Routing is the process of matching a URL pattern to a specific view or handler in a web application. URL patterns are a way of defining the structure and format of URLs in a web application.
In most web frameworks, routing is handled by a router or a routing module. The router parses the incoming URL and determines which view or handler should handle the request.
URL patterns can include placeholders or variables, which are used to capture dynamic parts of the URL. For example, in the URL pattern “/users/{id}/profile”, “{id}” is a placeholder that can match any value. The captured value can then be passed as an argument to the corresponding view or handler.
URL patterns can also include regular expressions to define more complex matching rules. For example, the URL pattern “/users/{id:\d+}/profile” matches URLs that start with “/users/”, followed by a numeric ID, and ending with “/profile”.
URL patterns can be used to define different types of routes, such as:
1. Static routes: These are fixed URLs that match a specific pattern. For example, “/home” or “/about”.
2. Parameterized routes: These include placeholders that capture dynamic parts of the URL. For example, “/users/{id}/profile”.
3. Regex routes: These use regular expressions to define more complex matching rules. For example, “/users/{id:\d+}/profile” matches URLs with numeric IDs.
4. Route groups: These group related routes together. For example, all the routes for a specific resource like “/users” can be grouped together.
Routing and URL patterns are essential for mapping incoming requests to the appropriate handler in a web application. They help create clean and structured URLs and provide a flexible way to handle different types of requests.