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Diffstat (limited to 'guides/source/debugging_rails_applications.md')
| -rw-r--r-- | guides/source/debugging_rails_applications.md | 43 |
1 files changed, 21 insertions, 22 deletions
diff --git a/guides/source/debugging_rails_applications.md b/guides/source/debugging_rails_applications.md index 5531dee343..70055c1d7d 100644 --- a/guides/source/debugging_rails_applications.md +++ b/guides/source/debugging_rails_applications.md @@ -23,7 +23,7 @@ One common task is to inspect the contents of a variable. In Rails, you can do t ### `debug` -The `debug` helper will return a \<pre>-tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view: +The `debug` helper will return a \<pre> tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view: ```html+erb <%= debug @post %> @@ -174,7 +174,7 @@ class PostsController < ApplicationController end ``` -Here's an example of the log generated by this method: +Here's an example of the log generated when this controller action is executed: ``` Processing PostsController#create (for 127.0.0.1 at 2008-09-08 11:52:54) [POST] @@ -194,11 +194,13 @@ Redirected to #<Post:0x20af760> Completed in 0.01224 (81 reqs/sec) | DB: 0.00044 (3%) | 302 Found [http://localhost/posts] ``` -Adding extra logging like this makes it easy to search for unexpected or unusual behavior in your logs. If you add extra logging, be sure to make sensible use of log levels, to avoid filling your production logs with useless trivia. +Adding extra logging like this makes it easy to search for unexpected or unusual behavior in your logs. If you add extra logging, be sure to make sensible use of log levels to avoid filling your production logs with useless trivia. ### Tagged Logging -When running multi-user, multi-account applications, it’s often useful to be able to filter the logs using some custom rules. `TaggedLogging` in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications. +When running multi-user, multi-account applications, it’s often useful +to be able to filter the logs using some custom rules. `TaggedLogging` +in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications. ```ruby logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT)) @@ -216,7 +218,7 @@ The debugger can also help you if you want to learn about the Rails source code ### Setup -Rails uses the `debugger` gem to set breakpoints and step through live code. To install it, just run: +You can use the `debugger` gem to set breakpoints and step through live code in Rails. To install it, just run: ```bash $ gem install debugger @@ -235,7 +237,7 @@ class PeopleController < ApplicationController end ``` -If you see the message in the console or logs: +If you see this message in the console or logs: ``` ***** Debugger requested, but was not available: Start server with --debugger to enable ***** @@ -246,12 +248,12 @@ Make sure you have started your web server with the option `--debugger`: ```bash $ rails server --debugger => Booting WEBrick -=> Rails 3.0.0 application starting on http://0.0.0.0:3000 +=> Rails 3.2.13 application starting on http://0.0.0.0:3000 => Debugger enabled ... ``` -TIP: In development mode, you can dynamically `require \'debugger\'` instead of restarting the server, if it was started without `--debugger`. +TIP: In development mode, you can dynamically `require \'debugger\'` instead of restarting the server, even if it was started without `--debugger`. ### The Shell @@ -266,7 +268,7 @@ For example: (rdb:7) ``` -Now it's time to explore and dig into your application. A good place to start is by asking the debugger for help... so type: `help` (You didn't see that coming, right?) +Now it's time to explore and dig into your application. A good place to start is by asking the debugger for help. Type: `help` ``` (rdb:7) help @@ -281,7 +283,7 @@ condition down finish list ps save thread var continue edit frame method putl set tmate where ``` -TIP: To view the help menu for any command use `help <command-name>` in active debug mode. For example: _`help var`_ +TIP: To view the help menu for any command use `help <command-name>` at the debugger prompt. For example: _`help var`_ The next command to learn is one of the most useful: `list`. You can abbreviate any debugging command by supplying just enough letters to distinguish them from other commands, so you can also use `l` for the `list` command. @@ -289,7 +291,7 @@ This command shows you where you are in the code by printing 10 lines centered a ``` (rdb:7) list -[1, 10] in /PathToProject/posts_controller.rb +[1, 10] in /PathTo/project/app/controllers/posts_controller.rb 1 class PostsController < ApplicationController 2 # GET /posts 3 # GET /posts.json @@ -325,7 +327,7 @@ On the other hand, to see the previous ten lines you should type `list-` (or `l- ``` (rdb:7) l- -[1, 10] in /PathToProject/posts_controller.rb +[1, 10] in /PathTo/project/app/controllers/posts_controller.rb 1 class PostsController < ApplicationController 2 # GET /posts 3 # GET /posts.json @@ -343,7 +345,7 @@ Finally, to see where you are in the code again you can type `list=` ``` (rdb:7) list= -[1, 10] in /PathToProject/posts_controller.rb +[1, 10] in /PathTo/project/app/controllers/posts_controller.rb 1 class PostsController < ApplicationController 2 # GET /posts 3 # GET /posts.json @@ -502,7 +504,7 @@ TIP: You can use the debugger while using `rails console`. Just remember to `req ``` $ rails console -Loading development environment (Rails 3.1.0) +Loading development environment (Rails 3.2.13) >> require "debugger" => [] >> author = Author.first @@ -655,21 +657,18 @@ Plugins for Debugging There are some Rails plugins to help you to find errors and debug your application. Here is a list of useful plugins for debugging: -* [Footnotes](https://github.com/josevalim/rails-footnotes:) Every Rails page has footnotes that give request information and link back to your source via TextMate. -* [Query Trace](https://github.com/ntalbott/query_trace/tree/master:) Adds query origin tracing to your logs. -* [Query Reviewer](https://github.com/nesquena/query_reviewer:) This rails plugin not only runs "EXPLAIN" before each of your select queries in development, but provides a small DIV in the rendered output of each page with the summary of warnings for each query that it analyzed. -* [Exception Notifier](https://github.com/smartinez87/exception_notification/tree/master:) Provides a mailer object and a default set of templates for sending email notifications when errors occur in a Rails application. +* [Footnotes](https://github.com/josevalim/rails-footnotes) Every Rails page has footnotes that give request information and link back to your source via TextMate. +* [Query Trace](https://github.com/ntalbott/query_trace/tree/master) Adds query origin tracing to your logs. +* [Query Reviewer](https://github.com/nesquena/query_reviewer) This rails plugin not only runs "EXPLAIN" before each of your select queries in development, but provides a small DIV in the rendered output of each page with the summary of warnings for each query that it analyzed. +* [Exception Notifier](https://github.com/smartinez87/exception_notification/tree/master) Provides a mailer object and a default set of templates for sending email notifications when errors occur in a Rails application. References ---------- * [ruby-debug Homepage](http://bashdb.sourceforge.net/ruby-debug/home-page.html) * [debugger Homepage](https://github.com/cldwalker/debugger) -* [Article: Debugging a Rails application with ruby-debug](http://www.sitepoint.com/article/debug-rails-app-ruby-debug/) -* [ruby-debug Basics screencast](http://brian.maybeyoureinsane.net/blog/2007/05/07/ruby-debug-basics-screencast/) +* [Article: Debugging a Rails application with ruby-debug](http://www.sitepoint.com/debug-rails-app-ruby-debug/) * [Ryan Bates' debugging ruby (revised) screencast](http://railscasts.com/episodes/54-debugging-ruby-revised) * [Ryan Bates' stack trace screencast](http://railscasts.com/episodes/24-the-stack-trace) * [Ryan Bates' logger screencast](http://railscasts.com/episodes/56-the-logger) * [Debugging with ruby-debug](http://bashdb.sourceforge.net/ruby-debug.html) -* [ruby-debug cheat sheet](http://cheat.errtheblog.com/s/rdebug/) -* [Ruby on Rails Wiki: How to Configure Logging](http://wiki.rubyonrails.org/rails/pages/HowtoConfigureLogging) |