Routing

Mapping URL parameters to server side logic

Types of Routes

1. Static Routes
   • Constant paths without variables (e.g., /api/books).
   • Always handle the same type of data or response pattern, regardless of input.
2. Dynamic Routes
   • Include variable parameters, often denoted with a colon (e.g., /api/users/:id).
   • The variable part is called a path parameter or route parameter, allowing requests like fetching a specific user by ID.

Query Parameters

• Key-value pairs appended after a ’?’ in the URL (e.g., /api/search?query=some+value).
• Primarily used in GET requests (which lack a body) to send metadata.
• Common applications: search queries, pagination (e.g., ?page=2&limit=20), filtering, and sorting (e.g., ascending/descending order).

Nested Routes

• Involve layering route segments for semantic clarity, often in REST APIs.
• Example: /api/users/:userId/posts/:postId to fetch a specific post from a specific user.
• Each level adds hierarchy: /api/users for all users, /api/users/:userId for one user, and so on, mapping to different handlers.

Route Versioning and Deprecation

• Incorporates version identifiers in paths (e.g., /api/v1/products vs. /api/v2/products).
• Enables API evolution (e.g., changing response formats) without disrupting existing clients.
• Supports deprecation: Notify users to migrate from v1 to v2 over time, then retire the old version.

Catch-All Route

• A wildcard route (e.g., /*) that captures any unmatched paths.
• Returns a user-friendly error message (e.g., “Route not found”) instead of a blank or null response.