CODEWITHSUNDEEP
pythonjsonfastapi
Ehud Lev
Ehud Lev

Reputation: 2891

python fastapi large json request are relativly slow

I have a simple service that gets a json and returns a json, those jsons are relativly large ~200Kb-~300Kb. Now I noticed that even if I don't do any processing on the json it still takes about 30-40 Milli seconds the full round trip (even from my own machine).

Here is my code:

from typing import Dict

from fastapi import FastAPI

app = FastAPI(title="My test")

@app.post("/large_json_test")
async def foo(request: dict) -> dict:
    something = request.get("something") or "NA"
    x = "whatever" + something
    return {"request": request, "x": x}

when running the following bash:

time curl -XPOST "127.0.0.1:8080/large_json_test" -d @large.json  -H "Content-Type: application/json" 1> /dev/null

returns the following results:

0.00s user 0.00s system 15% cpu 0.043 total

can also be 0.050 or so in total time!

Any suggestions of how can I make this faster?

Worth mentioning, when running with a small json request it will take 10Millis, which means that reading serializing and writing back the json takes about 30 - 40 milli seconds.

Upvotes: 1

Views: 3896

Answers (1)

Ehud Lev
Ehud Lev

Reputation: 2891

So as luk2302 suggested adding building the response using orjson or ujson make it significantly faster

code:

@app.post("/large_json_test1")
async def foo1(request: dict) -> Response:
    something = request.get("something") or "NA"
    x = "whatever" + something
    res = {"request": request, "x": x}
    return Response(
        content=ujson.dumps(res)
    )

@app.post("/large_json_test2")
async def foo2(request: dict) -> Response:
    something = request.get("something") or "NA"
    x = "whatever" + something
    res = {"request": request, "x": x}
    return Response(
        content=orjson.dumps(res)
    )

results:

ujson

curl -XPOST "127.0.0.1:8080/large_json_test1" -d @large.json -H  >   0.00s user 0.00s system 43% cpu 0.014 total

orjson

curl -XPOST "127.0.0.1:8080/large_json_test2" -d @example_session.json -H  >   0.00s user 0.00s system 41% cpu 0.016 total

Upvotes: 1

Related Questions