Initial work to support streams

fauna/client/client.py

@@ -10,6 +10,7 @@
 from fauna.client.headers import _DriverEnvironment, _Header, _Auth, Header
 from fauna.http.http_client import HTTPClient
 from fauna.query import Query, Page, fql
+from fauna.query.models import StreamToken
 from fauna.client.utils import _Environment, LastTxnTs
 from fauna.encoding import FaunaEncoder, FaunaDecoder
 from fauna.encoding import QuerySuccess, ConstraintFailure, QueryTags, QueryStats
@@ -375,6 +376,28 @@ def _query(
           schema_version=schema_version,
       )
 
+  def stream(self, token: StreamToken):
+    # todo: pass a token or a Query
+
+    if not isinstance(token, StreamToken):
+      err_msg = f"'token' must be a StreamToken but was a {type(token)}."
+      raise TypeError(err_msg)
+
+    headers = self._headers.copy()
+    headers[_Header.Format] = "tagged"
+    headers[_Header.Authorization] = self._auth.bearer()
+
+    data = { "token": token.token }
+
+    response = self._session.stream(
+        url=self._endpoint + "/stream/1",
+        headers=headers,
+        data=data,
+    )
+
+    for line in response:
+      yield FaunaDecoder.decode(line)
+
   def _check_protocol(self, response_json: Any, status_code):
     # TODO: Logic to validate wire protocol belongs elsewhere.
     should_raise = False

fauna/encoding/decoder.py

@@ -3,7 +3,7 @@
 from iso8601 import parse_date
 
 from fauna.query.models import Module, DocumentReference, Document, NamedDocument, NamedDocumentReference, Page, \
-    NullDocument
+    NullDocument, StreamToken
 
 
 class FaunaDecoder:
@@ -42,6 +42,8 @@ class FaunaDecoder:
      +--------------------+---------------+
      | Page               | @set          |
      +--------------------+---------------+
+     | StreamToken        | @stream       |
+     +--------------------+---------------+
 
      """
 
@@ -59,6 +61,7 @@ def decode(obj: Any):
             - { "@ref": ... } decodes to a DocumentReference or NamedDocumentReference
             - { "@mod": ... } decodes to a Module
             - { "@set": ... } decodes to a Page
+            - { "@stream": ... } decodes to a StreamToken
 
         :param obj: the object to decode
         """
@@ -165,4 +168,7 @@ def _decode_dict(dct: dict, escaped: bool):
 
         return Page(data=data, after=after)
 
+      if "@stream" in dct:
+        return StreamToken(dct["@stream"])
+
     return {k: FaunaDecoder._decode(v) for k, v in dct.items()}

fauna/encoding/encoder.py

@@ -1,7 +1,7 @@
 from datetime import datetime, date
 from typing import Any, Optional, Set
 
-from fauna.query.models import DocumentReference, Module, Document, NamedDocument, NamedDocumentReference, NullDocument
+from fauna.query.models import DocumentReference, Module, Document, NamedDocument, NamedDocumentReference, NullDocument, StreamToken
 from fauna.query.query_builder import Query, Fragment, LiteralFragment, ValueFragment
 
 _RESERVED_TAGS = [
@@ -58,6 +58,8 @@ class FaunaEncoder:
     +-------------------------------+---------------+
     | TemplateFragment              | string        |
     +-------------------------------+---------------+
+    | StreamToken                   | string        |
+    +-------------------------------+---------------+
 
     """
 
@@ -76,6 +78,7 @@ def encode(obj: Any) -> Any:
             - Query encodes to { "fql": [...] }
             - ValueFragment encodes to { "value": <encoded_val> }
             - LiteralFragment encodes to a string
+            - StreamToken encodes to a string
 
         :raises ValueError: If value cannot be encoded, cannot be encoded safely, or there's a circular reference.
         :param obj: the object to decode
@@ -151,6 +154,10 @@ def from_fragment(obj: Fragment):
   def from_query_interpolation_builder(obj: Query):
     return {"fql": [FaunaEncoder.from_fragment(f) for f in obj.fragments]}
 
+  @staticmethod
+  def from_streamtoken(obj: StreamToken):
+    return {"@stream": obj.token}
+
   @staticmethod
   def _encode(o: Any, _markers: Optional[Set] = None):
     if _markers is None:
@@ -191,6 +198,8 @@ def _encode(o: Any, _markers: Optional[Set] = None):
       return FaunaEncoder._encode_dict(o, _markers)
     elif isinstance(o, Query):
       return FaunaEncoder.from_query_interpolation_builder(o)
+    elif isinstance(o, StreamToken):
+      return FaunaEncoder.from_streamtoken(o)
     else:
       raise ValueError(f"Object {o} of type {type(o)} cannot be encoded")
 

fauna/http/httpx_client.py

@@ -98,8 +98,10 @@ def stream(
       url: str,
       headers: Mapping[str, str],
       data: Mapping[str, Any],
-  ) -> Iterator[HTTPResponse]:
-    raise NotImplementedError()
+  ) -> Iterator[Any]:
+    with self._c.stream("POST", url=url, headers=headers, json=data) as r:
+      for line in r.iter_lines():
+        yield json.loads(line)
 
   def close(self):
     self._c.close()

fauna/query/models.py

@@ -36,6 +36,19 @@ def __ne__(self, other):
     return not self.__eq__(other)
 
 
+class StreamToken:
+  """A class represeting a Stream in Fauna."""
+
+  def __init__(self, token: str = None):
+    self.token = token
+
+  def __eq__(self, other):
+    return isinstance(other, StreamToken) and self.token == other.token
+
+  def __hash__(self):
+    hash(self.token)
+
+
 class Module:
   """A class representing a Module in Fauna. Examples of modules include Collection, Math, and a user-defined
     collection, among others.

tests/unit/test_client.py

@@ -1,15 +1,17 @@
+import json
 from datetime import timedelta
 from typing import Dict
 
 import httpx
 import pytest
 import pytest_subtests
-from pytest_httpx import HTTPXMock
+from pytest_httpx import HTTPXMock, IteratorStream
 
 import fauna
 from fauna import fql
 from fauna.client import Client, Header, QueryOptions, Endpoints
 from fauna.errors import QueryCheckError, ProtocolError, QueryRuntimeError
+from fauna.query.models import StreamToken
 from fauna.http import HTTPXClient
 
 
@@ -413,3 +415,17 @@ def test_call_query_with_string():
       match="'fql' must be a Query but was a <class 'str'>. You can build a Query by "
       "calling fauna.fql()"):
     c.query("fake")  # type: ignore
+
+
+def test_client_stream(subtests, httpx_mock: HTTPXMock):
+  response = ['{"@int": "10"}\n', '{"@long": "20"}\n']
+
+  httpx_mock.add_response(stream=IteratorStream([bytes(r, 'utf-8') for r in response]))
+
+  with httpx.Client() as mockClient:
+    http_client = HTTPXClient(mockClient)
+    c = Client(http_client=http_client)
+    ret = [obj for obj in c.stream(StreamToken("token"))]
+
+    assert ret == [10, 20]
+

tests/unit/test_encoding.py

@@ -7,7 +7,7 @@
 from fauna import fql
 from fauna.encoding import FaunaEncoder, FaunaDecoder
 from fauna.query.models import DocumentReference, NamedDocumentReference, Document, NamedDocument, Module, Page, \
-    NullDocument
+    NullDocument, StreamToken
 
 fixed_datetime = datetime.fromisoformat("2023-03-17T00:00:00+00:00")
 
@@ -755,3 +755,18 @@ def test_encode_query_builder_sub_queries(subtests):
     }
 
     assert expected == actual
+
+
+def test_decode_stream(subtests):
+  with subtests.test(msg="decode @stream into StreamToken"):
+    test = {"@stream": "asdflkj"}
+    decoded = FaunaDecoder.decode(test)
+    assert decoded == StreamToken("asdflkj")
+
+
+def test_encode_stream(subtests):
+  with subtests.test(msg="encode StreamToken into @stream"):
+    test = {"@stream": "asdflkj"}
+    encoded = FaunaEncoder.encode(StreamToken("asdflkj"))
+    assert encoded == test
+

tests/unit/test_httpx_client.py

@@ -0,0 +1,22 @@
+import json
+
+import httpx
+from pytest_httpx import HTTPXMock, IteratorStream
+
+from fauna.client import Client
+from fauna.http import HTTPXClient
+
+def test_httx_client_stream(subtests, httpx_mock: HTTPXMock):
+  expected = [{"@int": "10"}, {"@long": "20"}]
+
+  def to_json_bytes(obj):
+    return bytes(json.dumps(obj) + "\n", "utf-8")
+
+  httpx_mock.add_response(stream=IteratorStream([to_json_bytes(obj) for obj in expected]))
+
+  with httpx.Client() as mockClient:
+    http_client = HTTPXClient(mockClient)
+    ret = [obj for obj in http_client.stream("http://localhost:8443", {}, {})]
+
+    assert ret == expected
+