Impara Working with httpx for HTTP Requests

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Every real asyncio application eventually makes HTTP requests. httpx is the standard choice – it mirrors the requests API you already know, adds full async support, and handles connection pooling, timeouts, and redirects out of the box.

Installation

pip install httpx

Making a Single Request

The async counterpart to requests.get() is await client.get(). Use httpx.AsyncClient as an async context manager to ensure connections are properly closed:


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import asyncio
import httpx
import nest_asyncio

nest_asyncio.apply()

# Fetching a single post from JSONPlaceholder
async def fetch_post(post_id):
    async with httpx.AsyncClient() as client:
        response = await client.get(
            f"https://jsonplaceholder.typicode.com/posts/{post_id}"
        )
        data = response.json()
        print(f"Title: {data['title']}")
        print(f"Status: {response.status_code}")

asyncio.run(fetch_post(1))

Reusing a Client Across Requests

Creating a new AsyncClient for every request is wasteful – it opens a fresh TCP connection each time. Pass a shared client into your functions:


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import asyncio
import httpx
import nest_asyncio

nest_asyncio.apply()

# Sharing a single client across multiple requests
async def fetch_post(client, post_id):
    response = await client.get(
        f"https://jsonplaceholder.typicode.com/posts/{post_id}"
    )
    return response.json()["title"]

async def main():
    async with httpx.AsyncClient() as client:
        titles = await asyncio.gather(
            fetch_post(client, 1),
            fetch_post(client, 2),
            fetch_post(client, 3),
        )

    for title in titles:
        print(title)

asyncio.run(main())

Setting Timeouts

Pass a timeout parameter to AsyncClient to apply it globally across all requests:


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import asyncio
import httpx
import nest_asyncio

nest_asyncio.apply()

# Applying a global timeout to all requests
async def fetch_posts(client):
    response = await client.get("https://jsonplaceholder.typicode.com/posts")
    return response.json()

async def main():
    async with httpx.AsyncClient(timeout=5.0) as client:
        try:
            posts = await fetch_posts(client)
            print(f"Fetched {len(posts)} posts")
        except httpx.TimeoutException:
            print("Request timed out")

asyncio.run(main())

Handling HTTP Errors

Use response.raise_for_status() to raise an exception for 4xx and 5xx responses:


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import asyncio
import httpx
import nest_asyncio

nest_asyncio.apply()

# Handling a 404 response gracefully
async def fetch_post(client, post_id):
    response = await client.get(
        f"https://jsonplaceholder.typicode.com/posts/{post_id}"
    )
    try:
        response.raise_for_status()
        return response.json()["title"]
    except httpx.HTTPStatusError as error:
        return f"Error {error.response.status_code} for post {post_id}"

async def main():
    async with httpx.AsyncClient() as client:
        results = await asyncio.gather(
            fetch_post(client, 1),
            fetch_post(client, 99999),  # Non-existent post – returns empty
        )

    for result in results:
        print(result)

asyncio.run(main())

`requests` vs `httpx.AsyncClient`

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