[b]"What's the best way to build a web crawler in Python from scratch?"[/b] or [b]"How can I optimize my web crawl

22 Replies, 697 Views

"What's the best way to build a web crawler in Python from scratch?"

Hey folks!

I'm trying to build a web crawler python project from scratch. Not sure where to start—should I use `requests` + `BeautifulSoup` or go straight for Scrapy?

Also, how do you handle pagination and storing the data?

Any tips or example code would be awesome. Thanks!

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OR

"How can I optimize my web crawler in Python for faster scraping?"

Yo!

My web crawler python script is kinda slow. Using `requests` and `bs4` rn, but it feels clunky.

Should I switch to async (like `aiohttp`)? Or maybe tweak the delay between requests?

Also, how do you guys manage proxies to avoid throttling?

Appreciate any hacks!

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OR

"Any tips for handling JavaScript-heavy sites with a web crawler in Python?"

Ugh, JS sites are the worst for my web crawler python setup. `requests` just gets empty HTML.

Do I *have* to use Selenium or Playwright? Or is there a lighter workaround?

Kinda wanna avoid the overhead if possible.

Thoughts?

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OR

"Is Scrapy still the best framework for a web crawler in Python?"

Scrapy fans—still worth it in 2024?

I’ve used it before, but wondering if something newer/simpler exists for web crawler python projects.

Or is Scrapy still king for large-scale scraping?

Lemme know your experiences!

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OR

"How do you avoid getting blocked when running a web crawler in Python?"

My web crawler python keeps getting blocked after a few requests.

Using random headers and delays, but sites still detect me.

Proxies? Rotating user-agents? Or am I missing something?

Help a noob out!
If you're starting with a web crawler python project, I'd say go for requests + BeautifulSoup first. Scrapy's powerful but has a learning curve.

For pagination, check for "next" buttons or URL patterns (like `?page=2`).

Store data in CSV or SQLite—super simple!

Example:
```python
import requests
from bs4 import BeautifulSoup
url = "..."
response = requests.get(url)
soup = BeautifulSoup(response.text, 'html.parser')
# Extract data here
```
Yo, for optimizing your web crawler python, async is a game-changer! aiohttp + asyncio speeds things up massively.

Also, set delays between 2-5 secs to avoid bans.

Proxies? Try free ones from https://free-proxy-list.net/, but paid ones like Luminati are way more reliable.
JS-heavy sites suck for web crawler python scripts. Sadly, requests won’t cut it.

Playwright’s lighter than Selenium and works great. Example:
```python
from playwright.sync_api import sync_playwright
with sync_playwright() as p:
browser = p.chromium.launch()
page = browser.new_page()
page.goto("https://example.com")
print(page.content())
```
Scrapy’s still king for large-scale web crawler python projects in 2024. Middlewares, pipelines, and built-in concurrency make it unbeatable.

Alternatives? Maybe `httpx` + `parsel` for smaller tasks, but Scrapy’s worth the effort.
Getting blocked? Rotate user-agents (fake-useragent lib) and use residential proxies.

Also, mimic human behavior—random delays, click-like patterns.

Check out https://scrapeops.io/ for anti-blocking tools.
For a web crawler python newbie, start simple!

Use `requests-html`—it’s like requests but handles JS. Not perfect, but easier than Selenium.

```python
from requests_html import HTMLSession
session = HTMLSession()
r = session.get('https://example.com')
r.html.render() # Executes JS
```
Scrapy vs. DIY? Depends on scale.

For one-off scripts, stick with requests + bs4.

For thousands of pages, Scrapy’s built-in throttling and retries save headaches.
Pro tip: Use `time.sleep(random.uniform(1, 3))` between requests in your web crawler python script.

Sites throttle based on request speed. Also, Cloudflare hates bots—proxies are a must.
If you’re scraping heavily, check out `scrapy-playwright` combo. Best of both worlds—Scrapy’s power + Playwright’s JS handling.

Docs: https://github.com/scrapy-plugins/scrapy-playwright



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