Add filters for htmlEscape and htmlUnescape

[ad8lmondy]

This PR adds the filters htmlEncode and htmlDecode, inspired by the urlEncode and urlDecode filters.

This allows content like: "a > b && a < c" to be encoded to "a > b && a < c" and back again.

I've added the filter to existing tests, and all are passing.

Regarding the info here: #1060 (comment) (thanks for that, btw!)

• Smaller PRs: I've split the PR into 4 commits of relatively logical blocks, but I'm not entirely sure if it's appropriate to make each a PR. I'm not sure the tests would pass without some of the code, so a certain size is going to be required, afaik. Please let me know if you'd prefer something else, happy to do as recommended.
• Adding a new crate: This PR adds in a new crate html-escape. I took inspiration from the existing code for the urlEncode filters, which uses the percent-encoding crate. I don't say this as justification for adding another crate, just that I'm not sure my skills in rust are up to task of implementing it myself 😅

Thanks!

[jcamiel]

Thanks for the PR @ad8lmondy

• regarding using an external crates: fair enough, I didn't check closely what we did on urlEncode. I think we're still going to remove this particular crate (need to check with @fabricereix) because, if I'm not missing anything, that's not a particular difficult task.
  For instance, in the Tera code, the following function escapes HTML:

pub fn escape_html(input: &str) -> String {
    let mut output = String::with_capacity(input.len() * 2);
    for c in input.chars() {
        match c {
            '&' => output.push_str("&"),
            '<' => output.push_str("&lt;"),
            '>' => output.push_str("&gt;"),
            '"' => output.push_str("&quot;"),
            '\'' => output.push_str("&#x27;"),
            '/' => output.push_str("&#x2F;"),
            _ => output.push(c),
        }
    }

    // Not using shrink_to_fit() on purpose
    output
}

It's small code and easy to understand. I much prefer having this code in our own source code than using an (even small) dependency. Unescaping is a "bit more" difficult but it is also not a "hard" tasks: for instance, HTML escape and unescape in Python standard lib. That's say, we can merge this PR and implement escaping / unescaping latter,

• regarding the naming. I think I prefer htmlEscape and htmlUnescape. I understand this is not symetric with urlEncode / urlDecode but, for instance, in Python you have urlEncode and htmlEscape/Unescape. The Tera function is also named escape_html. What do you think? Did you name it because of the existing functions urlEncode and urlDecode or another reasons?

[ad8lmondy]

Yes, I suppose you're right about the difficulty - not too bad, particularly for the encoding side. In saying that, abstracting any potential nuances to a seperate crate is appealing too 😄

In regard to the naming - I agree, it should htmlEscape and htmlUnescape. I think I named it as encode/decode because I was literally copying chunks of code. Only when I found the html-escape crate did I realise it was a better name. I meant to go back and rename it, but forgot.

I'll update the PR tomorrow with the new and better name.

[jcamiel]

Great, just don't forget to rebase your commits to appeal our CI and everything should be ok!

[ad8lmondy]

Filter names updated, all rebased, and quick test from my end looks to be working.

[ad8lmondy]

Oh yes, do let me know if there are any docs I should be updating. I wasn't sure if the grammar section on the website was generated or not - if not, I can update it 👍

[jcamiel]

/accept

[hurl-bot]

🕗 /accept is running, please wait for completion.

[hurl-bot]

✅ Pull request accepted and closed by jcamiel with fast forward merge..

# List of commits merged from ad8lmondy/hurl/htmldecode branch into Orange-OpenSource/hurl/master branch:

• 43487b0 Add integration tests for htmlEscape and htmlUnescape filters
• e6028f3 Add support for htmlEscape and htmlUnescape in hurlfmt
• db486f9 Add htmlEscape and htmlUnescape filters
• 7289930 Add grammar to support htmlEscape and htmlUnescape

[jcamiel]

Everything is good, once again thanks for the PR!