Base64 URL path segments

Unknown data in URL paths can result in invalid URLs, but base64url is designed to be URL-safe.

VCL

Use this solution in your VCL service (click RUN below to test this solution or clone it to make changes):

Compute@Edge

Use this solution in your Compute@Edge service:

Rust

    lazy_static! {
        static ref RE: Regex = Regex::new(r"/views/(?P<path>[^/]*)").unwrap();
    }

    let url = "/views/zqzOu8-GzrE=/path/filename.html";

    if let Some(encoded) = RE
        .captures(&url)
        .and_then(|cap| cap.name("path"))
        .map(|p| p.as_str().to_owned())
    {
        let decoded = base64::decode_config(encoded, base64::URL_SAFE)?;
        assert_eq!(decoded, "άλφα".as_bytes());
    }

    // When base64-encoded material is sent as a part of a URL, the `encode_config` and
    // `decode_config` functions should be used, specifying that we want to use a character
    // set that is safe for use in URL's.
    //
    // `URL_SAFE_NO_PAD` can also be used to omit `=` padding. For example, the segment path
    // in this demo is encoded like this:
    assert_eq!(
        base64::encode_config(
            "from=06/07/2013 query=\"Καλώς ορίσατε\"",
            base64::URL_SAFE_NO_PAD
        ),
        "ZnJvbT0wNi8wNy8yMDEzIHF1ZXJ5PSLOms6xzrvPjs-CIM6_z4HOr8-DzrHPhM61Ig"
    );

    // The normal base64 encoding of this text would include characters invalid in a URL path.
    // See below:
    assert_eq!(
        base64::encode_config("from=06/07/2013 query=\"Καλώς ορίσατε\"", base64::STANDARD),
        "ZnJvbT0wNi8wNy8yMDEzIHF1ZXJ5PSLOms6xzrvPjs+CIM6/z4HOr8+DzrHPhM61Ig=="
    );