Özel Request ve APIRoute sınıfı¶

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İngilizce sürüm

Bazı durumlarda, Request ve APIRoute sınıflarının kullandığı mantığı override etmek isteyebilirsiniz.

Özellikle bu yaklaşım, bir middleware içindeki mantığa iyi bir alternatif olabilir.

Örneğin, request body uygulamanız tarafından işlenmeden önce okumak veya üzerinde değişiklik yapmak istiyorsanız.

Uyarı

Bu "ileri seviye" bir özelliktir.

FastAPI'ye yeni başlıyorsanız bu bölümü atlamak isteyebilirsiniz.

Kullanım senaryoları¶

Bazı kullanım senaryoları:

JSON olmayan request body'leri JSON'a dönüştürmek (örn. msgpack).
gzip ile sıkıştırılmış request body'leri açmak (decompress).
Tüm request body'lerini otomatik olarak loglamak.

Özel request body encoding'lerini ele alma¶

Gzip request'lerini açmak için özel bir Request alt sınıfını nasıl kullanabileceğimize bakalım.

Ayrıca, o özel request sınıfını kullanmak için bir APIRoute alt sınıfı da oluşturacağız.

Özel bir `GzipRequest` sınıfı oluşturun¶

İpucu

Bu, nasıl çalıştığını göstermek için hazırlanmış basit bir örnektir; Gzip desteğine ihtiyacınız varsa sağlanan GzipMiddleware bileşenini kullanabilirsiniz.

Önce, uygun bir header mevcut olduğunda body'yi açmak için Request.body() metodunu overwrite edecek bir GzipRequest sınıfı oluşturuyoruz.

Header'da gzip yoksa body'yi açmayı denemez.

Böylece aynı route sınıfı, gzip ile sıkıştırılmış veya sıkıştırılmamış request'leri handle edebilir.

Python 3.10+

import gzip
from collections.abc import Callable
from typing import Annotated

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return {"sum": sum(numbers)}

🤓 Other versions and variants

Python 3.9+Python 3.10+ - non-AnnotatedPython 3.9+ - non-Annotated

import gzip
from typing import Annotated, Callable

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return {"sum": sum(numbers)}

Tip

Prefer to use the Annotated version if possible.

import gzip
from collections.abc import Callable

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: list[int] = Body()):
    return {"sum": sum(numbers)}

Tip

Prefer to use the Annotated version if possible.

import gzip
from typing import Callable

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: list[int] = Body()):
    return {"sum": sum(numbers)}

Özel bir `GzipRoute` sınıfı oluşturun¶

Sonra, GzipRequest'i kullanacak fastapi.routing.APIRoute için özel bir alt sınıf oluşturuyoruz.

Bu kez APIRoute.get_route_handler() metodunu overwrite edeceğiz.

Bu metot bir fonksiyon döndürür. Bu fonksiyon da request'i alır ve response döndürür.

Burada bu fonksiyonu, orijinal request'ten bir GzipRequest oluşturmak için kullanıyoruz.

Python 3.10+

import gzip
from collections.abc import Callable
from typing import Annotated

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return {"sum": sum(numbers)}

🤓 Other versions and variants

Python 3.9+Python 3.10+ - non-AnnotatedPython 3.9+ - non-Annotated

import gzip
from typing import Annotated, Callable

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return {"sum": sum(numbers)}

Tip

Prefer to use the Annotated version if possible.

import gzip
from collections.abc import Callable

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: list[int] = Body()):
    return {"sum": sum(numbers)}

Tip

Prefer to use the Annotated version if possible.

import gzip
from typing import Callable

from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")
async def sum_numbers(numbers: list[int] = Body()):
    return {"sum": sum(numbers)}

Teknik Detaylar

Bir Request'in, request ile ilgili metadata'yı içeren bir Python dict olan request.scope attribute'u vardır.

Bir Request ayrıca request.receive içerir; bu, request'in body'sini "almak" (receive etmek) için kullanılan bir fonksiyondur.

scope dict'i ve receive fonksiyonu, ASGI spesifikasyonunun parçalarıdır.

Ve bu iki şey, scope ve receive, yeni bir Request instance'ı oluşturmak için gerekenlerdir.

Request hakkında daha fazla bilgi için Starlette'ın Request dokümantasyonuna bakın.

GzipRequest.get_route_handler tarafından döndürülen fonksiyonun farklı yaptığı tek şey, Request'i bir GzipRequest'e dönüştürmektir.

Bunu yaptığımızda GzipRequest, veriyi (gerekliyse) path operations'larımıza geçirmeden önce açma (decompress) işini üstlenir.

Bundan sonra tüm işleme mantığı aynıdır.

Ancak GzipRequest.body içindeki değişikliklerimiz sayesinde, request body gerektiğinde FastAPI tarafından yüklendiğinde otomatik olarak decompress edilir.

Bir exception handler içinde request body'ye erişme¶

İpucu

Aynı problemi çözmek için, muhtemelen RequestValidationError için özel bir handler içinde body kullanmak çok daha kolaydır (Hataları Ele Alma).

Yine de bu örnek geçerlidir ve dahili bileşenlerle nasıl etkileşime geçileceğini gösterir.

Aynı yaklaşımı bir exception handler içinde request body'ye erişmek için de kullanabiliriz.

Tek yapmamız gereken, request'i bir try/except bloğu içinde handle etmek:

Python 3.10+

from collections.abc import Callable
from typing import Annotated

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return sum(numbers)

🤓 Other versions and variants

Python 3.9+Python 3.10+ - non-AnnotatedPython 3.9+ - non-Annotated

from typing import Annotated, Callable

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return sum(numbers)

Tip

Prefer to use the Annotated version if possible.

from collections.abc import Callable

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: list[int] = Body()):
    return sum(numbers)

Tip

Prefer to use the Annotated version if possible.

from typing import Callable

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: list[int] = Body()):
    return sum(numbers)

Bir exception oluşursa, Request instance'ı hâlâ scope içinde olacağı için, hatayı handle ederken request body'yi okuyup kullanabiliriz:

Python 3.10+

from collections.abc import Callable
from typing import Annotated

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return sum(numbers)

🤓 Other versions and variants

Python 3.9+Python 3.10+ - non-AnnotatedPython 3.9+ - non-Annotated

from typing import Annotated, Callable

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: Annotated[list[int], Body()]):
    return sum(numbers)

Tip

Prefer to use the Annotated version if possible.

from collections.abc import Callable

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: list[int] = Body()):
    return sum(numbers)

Tip

Prefer to use the Annotated version if possible.

from typing import Callable

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        return custom_route_handler


app = FastAPI()
app.router.route_class = ValidationErrorLoggingRoute


@app.post("/")
async def sum_numbers(numbers: list[int] = Body()):
    return sum(numbers)

Bir router içinde özel `APIRoute` sınıfı¶

Bir APIRouter için route_class parametresini de ayarlayabilirsiniz:

Python 3.10+

import time
from collections.abc import Callable

from fastapi import APIRouter, FastAPI, Request, Response
from fastapi.routing import APIRoute


class TimedRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")
            print(f"route response headers: {response.headers}")
            return response

        return custom_route_handler


app = FastAPI()
router = APIRouter(route_class=TimedRoute)


@app.get("/")
async def not_timed():
    return {"message": "Not timed"}


@router.get("/timed")
async def timed():
    return {"message": "It's the time of my life"}


app.include_router(router)

🤓 Other versions and variants

Python 3.9+

import time
from typing import Callable

from fastapi import APIRouter, FastAPI, Request, Response
from fastapi.routing import APIRoute


class TimedRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")
            print(f"route response headers: {response.headers}")
            return response

        return custom_route_handler


app = FastAPI()
router = APIRouter(route_class=TimedRoute)


@app.get("/")
async def not_timed():
    return {"message": "Not timed"}


@router.get("/timed")
async def timed():
    return {"message": "It's the time of my life"}


app.include_router(router)

Bu örnekte, router altındaki path operations'lar özel TimedRoute sınıfını kullanır ve response'u üretmek için geçen süreyi içeren ekstra bir X-Response-Time header'ı response'ta bulunur:

Python 3.10+

import time
from collections.abc import Callable

from fastapi import APIRouter, FastAPI, Request, Response
from fastapi.routing import APIRoute


class TimedRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")
            print(f"route response headers: {response.headers}")
            return response

        return custom_route_handler


app = FastAPI()
router = APIRouter(route_class=TimedRoute)


@app.get("/")
async def not_timed():
    return {"message": "Not timed"}


@router.get("/timed")
async def timed():
    return {"message": "It's the time of my life"}


app.include_router(router)

🤓 Other versions and variants

Python 3.9+

import time
from typing import Callable

from fastapi import APIRouter, FastAPI, Request, Response
from fastapi.routing import APIRoute


class TimedRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")
            print(f"route response headers: {response.headers}")
            return response

        return custom_route_handler


app = FastAPI()
router = APIRouter(route_class=TimedRoute)


@app.get("/")
async def not_timed():
    return {"message": "Not timed"}


@router.get("/timed")
async def timed():
    return {"message": "It's the time of my life"}


app.include_router(router)

Özel Request ve APIRoute sınıfı¶

Kullanım senaryoları¶

Özel request body encoding'lerini ele alma¶

Özel bir GzipRequest sınıfı oluşturun¶

Özel bir GzipRoute sınıfı oluşturun¶

Bir exception handler içinde request body'ye erişme¶

Bir router içinde özel APIRoute sınıfı¶

Özel bir `GzipRequest` sınıfı oluşturun¶

Özel bir `GzipRoute` sınıfı oluşturun¶

Bir router içinde özel `APIRoute` sınıfı¶