proposal: net/http/httputil: deprecate ReverseProxy.Director

[mpx]

The ReverseProxy.Rewrite API was added (#53002) to address security/other issues (#28168, #50580) with ReverseProxy.Director.

The current httputil.ReverseProxy documentation doesn't make it particularly clear why Rewrite is generally preferred over Director (eg, gotchas).

#50580 proposed:

Since in this case the existing API is inherently insecure, I propose that we [..] mark Director as deprecated

I think deprecation of the problematic API is a good idea, but maybe there was a reason this wasn't done when Rewrite was added?
Alternatively, the documentation for Rewrite and/or Director could be improved to make it clear why/when to use one over the other.

Cc @neild

[gabyhelp]

Related Issues

• doc: net/http/httputil: add example for reuse of Director #31406 (closed)
• net/http/httputil: replace Director with Rewrite #53002 (closed)
• net/http/httputil: ReverseProxy.Director comments unclear leads to potential race #18456 (closed)

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