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c# barcode generator library free <h1><%= link_to entry.title, :action => 'show', :id => entry.id %></h1> in Font
<h1><%= link_to entry.title, :action => 'show', :id => entry.id %></h1> DataMatrix Printer In None Using Barcode generation for Font Control to generate, create DataMatrix image in Font applications. www.OnBarcode.comEncode PDF 417 In None Using Barcode generation for Font Control to generate, create PDF417 image in Font applications. www.OnBarcode.comThis line creates a heading that contains a link to the show action for that entry and would render into final HTML like this: UPC-A Supplement 5 Maker In None Using Barcode drawer for Font Control to generate, create UPC-A Supplement 2 image in Font applications. www.OnBarcode.comEncoding Code 128B In None Using Barcode maker for Font Control to generate, create ANSI/AIM Code 128 image in Font applications. www.OnBarcode.com<a href="/entries/show/1">This is a test</a>
Creating EAN13 In None Using Barcode creator for Font Control to generate, create EAN-13 image in Font applications. www.OnBarcode.comBarcode Maker In None Using Barcode creator for Font Control to generate, create Barcode image in Font applications. www.OnBarcode.comIf you were to click the link, you would be redirected to the show action for the entries controller, and an ID of 1 would be passed through. Let s look at what the show action does with this: Make Quick Response Code In None Using Barcode maker for Font Control to generate, create QR image in Font applications. www.OnBarcode.comCreate British Royal Mail 4-State Customer Barcode In None Using Barcode creation for Font Control to generate, create RoyalMail4SCC image in Font applications. www.OnBarcode.comdef show @entry = Entry.find(params[:id]) end
Draw ECC200 In Visual Studio .NET Using Barcode creation for ASP.NET Control to generate, create ECC200 image in ASP.NET applications. www.OnBarcode.comECC200 Printer In .NET Framework Using Barcode creation for Visual Studio .NET Control to generate, create DataMatrix image in VS .NET applications. www.OnBarcode.comThe show action is simple, as all it does is retrieve a single entry from the database (using, as always, the find method provided by the Entry model from ActiveRecord::Base). You retrieve the ID from the URL through the params hash, a hash that is automatically populated by any data passed to the Rails application via the URL. If you use find with a single parameter containing an integer ID, then that row will be retrieved from the relevant table for the associated model, and returned as a single object. In this case, the entry retrieved is associated with @entry, then the view at app/views/entries/show.rhtml renders the page you see. Here are some examples of how some URLs relate to parameters that are found in the params hash: Painting Barcode In .NET Framework Using Barcode generator for Reporting Service Control to generate, create Barcode image in Reporting Service applications. www.OnBarcode.comDataMatrix Encoder In None Using Barcode drawer for Office Word Control to generate, create ECC200 image in Word applications. www.OnBarcode.comhttp://localhost/entries/show/1 Decode Code128 In .NET Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications. www.OnBarcode.comRead QR Code JIS X 0510 In Java Using Barcode reader for Java Control to read, scan read, scan image in Java applications. www.OnBarcode.comCHAPTER 13 RUBY ON RAILS: RUBY S KILLER APP
GTIN - 12 Creation In Java Using Barcode maker for Eclipse BIRT Control to generate, create UPC-A image in BIRT reports applications. www.OnBarcode.comPDF 417 Creator In None Using Barcode printer for Software Control to generate, create PDF417 image in Software applications. www.OnBarcode.comparams[:controller] == 'entries' params[:action] == 'show' params[:id] == '1' GS1 DataBar-14 Drawer In .NET Using Barcode creation for Visual Studio .NET Control to generate, create GS1 RSS image in .NET applications. www.OnBarcode.comANSI/AIM Code 39 Encoder In Java Using Barcode generation for Java Control to generate, create Code39 image in Java applications. www.OnBarcode.comhttp://localhost/entries/another_method/20 formfield1=test&formfield2=hello
Print Code 128C In None Using Barcode printer for Excel Control to generate, create Code 128B image in Microsoft Excel applications. www.OnBarcode.comBarcode Drawer In .NET Framework Using Barcode maker for Visual Studio .NET Control to generate, create Barcode image in VS .NET applications. www.OnBarcode.comparams[:controller] == 'entries' params[:action] == 'another_method' params[:id] == '20' params[:formfield1] == 'test' params[:formfield2] == 'hello' http://localhost/test/test2/ formfield1=test&formfield2=hello
params[:controller] == 'test' params[:action] == 'test2' params[:formfield1] == 'test' params[:formfield2] == 'hello' These examples demonstrate how you can pass data into methods within the URL (or, in the case of POST requests such as those that can be made from an HTML form within the HTTP request directly) and then access it by the controllers (or views) through the params hash. If you look at the code for the create action an action used to create the new entries as supplied by the form at http://localhost/entries/new you ll see how params is used to create new entries: def create @entry = Entry.new(params[:entry]) if @entry.save flash[:notice] = 'Entry was successfully created.' redirect_to :action => 'list' else render :action => 'new' end end CHAPTER 13 RUBY ON RAILS: RUBY S KILLER APP
In this method, you create a new entry with Entry.new(params[:entry]). The new method provided by ActiveRecord accepts the entire params hash and makes a new row of data from it. On the next line you save that row to the database using @entry.save, which returns true or false. If true (that is, the attempt is successful), the user will be redirected to the list action (try changing this to view_all). If the save isn t successful, the view for the new action is rendered using render :action => 'new'. Note how you can use redirect_to and render to perform operations that don t necessarily fit in with the usual controller action view life cycle, such as redirecting users elsewhere or rendering views associated with other controller actions. Concluding Thoughts
This section has covered only the basics of using controllers and views, but these are the most essential parts to learn. Other features provided by views and controllers rely on the concepts covered in this section. URLs are parsed into the desired controller and action, any other supplied data is passed through the action via the params hash, and once the action code has completed, a view is rendered. In the next section you ll take a look at how you can customize the URL parsing system so that URLs of your own formatting can be converted into any controller and method patterns that you wish. This technique is known as routing. Routing
When you request a page from a Rails application that isn t present within the public folder, the Rails application tries to work out which controller and action you are trying to use. In the previous sections, you ve seen how a URL such as http://localhost/ entries/view_all means that the request is put through to the entries controller s view_all action. You can use routing to override this default assumption that all URLs are of the form controller_name/action_name/id. Routing configurations for a Rails application are located in config/routes.rb. Let s look at what ours contains by default: ActionController::Routing::Routes.draw do |map| # The priority is based upon order of creation: first created -> highest priority # Sample of regular route: # map.connect 'products/:id', :controller => 'catalog', :action => 'view' # Keep in mind you can assign values other than :controller and :action
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