Get client IP when using Cloudflare

[ItalyPaleAle]

When proxying an app through Cloudflare, the user's real IP is set in the CF-Connecting-IP header. This is more convenient than having to manually maintain an allow-list of trusted proxies.

Reference: https://support.cloudflare.com/hc/en-us/articles/200170986-How-does-Cloudflare-handle-HTTP-Request-headers-

[codecov]

Codecov Report

Merging #2723 (e0e1d5c) into master (0cbb30a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2723   +/-   ##
=======================================
  Coverage   98.69%   98.69%           
=======================================
  Files          41       41           
  Lines        2070     2074    +4     
=======================================
+ Hits         2043     2047    +4     
  Misses         15       15           
  Partials       12       12           

Impacted Files	Coverage Δ
gin.go	99.18% <ø> (ø)
context.go	97.65% <100.00%> (+0.02%)	⬆️

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[ItalyPaleAle]

Thinking about it, I wonder if rather than using booleans, it might make more sense to create an enum platform (or something like that)?

This way, once the next platform is inevitably added, we don't add yet another boolean.

The downside is around what to do with the existing Google App Engine flag.

[thinkerou]

Thinking about it, I wonder if rather than using booleans, it might make more sense to create an enum platform (or something like that)?

This way, once the next platform is inevitably added, we don't add yet another boolean.

The downside is around what to do with the existing Google App Engine flag.

Yes, I also like enum

[ItalyPaleAle]

I can update to use an enum-like.

What should I do for the existing Google App Engine flag? Keep that for legacy and "translate" that into the enum?

[thinkerou]

lgtm

[ItalyPaleAle]

Wait before you merge.... I want to update it to use an enum. Before we introduce even more legacy. :) just let me know what I should do with the existing Boolean flag for Google App Engine

[thinkerou]

I can update to use an enum-like.

What should I do for the existing Google App Engine flag? Keep that for legacy and "translate" that into the enum?

@ItalyPaleAle I merged the pull request at first, please commit other pull request using(refactoring) enum, thanks!

[ItalyPaleAle]

Ok. Will do it over the weekend or sooner.

What do you want me to do with the existing Boolean for GAE? I can't remove it because it would be backwards-incompatible. I can keep it as a legacy alias that then is translated to the enum?

[thinkerou]

@ItalyPaleAle please read https://github.com/gin-gonic/gin/blob/master/deprecated.go for reference, we should deprecated warning at first and remove.

[ItalyPaleAle]

@thinkerou I made the change in #2739 hope this works!