RUBY ON RAILS DOCUMENTATION PDF
This guide documents the Ruby on Rails API documentation guidelines. Ruby on Rails Guides Guidelines. This guide documents the Ruby on Rails guides. git clone git://resourceone.info cd rails git checkout origin/stable -b stable cd railties/guides ruby resourceone.info cd output open resourceone.info This guide documents the Ruby on Rails API documentation guidelines. Generates a PDF document with information on the client and.
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Ruby on Rails API documentation with instant search, offline support, keyboard shortcuts, mobile version, and more. Guides, tutorials, and reference material to help you learn more about Ruby Ruby & Rails Searchable API Docs: Rails and Ruby documentation with smart. Ruby on Rails is an extremely productive web application framework point, when it encounters a Ruby code embedded in the document, it.
Abstraction ActiveInteraction - Manage application specific business logic. Apotomo - Based on Cells, Apotomo gives you widgets and encapsulation, bubbling events, AJAX page updates, rock-solid testing and more.
Cells - View Components for Rails. Decent Exposure - A helper for creating declarative interfaces in controllers. Docile - A tiny library that lets you map a DSL domain specific language to your Ruby objects in a snap. Interactor - Interactor provides a common interface for performing complex interactions in a single request.
Light Service - Series of Actions with an emphasis on simplicity. Mutations - Compose your business logic into commands that sanitize and validate input. It's your best companion for going with an event-driven architecture for your Rails application. Responders - A set of Rails responders to dry up your application.
Surrounded - Encapsulated related objects in a single system to add behavior during runtime. Extensible implementation of DCI. Trailblazer - Trailblazer is a thin layer on top of Rails.
It gently enforces encapsulation, an intuitive code structure and gives you an object-oriented architecture. Waterfall - A slice of functional programming to chain ruby services and blocks, thus providing a new approach to flow control. It's excellent for generating admin interfaces, managing Data-Heavy Applications, creating Widgets or for quick prototyping.
ActiveScaffold is completly customizable and offers a bunch of additional features including searching, pagination, layout control and overrides of fields, forms and templates.
Administrate - A Rails engine that helps you put together a super-flexible admin dashboard, by Thoughtbot. RailsAdmin - A Rails engine that provides an easy-to-use interface for managing your data. Trestle - A modern, responsive admin framework for Rails. Build a back-end in minutes that will grow with the needs of your application.
Typus - Ruby on Rails control panel to allow trusted users edit structured content. Analytical - Gem for managing multiple analytics services in your rails app. Gabba - Simple way to send server-side notifications to Google Analytics.
Impressionist - Rails Plugin that tracks impressions and page views. Rack::Tracker - Rack middleware that can be hooked up to multiple services and exposing them in a unified fashion. Blanket - A dead simple API wrapper. Crepe - The thin API stack. Roar - Resource-Oriented Architectures in Ruby.
Less Rails - The dynamic stylesheet language for the Rails asset pipeline. Rails Assets - Bundler to Bower proxy. Lastly, programs are written to transform abstractions from one form to another. When we learn simple arith- metic, we learn we can take the symbols for numbers and add them together to make a different number. Computer programs do more than add numbers; a program can transform words and other abstractions.
Assignment In Ruby, like many other programming languages, the equals sign indicates we are assigning a value. The equals sign is the assignment operator. And name is a variable that stores the value so it can be easily reused. Just as we can assign a value to a variable, we can reassign a new value when- ever we want. That is why we call them variables; the value can vary. Foobar Kadigan' Variables can be assigned strings of letters, numbers, or anything else.
Object-Oriented Terminology Software architects use a common vocabulary to talk about programming lan- guages: You can write code and intuitively grasp the meanings. Or you can gain an understanding by applying metaphors. Houses For example, some programming textbooks attempt to explain a class like this: A blueprint for a house design is like a class definition.
All the houses built from that blueprint are objects of a class we could call House. Vehicles Or: Vehicles can have attributes, like color or number of doors. They have behavior, or methods, like buttons that turn on lights or honk a horn. A class definition is like a cookie cutter. Bits in the computer memory are like cookie dough. The cookie cutter makes as many individual cookies as you want.
Each cookie is an instance of the Cookie class, with the same shape and size as the others. Cookies are objects. You can decorate each cookie with sprinkles, which are attributes that are unique to each instance. Running a program is like baking. The cookies change state from raw to cooked. Sticking a toothpick in a cookie is like calling a method. The method returns a result that tells you about the state: Is it done?
Limitations of Metaphors Metaphors are imperfect. If baking was like running a program, all the cookies would disappear as soon as the oven was turned off.
What values are possible for the attribute Gender? For many years, Facebook offered two choices, male and female. As Sarah Mei discusses in a blog post, Why Gender is a Text Field on Diaspora, your assumptions have conse- quences when you build a model. They typically represent an abstraction, like an Array or a Hash, which inherits char- acteristics from another abstraction, for example, a Collection.
Terminology such as class and instance describe the abstrac- tions and the relationships among them.
For the software architect, classes make it possible to create a structure for complex software programs. There is one class at the apex of the Ruby class hierarchy: BasicObject is a very simple class, with almost no methods of its own.
The Object class inherits from BasicObject. Object provides basic methods such as nil? The example just shows it for teaching purposes. Here is the Example class without the explicit subclassing from Object: Methods get the work done. Any class can have methods. Methods are a series of expressions that return a result a value.
We say methods describe the class behavior. Here we will return the string assigned to the variable name. This example shows how you can override any method inherited from a parent class.
This tiny punctuation symbol is a powerful operator in Ruby. It allows us to call a method to get a result. Sometimes we say we send a message to the object when we invoke a method, implying the object will send a result. For example, you can run this in the Rails console: For example: For example, String has methods reverse and upcase among many others. We could write: These characters are simply a naming con- vention for Ruby methods.
The question mark indicates the method will return a boolean value true or false. In Rails an excla- mation point often means the method will throw an exception on failure rather than failing silently. Initialize Method Objects are created from classes before they are used. When we call the new method, we press the cookie cutter into the dough and get a new object.
All the cookies will have the same shape but they can be decorated differently, by sprinkling attributes of different values. The initialize method is one of the ways we sprinkle attributes on our cookie. The new method calls the initialize method automatically. Method Parameters Methods are useful when they operate on data.
Parameters are placeholders for data values. The values that are passed to a method are arguments. Our initialize method takes name and date arguments: We separate our parameters with commas. For readability, we enclose our list of parameters in parentheses. In Ruby, parentheses are always optional but they often improve readability. We can assign any object to a variable. The variable works like an alias. We can use a variable anywhere as if it were the assigned object.
The variable can be assigned a string, a numeric value, or an instance of any class all are objects. You can assign a different kind of object if you want. Symbol Obviously, we see many symbols when we read Ruby code, such as punctua- tion marks and alphanumeric characters.
It is like a variable, but it can only be assigned a value once. After the initial assignment, it is immutable; it cannot be changed. We can use the initialize method to input data to the object.
Attributes are a convenient way to push data to an object and pull it out later. In Ruby, attributes are also called properties. For example, we could write: Instance Variable Inside an object, an ordinary variable only can be used within the method in which it appears. The scope of a variable is limited to the method in which it is used.
Often you want a variable to be available throughout an instance, within any method. The instance variable can be used by any method after the class is instantiated. If you create multiple instances of a class, each will have its own values for its instance variables. Here we create two instances of the Example class.
We use an instance variable when we want a model to be available to the view template. Rails beginners learn the simple rule that you have to use the at sign if you want a variable to be available in the view.
That leads to a question: Why is an instance variable available inside a view? There is a good reason. A Rails view is NOT a separate class. It is a tem- plate and, under the hood, it is part of the current controller object.
This example shows us that the programmer and the software architect have different perspectives on a Rails application. Understanding Rails requires an integration of multiple points of view. In this case, we only assign a value to the variable if no value has been previously assigned. Conditional Conditional logic is fundamental to programming.
Our code is always a path with many branches. If the expression is true, the statements following the condition are executed. If the expression is false, any statements are ignored, unless there is an else, in which case an alternative is executed. Or if can be followed by a variable that has been assigned a boolean value. Or you can call a method that returns a boolean result. If date is already assigned a value, we assign it to the instance variable date.
Ruby developers like to keep their code tight and compact. This compact conditional syntax is named the ternary operator because it has three components. Here is the syntax: For more Ruby code that has been condensed into obscurity, see an article on Ruby Golf. Ruby golf is the sport of writing code that uses as few characters as possible. We already know that we can assign a string to a variable: Foobar Kadigan" Single quote marks indicate a string. In the example above, we enclose a space character within quote marks so we add a space to our string.
You can eliminate the ungainly mix of plus signs, single quote marks, and space characters in the example above. Use double quote marks and you can perform interpolation, which gives a new job to the hashmark and curly brace characters: Foobar Kadigan" The hashmark indicates any expression within the curly braces is to be evalu- ated and returned as a string.
This only works when you surround the expres- sion with double quote marks. Sometimes you want to create a method that only can be used by other methods in the same class. This is common when you need a simple utility method that is used by several other methods. Any methods that follow the keyword private should only be used by meth- ods in the same class or a subclass.
Ruby provides a protected keyword as well, but the difference between protected and private is subtle and protected is seldom seen in Rails applications.
Computers have always been calculation machines; they are just as important in managing collections. One important type of collection is named a Hash.
A Hash is a data structure that associates a key to some value. You retrieve the value based upon its key. This construct is called a dictionary, an associative array, or a map in other languages. Ruby 1. In a Hash, a trailing colon makes a string into a symbol. If you want to transform a string containing spaces into a symbol in a Hash, you can do it, though the syntax is awkward: Arrays can hold objects of any data type.
In fact, arrays can contain a mix of different objects.
What Is YARD?
For example, an array can contain a string and another array this is an example of a nested array. An array can be instantiated with square brackets: See the Ruby API for a full list.
Iterator Of all the methods available for a Ruby collection such as Hash or Array, the iterator may be the most useful. Each item in an Ar- ray, or key-value pair in a Hash, is passed to the block of code to be processed. Block You can recognize a block in Ruby when you see a do A block is a common way to process each item when an iterator such as each is applied to a Hash or Array.
The block is like an unnamed method. The two variables are available only within the block. As each key-value pair is presented by the iterator, the vari- ables are assigned, and the statements in the block are executed.
Computer scientists consider a block to be a programming language construct called a closure. Ruby has other closures, including the proc short for proce- dure and the lambda. They are more common in the Rails source code where advanced programming techniques are used more frequently. The key point to know about a block or a proc or a lambda is that it works like a method.
The example code only uses keywords from the Ruby API. Rails has its own API, with hundreds of classes and methods. We say Ruby is a general-purpose language because it can be used for any- thing. Ruby is a great language to use for building a DSL, which is why it was used for Rails. Unlike some other programming languages, Ruby eas- ily can be extended or tweaked. Software archi- tects call this metaprogramming which simply means clever programming that twists and reworks the programming language.
Some of the most powerful gems add their own DSLs to your project. For example, the Cucumber gem provides a DSL for turning user stories into automated tests. Adding Rails, additional gems, and DSLs provides powerful functionality at the cost of complexity. But it all conforms to the syntax of the Ruby language. Spend time with a Ruby textbook or interactive course when you work on Rails projects.
No more fooling around. With the next chapter, we start building a real-world Rails website. Chapter 16 Layout and Views In previous chapters we created a dynamic home page and learned techniques for troubleshooting.
This chapter covers a lot of ground, so take a break before jumping in, or pace yourself to absorb it all. The Ruby code will be processed by a templating engine built into Rails. The output will be pure HTML sent to the browser. That is added by Rails to support turbolinks, for faster loading of webpages. For the most part, everything is ordinary HTML. Where did all the extra HTML come from? The default application layout is where you put HTML that you want to include on every page of your website.
Remember when we looked at the hidden code in the controller that renders a view? YIELD Alternatively, you could tell the controller to render the view without any ap- plication layout: The reference RailsGuides: Layouts and Rendering in Rails explains more about using alternative layouts.
Notice that the default application layout contains the Ruby keyword yield.
The content from the view is inserted where you place the yield keyword. For example, you could create an application layout that includes a sidebar. The example above will create three list items, like this: Ruby is an ideal choice for a web application development platform such as Rails because it can easily be used to create a domain-specific language or DSL. We can add new keywords that produce complex behaviour, creating entire new APIs such as Rails.
It turns out that almost any website that accepts user input via a form is vulnerable to a security bug an exploit named a cross-site request forgery. Rails provides a number of similar features that make websites more secure. Strange new keywords may be part of the Rails API.
Think of it this way: But they serve as shortcuts to produce complex snippets of HTML and content. The Rails default starter application, which we get when we run rails new, provides a barebones application layout.
Rails provides the rails generate command to run simple scripts that are packaged into gems. Viewport The viewport metatag improves the presentation of web pages on mobile devices. The tag is required for either Bootstrap or Zurb Foundation front-end frameworks. The viewport metatag looks like this: That means adding title and description metatags.
Google uses contents of the title tag to display titles in search results. And it will sometimes use the content of a description metatag in search results snip- pets. Good titles and descriptions improve clickthrough from Google searches.
Title and description looks like this: It uses the Ruby ternary operator which maximizes compactness at the price of intro- ducing obscurity.
The Rails asset pipeline utility is one of the most powerful features of the plat- form. It offers convenience to the developer and helps organize an applica- tion; more importantly, it improves the speed and responsiveness of any com- plex website. With multiple stylesheets, the HEAD section of your application layout might look like this: Instead, use the asset pipeline and simplify this.
Assets With Rails The asset pipeline consists of two folders: Navigation Links Every website needs navigation links. This is advantageous if we make changes to the location of the link destinations. Some webmasters like to use absolute URLs, specifying a host name in the link, for example http: We include the navigation partial in our application layout with the expression: The second parameter is the route.
For now, we have nothing to add. Flash Messages Rails provides a standard convention to display alerts including error mes- sages and other notices including success messages , called a flash message. Ac- tion Controller Overview. Flash message in Rails. When the page is reloaded or another page is visited, the message disappears.
Creating Flash Messages Flash messages are created in a controller. We can assign other messages, such as flash[: In practice, Rails uses only: Use flash. With flash. If you use flash. If you use the simple flash directive before a render directive, the message will appear on the rendered page and reappear on a subsequent page after the user clicks a link. In our example above, we really need to use the flash. The flash object is a Ruby hash. Hash is a type of collection. Because we have a collection with possibly multi- ple messages, we need to retrieve each message one at a time.
3 Rails documentation tools
We learned earlier that all collections support an iterator method named each. Iterators return all the elements of a collection, one after the other. The iterator returns each key-value pair, item by item, to a block. You can add any code to a block to process each item from the collection.
The output string will appear as HTML like this: The Flash Messages Partial Flash messages are a very useful feature for a dynamic website.
First, the expression if msg. String serves as a test to make sure we only display mes- sages that are strings. These elements are not unique to a Rails application and will be familiar to anyone who has done front-end development.
Notice the main tag: It typically contains links to copyright infor- mation, legal disclaimers, or contact information. Application Layout Our application layout is complete.
Front-end development has grown increasingly important as websites have be- come more sophisticated. And front-end technology has grown increasingly complex, to the degree that front-end development has become a job for spe- cialists. Front-end developers are primarily concerned with: Around the time that Rails became popular, front-end developers at large companies began to share best practices and establish open source projects to bring structure and consistency to front-end development, leading to development of CSS frameworks.
These plug-ins are used to add visual effects and interactivity to web pages. Examples are drop-down menus, modal windows, tabbed panels, autocomple- tion search forms, and sliders or carousels for images. Even without plugins, jQuery is useful as a high-level interface for manipulating the browser DOM document object model , to make it easy to do things like hiding or revealing HTML elements on a page.
Any Rails application can use jQuery because it is included by default in any new Rails application. Libraries such as jQuery add functionality to server-side applications, such as those built with Rails.
Producing Documentation for Your Rails API
Bootstrap is the best-known front-end framework. It is the result of an effort to document and share common design patterns and assets across projects at Twitter, released as an open source project in August Zurb Foundation was released as an open source project in October , after more than a year of internal use at Zurb, a Silicon Valley design consultancy.
As a result, CSS rules are ver- bose and often repetitive.
As a result, your stylesheets can use variables, mixins, and nesting of CSS rules, just like a real programming language. Mixins are like variables that let you use snippets of reusable CSS. Nesting eliminates repetition by layering CSS selectors. Bootstrap or Zurb Foundation?
Which should you use, Bootstrap or Zurb Foundation? Zurb Foundation has a solid following among Rails developers. It gained an initial advantage because Zurb provides a gem that adds Foundation to Rails. When Zurb releases new versions of Foundation, the company updates the gem immediately. Recently in January , the Bootstrap team started supporting a Ruby gem that provides a drop-in Sass version of Bootstrap for Rails.
Now any preference for Foundation over Bootstrap is primarily a matter of personal taste. Bootstrap has a larger developer community and more third-party projects, as evidenced by a Big Badass List of Useful Twitter Bootstrap Resources. In its sheer magnitude, this list, from Michael Buckbee and Bootstrap Hero, demon- strates the popularity of Bootstrap and the vitality of its open source commu- nity.
Graphic Design Options There are three approaches to graphic design for your Rails application. Consequently, sites that use Bootstrap or Zurb Foundation look very similar. A third option is to purchase a pre-designed theme for your website.
You may have visited ThemeForest or other theme galleries that offer pre-built themes for a few dollars each. Take a look at some of the inexpensive themes for Foundation that you can adapt for Rails: The site Themes for Bootstrap aggregates Bootstrap themes, or you can visit sites such as Start Bootstrap, Bootswatch, or the Themestrap gallery. Zurb Foundation Gem Zurb Foundation provides a standard grid for layout plus dozens of reusable components for common page elements such as navigation, forms, and buttons.
More importantly, it gives CSS the kind of structure and convention that makes Rails popular for back-end development. Zurb Foundation is packaged as a gem. Our approach is slightly different from the Zurb in- structions but yields the same results.
Note the. This will allow you to use the advantages of an improved syntax for your ap- plication stylesheet. You learned earlier that stylesheets can use variables, mixins, and nesting of CSS rules when you use Sass. Sass has two syntaxes. The Sass project also offers a second, older syntax with indented formatting that uses the extension. The asset pipeline will preprocess any. The application. Your CSS stylesheets get concatenated and compacted for delivery to the browser when you add them to this directory: If you are familiar with CSS syntax, it may seem odd that the relevant lines are commented out using asterisks.
Though they are com- mented out, the Rails asset pipeline reads and understands them. However, in practice, you are more likely to modify the style rules provided by Zurb Foundation.
How you organize your CSS is up to you; the asset pipeline lets you organize your CSS so it is easier to develop and maintain. In general, only large and complex sites need this optimization. Like the application.
Here are just a few examples: These are building blocks you use for page layout and typographic styling. For example, Foundation gives you CSS classes to set up rows and columns in a grid system. The layout will change at each breakpoint. The grid gives you 12 columns by default. You can organize your layout in horizontal and vertical sections using row and columns classes.
For example, you could use Foundation grid classes to set up an application layout with a footer as a row with two sections: The footer will con- tain two side-by-side sections. On phones, each section will expand to take the full browser width, appearing as stacked rows. To better understand the grid system with all its options, see the documentation for the Foundation Grid.
Presentational Versus Semantic Styles There are two schools of thought among front-end developers. For these developers, the Foundation classes are both practical and descriptive, making it easy for any developer who knows the Foundation framework to visualize the layout of a page. In an ideal world, all markup would be semantic, with class names describing the function or purpose of a style.
For example, a submit button often needs styling. Compare these two approaches to markup: Using Foundation Classes Directly Foundation often mixes presentational and semantic markup. For example, you can style a button like this: For example, the Foundation grid system is presentational. Specifying rows and columns, and quantifying the size of columns, describes the visual appear- ance of sections of the layout rather than the purpose of each section.
The pre- sentational approach makes it easy to visualize the layout of a page. If class names change in Foundation 6. Is it worth the effort to add the complexity of Sass mixins just to future-proof your website? Probably not for a simple website such as the one you are build- ing for Foobar Kadigan.
It will probably be very similar. Then we use mixins to create semantic classes. The second declaration mixin six-columns-centered makes a column that is six columns wide with centered text. Next we create a few classes that use the mixins or combine Foundation CSS classes. For example, the new submit class can be used for a rounded button. We use the include directive to add the mixins we need.
We also use the extend directive to add a Foundation CSS class. And we di- rectly set CSS properties such as background-color and margin-top. For a simple website, this could be over-engineering and counter-productive.
Set value to false to disable printing backgrounds to the PDF. Set HTML zoom in percents. It determines the precision used for rendering of the HTML content.
Set value to false to disable hyperlinks in the PDF. The default is utf If value is true then the print CSS media type is used if available. If value is set to true then the PDF is encrypted. This prevents search engines from indexing the document. The default is false. Protects the PDF with a user password. When a PDF has a user password, it must be supplied in order to view the document and to perform operations allowed by the access permissions.
At most 32 characters. Protects the PDF with an owner password. Supplying an owner password grants unlimited access to the PDF including changing the passwords and access permissions.
Set value to true disables printing the generated PDF. Set value to true to disable modifying the PDF.Initialize Method Objects are created from classes before they are used. If you are using Atom or Sublime Text, you can open two editor panels side-by-side. For more on CSS, there are thousands of tutorials on the web, but I like these: Rouge - A pure Ruby code highlighter that is compatible with Pygments.
The two variables are available only within the block.