title: Dependency Injection API
description: "API reference for dependency injection in JustAPI, the FastAPI alternative — Depends, Path, Query, Header, Cookie, Body, File, and Form extractors."
keywords: [dependency injection, fastapi alternative, justapi, depends, path, query, header, request extraction]
Depends()
Declare a dependency that is resolved before the handler executes:
from justapi import Depends
def common_params(q: str | None = None, skip: int = 0):
return {"q": q, "skip": skip}
@app.get("/items")
def list_items(request, params: dict = Depends(common_params)):
...
| Parameter |
Type |
Default |
Description |
dependency |
callable |
required |
The dependency function or class |
use_cache |
bool |
True |
Cache result for reuse across nested dependencies |
Parameter Extractors
These functions extract specific parts of the request:
Path()
from justapi import Path
@app.get("/items/{item_id}")
def read_item(
request,
item_id: int = Path(..., description="The item ID"),
):
| Parameter |
Type |
Default |
Description |
default |
any |
... |
... means required |
description |
str |
None |
OpenAPI description |
Query()
from justapi import Query
@app.get("/items")
def list_items(
request,
q: str = Query(None, max_length=50, description="Search query"),
):
| Parameter |
Type |
Default |
Description |
default |
any |
... |
Default value (... = required) |
description |
str |
None |
OpenAPI description |
max_length |
int |
None |
Max string length |
min_length |
int |
None |
Min string length |
regex |
str |
None |
Regex pattern |
Header()
from justapi import Header
@app.get("/protected")
def protected(
request,
authorization: str = Header(..., description="Bearer token"),
):
Cookie()
from justapi import Cookie
@app.get("/")
def home(
request,
session_id: str = Cookie(None, description="Session cookie"),
):
Body()
from justapi import Body
@app.post("/items")
def create_item(
request,
data: dict = Body(..., description="Request body"),
):
File()
from justapi import File, UploadFile
@app.post("/upload")
def upload(
request,
file: UploadFile = File(..., description="File to upload"),
):
Form()
from justapi import Form
@app.post("/submit")
def submit(
request,
name: str = Form(..., description="User name"),
):
Session (Agent)
from justapi import Session
@app.get("/agent/state")
def agent_state(request, session: Session):
return {"session_id": session.id, **session.get()}
| Attribute/Method |
Description |
session.id |
Unique session identifier |
session.get() |
Get all session data as dict |
session.update(**kwargs) |
Update session data |
See Also