Request timing middleware in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the correct module for timing.

FastAPI

from fastapi import FastAPI
import [1]

app = FastAPI()

Drag options to blanks, or click blank then click option'

Atime

Bdatetime

Cos

Dsys

Attempts:

3 left

💡 Hint

Common Mistakes

Importing datetime instead of time

Using os or sys which are unrelated to timing

The time module provides functions to measure time intervals, which is needed for timing requests.

2fill in blank

medium

Complete the code to define a middleware function that records the start time.

FastAPI

@app.middleware("http")
async def add_process_time_header(request, call_next):
    start_time = [1]()
    response = await call_next(request)
    return response

Drag options to blanks, or click blank then click option'

Atime.sleep

Btime.time

Cdatetime.now

Dtime.clock

Attempts:

3 left

💡 Hint

Common Mistakes

Using datetime.now which returns a datetime object

Using time.sleep which pauses execution

Using deprecated time.clock

time.time() returns the current time in seconds since the epoch, useful for measuring elapsed time.

3fill in blank

hard

Fix the error in calculating the process time by completing the blank.

FastAPI

@app.middleware("http")
async def add_process_time_header(request, call_next):
    start_time = time.time()
    response = await call_next(request)
    process_time = time.time() [1] start_time
    response.headers["X-Process-Time"] = str(process_time)
    return response

Drag options to blanks, or click blank then click option'

A/

B+

C-

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Adding times instead of subtracting

Multiplying or dividing times which is incorrect

To find the elapsed time, subtract the start time from the current time.

4fill in blank

hard

Fill both blanks to convert the process time to milliseconds and add it to the response headers.

FastAPI

@app.middleware("http")
async def add_process_time_header(request, call_next):
    start_time = time.time()
    response = await call_next(request)
    process_time = (time.time() - start_time) [1] 1000
    response.headers["X-Process-Time-ms"] = str(round(process_time, [2]))
    return response

Drag options to blanks, or click blank then click option'

A*

B//

C4

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using integer division instead of multiplication

Using addition instead of multiplication

Using wrong number of decimals like 5 or 3

Multiply seconds by 1000 to get milliseconds. Then round to 4 decimal places using round(process_time, 4).

5fill in blank

hard

Fill all three blanks to create a complete middleware that measures request time and adds it as a header rounded to 3 decimals.

FastAPI

from fastapi import FastAPI
import time

app = FastAPI()

@app.middleware("http")
async def add_process_time_header(request, call_next):
    start = [1]()
    response = await call_next(request)
    duration = [3]() - start
    response.headers["X-Process-Time"] = str(round(duration, [2]))
    return response

@app.get("/")
async def root():
    return {"message": "Hello World"}

Drag options to blanks, or click blank then click option'

Atime.time

Btime.sleep

C3

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using sleep instead of time for start

Not rounding or rounding to wrong decimal places

Use time.time() to get the start time, and round the duration to 3 decimals for readability.