JavaScript API

JavaScript API 概述

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Redis 对象

  • 自版本起：2.0.0

触发器和函数 JavaScript API 提供名为 redis 的对象的单一实例。Redis 实例使注册的函数能够与运行它们的 Redis 服务器进行交互。以下是 redis 实例提供的 API。

redis.registerFunction

  • 自版本起：2.0.0

注册一个稍后可以使用TFCALL命令。

//name and callback mandatory
//object with optional arguments
redis.registerFunction(
  'foo', //name
  function(client, args) {}, //callback
  {
    description: 'The description',
    flags: [redis.functionFlags.NO_WRITES, redis.functionFlags.ALLOW_OOM]
  } // optional arguments
);

redis.registerAsyncFunction

  • Since version: 2.0.0

Register a new async function that can later be invoke using TFCALLASYNC command.

redis.registerAsyncFunction(
  'foo', //Function name
  function(client, args){}, //callback
  {
    description: 'description',
    flags: [redis.functionFlags.NO_WRITES, redis.functionFlags.ALLOW_OOM]
  } //optional arguments
);

redis.registerKeySpaceTrigger

  • Since version: 2.0.0

Register a key space notification trigger that will run whenever a key space notification fired.

redis.registerKeySpaceTrigger(
  'foo', // trigger name
  'keys:*', //key prefix
  function(client, data) {}, //callback
  {
    description: 'description'
    onTriggerFired: function(client, data){}
  } //optional arguments
)

redis.registerStreamTrigger

  • Since version: 2.0.0

Register a stream trigger that will be invoke whenever a data is added to a stream.

redis.registerStreamTrigger(
  'foo', //trigger name
  'stream:*', //prefix
  function(client, data){},//callback
  {
    description: 'Description'
    window: 1,
    isStreamTrimmed: false 
  } //optional arguments
)

redis.registerClusterFunction

  • Since version: 2.0.0

Register a cluster function that can later be called using async_client.runOnKey() or async_client.runOnShards()

redis.registerClusterFunction(
  'foo', //name
  async function(client, ...args){} //callback
)

redis.config

  • Since version: 2.0.0
redis-cli -x RG.FUNCTION LOAD UPGRADE CONFIG '{"example_config": "example_config_value"}' < main.js

var configExample = redis.config.example_config;

Client object

Client object that is used to perform operations on Redis.

client.call

  • Since version: 2.0.0

Run a command on Redis. The command is executed on the current Redis instrance.

client.call(
  '',
  ...args
)

client.callRaw

  • Since version: 2.0.0

Run a command on Redis but does not perform UTF8 decoding on the result. The command is executed on the current Redis instrance.

client.callRaw(
  '',
  ...args
)

client.callAsync

  • Since version: 2.0.0

Call a command on Redis. Allow Redis to block the execution if needed (like blpop command) and return the result asynchronously. Returns a promise object that will be resolved when the command invocation finished.

client.callAsync(
  '',
  ...args
)

client.callAsyncRaw

  • Since version: 2.0.0

Call a command on Redis. Allow Redis to block the execution if needed (like blpop command) and return the result asynchronously. Returns a promise object that will be resolved when the command invocation finished. The command is executed on the current Redis instrance.

client.callRaw(
  '',
  ...args
)

client.isBlockAllowed

  • Since version: 2.0.0

Return true if it is allow to return promise from the function callback. In case it is allowed and a promise is return, Redis will wait for the promise to be fulfilled and only then will return the function result.

client.isBlockAllowed(); // True / False

client.executeAsync

  • Since version: 2.0.0

Execute the given function asynchroniusly. Return a promise that will be fulfilled when the promise will be resolved/rejected.

client.executeAsync(
  async function(client){}
)

Async client object

Background client object that is used to perform background operation on Redis. This client is given to any background task that runs as a JS coroutine.

async_client.block

  • Since version: 2.0.0

Blocks Redis for command invocation. All the command that are executed inside the given function is considered atomic and will be wrapped with Multi/Exec and send to the replica/AOF.

async_client.block(
  function(client){}
)

async_client.runOnKey

  • Since version: 2.0.0

Runs a remote function on a given key. If the key located on the current shard on which we currently runs on, the remote function will run write away. Otherwise the remote function will run on the remote shard. Returns a promise which will be fulfilled when the invocation finishes. Notice that the remote function must return a json serializable result so we can serialize the result back to the original shard.

Notice that remote function can only perform read operations, not writes are allowed.

async_client.runOnKey(
  'key1', // key
  'foo', // function name
  ...args
)

async_client.runOnShards

  • Since version: 2.0.0

Runs a remote function on all the shards. Returns a promise which will be fulfilled when the invocation finishes on all the shards.

The result is array of 2 elements, the first is another array of all the results. The second is an array of all the errors happened durring the invocation. Notice that the remote function must return a json serializable result so we can serialize the result back to the original shard.

Notice that remote function can only perform read operations, not writes are allowed.

async_client.runOnShards(
  'foo', //name
  ...args //arguments
)