community: Add token_usage and model_name metadata to ChatZhipuAI str…

…eam() and astream() response (#27677)

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- **Description:** Add token_usage and model_name metadata to
ChatZhipuAI stream() and astream() response
- **Issue:** None
- **Dependencies:** None
- **Twitter handle:** None


- [ ] **Add tests and docs**: If you're adding a new integration, please
include
1. a test for the integration, preferably unit tests that do not rely on
network access,
2. an example notebook showing its use. It lives in
`docs/docs/integrations` directory.


- [ ] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. See contribution
guidelines for more: https://python.langchain.com/docs/contributing/

Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to pyproject.toml files (even optional
ones) unless they are required for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.
- If you are adding something to community, do not re-import it in
langchain.

If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, ccurme, vbarda, hwchase17.

Co-authored-by: jianfehuang <[email protected]>

libs/community/langchain_community/chat_models/zhipuai.py

@@ -591,13 +591,19 @@ def _stream(
                     if len(chunk["choices"]) == 0:
                         continue
                     choice = chunk["choices"][0]
+                    usage = chunk.get("usage", None)
+                    model_name = chunk.get("model", "")
                     chunk = _convert_delta_to_message_chunk(
                         choice["delta"], default_chunk_class
                     )
                     finish_reason = choice.get("finish_reason", None)
 
                     generation_info = (
-                        {"finish_reason": finish_reason}
+                        {
+                            "finish_reason": finish_reason,
+                            "token_usage": usage,
+                            "model_name": model_name,
+                        }
                         if finish_reason is not None
                         else None
                     )
@@ -678,13 +684,19 @@ async def _astream(
                     if len(chunk["choices"]) == 0:
                         continue
                     choice = chunk["choices"][0]
+                    usage = chunk.get("usage", None)
+                    model_name = chunk.get("model", "")
                     chunk = _convert_delta_to_message_chunk(
                         choice["delta"], default_chunk_class
                     )
                     finish_reason = choice.get("finish_reason", None)
 
                     generation_info = (
-                        {"finish_reason": finish_reason}
+                        {
+                            "finish_reason": finish_reason,
+                            "token_usage": usage,
+                            "model_name": model_name,
+                        }
                         if finish_reason is not None
                         else None
                     )