fix: make query param order deterministic when adding params

[bpossolo]

Pull Request Checklist

• Have you read through the contributor guidelines?
• Have you signed the Typesafe CLA?
• Have you squashed your commits?
• Have you added copyright headers to new files?
• Have you checked that both Scala and Java APIs are updated?
• Have you updated the documentation for both Scala and Java sections?
• Have you added tests for any changed functionality?

Fixes

Fixes #48

Purpose

Ensure deterministic query param order when adding params through the WSRequest interface.
This does not address order when adding to a query param that already contains a value.
for example

req.addQueryParam("p1", "v1")
req.addQueryParam("p2", "v2")
req.addQueryParam("p1, "v3")

will yield p1=v1&p1=v3&p2=v2 which is still not perfect but is at least deterministic

Background Context

I wanted to make the minimal code change to achieve deterministic behaviour.
When generating digital signatures of urls (for example of an Authorization header) it's important to have a deterministic order to be able to correctly compute the digest.

References

playframework/playframework#6884
#102

[schmitch]

I think it would be good, to also have the example that you provided inside a test case, i.e. add p1 twice.

[bpossolo]

haha. that's funny. i originally wrote a test for it but then deleted it because i thought it might not be desired behaviour for the future. i'll re-add

[bpossolo]

updated

[bpossolo]

bump?

[schmitch]

The newly added test should be split into 3 test cases

[schmitch]

basically this should be split into multipe tests.

[bpossolo]

@schmitch thanks for clarifying. updated.

[schmitch]

/cc @marcospereira guess this can be merged

[bpossolo]

any chance we could get this in? its blocking a project

[ktoso]

WDYT @marcospereira ?

[richdougherty]

LGTM - as you say a better behaviour would be to avoid any reordering even if there are params with the same name, but I'm happy that this is an improvement because it is deterministic.

[bpossolo]

@richdougherty thank you!

[richdougherty]

Backported to 1.x.x branch.