Update agent session API, to support uploading files while create a new session (#5039)

### 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):

api/apps/sdk/session.py

@@ -33,7 +33,7 @@ from api.utils import get_uuid
 from api.utils.api_utils import get_error_data_result
 from api.utils.api_utils import get_result, token_required
 from api.db.services.llm_service import LLMBundle
-
+from api.db.services.file_service import FileService
 
 
 @manager.route('/chats/<chat_id>/sessions', methods=['POST'])  # noqa: F821
@@ -68,6 +68,11 @@ def create(tenant_id, chat_id):
 @token_required
 def create_agent_session(tenant_id, agent_id):
     req = request.json
+    if not request.is_json:
+        req = request.form
+    files = request.files
+    user_id = request.args.get('user_id', '')
+
     e, cvs = UserCanvasService.get_by_id(agent_id)
     if not e:
         return get_error_data_result("Agent not found.")
@@ -84,15 +89,33 @@ def create_agent_session(tenant_id, agent_id):
     if query:
         for ele in query:
             if not ele["optional"]:
-                if not req.get(ele["key"]):
-                    return get_error_data_result(f"`{ele['key']}` is required")
-                ele["value"] = req[ele["key"]]
-            if ele["optional"]:
-                if req.get(ele["key"]):
-                    ele["value"] = req[ele['key']]
+                if ele["type"] == "file":
+                    if files is None or not files.get(ele["key"]):
+                        return get_error_data_result(f"`{ele['key']}` with type `{ele['type']}` is required")
+                    upload_file = files.get(ele["key"])
+                    file_content = FileService.parse_docs([upload_file], user_id)
+                    file_name = upload_file.filename
+                    ele["value"] = file_name + "\n" + file_content
                 else:
-                    if "value" in ele:
-                        ele.pop("value")
+                    if req is None or not req.get(ele["key"]):
+                        return get_error_data_result(f"`{ele['key']}` with type `{ele['type']}` is required")
+                    ele["value"] = req[ele["key"]]
+            else:
+                if ele["type"] == "file":
+                    if files is not None and files.get(ele["key"]):
+                        upload_file = files.get(ele["key"])
+                        file_content = FileService.parse_docs([upload_file], user_id)
+                        file_name = upload_file.filename
+                        ele["value"] = file_name + "\n" + file_content
+                    else:
+                        if "value" in ele:
+                            ele.pop("value")
+                else:
+                    if req is not None and req.get(ele["key"]):
+                        ele["value"] = req[ele['key']]
+                    else:
+                        if "value" in ele:
+                            ele.pop("value")
     else:
         for ans in canvas.run(stream=False):
             pass
@@ -100,7 +123,7 @@ def create_agent_session(tenant_id, agent_id):
     conv = {
         "id": get_uuid(),
         "dialog_id": cvs.id,
-        "user_id": req.get("user_id", "") if isinstance(req, dict) else "",
+        "user_id": user_id,
         "message": [{"role": "assistant", "content": canvas.get_prologue()}],
         "source": "agent",
         "dsl": cvs.dsl

docs/references/http_api_reference.md

@@ -2171,15 +2171,14 @@ Creates a session with an agent.
 #### Request
 
 - Method: POST
-- URL: `/api/v1/agents/{agent_id}/sessions`
+- URL: `/api/v1/agents/{agent_id}/sessions?user_id={user_id}`
 - Headers:
-  - `'content-Type: application/json'`
+  - `'content-Type: application/json' or 'multipart/form-data'`
   - `'Authorization: Bearer <YOUR_API_KEY>'`
 - Body:
   - the required parameters:`str`
-  - the optional parameters:`str`
-    - `"user_id"`: `string`  
-      The optional user-defined ID.
+  - other parameters:
+    The parameters in the begin component.
 
 ##### Request example
 If `begin` component in the agent doesn't have required parameters:
@@ -2202,11 +2201,21 @@ curl --request POST \
             "file":"Who are you"
      }'
 ```
+If `begin` component in the agent has required file parameters:
+```bash
+curl --request POST \
+     --url http://{address}/api/v1/agents/{agent_id}/sessions?user_id={user_id} \
+     --header 'Content-Type: multipart/form-data' \
+     --header 'Authorization: Bearer <YOUR_API_KEY>' \
+     --form '<FILE_KEY>=@./test1.png'    
+```
 
 ##### Request parameters
 
 - `agent_id`: (*Path parameter*)  
   The ID of the associated agent.
+- `user_id`: (*Filter parameter*), string
+  The optional user-defined ID for parsing docs(especially images) when creating session while uploading files.
 
 #### Response