crawlee-python/docs/introduction/code_examples/03_transform_request.py

50 lines
1.5 KiB
Python

from __future__ import annotations
import asyncio
from crawlee import HttpHeaders, RequestOptions, RequestTransformAction
from crawlee.crawlers import BeautifulSoupCrawler, BeautifulSoupCrawlingContext
def transform_request(
request_options: RequestOptions,
) -> RequestOptions | RequestTransformAction:
# Skip requests to PDF files
if request_options['url'].endswith('.pdf'):
return 'skip'
if '/docs' in request_options['url']:
# Add custom headers to requests to specific URLs
request_options['headers'] = HttpHeaders({'Custom-Header': 'value'})
elif '/blog' in request_options['url']:
# Add label for certain URLs
request_options['label'] = 'BLOG'
else:
# Signal that the request should proceed without any transformation
return 'unchanged'
return request_options
async def main() -> None:
crawler = BeautifulSoupCrawler(max_requests_per_crawl=10)
@crawler.router.default_handler
async def request_handler(context: BeautifulSoupCrawlingContext) -> None:
context.log.info(f'Processing {context.request.url}.')
# Transform request before enqueueing
await context.enqueue_links(transform_request_function=transform_request)
@crawler.router.handler('BLOG')
async def blog_handler(context: BeautifulSoupCrawlingContext) -> None:
context.log.info(f'Blog Processing {context.request.url}.')
await crawler.run(['https://crawlee.dev/'])
if __name__ == '__main__':
asyncio.run(main())