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Merge pull request #668 from sdroege/make-relative
Add Url::make_relative() as the inverse of Url::join()
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‎url/src/lib.rs

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Original file line numberDiff line numberDiff line change
@@ -320,6 +320,8 @@ impl Url {
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/// Parse a string as an URL, with this URL as the base URL.
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///
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/// The inverse of this is [`make_relative`].
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///
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/// Note: a trailing slash is significant.
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/// Without it, the last path component is considered to be a “file” name
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/// to be removed to get at the “directory” that is used as the base:
@@ -349,11 +351,144 @@ impl Url {
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/// with this URL as the base URL, a [`ParseError`] variant will be returned.
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///
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/// [`ParseError`]: enum.ParseError.html
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/// [`make_relative`]: #method.make_relative
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#[inline]
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pub fn join(&self, input: &str) -> Result<Url, crate::ParseError> {
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Url::options().base_url(Some(self)).parse(input)
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}
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/// Creates a relative URL if possible, with this URL as the base URL.
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///
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/// This is the inverse of [`join`].
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///
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/// # Examples
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///
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/// ```rust
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/// use url::Url;
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/// # use url::ParseError;
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///
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/// # fn run() -> Result<(), ParseError> {
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/// let base = Url::parse("https://example.net/a/b.html")?;
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/// let url = Url::parse("https://example.net/a/c.png")?;
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/// let relative = base.make_relative(&url);
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/// assert_eq!(relative.as_ref().map(|s| s.as_str()), Some("c.png"));
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///
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/// let base = Url::parse("https://example.net/a/b/")?;
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/// let url = Url::parse("https://example.net/a/b/c.png")?;
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/// let relative = base.make_relative(&url);
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/// assert_eq!(relative.as_ref().map(|s| s.as_str()), Some("c.png"));
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///
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/// let base = Url::parse("https://example.net/a/b/")?;
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/// let url = Url::parse("https://example.net/a/d/c.png")?;
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/// let relative = base.make_relative(&url);
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/// assert_eq!(relative.as_ref().map(|s| s.as_str()), Some("../d/c.png"));
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///
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/// let base = Url::parse("https://example.net/a/b.html?c=d")?;
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/// let url = Url::parse("https://example.net/a/b.html?e=f")?;
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/// let relative = base.make_relative(&url);
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/// assert_eq!(relative.as_ref().map(|s| s.as_str()), Some("?e=f"));
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/// # Ok(())
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/// # }
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/// # run().unwrap();
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/// ```
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///
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/// # Errors
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///
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/// If this URL can't be a base for the given URL, `None` is returned.
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/// This is for example the case if the scheme, host or port are not the same.
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///
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/// [`join`]: #method.join
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pub fn make_relative(&self, url: &Url) -> Option<String> {
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if self.cannot_be_a_base() {
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return None;
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}
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// Scheme, host and port need to be the same
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if self.scheme() != url.scheme() || self.host() != url.host() || self.port() != url.port() {
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return None;
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}
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// We ignore username/password at this point
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// The path has to be transformed
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let mut relative = String::new();
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// Extract the filename of both URIs, these need to be handled separately
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fn extract_path_filename(s: &str) -> (&str, &str) {
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let last_slash_idx = s.rfind('/').unwrap_or(0);
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let (path, filename) = s.split_at(last_slash_idx);
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if filename.is_empty() {
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(path, "")
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} else {
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(path, &filename[1..])
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}
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}
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let (base_path, base_filename) = extract_path_filename(self.path());
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let (url_path, url_filename) = extract_path_filename(url.path());
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let mut base_path = base_path.split('/').peekable();
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let mut url_path = url_path.split('/').peekable();
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// Skip over the common prefix
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while base_path.peek().is_some() && base_path.peek() == url_path.peek() {
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base_path.next();
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url_path.next();
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}
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// Add `..` segments for the remainder of the base path
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for base_path_segment in base_path {
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// Skip empty last segments
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if base_path_segment.is_empty() {
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break;
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}
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if !relative.is_empty() {
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relative.push('/');
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}
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relative.push_str("..");
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}
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// Append the remainder of the other URI
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for url_path_segment in url_path {
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if !relative.is_empty() {
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relative.push('/');
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}
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relative.push_str(url_path_segment);
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}
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// Add the filename if they are not the same
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if base_filename != url_filename {
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// If the URIs filename is empty this means that it was a directory
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// so we'll have to append a '/'.
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//
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// Otherwise append it directly as the new filename.
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if url_filename.is_empty() {
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relative.push('/');
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} else {
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if !relative.is_empty() {
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relative.push('/');
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}
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relative.push_str(url_filename);
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}
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}
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// Query and fragment are only taken from the other URI
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if let Some(query) = url.query() {
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relative.push('?');
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relative.push_str(query);
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}
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if let Some(fragment) = url.fragment() {
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relative.push('#');
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relative.push_str(fragment);
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}
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Some(relative)
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}
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/// Return a default `ParseOptions` that can fully configure the URL parser.
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///
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/// # Examples

‎url/tests/unit.rs

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Original file line numberDiff line numberDiff line change
@@ -960,3 +960,127 @@ fn test_slicing() {
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assert_eq!(&url[..AfterFragment], expected_slices.full);
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}
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}
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#[test]
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fn test_make_relative() {
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let tests = [
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(
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"http://127.0.0.1:8080/test",
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"http://127.0.0.1:8080/test",
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"",
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),
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(
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"http://127.0.0.1:8080/test",
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"http://127.0.0.1:8080/test/",
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"test/",
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),
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(
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"http://127.0.0.1:8080/test/",
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"http://127.0.0.1:8080/test",
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"../test",
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),
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(
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"http://127.0.0.1:8080/",
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"http://127.0.0.1:8080/?foo=bar#123",
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"?foo=bar#123",
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),
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(
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"http://127.0.0.1:8080/",
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"http://127.0.0.1:8080/test/video",
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"test/video",
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),
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(
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"http://127.0.0.1:8080/test",
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"http://127.0.0.1:8080/test/video",
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"test/video",
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),
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(
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"http://127.0.0.1:8080/test/",
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"http://127.0.0.1:8080/test/video",
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"video",
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),
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(
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"http://127.0.0.1:8080/test",
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"http://127.0.0.1:8080/test2/video",
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"test2/video",
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),
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(
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"http://127.0.0.1:8080/test/",
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"http://127.0.0.1:8080/test2/video",
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"../test2/video",
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),
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(
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"http://127.0.0.1:8080/test/bla",
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"http://127.0.0.1:8080/test2/video",
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"../test2/video",
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),
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(
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"http://127.0.0.1:8080/test/bla/",
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"http://127.0.0.1:8080/test2/video",
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"../../test2/video",
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),
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(
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"http://127.0.0.1:8080/test/?foo=bar#123",
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"http://127.0.0.1:8080/test/video",
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"video",
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),
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(
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"http://127.0.0.1:8080/test/",
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"http://127.0.0.1:8080/test/video?baz=meh#456",
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"video?baz=meh#456",
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),
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(
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"http://127.0.0.1:8080/test",
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"http://127.0.0.1:8080/test?baz=meh#456",
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"?baz=meh#456",
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),
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(
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"http://127.0.0.1:8080/test/",
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"http://127.0.0.1:8080/test?baz=meh#456",
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"../test?baz=meh#456",
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),
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(
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"http://127.0.0.1:8080/test/",
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"http://127.0.0.1:8080/test/?baz=meh#456",
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"?baz=meh#456",
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),
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(
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"http://127.0.0.1:8080/test/?foo=bar#123",
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"http://127.0.0.1:8080/test/video?baz=meh#456",
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"video?baz=meh#456",
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),
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];
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for (base, uri, relative) in &tests {
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let base_uri = url::Url::parse(base).unwrap();
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let relative_uri = url::Url::parse(uri).unwrap();
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let make_relative = base_uri.make_relative(&relative_uri).unwrap();
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assert_eq!(
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make_relative, *relative,
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"base: {}, uri: {}, relative: {}",
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base, uri, relative
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);
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assert_eq!(
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base_uri.join(&relative).unwrap().as_str(),
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*uri,
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"base: {}, uri: {}, relative: {}",
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base,
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uri,
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relative
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);
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}
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let error_tests = [
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("http://127.0.0.1:8080/", "https://127.0.0.1:8080/test/"),
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("http://127.0.0.1:8080/", "http://127.0.0.1:8081/test/"),
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("http://127.0.0.1:8080/", "http://127.0.0.2:8080/test/"),
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("mailto:[email protected]", "mailto:[email protected]"),
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];
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for (base, uri) in &error_tests {
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let base_uri = url::Url::parse(base).unwrap();
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let relative_uri = url::Url::parse(uri).unwrap();
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let make_relative = base_uri.make_relative(&relative_uri);
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assert_eq!(make_relative, None, "base: {}, uri: {}", base, uri);
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}
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}

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