Support multiple values for query params

[sanjayatn]

Support Multiple Values for Query Params.
In the wikipedia article for https://en.wikipedia.org/wiki/Query_string it says "While there is no definitive standard, most web frameworks allow multiple values to be associated with a single field (e.g. field1=value1&field1=value2&field2=value3).
Many frameworks support this even though it is not the standard. Currently Pistache supports multiple values separated by a comma by default.

This PR adds two enhancements:

1. Transform the multiple value through duplicate param names into a list of values separated by a , to allow the rest of the framework to convert values to std::vector
2. Provide all the param/value pairs received with the request.
3. Add Query update method to replace a value in the Query collection.

[Tachi107]

Hi @sanjayatn, thanks for your patch! Could you please add more information about it (comments etc.)?

[kiplingw]

And rebase too.

[sanjayatn]

@Tachi107 @kiplingw I didn't realized you can see this branch but I love to submit it as a proper PR! Coming up today!

[codecov-commenter]

Codecov Report

Patch coverage: 26.66% and project coverage change: -0.12 ⚠️

Comparison is base (a68ad09) 78.48% compared to head (aa6c74a) 78.36%.

❗ Current head aa6c74a differs from pull request most recent head d268fdc. Consider uploading reports for the commit d268fdc to get more accurate results

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1130      +/-   ##
==========================================
- Coverage   78.48%   78.36%   -0.12%     
==========================================
  Files          53       53              
  Lines        6892     6907      +15     
==========================================
+ Hits         5409     5413       +4     
- Misses       1483     1494      +11     

Impacted Files	Coverage Δ
include/pistache/http.h	86.48% <ø> (ø)
src/common/http.cc	73.57% <26.66%> (-1.09%)	⬇️

☔ View full report in Codecov by Sentry.
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[sanjayatn]

@Tachi107 @kiplingw I see two things failing in the checks. Which one should focus on? If you can give me 2 sentence summary of what abidiff / abi step's goal, then I have better idea to fix it.

[kiplingw]

Hey @sanjayatn. For commitlint you can find what it's complaining about here. For abidiff my guess is you may have missed this.

[sanjayatn]

@kiplingw thanks!

[Tachi107]

Hi @sanjayatn, thanks for the added description and sorry for the delayed response.

I'm personally not a fan of multiple query parameters because, as you say, the behaviour is not standardized, and differences in how different software components handle them can be a source of security vulnerabilities, so much that this class of vulnerabilities got a name: "HTTP parameter pollution".

That being said, aligning to what others do is probably fine, as long as the others do sensible stuff.

Could you please add a couple of test cases showing this new behaviour? Thanks!