After updating to version 1.2.0, calling the API to obtain session history messages failed

[MichaelNie1994]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

There is an unknown issue with the /messages API endpoint in Dify version 1.2.0 that results in a status code 500 error when I tried to retrieve historical conversation content.

And I have modified the code of the file "api/controllers/service_api/app/message.py":
from
"retriever_resources": fields.Raw( attribute=lambda obj: json.loads(obj.message_metadata).get("retriever_resources", []) if obj.message_metadata else []
to "retriever_resources": fields.List( attribute=lambda obj: json.loads(obj.message_metadata).get("retriever_resources", []) if obj.message_metadata else []
but it didn't work.

And these are some errors shown from the logs:

2025-04-10 16:44:32.237 ERROR [Dummy-38] [app.py:875] - Exception on /v1/messages [GET]
Traceback (most recent call last):
File "/app/api/.venv/lib/python3.12/site-packages/flask/app.py", line 917, in full_dispatch_request
rv = self.dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask/app.py", line 902, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 489, in wrapper
resp = resource(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask/views.py", line 110, in view
return current_app.ensure_sync(self.dispatch_request)(**kwargs) # type: ignore[no-any-return]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 604, in dispatch_request
resp = meth(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^
File "/app/api/controllers/service_api/wraps.py", line 104, in decorated_view
return view_func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 701, in wrapper
return marshal(resp, self.fields, self.envelope)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 657, in marshal
return OrderedDict([(envelope, OrderedDict(items))]) if envelope else OrderedDict(items)
^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 655, in <genexpr>
else make(v).output(k, data))
^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/fields.py", line 197, in output
return self.format(value)
^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/fields.py", line 183, in format
self.container.output(idx,
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/fields.py", line 152, in output
return marshal(value, self.nested)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 657, in marshal
return OrderedDict([(envelope, OrderedDict(items))]) if envelope else OrderedDict(items)
^^^^^^^^^^^^^^^^^^
File "/app/api/.venv/lib/python3.12/site-packages/flask_restful/__init__.py", line 655, in <genexpr>
else make(v).output(k, data))
^^^^^^^^^^^^^^
AttributeError: 'function' object has no attribute 'output'

2. Additional context or comments

No response

[jasonfish568]

@liguochuan00 Could you please have a look at this as I believe it is a fatal error caused by the update of the code.

in service_api/app/message.py:

def get_retriever_resources(self):
        try:
            if self.message_metadata:
                return json.loads(self.message_metadata).get("retriever_resources", [])
            return []
        except (json.JSONDecodeError, TypeError):
            return []

message_fields = {
    "id": fields.String,
    "conversation_id": fields.String,
    "parent_message_id": fields.String,
    "inputs": FilesContainedField,
    "query": fields.String,
    "answer": fields.String(attribute="re_sign_file_url_answer"),
    "message_files": fields.List(fields.Nested(message_file_fields)),
    "feedback": fields.Nested(feedback_fields, attribute="user_feedback", allow_null=True),
    "retriever_resources": get_retriever_resources,
    "created_at": TimestampField,
    "agent_thoughts": fields.List(fields.Nested(agent_thought_fields)),
    "status": fields.String,
    "error": fields.String,
}

get_retriever_resources method is being used as as field in the message_fields. It doesn't make sense in any programming languages to be honest.

The original way of retriever_resource_fields is correct. The problem is the get method did not fetch the retriever information.

@crazywoola Please see if I have clearly stated the problem. I think I better fix the code and submit a hotfix by myself.

[crazywoola]

Already fixed it.

[MichaelNie1994]

So what should I do next to fix this problem? I've updated Dify to 1.2.0, and modified the codes in service_api/app/message.py, but it didn't work; thanks for that.

[jasonfish568]

As mentioned below it’s pending release so in the next release this will be fixed. In the meantime time, if you are running the development backend, you can pull the latest code from main branch and run the backend. This is explained in the api Readme file.

[jasonfish568]

This should be raised in the issue tracker.

[jasonfish568]

#17716

This already solved by crazywoola. Pending release.

[batteryhob]

I pulled the latest main branch and ran the project, but I'm still encountering the same error.
Could you please let me know how to resolve this?
Also, do you have an estimated timeline for the fix or the next release?

[jasonfish568]

You will have to wait until next release. It seems the team is pretty busy so no idea when they will release.
In the meantime, if you know how to build your own docker image. You can deploy your own docker with the latest commit on main branch.

[jasonfish568]

Pulling the latest main branch and run docker compose up in the docker folder doesn't mean you are running the latest main branch code. Because the docker compose file uses a pre build image from docker registry and that is v1.2.0

[jasonfish568]

There you go. 1.3.0 is live