How to get request body as bytes from Starlette request object in Flask function?

[chrisinmtown]

Please have patience with a noob sync/async question. I'm migrating a Connexion v2 app to v3. The old app accesses request data using request.data. That is no longer possible in Connexion v3, the request object is type starlette.requests.Request and has new ways to get the data. The doc at https://www.starlette.io/requests/ says:

There are a few different interfaces for returning the body of the request:
The request body as bytes: await request.body()

I am pretty sure I have a plain, synchronous Flask app function, and the async definition means I have to call that async function body appropriately. I asked the cloud about calling an async function from a sync function. I found https://stackoverflow.com/questions/51762227/how-to-call-a-async-function-from-a-synchronized-code-python which, if I am interpreting it correctly, means I should do something like this:

import asyncio
body_bytes = asyncio.run(request.body())

Just would like to confirm with an async expert, whether that is the right thing to do inside a function invoked by Connexion. I don't want to break the app in some subtle way out of sheer ignorance.

Thanks in advance!

[FelixSchwarz]

Ah, sorry I somehow overlooked this but maybe I can help here as I did the same (also using flask). In the end, this was quite simple. I am using a fully synchronous app.

OpenAPI Spec:

paths:
  /users/{user_id}/documents:
    post:
      summary: store a new document
      security:
        - ApiKeyAuth: []
      operationId: "document_upload"
      parameters:
        - in: path
          name: user_id
          required: true
          schema:
            type: integer
      requestBody:
        description: PDF document
        required: true
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                pdf:
                  type: string
                  format: binary

Accessing the body in the document is really, really simple:

def document_upload(user_id, pdf):
    pdf_bytes = pdf.read()

Of course I don't dare to admit how many hours I needed to discover this :-)