lychee/lychee-lib/src/helpers/url.rs

use linkify::LinkFinder;

use once_cell::sync::Lazy;

static LINK_FINDER: Lazy<LinkFinder> = Lazy::new(LinkFinder::new);

/// Remove all GET parameters from a URL.
/// The link is not a URL but a String as it may not have a base domain.
pub(crate) fn remove_get_params_and_fragment(url: &str) -> &str {
    let path = match url.split_once('#') {
        Some((path_without_fragment, _fragment)) => path_without_fragment,
        None => url,
    };
    let path = match path.split_once('?') {
        Some((path_without_params, _params)) => path_without_params,
        None => path,
    };
    path
}

/// Extract all semantically-known links from a given html attribute. Pattern-based extraction from
/// unstructured plaintext is done elsewhere.
pub(crate) fn extract_links_from_elem_attr(
    attr_name: &str,
    elem_name: &str,
    attr_value: &str,
) -> Vec<String> {
    // See a comprehensive list of attributes that might contain URLs/URIs
    // over at: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes
    let mut urls = Vec::new();

    match (attr_name, elem_name) {
        ("href" | "src" | "cite", _) | ("data", "object") | ("onhashchange", "body") => {
            urls.push(attr_value.to_owned());
        }
        ("srcset", _) => {
            for image_candidate_string in attr_value.trim().split(',') {
                for part in image_candidate_string.split_ascii_whitespace() {
                    if part.is_empty() {
                        continue;
                    }

                    urls.push(part.to_owned());
                    break;
                }
            }
        }
        _ => (),
    }

    urls
}

// Taken from https://github.com/getzola/zola/blob/master/components/link_checker/src/lib.rs
pub(crate) fn is_anchor(url: &str) -> bool {
    url.starts_with('#')
}

// Use `LinkFinder` to offload the raw link searching in plaintext
pub(crate) fn find_links(input: &str) -> impl Iterator<Item = linkify::Link> {
    LINK_FINDER.links(input)
}

#[cfg(test)]
mod test_fs_tree {
    use super::*;

    #[test]
    fn test_is_anchor() {
        assert!(is_anchor("#anchor"));
        assert!(!is_anchor("notan#anchor"));
    }

    #[test]
    fn test_remove_get_params_and_fragment() {
        assert_eq!(remove_get_params_and_fragment("/"), "/");
        assert_eq!(
            remove_get_params_and_fragment("index.html?foo=bar"),
            "index.html"
        );
        assert_eq!(
            remove_get_params_and_fragment("/index.html?foo=bar"),
            "/index.html"
        );
        assert_eq!(
            remove_get_params_and_fragment("/index.html?foo=bar&baz=zorx?bla=blub"),
            "/index.html"
        );
        assert_eq!(
            remove_get_params_and_fragment("https://example.org/index.html?foo=bar"),
            "https://example.org/index.html"
        );
        assert_eq!(
            remove_get_params_and_fragment("test.png?foo=bar"),
            "test.png"
        );

        assert_eq!(
            remove_get_params_and_fragment("https://example.org/index.html#anchor"),
            "https://example.org/index.html"
        );
        assert_eq!(
            remove_get_params_and_fragment("https://example.org/index.html?foo=bar#anchor"),
            "https://example.org/index.html"
        );
        assert_eq!(
            remove_get_params_and_fragment("test.png?foo=bar#anchor"),
            "test.png"
        );
        assert_eq!(
            remove_get_params_and_fragment("test.png#anchor?anchor!?"),
            "test.png"
        );
        assert_eq!(
            remove_get_params_and_fragment("test.png?foo=bar#anchor?anchor!"),
            "test.png"
        );
    }
}