# d2l-fetch-simple-cache

**Repository Path**: mirrors_Brightspace/d2l-fetch-simple-cache

## Basic Information

- **Project Name**: d2l-fetch-simple-cache
- **Description**: Provides a middleware function for caching fetch responses for the same url+auth combination
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-08
- **Last Updated**: 2026-05-23

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# d2l-fetch-simple-cache
Provides a middleware function for caching fetch responses for the same url+auth combination.

##### WARNING: This middleware ignores server Response cache-control directives and should be used with caution.

## Setup

```sh
npm install
```

## Usage

Reference the script in your html after your reference to `d2l-fetch` (see [here](https://github.com/Brightspace/d2l-fetch) for details on d2l-fetch):

Install `d2l-fetch-simple-cache` via npm:
```sh
npm install d2l-fetch-simple-cache
```

```javascript
import { fetchSimpleCache } from 'd2l-fetch-simple-cache';
```

### Simple-cache

Install the `simple-cache` middleware to d2lfetch via the `use` function and then start making your requests.

```js
d2lfetch.use({name: 'simple-cache' fn: fetchSimpleCache});

const response = await d2lfetch.fetch(
  new Request('http://example.com/api/someentity/')
);
```

Responses are cached based on the combination of `method`, `url` and `Authorization` request header value.
Any request that matches an existing cached item based on this combination will not result
in a subsequent network request but will rather be given a promise that resolves to a clone of
the original cached request's Response.

### Options

As of `d2l-fetch  v1.2.0` it is possible to provide configuration options during middleware setup. `d2l-fetch-simple-cache` accepts the following options arguments:

* `cacheLengthInSeconds`: This can be used to override the default cache length. (Default is 120 seconds)
```js
//cache responses for 5 minutes
d2lfetch.use({
	name: 'simple-cache',
	fn: simpleCache,
	options: { cacheLengthInSeconds: 600 }
});
```

* `methods`: This can be used to override the default http methods that are allowed to be cached. (Default is `['GET', 'HEAD', 'OPTIONS']`)
```js
//only cache responses from GET requests
d2lfetch.use({
	name: 'simple-cache',
	fn: simpleCache,
	options: { methods: ['GET'] }
});
```

### Cache-Control

By default `d2l-fetch-simple-cache` will cache responses for 2 minutes, or the time provided at setup in the `cacheLengthInSeconds` option parameter (see Options above). This can be modified on a `Request`-level basis by supplying arguments in the `cache-control` header of the `Request`. The following values are accepted:

* `cache-control: no-cache` will effectively 'bust' the cache. Any matching cached Response will be removed from the cache and the Request will continue through the middleware chain. **Note that the Response will still be cached for future requests (assuming they don't also contain a `no-cache` directive)**.
* `cache-control: no-store` will indicate that the Response returned from the server should not be cached. **Note that this does not prevent the Request from being served from an existing valid cached Response**.
* `cache-control: max-age=<seconds>` can be used to override the configured middleware time-to-live. For example if the middleware is configured with the default 2 minute TTL a Request sent with a header of `cache-control: max-age=60` will only be cached for 60 seconds. **Note that if a previous matching Request had already been cached the shorter of the two values (middleware configuration and `max-age` header value) will be used for determining cache expiry**.

## Versioning and Releasing

This repo is configured to use `semantic-release`. Commits prefixed with `fix:` and `feat:` will trigger patch and minor releases when merged to `main`.

To learn how to create major releases and release from maintenance branches, refer to the [semantic-release GitHub Action](https://github.com/BrightspaceUI/actions/tree/main/semantic-release) documentation.