Handling CORS ​

The @stricjs/utils package simplifies Cross-Origin Resource Sharing (CORS) handling in web applications. Here's how you can use the CORS class for effective CORS management.

Basic Setup ​

First, import and configure the CORS class:

import { CORS } from '@stricjs/utils';

const cors = new CORS({
    // Define allowed methods (as a string for single method)
    allowMethods: 'GET',

    // Enable credentials
    allowCredentials: true,

    // Specify allowed origins (array for multiple values)
    allowOrigins: ['http://localhost:8000', 'http://example.com'],

    // Append headers instead of overwriting (affects plugin behavior)
    appendHeaders: true
});

import { CORS } from '@stricjs/utils';

const cors = new CORS({
    // Define allowed methods (as a string for single method)
    allowMethods: 'GET',

    // Enable credentials
    allowCredentials: true,

    // Specify allowed origins (array for multiple values)
    allowOrigins: ['http://localhost:8000', 'http://example.com'],

    // Append headers instead of overwriting (affects plugin behavior)
    appendHeaders: true
});

Key Properties ​

• cors.static: Indicates if headers are static (not applicable for multiple origins).
• cors.headers: The parsed CORS headers (not for direct use).

Methods ​

• validate(headersObj, requestOrigin): Validates the request origin and sets Access-Control-Allow-Origin.
• set(ctx): Sets CORS headers in ctx.headers without overwriting existing headers.
• write(ctx): Similar to set, but overwrites existing headers.
• assign(headerObj): Extends a header object with CORS headers.

Handling Multiple Origins ​

Access-Control-Allow-Origin is dynamic, typically accepting a single origin. For multiple origins, CORS requires a validation step.

Using as a Plugin ​

CORS integrates directly as a plugin with @stricjs/app routes.

routes.use(cors);

routes.use(cors);

This configuration automatically:

• Adds a layer handler to set CORS headers.
• Registers an OPTIONS handler at /*.

Header Behavior ​

• By default, CORS uses the write method, overwriting all headers.
• To append CORS headers instead, set appendHeaders to true.

By leveraging the CORS class from @stricjs/utils, developers can efficiently manage CORS policies in their Stricjs applications, ensuring both flexibility and compliance with cross-origin resource sharing requirements.