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The hypertext transfer protocol (HTTP) defines four basic operations, corresponding to the four verbs get, post, put, and delete. These refer to operations between a client computer (typically running a web browser such as Firefox or Safari) and a server (typically running a web server such as Apache or Nginx). (It’s important to understand that, when developing Rails applications on a local computer, the client and server are the same physical machine, but in general they are different.) An emphasis on HTTP verbs is typical of web frameworks (including Rails) influenced by the REST architecture, which we saw briefly in Chapter 2 and will start learning about more in Chapter 7.

GET is the most common HTTP operation, used for reading data on the web; it just means ‘‘get a page,’’ and every time you visit a site like google.com or wikipedia.org, your browser is submitting a GET request. POST is the next most common operation; it is the request sent by your browser when you submit a form. In Rails applications, POST requests are typically used for creating things (although HTTP also allows POST to perform updates); for example, the POST request sent when you submit a registration form creates a new user on the remote site. The other two verbs, PUT and DELETE, are designed for updating and destroying things on the remote server. These requests are less common than GET and POST since browsers are incapable of sending them natively, but some web frameworks (including Ruby on Rails) have clever ways of making it seem like browsers are issuing such requests.