Support disabling the proxy by setting to falsey.

Newer ruby versions of Net::HTTP will use ENV['http_proxy'] directly.
You should be able to disable the proxy in RestClient without overriding
ENV['http_proxy'] directly.

Now, detect when a proxy has been explicitly set to falsey, and
explicitly create a Net::HTTP object with proxy disabled in that case.

lib/restclient.rb

@@ -90,8 +90,23 @@ module RestClient
     Request.execute(:method => :options, :url => url, :headers => headers, &block)
   end
 
-  class << self
-    attr_accessor :proxy
+  # A global proxy URL to use for all requests. This can be overridden on a
+  # per-request basis by passing `:proxy` to RestClient::Request.
+  def self.proxy
+    @proxy
+  end
+  def self.proxy=(value)
+    @proxy = value
+    @proxy_set = true
+  end
+
+  # Return whether RestClient.proxy was set explicitly. We use this to
+  # differentiate between no value being set and a value explicitly set to nil.
+  #
+  # @return [Boolean]
+  #
+  def self.proxy_set?
+    !!@proxy_set
   end
 
   # Setup the log for RestClient calls.

lib/restclient/request.rb

@@ -273,29 +273,41 @@ module RestClient
     # The proxy URI for this request. If `:proxy` was provided on this request,
     # use it over `RestClient.proxy`.
     #
-    # @return [URI, nil]
+    # Return false if a proxy was explicitly set and is falsy.
+    #
+    # @return [URI, false, nil]
     #
     def proxy_uri
       if defined?(@proxy)
         if @proxy
           URI.parse(@proxy)
         else
-          nil
+          false
+        end
+      elsif RestClient.proxy_set?
+        if RestClient.proxy
+          URI.parse(RestClient.proxy)
+        else
+          false
         end
-      elsif RestClient.proxy
-        URI.parse(RestClient.proxy)
       else
         nil
       end
     end
 
-    def net_http_class
+    def net_http_object(hostname, port)
       p_uri = proxy_uri
 
-      if p_uri
-        Net::HTTP::Proxy(p_uri.hostname, p_uri.port, p_uri.user, p_uri.password)
+      if p_uri.nil?
+        # no proxy set
+        Net::HTTP.new(hostname, port)
+      elsif !p_uri
+        # proxy explicitly set to none
+        Net::HTTP.new(hostname, port, nil, nil, nil, nil)
       else
-        Net::HTTP
+        Net::HTTP.new(hostname, port,
+                      p_uri.hostname, p_uri.port, p_uri.user, p_uri.password)
+
       end
     end
 
@@ -409,7 +421,7 @@ module RestClient
 
       setup_credentials req
 
-      net = net_http_class.new(uri.hostname, uri.port)
+      net = net_http_object(uri.hostname, uri.port)
       net.use_ssl = uri.is_a?(URI::HTTPS)
       net.ssl_version = ssl_version if ssl_version
       net.ciphers = ssl_ciphers if ssl_ciphers

spec/unit/request_spec.rb

@@ -413,43 +413,77 @@ describe RestClient::Request, :include_helpers do
   end
 
   describe "proxy" do
+    before do
+      allow(Net::HTTP).to receive(:new).and_call_original
+      @proxy_req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload')
+    end
+
     it "creates a proxy class if a proxy url is given" do
       RestClient.stub(:proxy).and_return("http://example.com/")
-      @request.net_http_class.proxy_class?.should be true
+      RestClient.stub(:proxy_set?).and_return(true)
+      @proxy_req.net_http_object('host', 80).proxy?.should be true
     end
 
     it "creates a proxy class with the correct address if a IPv6 proxy url is given" do
       RestClient.stub(:proxy).and_return("http://[::1]/")
-      @request.net_http_class.proxy_address.should == "::1"
+      RestClient.stub(:proxy_set?).and_return(true)
+      @proxy_req.net_http_object('host', 80).proxy?.should be true
+      @proxy_req.net_http_object('host', 80).proxy_address.should == '::1'
     end
 
     it "creates a non-proxy class if a proxy url is not given" do
-      @request.net_http_class.proxy_class?.should be_falsey
+      @proxy_req.net_http_object('host', 80).proxy?.should be_falsey
     end
 
     it "disables proxy on a per-request basis" do
+      allow(Net::HTTP).to receive(:new).and_call_original
       RestClient.stub(:proxy).and_return('http://example.com')
-      @request.net_http_class.proxy_class?.should be true
+      RestClient.stub(:proxy_set?).and_return(true)
+      @proxy_req.net_http_object('host', 80).proxy?.should be true
 
       disabled_req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload', :proxy => nil)
-      disabled_req.net_http_class.proxy_class?.should be_falsey
+      disabled_req.net_http_object('host', 80).proxy?.should be_falsey
     end
 
     it "sets proxy on a per-request basis" do
-      @request.net_http_class.proxy_class?.should be_falsey
+      allow(Net::HTTP).to receive(:new).and_call_original
+      @proxy_req.net_http_object('some', 80).proxy?.should be_falsey
 
       req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload', :proxy => 'http://example.com')
-      req.net_http_class.proxy_class?.should be true
+      req.net_http_object('host', 80).proxy?.should be true
+    end
+
+    it "overrides proxy from environment" do
+      allow(Net::HTTP).to receive(:new).and_call_original
+      allow(ENV).to receive(:[]).with("http_proxy").and_return("http://127.0.0.1")
+      allow(ENV).to receive(:[]).with("no_proxy").and_return(nil)
+      allow(ENV).to receive(:[]).with("NO_PROXY").and_return(nil)
+      req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload')
+      obj = req.net_http_object('host', 80)
+      obj.proxy?.should be true
+      obj.proxy_address.should eq '127.0.0.1'
+
+      req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload', :proxy => nil)
+      obj = req.net_http_object('host', 80)
+      obj.proxy?.should be_falsey
+
+      RestClient.stub(:proxy_set?).and_return(true)
+      req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload')
+      obj = req.net_http_object('host', 80)
+      obj.proxy?.should be_falsey
     end
 
     it "overrides global proxy with per-request proxy" do
+      allow(Net::HTTP).to receive(:new).and_call_original
       RestClient.stub(:proxy).and_return('http://example.com')
-      @request.net_http_class.proxy_class?.should be true
-      @request.net_http_class.proxy_address.should == 'example.com'
+      RestClient.stub(:proxy_set?).and_return(true)
+      obj = @proxy_req.net_http_object('host', 80)
+      obj.proxy?.should be true
+      obj.proxy_address.should eq 'example.com'
 
       req = RestClient::Request.new(:method => :put, :url => 'http://some/resource', :payload => 'payload', :proxy => 'http://127.0.0.1/')
-      req.net_http_class.proxy_class?.should be true
-      req.net_http_class.proxy_address.should == '127.0.0.1'
+      req.net_http_object('host', 80).proxy?.should be true
+      req.net_http_object('host', 80).proxy_address.should == '127.0.0.1'
     end
   end