How to change the value of request body?

[Songjiadong]

I want to change the request body value of simple_invoke,would you give me a demo? I can't change request body value.
Based on my experience with Java and C #, I believe this can be solved, but I am not very familiar with FastAPI . Can you help me?
Thanks!

def add_one(x: int) -> int:
    """Add one to the given number."""
    return x + 1


chain = RunnableLambda(add_one)

api_handler = APIHandler(chain, path="/simple")


# First register the endpoints without documentation
@app.post("/simple/invoke", include_in_schema=False)
async def simple_invoke(request: Request) -> Response:
    """Handle a request."""
    ### NOTE: I want change the value of request body at this position !!!! for example:  if  value of request body equals '1',I want change it to '100'
    return await api_handler.invoke(request)

[eyurtsev]

What do you need to accomplish? I'm sure there's a way to mutate the Request body, but it's not super common practice.

If you're already mutating the request body, why not avoid using langserve and just use the underlying runnable with fast API directly?

Chat gpt suggests doing something like this:

        body = await request.json()
        
        # Modify the body
        body["extra_field"] = "extra_value"
        
        # Create a new request with the modified body
        request.scope["body"] = json.dumps(body).encode("utf-8")     

[Songjiadong]

@eyurtsev I achieved it this way.

@app.post(f"/{APP_USER_NAME}/invoke", include_in_schema=True)
async def invoke(request: Request) -> Response:
    request_json = await request.json()
    input = request_json["input"]["input"]
    rag_message = retriever.rag(input=input, k=2, score_threshold=0.9, verbose=verbose)
    if verbose is True:
        print("\033[0;33m" + f"my prompt is: {rag_message}" + "\033[0m")

    async def receive_func() -> Message:
        m: dict[str, Any] = {"input": {"input": rag_message}}
        s = json.dumps(m, ensure_ascii=False)
        result: Message = {
            "type": "http.request",
            "body": s.encode("utf-8")
        }
        return result

    r = Request(scope=request.scope, receive=receive_func)
    return await api_handler.invoke(request=r)