kitten.sh
1---
2title: '@urql/exchange-request-policy'
3order: 9
4---
5
6# Request Policy Exchange
7
8> **Note:** These API docs are deprecated as we now keep TSDocs in all published packages.
9> You can view TSDocs while using these packages in your editor, as long as it supports the
10> TypeScript Language Server.
11> We're planning to replace these API docs with a separate web app soon.
12
13The `@urql/exchange-request-policy` package contains an addon `requestPolicyExchange` for `urql`
14that may be used to upgrade [Operations' Request Policies](./core.md#requestpolicy) on a
15time-to-live basis.
16
17[Read more about request policies on the "Document Caching" page.](../basics/document-caching.md#request-policies)
18
19This exchange will conditionally upgrade `cache-first` and `cache-only` operations to use
20`cache-and-network`, so that the client gets an opportunity to update its cached data, when the
21operation hasn't been seen within the given `ttl` time. This is often preferable to setting the
22default policy to `cache-and-network` to avoid an unnecessarily high amount of requests to be sent
23to the API when switching pages.
24
25## Installation and Setup
26
27First install `@urql/exchange-request-policy` alongside `urql`:
28
29```sh
30yarn add @urql/exchange-request-policy
31# or
32npm install --save @urql/exchange-request-policy
33```
34
35Then add it to your `Client`, preferably in front of the `cacheExchange` and in front of any asynchronous
36exchanges, like the `fetchExchange`:
37
38```js
39import { createClient, cacheExchange, fetchExchange } from 'urql';
40import { requestPolicyExchange } from '@urql/exchange-request-policy';
41
42const client = createClient({
43 url: 'http://localhost:3000/graphql',
44 exchanges: [
45 requestPolicyExchange({
46 /* config */
47 }),
48 cacheExchange,
49 fetchExchange,
50 ],
51});
52```
53
54## Options
55
56| Option | Description |
57| --------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
58| `ttl` | The "time-to-live" until an `Operation` will be upgraded to the `cache-and-network` policy in milliseconds. By default 5 minutes is set. |
59| `shouldUpgrade` | An optional function that receives an `Operation` as the only argument and may return `true` or `false` depending on whether an operation should be upgraded. This can be used to filter out operations that should never be upgraded to `cache-and-network`. |