fastapi-globals 0.2.0

Use request global variables in FastAPI

fastapi-globals

Allows you to use request global values. Can be used to store request speficic data, like state, database connection, etc.

Installation

Just use pip install fastapi-globals to install the library.

Note: fastapi-globals is compatible with fastapi versions 0.100.0 and later on Python 3.9, 3.10, 3.11, 3.12 and 3.13. This is also ensured running all tests on all those versions using tox.

Setup

Add the GlobalsMiddleware to your app:

app = fastapi.FastAPI(
    title="Your app API",
)
app.add_middleware(GlobalsMiddleware)  # <-- This line is necessary

Usage

Import g and then access (set/get) attributes of it:

from fastapi_globals import g


g.foo = "foo"

# In some other code
assert g.foo == "foo"

Best way to utilize the global g in your code is to set the desired value in a FastAPI dependency, like so:

async def set_global_foo() -> None:
    g.foo = "foo"


@app.get("/test/", dependencies=[Depends(set_global_foo)])
async def test():
    assert g.foo == "foo"

Default values

You may use g.set_default("name", some_value) to set a default value for a global variable. This default value will then be used instead of None when the variable is accessed before it was set.

Note that default values should only be set at startup time, never inside dependencies or similar. Otherwise you may run into the issue that the value was already used any thus have a value of None set already, which would result in the default value not being used.