Middleware

A "middleware" is a function that works with every request before it is processed by any specific path operation and also with every response before returning it.

• It takes each request that comes to your application.
• It can then do something to that request or run any needed code.
• Then it passes the request to be processed by the rest of the application (by some path operation).
• It then takes the response generated by the application (by some path operation).
• It can do something to that response or run any needed code.

• Then it returns the response.

  Note: If you have dependencies with yield, the exit code will run after the middleware.

  If there were any background tasks, they will run after all the middleware.

Add Middleware(s)

To add a middleware, import it into your settings file and add it to the middleware list as a dictionary with the label "root" pointing towards your function and the keyword arguments specified later in the dict, an example is shown below

from fastapi.middleware.cors import CORSMiddleware

MIDDLEWARE = [
    {
        "root":CORSMiddleware,
        "allow_origins":ALLOWED_ORIGINS,
        "allow_credentials":ALLOW_CREDENTIALS,
        "allow_methods":ALLOW_METHODS,
        "allow_headers":ALLOW_HEADERS
    },
]