feat: ui build in one single http request (#3020)

* feat: ui build in one single http request

* fix use session_id

* fix frozen

* [autofix.ci] apply automated fixes

* prettier

* add tests

* add tests

* fix mypy

* [autofix.ci] apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

src/backend/tests/conftest.py

@@ -53,6 +53,7 @@ def pytest_configure(config):
     pytest.TWO_OUTPUTS = data_path / "TwoOutputsTest.json"
     pytest.VECTOR_STORE_PATH = data_path / "Vector_store.json"
     pytest.SIMPLE_API_TEST = data_path / "SimpleAPITest.json"
+    pytest.MEMORY_CHATBOT_NO_LLM = data_path / "MemoryChatbotNoLLM.json"
     pytest.CODE_WITH_SYNTAX_ERROR = """
 def get_text():
     retun "Hello World"
@@ -70,6 +71,7 @@ def get_text():
         pytest.CHAT_INPUT,
         pytest.TWO_OUTPUTS,
         pytest.VECTOR_STORE_PATH,
+        pytest.MEMORY_CHATBOT_NO_LLM,
     ]:
         assert path.exists(), f"File {path} does not exist. Available files: {list(data_path.iterdir())}"
 
@@ -232,6 +234,12 @@ def json_webhook_test():
         return f.read()
 
 
+@pytest.fixture
+def json_memory_chatbot_no_llm():
+    with open(pytest.MEMORY_CHATBOT_NO_LLM, "r") as f:
+        return f.read()
+
+
 @pytest.fixture(name="client", autouse=True)
 def client_fixture(session: Session, monkeypatch, request, load_flows_dir):
     # Set the database url to a test database

src/backend/tests/unit/test_chat_endpoint.py

@@ -0,0 +1,93 @@
+import json
+from uuid import UUID
+from orjson import orjson
+
+from langflow.memory import get_messages
+from langflow.services.database.models.flow import FlowCreate, FlowUpdate
+
+
+def test_build_flow(client, json_memory_chatbot_no_llm, logged_in_headers):
+    flow_id = _create_flow(client, json_memory_chatbot_no_llm, logged_in_headers)
+
+    with client.stream("POST", f"api/v1/build/{flow_id}/flow", json={}, headers=logged_in_headers) as r:
+        consume_and_assert_stream(r)
+
+    check_messages(flow_id)
+
+
+def test_build_flow_from_request_data(client, json_memory_chatbot_no_llm, logged_in_headers):
+    flow_id = _create_flow(client, json_memory_chatbot_no_llm, logged_in_headers)
+    flow_data = client.get("api/v1/flows/" + str(flow_id), headers=logged_in_headers).json()
+
+    with client.stream(
+        "POST", f"api/v1/build/{flow_id}/flow", json={"data": flow_data["data"]}, headers=logged_in_headers
+    ) as r:
+        consume_and_assert_stream(r)
+
+    check_messages(flow_id)
+
+
+def test_build_flow_with_frozen_path(client, json_memory_chatbot_no_llm, logged_in_headers):
+    flow_id = _create_flow(client, json_memory_chatbot_no_llm, logged_in_headers)
+
+    flow_data = client.get("api/v1/flows/" + str(flow_id), headers=logged_in_headers).json()
+    flow_data["data"]["nodes"][0]["data"]["node"]["frozen"] = True
+    response = client.patch(
+        "api/v1/flows/" + str(flow_id),
+        json=FlowUpdate(name="Flow", description="description", data=flow_data["data"]).model_dump(),
+        headers=logged_in_headers,
+    )
+    response.raise_for_status()
+
+    with client.stream("POST", f"api/v1/build/{flow_id}/flow", json={}, headers=logged_in_headers) as r:
+        consume_and_assert_stream(r)
+
+    check_messages(flow_id)
+
+
+def check_messages(flow_id):
+    messages = get_messages(flow_id=UUID(flow_id), order="ASC")
+    assert len(messages) == 2
+    assert messages[0].session_id == flow_id
+    assert messages[0].sender == "User"
+    assert messages[0].sender_name == "User"
+    assert messages[0].text == ""
+    assert messages[1].session_id == flow_id
+    assert messages[1].sender == "Machine"
+    assert messages[1].sender_name == "AI"
+
+
+def consume_and_assert_stream(r):
+    count = 0
+    for line in r.iter_lines():
+        # httpx split by \n, but ndjson sends two \n for each line
+        if not line:
+            continue
+        parsed = json.loads(line)
+        if count == 0:
+            assert parsed["event"] == "vertices_sorted"
+            ids = parsed["data"]["ids"]
+            ids.sort()
+            assert ids == ["ChatInput-CIGht", "Memory-amN4Z"]
+
+            to_run = parsed["data"]["to_run"]
+            to_run.sort()
+            assert to_run == ["ChatInput-CIGht", "ChatOutput-QA7ej", "Memory-amN4Z", "Prompt-iWbCC"]
+        elif count > 0 and count < 5:
+            assert parsed["event"] == "end_vertex"
+            assert parsed["data"]["build_data"] is not None
+        elif count == 5:
+            assert parsed["event"] == "end"
+        else:
+            raise ValueError(f"Unexpected line: {line}")
+        count += 1
+
+
+def _create_flow(client, json_memory_chatbot_no_llm, logged_in_headers):
+    vector_store = orjson.loads(json_memory_chatbot_no_llm)
+    data = vector_store["data"]
+    vector_store = FlowCreate(name="Flow", description="description", data=data, endpoint_name="f")
+    response = client.post("api/v1/flows/", json=vector_store.model_dump(), headers=logged_in_headers)
+    response.raise_for_status()
+    flow_id = response.json()["id"]
+    return flow_id