3 releases
| 0.1.2 | Jun 15, 2020 |
|---|---|
| 0.1.1 | Apr 4, 2020 |
| 0.1.0 | Feb 19, 2020 |
#744 in Asynchronous
52KB
729 lines
QuickCrawler
QuickCrawler is a Rust crate that provides a completely async, declarative web crawler with domain-specific request rate-limiting built-in.
Examples
Let's say you are trying to crawl a subset of pages for a given domain:
https://bike-site.com/search?q=red-bikes
and a regular GET request will return:
<html>
<body>
<div>
<a class="bike-item" href="https://bike-site.com/red-bike-1">
cool red bike 1
</a><a class="bike-item" href="https://bike-site.com/red-bike-2">
cool red bike 2
</a>
<a class="bike-item" href="https://bike-site.com/red-bike-3">
cool red bike 3
</a>
<div>
<a class="bike-other-item" href="https://bike-site.com/other-red-bike-4">
other cool red bike 4
</a>
</div>
</div>
</body>
</html>
and when navigating to links 1 through 3 on that page, EACH PAGE returns:
<html>
<body>
<div class='awesome-bike'>
<div class='bike-info'>
The best bike ever.
</div>
<ul class='bike-specs'>
<li>
Super fast.
</li>
<li>
Jumps high.
</li>
</ul>
</div>
</body>
</html>
and when navigating to the last link on that page, it returns:
<html>
<body>
<div class='other-bike'>
<div class='other-bike-info'>
The best bike ever.
</div>
<ul class='other-bike-specs'>
<li>
Super slow.
</li>
<li>
Doesn't jump.
</li>
</ul>
</div>
</body>
</html>
QuickCrawler declaratively helps you crawl, and scrape data from each of the given pages with ease:
use quick_crawler::{
QuickCrawler,
QuickCrawlerBuilder,
limiter::Limiter,
scrape::{
ResponseLogic::Parallel,
StartUrl,
Scrape,
ElementUrlExtractor,
ElementDataExtractor
}
};
fn main() {
let mut builder = QuickCrawlerBuilder::new();
let start_urls = vec![
StartUrl::new()
.url("https://bike-site.com/search?q=red-bikes")
.method("GET")
.response_logic(Parallel(vec![
// All Scrapers below will be provided the html page response body
Scrape::new()
.find_elements_with_urls(".bike-item")
.extract_urls_from_elements(ElementUrlExtractor::Attr("href".to_string()))
// now setup the logic to execute on each of the return html pages
.response_logic(Parallel(vec![
Scrape::new()
.find_elements_with_data(".awesome-bike .bike-info")
.extract_data_from_elements(ElementDataExtractor::Text)
.store(|vec: Vec<String>| async move {
println!("store bike info in DB: {:?}", vec);
}),
Scrape::new()
.find_elements_with_data(".bike-specs li")
.extract_data_from_elements(ElementDataExtractor::Text)
.store(|vec: Vec<String>| async move {
println!("store bike specs in DB: {:?}", vec);
}),
])),
Scrape::new()
.find_elements_with_urls(".bike-other-item")
.extract_urls_from_elements(ElementUrlExtractor::Attr("href".to_string()))
.response_logic(Parallel(vec![
Scrape::new()
.find_elements_with_data(".other-bike .other-bike-info")
.extract_data_from_elements(ElementDataExtractor::Text)
.store(|vec: Vec<String>| async move {
println!("store other bike info in DB: {:?}", vec);
}),
Scrape::new()
.find_elements_with_data(".other-bike-specs li")
.extract_data_from_elements(ElementDataExtractor::Text)
.store(|vec: Vec<String>| async move {
println!("store other bike specs in DB: {:?}", vec);
}),
]))
])
)
// more StartUrl::new 's if you feel ambitious
] ;
// It's smart to use a limiter - for now automatically set to 3 request per second per domain.
// This will soon be configurable.
let limiter = Limiter::new();
builder
.with_start_urls(
start_urls
)
.with_limiter(
limiter
)
// Optionally configure how to make a request and return an html string
.with_request_handler(
|config: RequestHandlerConfig| async move {
// ... use any request library, like reqwest
surf::get(config.url.clone()).recv_string().await.map_err(|_| QuickCrawlerError::RequestErr)
}
);
let crawler = builder.finish().map_err(|_| "Builder could not finish").expect("no error");
// QuickCrawler is async, so choose your favorite executor.
// (Tested and working for both async-std and tokio)
let res = async_std::task::block_on(async {
crawler.process().await
});
}
Contribute
clone the repo.
To run tests:
cargo watch -x check -x 'test -- --nocapture'
See the src/lib.rs test for example usage.
Thank You For Using!
If you use this crate and you found it helpful to your project, please star it!
License
MIT
Dependencies
~16–29MB
~466K SLoC