fastify-cors:加速 CORS

# fastify-cors  [](https://www.npmjs.com/package/fastify-cors) [](https://snyk.io/test/github/fastify/fastify-cors) [](https://coveralls.io/github/fastify/fastify-cors?branch=master) [](https://standardjs.com/) `fastify-cors` enables the use of [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing) in a Fastify application. Supports Fastify versions `3.x`. Please refer to [this branch](https://github.com/fastify/fastify-cors/tree/3.x) and related versions for Fastify `^2.x` compatibility. Please refer to [this branch](https://github.com/fastify/fastify-cors/tree/1.x) and related versions for Fastify `^1.x` compatibility. ## Install ``` npm i fastify-cors ``` ## Usage Require `fastify-cors` and register it as any other plugin, it will add a `preHandler` hook and a [wildcard options route](https://github.com/fastify/fastify/issues/326#issuecomment-411360862). ```js const fastify = require('fastify')() fastify.register(require('fastify-cors'), { // put your options here }) fastify.get('/', (req, reply) => { reply.send({ hello: 'world' }) }) fastify.listen(3000) ``` You can use it as is without passing any option or you can configure it as explained below. ### Options * `origin`: Configures the **Access-Control-Allow-Origin** CORS header. The value of origin could be of different types: - `Boolean` - set `origin` to `true` to reflect the [request origin](http://tools.ietf.org/html/draft-abarth-origin-09), or set it to `false` to disable CORS. - `String` - set `origin` to a specific origin. For example if you set it to `"http://example.com"` only requests from "http://example.com" will be allowed. The special `*` value (default) allows any origin. - `RegExp` - set `origin` to a regular expression pattern that will be used to test the request origin. If it is a match, the request origin will be reflected. For example, the pattern `/example\.com$/` will reflect any request that is coming from an origin ending with "example.com". - `Array` - set `origin` to an array of valid origins. Each origin can be a `String` or a `RegExp`. For example `["http://example1.com", /\.example2\.com$/]` will accept any request from "http://example1.com" or from a subdomain of "example2.com". - `Function` - set `origin` to a function implementing some custom logic. The function takes the request origin as the first parameter and a callback as a second (which expects the signature `err [Error | null], origin`), where `origin` is a non-function value of the origin option. *Async-await* and promises are supported as well. The Fastify instance is bound to function call and you may access via `this`. For example: ```js origin: (origin, cb) => { if(/localhost/.test(origin)){ // Request from localhost will pass cb(null, true) return } // Generate an error on other origins, disabling access cb(new Error("Not allowed")) } ``` * `methods`: Configures the **Access-Control-Allow-Methods** CORS header. Expects a comma-delimited string (ex: 'GET,PUT,POST') or an array (ex: `['GET', 'PUT', 'POST']`). * `allowedHeaders`: Configures the **Access-Control-Allow-Headers** CORS header. Expects a comma-delimited string (ex: `'Content-Type,Authorization'`) or an array (ex: `['Content-Type', 'Authorization']`). If not specified, defaults to reflecting the headers specified in the request's **Access-Control-Request-Headers** header. * `exposedHeaders`: Configures the **Access-Control-Expose-Headers** CORS header. Expects a comma-delimited string (ex: `'Content-Range,X-Content-Range'`) or an array (ex: `['Content-Range', 'X-Content-Range']`). If not specified, no custom headers are exposed. * `credentials`: Configures the **Access-Control-Allow-Credentials** CORS header. Set to `true` to pass the header, otherwise it is omitted. * `maxAge`: Configures the **Access-Control-Max-Age** CORS header. In seconds. Set to an integer to pass the header, otherwise it is omitted. * `preflightContinue`: Pass the CORS preflight response to the route handler (default: `false`). * `optionsSuccessStatus`: Provides a status code to use for successful `OPTIONS` requests, since some legacy browsers (IE11, various SmartTVs) choke on `204`. * `preflight`: if needed you can entirely disable preflight by passing `false` here (default: `true`). * `strictPreflight`: Enforces strict requirement of the CORS preflight request headers (**Access-Control-Request-Method** and **Origin**) as defined by the [W3C CORS specification](https://www.w3.org/TR/2020/SPSD-cors-20200602/#resource-preflight-requests) (the current [fetch living specification](https://fetch.spec.whatwg.org/) does not define server behavior for missing headers). Preflight requests without the required headers will result in 400 errors when set to `true` (default: `true`). * `hideOptionsRoute`: hide options route from the documentation built using [fastify-swagger](https://github.com/fastify/fastify-swagger) (default: `true`). ### Configuring CORS Asynchronously ```js const fastify = require('fastify')() fastify.register(require('fastify-cors'), (instance) => (req, callback) => { let corsOptions; // do not include CORS headers for requests from localhost if (/localhost/.test(origin)) { corsOptions = { origin: false } } else { corsOptions = { origin: true } } callback(null, corsOptions) // callback expects two parameters: error and options }) fastify.get('/', (req, reply) => { reply.send({ hello: 'world' }) }) fastify.listen(3000) ``` ## Acknowledgements The code is a port for Fastify of [`expressjs/cors`](https://github.com/expressjs/cors). ## License Licensed under [MIT](./LICENSE).<br/> [`expressjs/cors` license](https://github.com/expressjs/cors/blob/master/LICENSE)