucket_id = request.matchdict['bucket_id']
48         self.collection_id = request.matchdict['collection_id']
49         return '/buckets/%s/collections/%s' % (self.bucket_id,
50                                                self.collection_id)
51 
52     def is_known_field(self, field_name):
53         """Without schema, any field is considered as known."""
54         return True
55 
56     def process_record(self, new, old=None):
57         """Validate records against collection schema, if any."""
58         new = super(Record, self).process_record(new, old)
59 
60         schema = self._collection.get('schema')
61         settings = self.request.registry.settings
62         schema_validation = 'experimental_collection_schema_validation'
63         if not schema or not asbool(settings.get(schema_validation)):
64             return new
65 
66         collection_timestamp = self._collection[self.model.modified_field]
67 
68         try:
69             stripped = copy.deepcopy(new)
70             stripped.pop(self.model.id_field, None)
71             stripped.pop(self.model.modified_field, None)
72             stripped.pop(self.model.permissions_field, None)
73             stripped.pop(self.schema_field, None)
74             jsonschema.validate(stripped, schema)
75         except jsonschema_exceptions.ValidationError as e:
76             try:
77                 field = e.path.pop() if e.path else e.validator_value.pop()
78             except AttributeError:
79                 field = None
80             raise_invalid(self.request, name=field, description=e.message)
81 
82         new[self.schema_field] = collection_timestamp
83         return new
84 
85     def collection_get(self):
86         result = super(Record, self).collection_get()
87         self._handle_cache_expires(self.request.response)
88         return result
89 
90     def get(self):
91         result = super(Record, self).get()
92         self._handle_cache_expires(self.request.response)
93         return result
94 
95     def _handle_cache_expires(self, response):
96         """If the parent collection defines a ``cache_expires`` attribute,
97         then cache-control response headers are sent.
98 
99         .. note::
100 
101             Those headers are also sent if the
102             ``kinto.record_cache_expires_seconds`` setting is defined.
103         """
104         is_anonymous = Authenticated not in self.request.effective_principals
105         if not is_anonymous:
106             return
107 
108         cache_expires = self._collection.get('cache_expires')
109         if cache_expires is None:
110             by_bucket = '%s_record_cache_expires_seconds' % (self.bucket_id)
111             by_collection = '%s_%s_record_cache_expires_seconds' % (
112                 self.bucket_id, self.collection_id)
113             settings = self.request.registry.settings
114             cache_expires = settings.get(by_collection,
115                                          settings.get(by_bucket))
116 
117         if cache_expires is not None:
118             response.cache_expires(seconds=int(cache_expires))
119
```

Path: `kinto/views/__init__.py`
Content:
```
1 import random
2 import string
3 
4 from kinto.core.storage import generators, exceptions
5 from pyramid import httpexceptions
6 
7 
8 class NameGenerator(generators.Generator):
9     def __call__(self):
10         ascii_letters = ('abcdefghijklmopqrstuvwxyz'
11                          'ABCDEFGHIJKLMOPQRSTUVWXYZ')
12         alphabet = ascii_letters + string.digits + '-_'
13         letters = [random.choice(ascii_letters + string.digits)]
14         letters += [random.choice(alphabet) for x in range(7)]
15         return ''.join(letters)
16 
17 
18 def object_exists_or_404(request, collection_id, object_id, parent_id=''):
19     storage = request.registry.storage
20     try:
21         return storage.get(collection_id=collection_id,
22                            parent_id=parent_id,
23                            object_id=object_id)
24     except exceptions.RecordNotFoundError:
25         # XXX: We gave up putting details about parent id here (See #53).
26         raise httpexceptions.HTTPNotFound()
27
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/kinto/views/__init__.py b/kinto/views/__init__.py
--- a/kinto/views/__init__.py
+++ b/kinto/views/__init__.py
@@ -15,6 +15,12 @@
         return ''.join(letters)
 
 
+class RelaxedUUID(generators.UUID4):
+    """A generator that generates UUIDs but accepts any string.
+    """
+    regexp = generators.Generator.regexp
+
+
 def object_exists_or_404(request, collection_id, object_id, parent_id=''):
     storage = request.registry.storage
     try:
diff --git a/kinto/views/records.py b/kinto/views/records.py
--- a/kinto/views/records.py
+++ b/kinto/views/records.py
@@ -7,7 +7,7 @@
 from pyramid.security import Authenticated
 from pyramid.settings import asbool
 
-from kinto.views import object_exists_or_404
+from kinto.views import RelaxedUUID, object_exists_or_404
 
 
 class RecordSchema(resource.ResourceSchema):
@@ -29,6 +29,8 @@
     def __init__(self, *args, **kwargs):
         super(Record, self).__init__(*args, **kwargs)
 
+        self.model.id_generator = RelaxedUUID()
+
         # Check if already fetched before (in batch).
         collections = self.request.bound_data.setdefault('collections', {})
         collection_uri = self.get_parent_id(self.request)

{"golden_diff": "diff --git a/kinto/views/__init__.py b/kinto/views/__init__.py\n--- a/kinto/views/__init__.py\n+++ b/kinto/views/__init__.py\n@@ -15,6 +15,12 @@\n         return ''.join(letters)\n \n \n+class RelaxedUUID(generators.UUID4):\n+    \"\"\"A generator that generates UUIDs but accepts any string.\n+    \"\"\"\n+    regexp = generators.Generator.regexp\n+\n+\n def object_exists_or_404(request, collection_id, object_id, parent_id=''):\n     storage = request.registry.storage\n     try:\ndiff --git a/kinto/views/records.py b/kinto/views/records.py\n--- a/kinto/views/records.py\n+++ b/kinto/views/records.py\n@@ -7,7 +7,7 @@\n from pyramid.security import Authenticated\n from pyramid.settings import asbool\n \n-from kinto.views import object_exists_or_404\n+from kinto.views import RelaxedUUID, object_exists_or_404\n \n \n class RecordSchema(resource.ResourceSchema):\n@@ -29,6 +29,8 @@\n     def __init__(self, *args, **kwargs):\n         super(Record, self).__init__(*args, **kwargs)\n \n+        self.model.id_generator = RelaxedUUID()\n+\n         # Check if already fetched before (in batch).\n         collections = self.request.bound_data.setdefault('collections', {})\n         collection_uri = self.get_parent_id(self.request)\n", "issue": "Relax record id validation\nDo we really need to ensure that posted record ids match a uuid regex?\n\nWe can generate a uuid when a record without id is posted, and leave the usage of uuid in our official clients.\nBut is there any reason to use a different regex that collection and bucket names?\n\nedit: The usecase is the Web sync extension chrome.storage.sync: since any key is accepted, it takes the md5 of the key to \"generate\" UUIDs. Instead we could let the client push any key as record id.\n- Related #140 \n\n", "before_files": [{"content": "import copy\n\nimport jsonschema\nfrom kinto.core import resource\nfrom kinto.core.errors import raise_invalid\nfrom jsonschema import exceptions as jsonschema_exceptions\nfrom pyramid.security import Authenticated\nfrom pyramid.settings import asbool\n\nfrom kinto.views import object_exists_or_404\n\n\nclass RecordSchema(resource.ResourceSchema):\n    class Options:\n        preserve_unknown = True\n\n\n_parent_path = '/buckets/{{bucket_id}}/collections/{{collection_id}}'\n\n\n@resource.register(name='record',\n                   collection_path=_parent_path + '/records',\n                   record_path=_parent_path + '/records/{{id}}')\nclass Record(resource.ShareableResource):\n\n    mapping = RecordSchema()\n    schema_field = 'schema'\n\n    def __init__(self, *args, **kwargs):\n        super(Record, self).__init__(*args, **kwargs)\n\n        # Check if already fetched before (in batch).\n        collections = self.request.bound_data.setdefault('collections', {})\n        collection_uri = self.get_parent_id(self.request)\n        if collection_uri not in collections:\n            # Unknown yet, fetch from storage.\n            collection_parent_id = '/buckets/%s' % self.bucket_id\n            collection = object_exists_or_404(self.request,\n                                              collection_id='collection',\n                                              parent_id=collection_parent_id,\n                                              object_id=self.collection_id)\n            collections[collection_uri] = collection\n\n        self._collection = collections[collection_uri]\n\n    def get_parent_id(self, request):\n        self.bucket_id = request.matchdict['bucket_id']\n        self.collection_id = request.matchdict['collection_id']\n        return '/buckets/%s/collections/%s' % (self.bucket_id,\n                                               self.collection_id)\n\n    def is_known_field(self, field_name):\n        \"\"\"Without schema, any field is considered as known.\"\"\"\n        return True\n\n    def process_record(self, new, old=None):\n        \"\"\"Validate records against collection schema, if any.\"\"\"\n        new = super(Record, self).process_record(new, old)\n\n        schema = self._collection.get('schema')\n        settings = self.request.registry.settings\n        schema_validation = 'experimental_collection_schema_validation'\n        if not schema or not asbool(settings.get(schema_validation)):\n            return new\n\n        collection_timestamp = self._collection[self.model.modified_field]\n\n        try:\n            stripped = copy.deepcopy(new)\n            stripped.pop(self.model.id_field, None)\n            stripped.pop(self.model.modified_field, None)\n            stripped.pop(self.model.permissions_field, None)\n            stripped.pop(self.schema_field, None)\n            jsonschema.validate(stripped, schema)\n        except jsonschema_exceptions.ValidationError as e:\n            try:\n                field = e.path.pop() if e.path else e.validator_value.pop()\n            except AttributeError:\n                field = None\n            raise_invalid(self.request, name=field, description=e.message)\n\n        new[self.schema_field] = collection_timestamp\n        return new\n\n    def collection_get(self):\n        result = super(Record, self).collection_get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def get(self):\n        result = super(Record, self).get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def _handle_cache_expires(self, response):\n        \"\"\"If the parent collection defines a ``cache_expires`` attribute,\n        then cache-control response headers are sent.\n\n        .. note::\n\n            Those headers are also sent if the\n            ``kinto.record_cache_expires_seconds`` setting is defined.\n        \"\"\"\n        is_anonymous = Authenticated not in self.request.effective_principals\n        if not is_anonymous:\n            return\n\n        cache_expires = self._collection.get('cache_expires')\n        if cache_expires is None:\n            by_bucket = '%s_record_cache_expires_seconds' % (self.bucket_id)\n            by_collection = '%s_%s_record_cache_expires_seconds' % (\n                self.bucket_id, self.collection_id)\n            settings = self.request.registry.settings\n            cache_expires = settings.get(by_collection,\n                                         settings.get(by_bucket))\n\n        if cache_expires is not None:\n            response.cache_expires(seconds=int(cache_expires))\n", "path": "kinto/views/records.py"}, {"content": "import random\nimport string\n\nfrom kinto.core.storage import generators, exceptions\nfrom pyramid import httpexceptions\n\n\nclass NameGenerator(generators.Generator):\n    def __call__(self):\n        ascii_letters = ('abcdefghijklmopqrstuvwxyz'\n                         'ABCDEFGHIJKLMOPQRSTUVWXYZ')\n        alphabet = ascii_letters + string.digits + '-_'\n        letters = [random.choice(ascii_letters + string.digits)]\n        letters += [random.choice(alphabet) for x in range(7)]\n        return ''.join(letters)\n\n\ndef object_exists_or_404(request, collection_id, object_id, parent_id=''):\n    storage = request.registry.storage\n    try:\n        return storage.get(collection_id=collection_id,\n                           parent_id=parent_id,\n                           object_id=object_id)\n    except exceptions.RecordNotFoundError:\n        # XXX: We gave up putting details about parent id here (See #53).\n        raise httpexceptions.HTTPNotFound()\n", "path": "kinto/views/__init__.py"}], "after_files": [{"content": "import copy\n\nimport jsonschema\nfrom kinto.core import resource\nfrom kinto.core.errors import raise_invalid\nfrom jsonschema import exceptions as jsonschema_exceptions\nfrom pyramid.security import Authenticated\nfrom pyramid.settings import asbool\n\nfrom kinto.views import RelaxedUUID, object_exists_or_404\n\n\nclass RecordSchema(resource.ResourceSchema):\n    class Options:\n        preserve_unknown = True\n\n\n_parent_path = '/buckets/{{bucket_id}}/collections/{{collection_id}}'\n\n\n@resource.register(name='record',\n                   collection_path=_parent_path + '/records',\n                   record_path=_parent_path + '/records/{{id}}')\nclass Record(resource.ShareableResource):\n\n    mapping = RecordSchema()\n    schema_field = 'schema'\n\n    def __init__(self, *args, **kwargs):\n        super(Record, self).__init__(*args, **kwargs)\n\n        self.model.id_generator = RelaxedUUID()\n\n        # Check if already fetched before (in batch).\n        collections = self.request.bound_data.setdefault('collections', {})\n        collection_uri = self.get_parent_id(self.request)\n        if collection_uri not in collections:\n            # Unknown yet, fetch from storage.\n            collection_parent_id = '/buckets/%s' % self.bucket_id\n            collection = object_exists_or_404(self.request,\n                                              collection_id='collection',\n                                              parent_id=collection_parent_id,\n                                              object_id=self.collection_id)\n            collections[collection_uri] = collection\n\n        self._collection = collections[collection_uri]\n\n    def get_parent_id(self, request):\n        self.bucket_id = request.matchdict['bucket_id']\n        self.collection_id = request.matchdict['collection_id']\n        return '/buckets/%s/collections/%s' % (self.bucket_id,\n                                               self.collection_id)\n\n    def is_known_field(self, field_name):\n        \"\"\"Without schema, any field is considered as known.\"\"\"\n        return True\n\n    def process_record(self, new, old=None):\n        \"\"\"Validate records against collection schema, if any.\"\"\"\n        new = super(Record, self).process_record(new, old)\n\n        schema = self._collection.get('schema')\n        settings = self.request.registry.settings\n        schema_validation = 'experimental_collection_schema_validation'\n        if not schema or not asbool(settings.get(schema_validation)):\n            return new\n\n        collection_timestamp = self._collection[self.model.modified_field]\n\n        try:\n            stripped = copy.deepcopy(new)\n            stripped.pop(self.model.id_field, None)\n            stripped.pop(self.model.modified_field, None)\n            stripped.pop(self.model.permissions_field, None)\n            stripped.pop(self.schema_field, None)\n            jsonschema.validate(stripped, schema)\n        except jsonschema_exceptions.ValidationError as e:\n            try:\n                field = e.path.pop() if e.path else e.validator_value.pop()\n            except AttributeError:\n                field = None\n            raise_invalid(self.request, name=field, description=e.message)\n\n        new[self.schema_field] = collection_timestamp\n        return new\n\n    def collection_get(self):\n        result = super(Record, self).collection_get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def get(self):\n        result = super(Record, self).get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def _handle_cache_expires(self, response):\n        \"\"\"If the parent collection defines a ``cache_expires`` attribute,\n        then cache-control response headers are sent.\n\n        .. note::\n\n            Those headers are also sent if the\n            ``kinto.record_cache_expires_seconds`` setting is defined.\n        \"\"\"\n        is_anonymous = Authenticated not in self.request.effective_principals\n        if not is_anonymous:\n            return\n\n        cache_expires = self._collection.get('cache_expires')\n        if cache_expires is None:\n            by_bucket = '%s_record_cache_expires_seconds' % (self.bucket_id)\n            by_collection = '%s_%s_record_cache_expires_seconds' % (\n                self.bucket_id, self.collection_id)\n            settings = self.request.registry.settings\n            cache_expires = settings.get(by_collection,\n                                         settings.get(by_bucket))\n\n        if cache_expires is not None:\n            response.cache_expires(seconds=int(cache_expires))\n", "path": "kinto/views/records.py"}, {"content": "import random\nimport string\n\nfrom kinto.core.storage import generators, exceptions\nfrom pyramid import httpexceptions\n\n\nclass NameGenerator(generators.Generator):\n    def __call__(self):\n        ascii_letters = ('abcdefghijklmopqrstuvwxyz'\n                         'ABCDEFGHIJKLMOPQRSTUVWXYZ')\n        alphabet = ascii_letters + string.digits + '-_'\n        letters = [random.choice(ascii_letters + string.digits)]\n        letters += [random.choice(alphabet) for x in range(7)]\n        return ''.join(letters)\n\n\nclass RelaxedUUID(generators.UUID4):\n    \"\"\"A generator that generates UUIDs but accepts any string.\n    \"\"\"\n    regexp = generators.Generator.regexp\n\n\ndef object_exists_or_404(request, collection_id, object_id, parent_id=''):\n    storage = request.registry.storage\n    try:\n        return storage.get(collection_id=collection_id,\n                           parent_id=parent_id,\n                           object_id=object_id)\n    except exceptions.RecordNotFoundError:\n        # XXX: We gave up putting details about parent id here (See #53).\n        raise httpexceptions.HTTPNotFound()\n", "path": "kinto/views/__init__.py"}]}