node.js - Redis - 在具有 promise 的事务中插入数组中的值( Bluebird )

Question

我有一个这样的数组:

var names = ['Irina', 'Michael', 'Carl'];

我想使用 promise 交易将它们插入 redis(我不知道其他方式)。但是我对如何做到这一点感到困惑；这是我的代码:

var Promise = require("bluebird");
var redis = require("redis");

Promise.promisifyAll(redis.RedisClient.prototype);
Promise.promisifyAll(redis.Multi.prototype);

var client = redis.createClient(), multi;

var names = ['Irina', 'Michael', 'Carl'];

var result = names.map(function(item) {
    client.watch('user:id');
    client.getAsync('user:id', function(err, data) {
      var multi = client.multi();
      var user_id = parseInt(data) + 1;
      multi.hmsetAsync('user:' + user_id, 'username', item, 'about', 'love to coding');
      multi.incrAsync('user:id');
      multi.execAsync(function(err,data){
        console.log(data);
      });
    });
});

Promise.all(result).then(function(response) {
    console.log(response);
});

但这行不通(:

编辑:这是应用程序抛出的错误:

未处理的拒绝错误:ERR 'get' 命令的参数数量错误

谁能帮帮我!

---

编辑 2: 我更改了我的代码，但现在只保存数组的最后一个值:

client.watch('user:id');
var result = names.map(function(item) {        
    var multi = client.multi();
    client.getAsync('user:id').then(function(value) {
        var user_id = parseInt(value) + 1;
        return user_id;
    }).then(function(user_id) {
        multi.hmsetAsync('user:' + user_id, 'username', item, 'about', 'love to coding');
        multi.incrAsync('user:id');
    }).then(function() {
        multi.execAsync().spread(function(err,data){
            console.log(data);
        });
    });
});

---

编辑 3:

当使用 redis 的 MONITOR 时，这是输出:

[0 127.0.0.1:54439] "info"
[0 127.0.0.1:54439] "watch" "user:id"
[0 127.0.0.1:54439] "get" "user:id"
[0 127.0.0.1:54439] "get" "user:id"
[0 127.0.0.1:54439] "get" "user:id"
[0 127.0.0.1:54439] "MULTI"
[0 127.0.0.1:54439] "hmset" "user:88" "username" "Irina" "about" "love to coding"
[0 127.0.0.1:54439] "incr" "user:id"
[0 127.0.0.1:54439] "EXEC"
[0 127.0.0.1:54439] "MULTI"
[0 127.0.0.1:54439] "hmset" "user:88" "username" "Michael" "about" "love to coding"
[0 127.0.0.1:54439] "incr" "user:id"
[0 127.0.0.1:54439] "EXEC"
[0 127.0.0.1:54439] "MULTI"
[0 127.0.0.1:54439] "hmset" "user:88" "username" "Carl" "about" "love to coding"
[0 127.0.0.1:54439] "incr" "user:id"
[0 127.0.0.1:54439] "EXEC"

执行 get user:id 3 次，然后执行其他方法。为什么？

Answer 1

我用这种方式解决了我的问题:

client.watch('user:id');
Promise.each(names, function(item) {
    var multi = client.multi();
    return client.getAsync('user:id').then(function(value) {
        var user_id = parseInt(value) + 1;
        return user_id;    
    }).then(function(user_id) {
        multi.hmsetAsync('user:' + user_id, 'username', item, 'about', 'love to coding');
        multi.incrAsync('user:id');
    }).then(function() {
        return multi.execAsync().spread(function(err,data){
            console.log(data);
        });
    });
})
.then(function() {
    console.log("Ended process ...");
});

诀窍是改变:

var result = names.map(function(item) {...});

promise :

Promise.each(names, function(item) {...});

然后将 client.getAsync(user:id) 返回给它。

这是 redis 的 MONITOR 的输出:

[0 127.0.0.1:53290] "info"
[0 127.0.0.1:53290] "watch" "user:id"
[0 127.0.0.1:53290] "get" "user:id"
[0 127.0.0.1:53290] "MULTI"
[0 127.0.0.1:53290] "hmset" "user:88" "username" "Irina" "about" "love to coding"
[0 127.0.0.1:53290] "incr" "user:id"
[0 127.0.0.1:53290] "EXEC"
[0 127.0.0.1:53290] "get" "user:id"
[0 127.0.0.1:53290] "MULTI"
[0 127.0.0.1:53290] "hmset" "user:89" "username" "Michael" "about" "love to coding"
[0 127.0.0.1:53290] "incr" "user:id"
[0 127.0.0.1:53290] "EXEC"
[0 127.0.0.1:53290] "get" "user:id"
[0 127.0.0.1:53290] "MULTI"
[0 127.0.0.1:53290] "hmset" "user:90" "username" "Carl" "about" "love to coding"
[0 127.0.0.1:53290] "incr" "user:id"
[0 127.0.0.1:53290] "EXEC"

惊人的，但真实的! (线索:https://stackoverflow.com/a/25129878/2954267)