As usual with partials, you will have to create the file by hand using your text editor. As with header , the footer tag is new in HTML5. We can render the footer partial in the layout by following the same pattern as the stylesheets and header partials Listing 5. Of course, the footer will be ugly without some styling Listing 5. The results appear in Figure 5.
One of the most notable additions in recent versions of Rails is the asset pipeline , which significantly improves the production and management of static assets such as CSS, JavaScript, and images.
This section first gives a high-level overview of the asset pipeline, and then shows how to use Sass , a powerful tool for writing CSS.
In Rails version 3. Files in these directories are even post In the latest version of Rails, there are three canonical directories for static assets, each with its own purpose:. The key lines here are actually CSS comments, but they are used by Sprockets to include the proper files:.
The line. We tell Rails which processor to use using filename extensions; the three most common cases are. We first covered ERb in Section 3. The RailsCast on CoffeeScript basics is a good place to start. One of the best things about the asset pipeline is that it automatically results in assets that are optimized to be efficient in a production application.
Traditional methods for organizing CSS and JavaScript involve splitting functionality into separate files and using nice formatting with lots of indentation. While convenient for the programmer, this is inefficient in production. In particular, including multiple full-sized files can significantly slow page-load times, which is one of the most important factors affecting the quality of the user experience.
In particular, the asset pipeline combines all the application stylesheets into one CSS file application. The result is the best of both worlds: convenience in development and efficiency in production. Sass is a language for writing stylesheets that improves on CSS in many ways.
In this section, we cover two of the most important improvements, nesting and variables. A third technique, mixins , is introduced in Section 7. As noted briefly in Section 5. Since the Rails asset pipeline automatically uses Sass to process files with the. A common pattern in stylesheets is having rules that apply to nested elements.
For example, in Listing 5. Here the logo id logo appears twice, once by itself and once with the hover attribute which controls its appearance when the mouse pointer hovers over the element in question. Both of these nesting techniques apply to the footer CSS in Listing 5. Converting Listing 5. Sass allows us to define variables to eliminate duplication and write more expressive code.
For example, looking at Listing 5. In this case, is a light gray, and we can give it a name by defining a variable as follows:. Indeed, the Bootstrap framework defines a large number of variables for colors, available online on the Bootstrap page of Less variables.
That page defines variables using Less, not Sass, but the bootstrap-sass gem provides the Sass equivalents. Looking at the Bootstrap variable page, we see that there is a variable for light gray:. This uses both Sass variables as inferred from the Bootstrap Less variable page and built-in named colors i. Note in particular the dramatic improvement in the rules for the footer tag.
Sass gives us even more ways to simplify our stylesheets, but the code in Listing 5. See the Sass website for more details. Of course, we could hard-code links like. Moreover, Rails conventionally uses named routes , which involves code like. The full list of our planned links appears in Table 5. We took care of the first route in Section 3.
The test appears as in Listing 5. At this point, the tests in Listing 5. The application code parallels the addition of the About page in Section 3. Now make sure that the tests are green :. Defining the root route in this way has a second important effect, which is to create named routes that allow us to refer to routes by a name rather than by the raw URL.
To define the named routes for the Help, About, and Contact pages, we need to make changes to the get rules from Listing 5. Applying this rule change to the remaining static page routes from Listing 5. With the routes defined in Listing 5. We could do this by hand with a browser, first visiting the root path and then checking the links by hand, but this quickly becomes cumbersome.
Listing 5. In this case, we use a syntax that allows us to test for the presence of a particular link—URL combination by specifying the tag name a and attribute href , as in. Note that the assertion for the root path verifies that there are two such links one each for the logo and navigation menu element :.
This ensures that both links to the Home page defined in Listing 5. Now let's create a new file called style. Add the following code to this file. The next chapter explains how to develop applications using Rails Scaffolding to give user access to add, delete, and modify the records in any database.
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