Does Scraper (Rust) allow for custom headers and user agents?

Yes, Scraper in Rust allows for custom headers and user agents. When you perform web scraping using Scraper, you often need to make HTTP requests that resemble those made by a regular web browser. Custom headers and user agents can help with this by making your requests appear more legitimate to the server, which can prevent you from being blocked or rate-limited.

To use custom headers and user agents with Scraper, you'll also need to use an HTTP client library such as reqwest, which allows you to make HTTP requests with custom configurations. Scraper itself is focused on HTML parsing, so you would typically fetch the page content using reqwest and then parse it with Scraper.

Here’s an example of how to use reqwest to make an HTTP GET request with custom headers and a user agent in Rust:

// Include dependencies in your Cargo.toml
// [dependencies]
// reqwest = { version = "0.11", features = ["blocking"] }
// scraper = "0.12"

use reqwest::header::{HeaderMap, HeaderValue, USER_AGENT};
use scraper::{Html, Selector};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create an instance of HeaderMap to hold our custom headers
    let mut headers = HeaderMap::new();

    // Create a custom User-Agent header
    headers.insert(USER_AGENT, HeaderValue::from_static("MyCustomUserAgent/1.0"));

    // Add any additional headers you require, for example:
    // headers.insert("Custom-Header", HeaderValue::from_static("CustomValue"));

    // Build an HTTP client with your custom headers
    let client = reqwest::blocking::Client::builder()
        .default_headers(headers)
        .build()?;

    // The URL you want to scrape
    let url = "http://example.com";

    // Perform the HTTP GET request to the URL
    let response = client.get(url).send()?;

    // Make sure the request was successful
    if response.status().is_success() {
        // Parse the response text into HTML
        let body = response.text()?;
        let document = Html::parse_document(&body);

        // Now you can use Scraper to parse the document
        // For example, selecting all elements with the class "info"
        let selector = Selector::parse(".info").unwrap();
        for element in document.select(&selector) {
            println!("{}", element.inner_html());
        }
    }

    Ok(())
}

In the example above, we've used the reqwest library with the "blocking" feature to make synchronous HTTP requests. We created a custom HeaderMap to include our User-Agent and potentially other headers. Then, we built a reqwest client with those default headers and made a GET request to the desired URL. Finally, we used Scraper to parse the HTML response and select elements with a specific class.

Remember that when scraping websites, you should always respect the robots.txt file and the website's terms of service. Additionally, making too many requests in a short period can overload the server, so it's good practice to rate-limit your requests and handle them responsibly.