Support request.query decoding

[alexsnaps]

See test, but this effectively works like this, given the query string param1=%F0%9F%91%BE%20&param2=Exterminate%21&%F0%9F%91%BE=123&%F0%9F%91%BE=456

queryMap(request.query)['param1'] == '👾 ' &&
queryMap(request.query)['param2'] == 'Exterminate!' &&
queryMap(request.query)['👾'][0] == '123' &&
queryMap(request.query)['👾'][1] == '456'

i.e.:

• Doesn't trim
• decodes all utf-8
• supports lists of values

It is exposed as an "extension" that's only enabled via Expression::new_extended, but mostly thru Predicate::route_rule that's now only used in the config, when compiling RouteRuleConditions

[eguzki]

LGTM

Add some doc and ready to be merged

[alexsnaps]

@guicassolato so this works for your use-case(s)?
Also, that last test is somewhat sad... wdy'all think?

[didierofrivia]

👾

[alexsnaps]

@eguzki is this ok? Or are you still expecting more changes?

[alexsnaps]

So reading this:

// If a query param is repeated in an HTTP request, the behavior is
// purposely left undefined, since different data planes have different
// capabilities. However, it is *recommended* that implementations should
// match against the first value of the param if the data plane supports it,
// as this behavior is expected in other load balancing contexts outside of
// the Gateway API.
//
// Users SHOULD NOT route traffic based on repeated query params to guard
// themselves against potential differences in the implementations.

Wondering if we shouldn't always have the first param in our Map and drop the List altogether...
I have a PR getting ready that would:

fmt.Sprintf("decodeQueryString(request.query)['%s'] == '%s'", queryParam.Name, queryParam.Value)

@guicassolato do you have an opinion?

[alexsnaps]

Alternate proposal, that I'll implement here right now, pass an optional 2nd bool param, that would dictate whether to return a List when repeated params are present, or only the first one (includeRepeatedParams: bool kinda thing).

See this PR on the Kuadrant Operator side

[eguzki]

In description it says decodeQueryString but in the implementation I see queryMap.