javascript – golang中的pubsub替代品

2019年7月28日 192次阅读

我有使用pubsub在
javascript中完成的简单任务,这是任务：

我有对象让A和另外两个对某些元素感兴趣的对象(在这种情况下是字符串),假设Foo对元素m,n和bar感兴趣的元素n,o,p.兴趣可以相交.

A对象有方法添加/删除元素,当该对象包含Foo感兴趣的m,n元素时,那么存储在Foo中的那个对象是javascript中使用pubsub的伪代码

var A = {};

var Foo = {
    interests: ['m', 'n'],
    storedObj: {},
    tempObj: {}
};

// Bar same as Foo with different interest ['n', 'o', 'p']

// somewhere in Foo and Bar constructor
// Foo and Bar subscribe too each interests element
// for each interests when add
subscribe('add'+interest, function(obj) {
    // store this obj in tempObj and increment until satisfy all 
    // interest
    tempObj[obj]++;

    // if this obj satisfy all interest then store it in array of obj
    if(tempObj[obj] === len(interests)) {
        storedObj[obj] = true;
    }
});

// for each interests when remove
subscribe('remove'+interest, function(obj) {
    // remove from storedObj
    delete storedObj[obj];

    // decrement tempObj so it can be used for later if the interest 
    // is adding again
    tempObj[obj]--;
});

// inside A prototype
prototype.add = function(interest) {
    publish('add'+interest, this);
    return this;
}
prototype.remove = function(interest) {
    publish('remove'+interest, this);
    return this;
}

// implementation
A.add('m')
 .add('n')
 .add('o')

// then A is stored inside Foo but not in Bar because A doesn't have 
// `p`, but it still stored Bar.tempObj and have value 2 and waiting 
// for `p` to be add

A.remove('m')
 .add('p')

// then A is removed from Foo and stored in Bar

我想把这个任务移植到golang但是我不想使用pubsub,我想要更加惯用的golang方式.注意：我已经在golang中使用了pubsub.

你能告诉我怎么在golang做吗？我正在使用频道,但无法找到解决方案.

最佳答案 只是为了给你一个想法,不一定是你的真实用例.

package main

import (
    "fmt"
    "time"
)

type Publisher struct {
    subscription map[string]chan string
}

func (p *Publisher)Subscribe(interest string) chan string{
    if p.subscription == nil {
        p.subscription = make(map[string]chan string)
    }
    p.subscription[interest] = make(chan string)
    return p.subscription[interest]
}

func (p *Publisher) Add(val string) {
    if p.subscription[val] != nil {
        fmt.Println("Adding " + val)
        p.subscription[val] <- "added " + val
    }
}
func (p *Publisher) Remove(val string) {
    if p.subscription[val] != nil {
        p.subscription[val] <- "removed " + val
    }
}

type Subscriber struct {
    subscriptions [] chan string
    publisher *Publisher
}

func (s *Subscriber) RegisterInterest(interest string){
    s.subscriptions = append(s.subscriptions, s.publisher.Subscribe(interest))
}
func (s *Subscriber) run(channel chan string) {
    for  {
        fmt.Println("Waiting for message")
        m := <- channel
        fmt.Println("Got message : " + m)
    }
}
func (s *Subscriber) Listen()  {
    for _, elem := range s.subscriptions {
        go s.run(elem)
    }

}
func main() {
    pub := Publisher{}
    sub := &Subscriber{publisher: &pub}
    sub.RegisterInterest("m")
    sub.RegisterInterest("n")
    sub.Listen()
    pub.Add("m")
    pub.Add("n")
    pub.Remove("m")
    pub.Remove("n")
    time.Sleep(time.Second * 10)
}
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