diff --git a/README.md b/README.md index 8ece116..962fe74 100644 --- a/README.md +++ b/README.md @@ -27,7 +27,7 @@ in the table above. See [Fastify's LTS policy](https://github.com/fastify/fastify/blob/main/docs/Reference/LTS.md) for more details. ## Usage -Require `@fastify/cors` and register it as any other plugin, it will add an `onRequest` hook and a [wildcard options route](https://github.com/fastify/fastify/issues/326#issuecomment-411360862). +Require `@fastify/cors` and register it as any other plugin. It adds an `onRequest` hook and a [wildcard options route](https://github.com/fastify/fastify/issues/326#issuecomment-411360862). ```js import Fastify from 'fastify' import cors from '@fastify/cors' @@ -45,12 +45,12 @@ await fastify.listen({ port: 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: +* `origin`: Configures the **Access-Control-Allow-Origin** CORS header. The value of origin can be: + - `Boolean`: Set to `true` to reflect the [request origin](http://tools.ietf.org/html/draft-abarth-origin-09), or `false` to disable CORS. + - `String`: Set to a specific origin (e.g., `"http://example.com"`). The special `*` value (default) allows any origin. + - `RegExp`: Set to a regular expression pattern to test the request origin. If it matches, the request origin is reflected (e.g., `/example\.com$/` returns the origin only if it ends with `example.com`). + - `Array`: Set to an array of valid origins, each being a `String` or `RegExp` (e.g., `["http://example1.com", /\.example2\.com$/]`). + - `Function`: Set to a function with custom logic. The function takes the request origin as the first parameter and a callback as the second (signature `err [Error | null], origin`). *Async-await* and promises are supported. The Fastify instance is bound to the function call and can be accessed via `this`. For example: ```js origin: (origin, cb) => { const hostname = new URL(origin).hostname @@ -63,23 +63,23 @@ You can use it as is without passing any option or you can configure it as expla cb(new Error("Not allowed"), false) } ``` -* `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']`); (default: `GET,HEAD,PUT,PATCH,POST,DELETE`) -* `hook`: See the section `Custom Fastify hook name` (default: `onRequest`) -* `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. -* `cacheControl`: Configures the **Cache-Control** header for CORS preflight responses. Set to an integer to pass the header as `Cache-Control: max-age=${cacheControl}`, or set to a string to pass the header as `Cache-Control: ${cacheControl}` (fully define the header value), otherwise the header 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 requirements 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`). +* `methods`: Configures the **Access-Control-Allow-Methods** CORS header. Expects a comma-delimited string (e.g., 'GET,PUT,POST') or an array (e.g., `['GET', 'PUT', 'POST']`). Default: `GET,HEAD,PUT,PATCH,POST,DELETE`. +* `hook`: See the section `Custom Fastify hook name`. Default: `onRequest`. +* `allowedHeaders`: Configures the **Access-Control-Allow-Headers** CORS header. Expects a comma-delimited string (e.g., `'Content-Type,Authorization'`) or an array (e.g., `['Content-Type', 'Authorization']`). Defaults to reflecting the headers specified in the request's **Access-Control-Request-Headers** header if not specified. +* `exposedHeaders`: Configures the **Access-Control-Expose-Headers** CORS header. Expects a comma-delimited string (e.g., `'Content-Range,X-Content-Range'`) or an array (e.g., `['Content-Range', 'X-Content-Range']`). No custom headers are exposed if not specified. +* `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. +* `cacheControl`: Configures the **Cache-Control** header for CORS preflight responses. Set to an integer to pass the header as `Cache-Control: max-age=${cacheControl}`, or set to a string to pass the header as `Cache-Control: ${cacheControl}`. Otherwise, the header is omitted. +* `preflightContinue`: Passes the CORS preflight response to the route handler. Default: `false`. +* `optionsSuccessStatus`: Provides a status code for successful `OPTIONS` requests, as some legacy browsers (IE11, various SmartTVs) choke on `204`. +* `preflight`: Disables preflight by passing `false`. Default: `true`. +* `strictPreflight`: Enforces strict requirements for 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). Preflight requests without the required headers result in 400 errors when set to `true`. Default: `true`. +* `hideOptionsRoute`: Hides the options route from documentation built using [@fastify/swagger](https://github.com/fastify/fastify-swagger). Default: `true`. #### :warning: DoS attacks -The use of `RegExp` or a `function` for the `origin` parameter might allow an attacker to perform a Denial of Service -attack. Craft those with extreme care. +Using `RegExp` or a `function` for the `origin` parameter may enable Denial of Service attacks. +Craft with extreme care. ### Configuring CORS Asynchronously @@ -114,7 +114,7 @@ fastify.listen({ port: 3000 }) ### Custom Fastify hook name -By default, `@fastify/cors` adds an `onRequest` hook where the validation and header injection are executed. This can be customized by passing `hook` in the options. Valid values are `onRequest`, `preParsing`, `preValidation`, `preHandler`, `preSerialization`, and `onSend`. +By default, `@fastify/cors` adds an `onRequest` hook for validation and header injection. This can be customized by passing `hook` in the options. Valid values are `onRequest`, `preParsing`, `preValidation`, `preHandler`, `preSerialization`, and `onSend`. ```js import Fastify from 'fastify' @@ -132,7 +132,7 @@ fastify.get('/', (req, reply) => { await fastify.listen({ port: 3000 }) ``` -When configuring CORS asynchronously, an object with `delegator` key is expected: +To configure CORS asynchronously, provide an object with the `delegator` key: ```js const fastify = require('fastify')()