ZeroMQ在Go语言中无法打印我从PULL套接字接收到的JSON消息字节。

huangapple
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英文:

ZeroMQ in go won't print my json message bytes received from PULL socket

问题

我正在尝试一个简单的代码：

  1. package main
  3. import (
  4.     "fmt"
  5.     zmq "github.com/alecthomas/gozmq"
  6. )
  8. func main() {
  9.     context, _ := zmq.NewContext()
  10.     defer context.Close()
  12.     //  Socket to receive messages on
  13.     receiver, _ := context.NewSocket(zmq.PULL)
  14.     defer receiver.Close()
  15.     receiver.Connect("tcp://localhost:5557")
  17.     //  Process tasks forever
  18.     for {
  19.         msgbytes, _ := receiver.Recv(0)
  20.         fmt.Println("received")
  21.         fmt.Println(string(msgbytes))
  22.     }
  23. }

在Node.js中，我这样发送消息：

  1. console.log(payload);
  2. sender.send(JSON.stringify(payload));

我可以在控制台看到JSON，所以sender.send()实际上是在发送东西。此外，每个payload的.go程序的输出是：

  1. received
  2. []
  3. received
  4. []

没有输出。我在[GoDocs][1]中搜索了Recv方法，发现没有像其他语言中的recv_json、recv_message等分离，它们都是字节。那么发生了什么？我发送的是字符串，因为它被发送为字符串化，对吗？

更新

如Nehal在下面所说，我将导入语句更改为官方的库，并且这是新代码：

  1. package main
  3. import (
  4.     "fmt"
  5.     zmq "gopkg.in/zeromq/goczmq.v4"
  6. )
  8. func main() {
  9.     //  Socket to receive messages on
  10.     receiver, _ := zmq.NewPull("tcp://*:5557")
  11.     defer receiver.Destroy()
  13.     //  Process tasks forever
  14.     for {
  15.         request, _ := receiver.RecvMessage()
  16.         fmt.Println("received")
  17.         fmt.Println(request)
  18.     }
  19. }

但这次连received都没有打印出来，似乎根本没有接收到任何消息。
[1]: https://godoc.org/github.com/zeromq/goczmq

英文:

I'm trying a simple code:

  1. package main
  3. import (
  4.     "fmt"
  5.     zmq "github.com/alecthomas/gozmq"
  6. )
  8. func main() {
  9.     context, _ := zmq.NewContext()
  10.     defer context.Close()
  12.     //  Socket to receive messages on
  13.     receiver, _ := context.NewSocket(zmq.PULL)
  14.     defer receiver.Close()
  15.     receiver.Connect("tcp://localhost:5557")
  17.     //  Process tasks forever
  18.     for {
  19.         msgbytes, _ := receiver.Recv(0)
  20. 	fmt.Println("received")
  21.         fmt.Println(string(msgbytes))
  22.     }
  23. }

In NodeJS I send messages like this:

  1. console.log(payload);
  2. sender.send(JSON.stringify(payload));

I can see the json in the console, so sender.sen() is actually sending things. Also, the output from the .go program for each payload is:

  1. received
  2. []
  3. received
  4. []

There's no output. I've searched the [GoDocs][1] for the Recv method and there's no separation like recv_json, recv_message, etc like in other languages, it's all bytes. So what's happening? I'm sending a string because it's sent as stringfy, right?

UPDATE

As Nehal said below, I changed the import statement to the official rep, and this is the new code:

package main

  1. import (
  2.     "fmt"
  3.     zmq "gopkg.in/zeromq/goczmq.v4"
  4. )
  6. func main() {
  7.     //  Socket to receive messages on
  8.     receiver, _ := zmq.NewPull("tcp://*:5557")
  9.     defer receiver.Destroy()
  11.     //  Process tasks forever
  12.     for {
  13.         request, _ := receiver.RecvMessage()
  14. 	fmt.Println("received")
  15.         fmt.Println(request)
  16.     }
  17. }

But this time 'received' isn't even printed, it seems that no message is being received at all
[1]: https://godoc.org/github.com/zeromq/goczmq

答案1

得分: 0

在Go中的服务器代码：

  1. import (
  2.     "fmt"
  3.     zmq "gopkg.in/zeromq/goczmq.v4"
  4. )
  6. func main() {
  7.     //  Socket to receive messages on
  8.     receiver, err := zmq.NewPull("tcp://*:5557")
  9.     if err != nil {
  10.         panic(err)
  11.     }
  13.     defer receiver.Destroy()
  15.     //  Process tasks forever
  16.     for {
  17.         request, err := receiver.RecvMessage()
  18.         if err != nil {
  19.             panic(err)
  20.         }
  21.         fmt.Printf("Received: '%s'\n", request)
  22.     }
  23. }

在Node.js中的客户端代码：

  1. var zmq = require('zmq'),
  2.     sock = zmq.socket('push');
  4. sock.connect('tcp://127.0.0.1:5557');
  5. setInterval(function(){
  6.    console.log('Sending data');
  7.    sock.send(JSON.stringify({'msg': 'Hi There!'}));
  8. }, 500);

服务器端：

  1. $ go run a.go
  2. Received: '[{"msg":"Hi There!"}]'
  3. Received: '[{"msg":"Hi There!"}]'
  4. ...

客户端端：

  1. $ node a.js 
  2. Sending data
  3. Sending data
  4. ...

RecvMessage文档：https://godoc.org/github.com/zeromq/goczmq#Sock.RecvMessage

Node.js包：https://github.com/JustinTulloss/zeromq.node

Go中的优秀zmq示例：https://github.com/booksbyus/zguide/tree/master/examples/Go

入门教程：http://taotetek.github.io/oldschool.systems/post/goczmq1/

英文:

Server in go:

  1. import (
  2.     "fmt"
  3.     zmq "gopkg.in/zeromq/goczmq.v4"
  4. )
  6. func main() {
  7.     //  Socket to receive messages on
  8.     receiver, err := zmq.NewPull("tcp://*:5557")
  9.     if err != nil {
  10.         panic(err)
  11.     }
  13.     defer receiver.Destroy()
  15.     //  Process tasks forever
  16.     for {
  17.         request, err := receiver.RecvMessage()
  18.         if err != nil {
  19.             panic(err)
  20.         }
  21.         fmt.Printf("Received: '%s'\n", request)
  22.     }
  23. }

Client in Node.js:

  1. var zmq = require('zmq')
  2.   , sock = zmq.socket('push');
  3.  
  4. sock.connect('tcp://127.0.0.1:5557');
  5. setInterval(function(){
  6.    console.log('Sending data');
  7.    sock.send(JSON.stringify({'msg': 'Hi There!'}));
  8. }, 500);

Server Side:

  1. $ go run a.go
  2. Received: '[{"msg":"Hi There!"}]'
  3. Received: '[{"msg":"Hi There!"}]'
  4. ...

Client Side:

  1. $ node a.js 
  2. Sending data
  3. Sending data
  4. ...

RecvMessage Documentation: https://godoc.org/github.com/zeromq/goczmq#Sock.RecvMessage

Node.js package: https://github.com/JustinTulloss/zeromq.node

Excellent zmq examples in go: https://github.com/booksbyus/zguide/tree/master/examples/Go

Nice getting started tutorial: http://taotetek.github.io/oldschool.systems/post/goczmq1/

huangapple
  • 本文由 发表于 2017年2月8日 01:29:01
  • 转载请务必保留本文链接：https://go.coder-hub.com/42096226.html
  • go
  • json
  • node.js
  • zeromq
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