Allow using Browsermob server in parallel

README.md

@@ -52,7 +52,27 @@ driver.quit
 
 proxy_listener.hars #=> [#<HAR::Archive:0x-27066c42d7e75fa6>, #<HAR::Archive:0x-d7e75fa627066c42>]
 proxy.close
+```
+
+Parallel usage of a single Browsermob server (it will start server process only if it hasn't already been started):
 
+```ruby
+BROWSERMOB_SERVER_PORT = 8080
+
+begin
+  TCPSocket.new("127.0.0.1", BROWSERMOB_SERVER_PORT).close
+rescue
+  server_location = "/path/to/download/browsermob-proxy"
+  browsermob_server = BrowserMob::Proxy::Server.new(server_location, port: BROWSERMOB_SERVER_PORT, stop_at_exit: false)
+  browsermob_server.start
+end
+
+server_url = BrowserMob::Proxy::Server.form_server_url(BROWSERMOB_SERVER_PORT)
+proxy = BrowserMob::Proxy::Client.from server_url
+
+at_exit do
+  proxy.close
+end
 ```
 
 Viewing HARs

lib/browsermob/proxy/server.rb

@@ -5,7 +5,11 @@ module BrowserMob
   module Proxy
 
     class Server
-      attr_reader :port
+      attr_reader :port, :url, :process
+
+      def self.form_server_url(port)
+        "http://localhost:#{port}"
+      end
 
       #
       # Create a new server instance
@@ -24,6 +28,8 @@ def initialize(path, opts = {})
         @port    = Integer(opts[:port] || 8080)
         @timeout = Integer(opts[:timeout] || 10)
         @log     = !!opts[:log]
+        @stop_at_exit = (opts[:stop_at_exit].nil?) ? true : opts[:stop_at_exit]
+        @url = self.class.form_server_url(@port)
 
         @process = create_process
       end
@@ -33,16 +39,14 @@ def start
 
         wait_for_startup
 
-        pid = Process.pid
-        at_exit { stop if Process.pid == pid }
+        if @stop_at_exit
+          pid = Process.pid
+          at_exit { stop if Process.pid == pid }
+        end
 
         self
       end
 
-      def url
-        "http://localhost:#{port}"
-      end
-
       def create_proxy
         Client.from url
       end
@@ -108,4 +112,4 @@ class ServerDiedError < StandardError
 
     end # Server
   end # Proxy
-end # BrowserMob
+end # BrowserMob

spec/e2e/server_spec.rb

@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe "Server" do
+  it 'should not stop itself at exit if :stop_at_exit is false' do
+    server_pid = run_in_isolation do
+      server = BrowserMob::Proxy::Server.new(
+          File.join(home, "bin", "browsermob-proxy"),
+          port: Selenium::WebDriver::PortProber.above(3000),
+          log: true,
+          stop_at_exit: false
+        ).start
+      server.process.pid
+    end
+
+    expect(process_alive?(server_pid)).to eq(true)
+    Process.kill 'TERM', server_pid
+  end
+
+  it 'should stop itself at exit if :stop_at_exit is not set (true by default)' do
+    server_pid = run_in_isolation do
+      server = BrowserMob::Proxy::Server.new(
+          File.join(home, "bin", "browsermob-proxy"),
+          port: Selenium::WebDriver::PortProber.above(3000),
+          log: true
+        ).start
+      server.process.pid
+    end
+
+    expect(process_alive?(server_pid)).to eq(false)
+  end
+end

spec/spec_helper.rb

@@ -82,13 +82,43 @@ def call(env)
             @app.call(env)
           end
         end
+      end
+    end
+
+    module ServerSpecHelper
+      def run_in_isolation
+        # See http://stackoverflow.com/a/1076445/841064
+        read, write = IO.pipe
+
+        pid = fork do
+          read.close
+          ChildProcess.close_on_exec(write)
+          result = yield
+          Marshal.dump(result, write)
+          exit
+        end
 
+        write.close
+        result = read.read
+        Process.wait(pid)
+        raise 'child failed' if result.empty?
+        Marshal.load(result)
+      end
+
+      def process_alive?(pid)
+        begin
+          Process.kill(0, pid)
+          true
+        rescue Errno::ESRCH
+          false
+        end
       end
     end
   end
 end
 
 RSpec.configure do |c|
   c.include(BrowserMob::Proxy::SpecHelper)
+  c.include(BrowserMob::Proxy::ServerSpecHelper)
   c.after(:suite) { $_bm_server.stop if $_bm_server }
 end