Allow call #persistent with block

Example Usage:
==============

``` ruby
def keys(users)
  HTTP.persistent("https://github.com") do |http|
    users.map { |u| http.get("/#{u}.keys").to_s }
  end
end
```

Resolves #200

Author: ixti

lib/http/chainable.rb

@@ -72,11 +72,41 @@ def request(verb, uri, options = {})
       branch(options).request verb, uri
     end
 
-    # Flag as persistent
-    # @param [String] host
-    # @raise [Request::Error] if Host is invalid
+    # @overload persistent(host)
+    #   Flags as persistent
+    #   @param [String] host
+    #   @raise [Request::Error] if Host is invalid
+    #   @return [HTTP::Client] Persistent client
+    # @overload persistent(host, &block)
+    #   Executes given block with persistent client and automatically closes
+    #   connection at the end of execution.
+    #
+    #   @example
+    #
+    #       def keys(users)
+    #         HTTP.persistent("https://github.com") do |http|
+    #           users.map { |u| http.get("/#{u}.keys").to_s }
+    #         end
+    #       end
+    #
+    #       # same as
+    #
+    #       def keys(users)
+    #         http = HTTP.persistent "https://github.com"
+    #         users.map { |u| http.get("/#{u}.keys").to_s }
+    #       ensure
+    #         http.close if http
+    #       end
+    #
+    #
+    #   @yieldparam [HTTP::Client] client Persistent client
+    #   @return [Object] result of last expression in the block
     def persistent(host)
-      branch default_options.with_persistent host
+      p_client = branch default_options.with_persistent host
+      return p_client unless block_given?
+      yield p_client
+    ensure
+      p_client.close
     end
 
     # Make a request through an HTTP proxy

lib/http/client.rb

@@ -1,3 +1,5 @@
+require "forwardable"
+
 require "cgi"
 require "uri"
 
@@ -10,6 +12,7 @@
 module HTTP
   # Clients make requests and receive responses
   class Client
+    extend Forwardable
     include Chainable
 
     CONNECTION         = "Connection".freeze
@@ -58,6 +61,11 @@ def perform(req, options)
       end
     end
 
+    # @!method persistent?
+    #   @see Options#persistent?
+    #   @return [Boolean] whenever client is persistent
+    def_delegator :default_options, :persistent?
+
     def make_request(req, options)
       verify_connection!(req.uri)
 
@@ -79,12 +87,10 @@ def make_request(req, options)
       @state = :clean
 
       res
-
-    # On any exception we reset the conn. This is a safety measure, to ensure
-    # we don't have conns in a bad state resulting in mixed requests/responses
     rescue
-      close if default_options.persistent?
-
+      # On any exception we reset the conn. This is a safety measure, to ensure
+      # we don't have conns in a bad state resulting in mixed requests/responses
+      close if persistent?
       raise
     end
 

spec/lib/http_spec.rb

@@ -163,4 +163,27 @@
       expect(client.default_options[:cache]).to eq cache
     end
   end
+
+  describe ".persistent" do
+    let(:host) { "https://api.github.com" }
+
+    context "with host only given" do
+      subject { HTTP.persistent host }
+      it { is_expected.to be_an HTTP::Client }
+      it { is_expected.to be_persistent }
+    end
+
+    context "with host and block given" do
+      it "returns last evaluation of last expression" do
+        expect(HTTP.persistent(host) { :http }).to be :http
+      end
+
+      it "auto-closes connection" do
+        HTTP.persistent host do |client|
+          expect(client).to receive(:close).and_call_original
+          client.get("/repos/httprb/http.rb")
+        end
+      end
+    end
+  end
 end