node-fetchvsaiohttp
node-fetch is a lightweight library that provides a fetch()-like API for making HTTP requests in Node.js. It is a light-weight implementation of the Fetch API, which is mostly compatible with the browser's version.
node-fetch is primarily known as almost identical package fetch() is included in web browsers so it shares the same use common API. It's great starting point for people coming from front-end environment.
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. It provides a simple API for making HTTP requests and handling both client and server functionality. Like the requests package, aiohttp is designed to be easy to use and handle many of the low-level details of working with HTTP.
The main benefit of aiohttp over requests is that it is built on top of the asyncio library, which means that it can handle many requests at the same time without blocking the execution of your program. This can lead to significant performance improvements when making many small requests, or when dealing with slow or unreliable network connections.
aiohttp provides both client and server side functionality, so you can use it to create web servers and handle client requests in a non-blocking manner. It also supports WebSocket protocol, so it can be used for building real-time application like chat, game, etc.
aiohttp also provide several features for handling connection errors, managing timeouts, and client sessions. It also provide similar features like requests package like redirect handling, cookies, and support for several authentication modules.
You can install aiohttp via pip package manager:
pip install aiohttp
In terms of API design, aiohttp is similar to requests and thus should be familiar to anyone who has used the requests library, but it provides an async with block to manage the context of the connection and used await statement to wait for the result.
It''s worth noting that aiohttp is built on top of asyncio and is designed to be used in Python 3.5 and above. It provides the same functionality as httpx but it is specifically built for the asyncio framework.
Highlights
Example Use
const fetch = require('node-fetch');
// fetch supports both Promises and async/await
fetch('http://httpbin.org/get')
.then(res => res.text())
.then(body => console.log(body))
.catch(err => console.error(err));
const response = await fetch('http://httpbin.org/get');
// for concurrent scraping Promise.all can be used
const results = await Promise.all([
fetch('http://httpbin.org/html'),
fetch('http://httpbin.org/html'),
fetch('http://httpbin.org/html'),
])
// POST requests
await fetch('http://httpbin.org/post', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ name: 'John Doe' }),
})
// Proxy use:
const agent = new https.Agent({
rejectUnauthorized: false,
proxy: {
host: 'proxy.example.com',
port: 8080
}
});
await fetch('https://httpbin.org/ip', { agent })
// setting headers and cookies
const headers = new fetch.Headers();
headers.append('Cookie', 'myCookie=123');
headers.append('X-My-Header', 'myValue');
await fetch('https://httpbin.org/headers', { headers })
import asyncio
from aiohttp import ClientSession, WSMsgType
# aiohttp only provides async client so we must use a coroutine:
async def run():
async with ClientSession(headers={"User-Agent": "webscraping.fyi"}) as session:
# we can use the session to make requests:
response = await session.get("http://httpbin.org/headers")
print(response.status)
# note: to read the response body we must use await:
print(await response.text())
# aiohttp also comes with convenience methods for common requests:
# POST json
resp = await session.post("http://httpbin.org/post", json={"key": "value"})
# POST form data
resp = await session.post("http://httpbin.org/post", data={"key": "value"})
# decode response as json
resp = await session.get("http://httpbin.org/json")
data = await resp.json()
print(data)
# aiohttp also supports websocket connections
# which can be used to scrape websites that use websockets:
async with session.ws_connect("http://example.org/ws") as ws:
async for msg in ws:
if msg.type == WSMsgType.TEXT:
if msg.data == "close cmd":
await ws.close()
break
else:
await ws.send_str(msg.data + "/answer")
elif msg.type == WSMsgType.ERROR:
break
asyncio.run(run())