serviceberry-cache-control

Cache control plugin for Serviceberry.

Install

npm install serviceberry-cache-control

Usage

This plugin exports an abstract class CacheControl for extending by your class that knows how to get ETags and Last Modified for the requested resource. To use this plugin extend CacheControl and implement at least getETag(request, response) or getLastModified(request, response). The ETag or Last Modified is then used to validate the client cache using information passed in request headers.

This plugin sets a Cache-Control response header describing how the response should be cached based on the plugin options and halts the request and responds with a 304 Not Modified status if the cache validates using the ETag or Last Modified as described above.

const CacheControl = require("serviceberry-cache-control");

class Caching extends CacheControl {
	getETag (request) {
		return data.getETag(request.getUrl()); // can also return a promise or use async/await
	}
}

trunk.use(new Caching(options));

Options

• noStore boolean

  When true the no-store directive is set in the Cache-Control response header. Defaults to false.

• noCache boolean

  When true the no-cache directive is set in the Cache-Control response header. Defaults to false.

• mustRevalidate boolean

  When true the must-revalidate directive is set in the Cache-Control response header. Defaults to false.

• public boolean

  When true the public directive is set in the Cache-Control response header. Defaults to false.

• private boolean

  When true the private directive is set in the Cache-Control response header. Defaults to false.

• maxAge number

  When greater than 0 the max-age directive is set in the Cache-Control response header. Defaults to NaN.

• vary array

  An array of header field names that might may vary the response and should be considered by caches. Values are appended to the Vary response header.

  Defaults to [].

CacheControl

Abstract class

constructor([options])

• options

  Sets this.options. See options above.

getETag(request, response)

You should extend this class and at least implement this method or getLastModified().

Called by the setETag method for fetching an ETag to be set as a response headers and used to validate the cache. This can be an async function or it can return a promise. It should return an ETag string or eventually resolve to one.

• request object

  Serviceberry request.

• response object

  Serviceberry response.

getLastModified(request, response)

You should extend this class and at least implement this method or getETag().

Called by the validate method for fetching the date the requested resource was last modified to be used to validate the cache. This can be an async function or it can return a promise. It should return an ETag string or eventually resolve to one.

• request object

  Serviceberry request.

• response object

  Serviceberry response.

use(request, response)

The handler method. This is the method called by Serviceberry. This is an async function. If it determines the response status should be 304 Not Modified the request will be halted and the response sent with a 304 status.

• request object

  Serviceberry request.

• response object

  Serviceberry response.

validate(request, response)

Called by the use method to validate the cache. This is an async function.

• request object

  Serviceberry request.

• response object

  Serviceberry response.