You can change the Rails version to a newer version of Rails. For example, update it to Rails 4. The Rails gem will be updated by bundler and the Gemfile. This approach is appropriate if you are moving between patch versions. You can install Rails directly into the global gemset. However, many developers prefer to keep the global gemset sparse and install Rails into project-specific gemsets, so each project has the appropriate version of Rails. You may also wish to have gemsets for different versions of Rails, for example Rails 4.
The next time you cd into the project directory, RVM will read the. If it is a new gemset, and a Gemfile is present in the project directory, you can use bundle install to install the necessary gems. Before you update Rails, take time to find out how the default new Rails application has changed. The best way to see differences between versions of the Rails default application is by visiting the railsdiff.
If you want to see the differences and copy and paste code, you can create two versions of a starter application. First, create a starter app with the old version of Rails. Then switch gemsets and create a starter app with the new version of Rails. Major Rails updates often make many changes. Patch updates seldom change the default new Rails application.
The release notes are very detailed. In many cases, none of the changes will affect your application. Scan the release notes to identify any issues that may affect you. If you have difficulties with new gem versions, you can switch back to the older gemset easily, without reinstalling your old gems. Check a list of versions of Rails to find the newest version of Rails. Each gem specified in the Gemfile will be installed by bundler and the Gemfile.
You can run gem list again to see the gems that were installed in the gemset. Minor Rails version updates seldom require changes to configuration files. Major Rails updates often change configuration files.
Rails provides a rails rails:update task to update configuration files. The rails rails:update will identify every configuration file in your application that differs from a new Rails application. When it detects a conflict, it will offer to overwrite your file. Most differences will be your own. If you are certain that the difference is due to a Rails version change, you can allow rails rails:update to overwrite the file. As of Rails 5.
Take a look at the file:. Examine this file and see if your application relies on any configuration settings that have changed from defaults in the new Rails version. Most simple applications will not be affected by the changed defaults. After updating Rails and configuration files, run your test suite hopefully, you have tests; this is why you need them! Often, when the changes to Rails are minor, you will not need to update your application.
When a major new version of Rails is released, you will have to rework parts of your application. Here are resources you can use to identify specific code that needs to be updated.
Take a look at a checklist from Jesse Wolgamott:. You can track updates to gems by creating an account and visiting your dashboard at the RubyGems. As an alternative, use the Gemnasium or VersionEye services which survey your GitHub repo and send email notifications when gem versions change. The services are free for public repositories with a premium plan for private repositories. You can run bundle update to update all gems at once. Running bundle update installs new gem versions and updates the Gemfile.
The raise method will cause the application to pause and print out the params on an error page. You could also see the params if you called puts params. As you can see, the parameters are being passed to the update action. With that in mind, let's implement the functionality needed inside of the update action so that it will take the form data and update the specified record.
Let's sketch out a basic flow for what the update action should do:. Query the database for the Article record that matches the :id passed to the route. Update the values passed from the form the update method here is the update method supplied by Active Record, not the update method we're creating. The update method takes a hash of the attributes for the model as its argument, e. We'll take advantage of Active Record's update method so that we're not manually assigning each attribute:.
Now if you go to the edit page and make changes to the title or description form elements, you will see they are changed when the form is submitted. The edit and update functions are working properly! When only one form element is updated, such as the title , does the description also get updated? How could we refactor this form code?
You may notice that we have a form for the new and edit actions. Is there a better way of doing this? For example: The new action in the controller simply renders the new form The create action is what actually handles the process of inserting the form data into the database In like fashion, the edit and update actions have a similar convention: The edit action will handle rendering the edit form The update action will be the method that updates the database record itself Rendering the edit form To start off, let's draw a get route for our edit form.
That would accomplish the same goal that these two lines do: resources :articles , only: [ :index , :show , :new , :create , :edit , :update ] This will give you the same routes along with a PUT route for articles update.
With our routes in place, let's add in the controller actions Enter the following code inside of the update method: def update raise params. Let's sketch out a basic flow for what the update action should do: Query the database for the Article record that matches the :id passed to the route. The correct syntax is: self.
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