lib/flammarion/revelator.rb in flammarion-0.1.0 vs lib/flammarion/revelator.rb in flammarion-0.1.1

@@ -1,17 +1,29 @@
 module Flammarion
+  # Raised when flammarion cannot find any way to display an engraving.
+  # On Linux, Flammarion will first try to launch Electron using the command
+  # +electron+. If that fails, it will try common aliases of Google Chrome. If
+  # none of them execute succesfully, it will raise this error. On Windows, it
+  # will try to launch Google Chrome from Program Files (x86). If chrome has
+  # been installed somewhere else, the user can set the environment variable
+  # FLAMMARION_REVELATOR_PATH to point to +chrome.exe+.
+  # @see http://electron.atom.io/
+  # @see http://www.google.com/chrome/
+  class SetupError < StandardError; end
+
   # @api private
   # @todo This all needs a lot of clean up
   module Revelator
-    CHROME_PATH = 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe'
+    CHROME_PATH = ENV["FLAMMARION_REVELATOR_PATH"] || 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe'
     def open_a_window_on_windows(options)
       file_path = File.absolute_path(File.join(File.dirname(__FILE__), ".."))
       file_path = `cygpath -w '#{file_path}'`.strip if RbConfig::CONFIG["host_os"] == "cygwin"
       resource = %[file\://#{file_path}/html/build/index.html]
       resource = "http://localhost:4567/" if ENV["FLAMMARION_DEVELOPMENT"] == "true"
       chrome_path = CHROME_PATH
       chrome_path = `cygpath -u '#{CHROME_PATH}'`.strip if RbConfig::CONFIG["host_os"] == "cygwin"
+      raise SetupError.new("Cannot find #{chrome_path}. You need to install Google Chrome or set the environment variable FLAMMARION_REVELATOR_PATH to point to chrome.exe") unless File.exist?(chrome_path)
       Process.detach(spawn(chrome_path, %[--app=#{resource}?path=#{@window_id}&port=#{server.port}&title="#{options[:title] || "Flammarion%20Engraving"}"]))
     end
 
     def open_a_window(options = {})
       return open_a_window_on_windows(options) if RbConfig::CONFIG["host_os"] =~ /cygwin|mswin|mingw/
@@ -24,15 +36,16 @@
       if which('electron') then
         Process.detach(spawn("electron #{File.dirname(File.absolute_path(__FILE__))}/../../electron '#{host}?path=#{@window_id}&port=#{server.port}&title=#{@expect_title}'"))
         return
       end
 
-      %w[google-chrome google-chrome-stable chromium chromium-browser chrome C:\Program\ Files\ (x86)\Google\Chrome\Application\chrome.exe].each do |executable|
+      %w[google-chrome google-chrome-stable chromium chromium-browser chrome].each do |executable|
+        next unless which(executable)
         @chrome.in, @chrome.out, @chrome.err, @chrome.thread = Open3.popen3("#{executable} --app='#{host}?path=#{@window_id}&port=#{server.port}&title=#{@expect_title}'")
         break if @chrome.in
       end
 
-      raise StandardError.new("Cannot launch any browser") unless @chrome.in
+      raise SetupError.new("You must have either electron or google-chrome installed and accesible via your path.") unless @chrome.in
     end
 
     private
     def which(cmd)
       exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']