Faraday: Ability to ignore env proxy settings for a single connection

Created on 22 Aug 2019 · 3Comments · Source: lostisland/faraday

Basic Info

Faraday Version: 0.15.4
Ruby Version: 2.4.3

Issue description

We're running a pretty large app with hundreds of sub-components that use Faraday to some extent. Most of these components expect to configure Faraday with the environment variables http_proxy and so on; they don't pass an explicit :proxy setting to the connection constructors.

Some components (2 or 3 out of about 100) however, must use a Faraday connection without a proxy. That means we can't use Faraday.ignore_env_proxy = true, otherwise the remaining ~100 components break.

What I'd like to have is a way for those few components to be able to create a Faraday connection object that does not use a proxy, neither from the environment nor otherwise.

Steps to reproduce

Similar to #752, this yields a faraday object that will use the proxy settings from the environment when it makes connections:

c = Faraday.new('https://www.google.com', proxy: nil)

I also tried being Very Smart and passing an empty hash as the Proxy Options instead, like so:

c = Faraday.new('https://www.google.com', proxy: {})

but using this connection errors with:

NoMethodError: undefined method `hostname' for nil:NilClass
from vendor/bundle/ruby/2.4.0/gems/faraday-0.15.4/lib/faraday/adapter/net_http.rb:97:in `net_http_connection'

I believe having this (or another way of saying "don't use a proxy" via :proxy settings) be supported would fully resolve this issue for me.

info

Source

asf-stripe

Most helpful comment

OMG, that's definitely a work-around. What we did so far was a middleware like this (for our use of Octokit):

    # A Faraday middleware that throws out any configured proxy away
    # from the request environment, to make connections to GHE work
    # (those must not be proxied).
    class ProxyDroppingMiddleware < Faraday::Middleware
      def call(request_env)
        request_env[:request][:proxy] = nil
        @app.call(request_env)
      end
    end

And then, when it comes time to initialize octokit:

        stack = Faraday::RackBuilder.new do |builder|
          builder.use ProxyDroppingMiddleware
          # What follows is the default octokit middleware:
          builder.use Faraday::Request::Retry, exceptions: [Octokit::ServerError]
          builder.use Octokit::Middleware::FollowRedirects
          builder.use Octokit::Response::RaiseError
          builder.use Octokit::Response::FeedParser
          builder.adapter Faraday.default_adapter
        end
        options[:middleware] = stack

From what I can tell, the middleware work-around will work more nicely with octokit, otherwise we'd have to make an octokit wrapper to patch the Faraday object after creation.

asf-stripe on 23 Aug 2019

👍2

All 3 comments

@asf-stripe I have never tried doing this (it's usually all or none), but I think you can try setting the proxy to nil AFTER the connection initialisation with the setter (https://github.com/lostisland/faraday/blob/master/lib/faraday/connection.rb#L397)

c = Faraday.new('https://www.google.com')
c.proxy = nil

This should set the @manual_proxy env to true and force Faraday to ignore the env for that particular connection.
Please let me know if that works 😄

iMacTia on 22 Aug 2019

👍1

OMG, that's definitely a work-around. What we did so far was a middleware like this (for our use of Octokit):

    # A Faraday middleware that throws out any configured proxy away
    # from the request environment, to make connections to GHE work
    # (those must not be proxied).
    class ProxyDroppingMiddleware < Faraday::Middleware
      def call(request_env)
        request_env[:request][:proxy] = nil
        @app.call(request_env)
      end
    end

And then, when it comes time to initialize octokit:

        stack = Faraday::RackBuilder.new do |builder|
          builder.use ProxyDroppingMiddleware
          # What follows is the default octokit middleware:
          builder.use Faraday::Request::Retry, exceptions: [Octokit::ServerError]
          builder.use Octokit::Middleware::FollowRedirects
          builder.use Octokit::Response::RaiseError
          builder.use Octokit::Response::FeedParser
          builder.adapter Faraday.default_adapter
        end
        options[:middleware] = stack

From what I can tell, the middleware work-around will work more nicely with octokit, otherwise we'd have to make an octokit wrapper to patch the Faraday object after creation.

asf-stripe on 23 Aug 2019

👍2

Ah yes, my solution only works if you have access to the actual connection (either using a wrapper or things like instance_variable_get). I assumed that was the case looking at the attempts you mentioned on your first post.

Glad to hear my suggestion works and you even have a custom middleware for other cases.
I'll close this issue but please reach out if you still need any help 😄

iMacTia on 23 Aug 2019

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