Whenever you start a process to handle requests with Rails (such as a Webrick server), one of the first things that happens is that config/environment.rb is loaded. For instance, take a look at the top of public/dispatch.rb:
require File.dirname(__FILE__) + “/../config/environment”
A word of caution: If you were to set the RAILS_ENV environment variable to production here, or the constant variable RAILS_ENV for that matter, it would cause everything you did in Rails to run in production mode. For instance, your test suite would not work correctly, since test_helper.rb sets RAILS_ENV to test right before loading the environment.
ENV["RAILS_ENV"] = "test"再是：
require File.expand_path(File.dirname(__FILE__) + "/../config/environment")而在加载environment.rb时，又将RAILS_ENV覆写为prodoction。
项目中使用的Rails的版本：
# Specifies gem version of Rails to use when vendor/rails is not present
RAILS_GEM_VERSION = '2.0.1' unless defined? RAILS_GEM_VERSION
定义项目根目录：
RAILS_ROOT = "#{File.dirname(__FILE__)}/.." unless defined?(RAILS_ROOT)
RAILS_ROOT is used all over the place in the Rails codebase for finding files
read the config/environment.rb file as text (minus the commented lines) and parse out the RAILS_GEM_VERSION setting with a regexp.
parse_gem_version(read_environment_rb)
def parse_gem_version(text)
$1 if text =~ /^[^#]*RAILS_GEM_VERSION\s*=\s*'([!~<>=]*\s*[\d.]+)'/
end
def read_environment_rb
File.read("#{RAILS_ROOT}/config/environment.rb")
end
Default Load Paths:
def default_frameworks
[ :active_record, :action_controller, :action_view, :action_mailer, :active_resource ]
end
def default_load_paths
paths = ["#{root_path}/test/mocks/#{environment}"]
# Add the app's controller directory
paths.concat(Dir["#{root_path}/app/controllers/"])
# Then components subdirectories.
paths.concat(Dir["#{root_path}/components/[_a-z]*"])
# Followed by the standard includes.
paths.concat %w(
app
app/models
app/controllers
app/helpers
app/services
components
config
lib
vendor
).map { |dir| "#{root_path}/#{dir}" }.select { |dir| File.directory?(dir) }
paths.concat builtin_directories
end
def builtin_directories
# Include builtins only in the development environment.
(environment == 'development') ? Dir["#{RAILTIES_PATH}/builtin/*/"] : []
end
def default_plugin_paths
["#{root_path}/vendor/plugins"]
end
上面这个builtin_directories指的是：
It is the place for Rails to include application behavior (meaning models, helpers, and controllers). You can think about it as kind of like a framework-provided plugin mechanism.
http://localhost:3000/rails/info/properties
和在命令行下用script/about是一样的
在Rails项目里，绝大多数情况下，都不需要手动去load一个class或module，Rails有默认的规则去自动load需要的文件，其规则如下：
• If the class or module is not nested, insert an underscore between the constant’s names and require a file of this name. For example:
EstimationCalculator becomes require ‘estimation_calculator’
• If the class or module is nested, Rails inserts an underscore between each of the containing modules and requires a file in the corresponding set of subdirectories.For example:
MacGyver::SwissArmyKnife becomes require ‘mac_gyver/swiss_army_knife’
you should rarely need to explicitly load Ruby code in your Rails applications (using require) if you follow the naming conventions.
Rails::Initializer.run do |config|里面的代码是关于Configuration的
...
end
# Settings in config/environments/* take precedence over those specified here.
The comment reminds you that the settings in the mode-specific environment files will take precedence over settings in environment.rb, which is essentially because they are loaded afterward and will overwrite your settings.
# Skip frameworks you're not going to use (only works if using vendor/rails).如果项目中不用数据库，就去掉Active Record，如果不用Web service或Email，也去掉相应的模块
# To use Rails without a database, you must remove the Active Record framework
# config.frameworks -= [ :active_record, :active_resource, :action_mailer ]
为什么要去掉呢：
Ruby is, of course, interpreted, and if you can get away with a smallersized codebase for the interpreter to parse, you should do so, simply for performance reasons.
# Only load the plugins named here, in the order given. By default, all pluginsplugins默认是按照字母顺序load的，也可以指定先load哪些plugin，再load剩下的(:all)
# in vendor/plugins are loaded in alphabetical order.
# :all can be used as a placeholder for all plugins not explicitly named
# config.plugins = [ :exception_notification, :ssl_requirement, :all ]
Rails takes advantage of the fact that Ruby provides a callback mechanism for missing constants. When Rails encounters an undefined constant in the code, it uses a classloader routine based on file-naming conventions to find and require the needed Ruby script.
Want to see the contents of your project’s load path? Just fire up the console and type $:
除了Rails提供的三种environment外，还可以自定义environment，比如：
Use the normal environment settings for development mode, but point its database connection to a production database server. It’s a potentially life-saving combination when you need to quickly diagnose issues in production.
使用log的方法：在irb里敲入：
require ‘logger’
logger = Logger.new STDOUT
logger.warn “do not want!!!”
log的级别（按严重程度由低到高）：
debug -> info -> warn -> error -> fatal
debug是开发时方便调试程序的，生产环境中用不到。
info是一些不常发生的事件，但仍然属于正常行为范围内。
warn表示正常范畴之外的事件发生了，需要注意，值得去研究研究问题，例如：
def createerror表示还不需要重启服务器的错误。
begin
@group.add_member(current_user)
flash[:notice] = “Successfully joined #{@scene.display_name}”
rescue ActiveRecord::RecordInvalid
flash[:error] = “You are already a member of #{@group.name}”
logger.warn “A user tried to join a group twice. UI should not have allowed it.”
end
redirect_to :back
end
fatal是指能想到的最坏的情况已经发生了，你的应用现在已经挂了，需要重启服务器了。
清空log/目录下的所有.log文件
rake log:clear
development.log里包含的信息：
• The controller and action that were invoked
• The remote IP address of the computer making the request
• A timestamp indicating when the request happened
• The session ID associated with the request
• The hash of parameters associated with the request
• Database request information including the time and the SQL statement executed
• Query cache hit info including time and the SQL statement triggering results from the cache instead of a roundtrip to the database
• Rendering information for each template involved in rendering the view output and time consumed by each
• Total time used in completing the request with corresponding request-per-second figures
• Analysis of the time spent in database operations versus rendering
• The HTTP status code and URL of the response sent back to the client
资源/链接：
Rails Plugins: Extending Rails Beyond the Core
http://weblog.jamisbuck.org/2007/1/31/more-on-watchingactiverecord
http://seattlerb.rubyforge.org/SyslogLogger/
没有评论:
发表评论