Crabler - Web crawler for Crabs

Asynchronous web scraper engine written in rust.

Features:

• fully based on async-std
• derive macro based api
• struct based api
• stateful scraper (structs can hold state)
• ability to download files
• ability to schedule navigation jobs in an async manner

Example

extern crate crabler;

use crabler::*;

#[derive(WebScraper)]
#[on_response(response_handler)]
#[on_html("a[href]", walk_handler)]
struct Scraper {}

impl Scraper {
    async fn response_handler(&self, response: Response) -> Result<()> {
        if response.url.ends_with(".jpg") && response.status == 200 {
            println!("Finished downloading {} -> {}", response.url, response.download_destination);
        }
        Ok(())
    }

    async fn walk_handler(&self, response: Response, a: Element) -> Result<()> {
        if let Some(href) = a.attr("href") {
            // attempt to download an image
            if href.ends_with(".jpg") {
                let p = Path::new("/tmp").join("image.jpg");
                let destination = p.to_string_lossy().to_string();

                if !p.exists() {
                    println!("Downloading {}", destination);
                    // schedule crawler to download file to some destination
                    // downloading will happen in the background, await here is just to wait for job queue
                    response.download_file(href, destination).await?;
                } else {
                    println!("Skipping exist file {}", destination);
                }
            } else {
              // or schedule crawler to navigate to a given url
              response.navigate(href).await?;
            };
        }

        Ok(())
    }
}

#[async_std::main]
async fn main() -> Result<()> {
    let scraper = Scraper {};

    // Run scraper starting from given url and using 20 worker threads
    scraper.run(Opts::new().with_urls(vec!["https://www.rust-lang.org/"]).with_threads(20)).await
}

Sample project

Gonzih/apod-nasa-scraper-rs