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* Update README.MD * docs: update programmability.md examples + add Programmability section to README and * fix imports according to the new v5 exports * more v5 docs updates --------- Co-authored-by: Nikolay Karadzhov <nkaradzhov89@gmail.com>
88 lines
2.5 KiB
Markdown
88 lines
2.5 KiB
Markdown
# [Programmability](https://redis.io/docs/manual/programmability/)
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Redis provides a programming interface allowing code execution on the redis server.
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## [Functions](https://redis.io/docs/manual/programmability/functions-intro/)
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The following example retrieves a key in redis, returning the value of the key, incremented by an integer. For example, if your key _foo_ has the value _17_ and we run `add('foo', 25)`, it returns the answer to Life, the Universe and Everything.
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```lua
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#!lua name=library
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redis.register_function {
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function_name = 'add',
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callback = function(keys, args) return redis.call('GET', keys[1]) + args[1] end,
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flags = { 'no-writes' }
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}
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```
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Here is the same example, but in a format that can be pasted into the `redis-cli`.
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```
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FUNCTION LOAD "#!lua name=library\nredis.register_function{function_name='add', callback=function(keys, args) return redis.call('GET', keys[1])+args[1] end, flags={'no-writes'}}"
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```
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Load the prior redis function on the _redis server_ before running the example below.
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```typescript
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import { CommandParser } from '@redis/client/lib/client/parser';
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import { NumberReply } from '@redis/client/lib/RESP/types';
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import { createClient, RedisArgument } from 'redis';
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const client = createClient({
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functions: {
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library: {
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add: {
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NUMBER_OF_KEYS: 1,
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parseCommand(
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parser: CommandParser,
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key: RedisArgument,
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toAdd: RedisArgument
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) {
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parser.pushKey(key)
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parser.push(toAdd)
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},
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transformReply: undefined as unknown as () => NumberReply
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}
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}
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}
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});
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await client.connect();
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await client.set('key', '1');
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await client.library.add('key', '2'); // 3
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```
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## [Lua Scripts](https://redis.io/docs/manual/programmability/eval-intro/)
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The following is an end-to-end example of the prior concept.
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```typescript
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import { CommandParser } from '@redis/client/lib/client/parser';
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import { NumberReply } from '@redis/client/lib/RESP/types';
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import { createClient, defineScript, RedisArgument } from 'redis';
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const client = createClient({
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scripts: {
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add: defineScript({
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SCRIPT: 'return redis.call("GET", KEYS[1]) + ARGV[1];',
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NUMBER_OF_KEYS: 1,
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FIRST_KEY_INDEX: 1,
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parseCommand(
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parser: CommandParser,
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key: RedisArgument,
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toAdd: RedisArgument
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) {
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parser.pushKey(key)
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parser.push(toAdd)
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},
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transformReply: undefined as unknown as () => NumberReply
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})
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}
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});
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await client.connect();
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await client.set('key', '1');
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await client.add('key', '2'); // 3
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```
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