### What problem does this PR solve?

Close #7655

Based on the codes atthe api_app, I think the reference is one-to-one
with the message
`
    def fillin_conv(ans):
        nonlocal conv, message_id
        if not conv.reference:
            conv.reference.append(ans["reference"])
        else:
            conv.reference[-1] = ans["reference"]
conv.message[-1] = {"role": "assistant", "content": ans["answer"], "id":
message_id}
        ans["id"] = message_id
`



### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

resolve this issue：https://github.com/infiniflow/ragflow/issues/6876

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: wenju.li <wenju.li@deepctr.cn>

### What problem does this PR solve?

The old logic filters out all assistant messages from messages, which,
in multi-turn conversations, results in only user messages being
retained. This leads to an error in locally deployed models:
Conversation roles must alternate user/assistant/user/assistant/...

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

### What problem does this PR solve?

This PR introduces ​**​primitive support for function calls​**​,
enabling the system to handle basic function call capabilities.
However, this feature is currently experimental and ​**​not yet enabled
for general use​**​, as it is only supported by a subset of models,
namely, Qwen and OpenAI models.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?
add openai agent
_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

### Type of change

- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

Fix #5418

Actually, the fix #4329 also works for agent flows with parameters, so
this PR just relaxes the `else` branch of that. With this PR, it works
fine on my side, may need more testing to make sure this does not break
something.

I guess the real problem may be deeply hidden in the code which relates
to conversation and canvas execution. After a few hours of debugging, I
see the only difference between with and without parameters in `begin`
component, is the `history` field of canvas data. When the `begin`
component contains some parameters, the debug log shows:

```
025-03-29 19:50:38,521 DEBUG    356590 {
            "component_name": "Begin",
            "params": {"output_var_name": "output", "message_history_window_size": 22, "query": [{"type": "fileUrls", "key": "fileUrls", "name": "files", "optional": true, "value": "问题.txt\n今天天气怎么样"}], "inputs": [], "debug_inputs": [], "prologue": "你好！ 我是你的助理，有什么可以帮到你的吗？", "output": null},
            "output": null,
            "inputs": []
        }, history: [["user", "请回答我上传文件中的问题。"]], kwargs: {"stream": false}
2025-03-29 19:50:38,523 DEBUG    356590 {
            "component_name": "Answer",
            "params": {"output_var_name": "output", "message_history_window_size": 22, "query": [], "inputs": [], "debug_inputs": [], "post_answers": [], "output": null},
            "output": null,
            "inputs": []
        }, history: [["user", "请回答我上传文件中的问题。"]], kwargs: {"stream": false}
```

Then it does not go further along the flow.

When the `begin` component does not contain any parameter, the debug log
shows:

```
2025-03-29 19:41:13,518 DEBUG    353596 {
            "component_name": "Begin",
            "params": {"output_var_name": "output", "message_history_window_size": 22, "query": [], "inputs": [], "debug_inputs": [], "prologue": "你好！ 我是你的助理，有什么可以帮到你的吗？", "output": null},
            "output": null,
            "inputs": []
        }, history: [], kwargs: {"stream": false}
2025-03-29 19:41:13,520 DEBUG    353596 {
            "component_name": "Answer",
            "params": {"output_var_name": "output", "message_history_window_size": 22, "query": [], "inputs": [], "debug_inputs": [], "post_answers": [], "output": null},
            "output": null,
            "inputs": []
        }, history: [], kwargs: {"stream": false}
2025-03-29 19:41:13,556 INFO     353596 127.0.0.1 - - [29/Mar/2025 19:41:13] "POST /api/v1/agents/fee6886a0c6f11f09b48eb8798e9aa9b/sessions?user_id=123 HTTP/1.1" 200 -
2025-03-29 19:41:21,115 DEBUG    353596 Canvas.prepare2run: Retrieval:LateGuestsNotice
2025-03-29 19:41:21,116 DEBUG    353596 {
            "component_name": "Retrieval",
            "params": {"output_var_name": "output", "message_history_window_size": 22, "query": [], "inputs": [], "debug_inputs": [], "similarity_threshold": 0.2, "keywords_similarity_weight": 0.3, "top_n": 8, "top_k": 1024, "kb_ids": ["9aca3c700c5911f0811caf35658b9385"], "rerank_id": "", "empty_response": "", "tavily_api_key": "", "use_kg": false, "output": null},
            "output": null,
            "inputs": []
        }, history: [["user", "请回答我上传文件中的问题。"]], kwargs: {"stream": false}
```

It correctly goes along the flow and generates correct answer.

You can see the difference: when the `begin` component has any
parameter, the `history` field is filled from the beginning, while it is
just `[]` if the `begin` component has no parameter.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

### What problem does this PR solve?

Change LLM chat output from full to delta (incremental)

### Type of change

- [x] Refactoring

### What problem does this PR solve?

#6210

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

fix chat_completion answer data incorrect

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: renqi <renqi08266@fxomail.com>

### What problem does this PR solve?

#5944

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?


### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: renqi <renqi08266@fxomail.com>

When accessing the /api/v1/agents/{agent_id}/completions API, sessions
created before agent modifications retain the old DSL data. To use the
latest agent configuration (like new prompts) in historical sessions, I
added the sync_dsl parameter. It defaults to False to maintain existing
behavior and only synchronizes when set to True. If needed, a manual
synchronization API can be created to trigger the sync explicitly.

1. **Issue**: When calling `list_agent_session` via the HTTP API, users
may only need to display conversation messages, and do not want to see
the associated dsl, which can be very large. Therefore, consider adding
a control option to determine whether the DSL should be returned, with
the default being to return it.

2. **Documentation Discrepancy**: In the HTTP API documentation, under
"List agent sessions," the "Response" section states that the "data"
field is a dictionary when "success" is returned. However, the actual
returned data is a list. This discrepancy has been corrected.

### What problem does this PR solve?

Add sessions deletion support for agent in http and python api

### Type of change

- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [x] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

Fixed OpenAI compatibility stream [DONE]



- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

Add OpenAI-compatible http and python api reference

### Type of change

- [x] Documentation Update

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

### What problem does this PR solve?

Added OpenAI-like completion api, related to #4672, #4705 

This function allows users to interact with a model to get responses
based on a series of messages.
If `stream` is set to True, the response will be streamed in chunks,
mimicking the OpenAI-style API.

#### Example usage:

```bash
curl -X POST https://ragflow_address.com/api/v1/chats_openai/<chat_id>/chat/completions \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer $RAGFLOW_API_KEY" \
    -d '{
        "model": "model",
        "messages": [{"role": "user", "content": "Say this is a test!"}],
        "stream": true
    }'
```

Alternatively, you can use Python's `OpenAI` client:

```python
from openai import OpenAI

model = "model"
client = OpenAI(api_key="ragflow-api-key", base_url=f"http://ragflow_address/api/v1/chats_openai/<chat_id>")

completion = client.chat.completions.create(
    model=model,
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Who you are?"},
        {"role": "assistant", "content": "I am an AI assistant named..."},
        {"role": "user", "content": "Can you tell me how to install neovim"},
    ],
    stream=True
)

stream = True
if stream:
    for chunk in completion:
        print(chunk)
else:
    print(completion.choices[0].message.content)
```
### Type of change
- [x] New Feature (non-breaking change which adds functionality)

### Related Issues
Related to #4672, #4705

### What problem does this PR solve?

API options like `stream` was ignored when no session_id was provided.

This PR fixes the issue.

Test command and expected result:
```
curl  --request POST \
     --url http://:9222/api/v1/chats/2f2e1d30ee6111efafe211749b004925/completions \
     --header 'Content-Type: application/json' \
     --header 'Authorization: Bearer ragflow-xxx' \
     --data '{
   "question":"Who are you",
   "stream":false
}'
{"code":0,"data":"data:{\"code\": 0, \"message\": \"\", \"data\": {\"answer\": \"Hi! I'm your assistant, what can I do for you?\", \"reference\": {}, \"audio_binary\": null, \"id\": null, \"session_id\": \"82ceb0fcee7111efafe211749b004925\"}}\n\n"}

```



### Type of change

- [*] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?
Update the agent session API "POST /api/v1/agents/{agent_id}/sessions",
to support uploading files while create a new session:
- currently, the API only supports requesting with a json body. If user
wants to upload a doc or image when create session, like what is already
supported on the web client, we need to update the API.
- if upload an image, ragflow will call image2text, and a user_id is
needed for the image2text model. So we need to send user_id in the API
request. As form-data is needed to upload files, not json body, seems we
need to put the user_id in the url as an optional parameter (currently
user_id is an optional in json body).


### Type of change

- [x] Documentation Update
- [x] Other (please describe):

### What problem does this PR solve?

#4385

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Fix agent_completion bug  #4320

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?


### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

1. Refactor error message
2. Fix knowledges are created on ES and can't be found in Infinity. The
document chunk fetch error.

### Type of change

- [x] Fix bug
- [x] Refactoring

---------

Signed-off-by: jinhai <haijin.chn@gmail.com>

### What problem does this PR solve?
#4216

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?


### Type of change

- [x] New Feature (non-breaking change which adds functionality)
- [x] Documentation Update

---------

Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

### What problem does this PR solve?

Update the  component of the agent API with parameters.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [x] Refactoring

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

### What problem does this PR solve?

Add parameters for ask_chat and fix bugs in list_sessions
#4105
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Fix bugs in agent api and update api document

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

#3909

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?


### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

#3909

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?

Added static check at PR CI

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Refactoring

### What problem does this PR solve?

Fix errors detected by Ruff

### Type of change

- [x] Refactoring

### What problem does this PR solve?
#3700
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Add api for list agents and agent seesions

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Fix the agent reference bug and the session prologue
#3285 #3819
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Fix the bug that the agent could not find the context
#3682
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

#3769
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

#3731

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Fix the context of the agent interface call to the context during web
testing, and change it to the context record of user chat
Remove duplicate messages and add them, which can be viewed in the
messages section of database api_4_comversation

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
Co-authored-by: Jin Hai <haijin.chn@gmail.com>

### What problem does this PR solve?

Fix a bug in completions

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

#3488

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

#3585
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

#3570 

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

#3511

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Add api for sessions and add max_tokens for tenant_llm

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

This PR addresses the inconsistency in property naming within the
codebase by renaming the 'chat' property to 'chat_id' in the session.py
file. This change aims to align the naming convention with other parts
of the application that refer to chat identifiers as 'chat_id', thereby
improving code clarity and maintainability.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Add sdk for Agent API

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Fix bugs in API

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>