Is there a way to emulate different devices using headless_chrome (Rust) in Rust?

headless_chrome, which is a Rust crate for driving a real Chrome browser in headless mode, may not provide direct APIs to emulate different devices similarly to how you can in languages like Python or JavaScript using tools like Puppeteer or Selenium. However, you can still achieve this by using the Chrome DevTools Protocol (CDP) to send commands to the Chrome instance that headless_chrome controls.

Here's a general idea of how you might go about emulating different devices using headless_chrome in Rust:

1. Create a browser instance using headless_chrome.
2. Navigate to the desired page.
3. Use CDP to set device metrics and user agent to emulate a particular device.

Below is a hypothetical code example that illustrates these steps. Keep in mind that the actual implementation might vary depending on the version of the headless_chrome crate and its API at the time you are using it. This code is for illustrative purposes only, as the crate might not have the exact functions as shown:

extern crate headless_chrome;

use headless_chrome::{Browser, protocol::cdp::Emulation};

fn main() -> Result<(), failure::Error> {
    // Launch the browser
    let browser = Browser::new(Default::default())?;

    // Create a new tab and navigate to the desired URL
    let tab = browser.wait_for_initial_tab()?;
    tab.navigate_to("http://example.com")?;

    // Wait for network/javascript/dom to make the page idle.
    tab.wait_until_navigated()?;

    // Emulate device metrics
    // These metrics would need to correspond to the device you're trying to emulate
    let device_metrics = Emulation::SetDeviceMetricsOverride {
        width: 375,
        height: 667,
        device_scale_factor: 2.0,
        mobile: true,
        fit_window: false,
        // Other fields...
    };

    // Send the command to set device metrics
    tab.call_method(device_metrics)?;

    // Optionally, set the user agent string
    let user_agent = "Mozilla/5.0 (iPhone; CPU iPhone OS 10_3 like Mac OS X) AppleWebKit/602.1.50 (KHTML, like Gecko) CriOS/56.0.2924.75 Mobile/14E5239e Safari/602.1";
    let set_user_agent = Emulation::SetUserAgentOverride {
        user_agent: user_agent.to_string(),
        // Other fields...
    };

    // Send the command to set the user agent
    tab.call_method(set_user_agent)?;

    // Your scraping logic here...

    Ok(())
}

Make sure you refer to the latest headless_chrome documentation to understand the current API and how to use it correctly. Additionally, ensure that the actions you are performing comply with the terms of service of the website you are scraping and with relevant laws and regulations.

If you find that headless_chrome does not support device emulation as you require, you may need to consider alternative approaches, such as using a different language that has more mature headless browser automation libraries (e.g., Puppeteer with JavaScript or Selenium with Python) or directly interfacing with the Chrome DevTools Protocol in Rust.