英文:
Golang Working with types
问题
问题
我在使用Golang中的类型时遇到了一些困惑,我需要一些帮助。我正在尝试修改Gorilla的websocket聊天示例,并且我想要传入JSON并相应地处理它。例如,我想要设置一个用户,并向websocket发送一条消息。
在当前的实现中,它只是接收一个字符串,并通过广播将其发送回所有连接的客户端。
例如,我想要能够设置以下数据结构并以不同的方式处理它。
传入的用户将是:
{
'type': 'user',
'value': 'John Doe'
}
传入的消息将是:
{
'type': 'message',
'value': 'Hi There, how are you?'
}
请参考以下代码:
https://github.com/gorilla/websocket/blob/master/examples/chat/conn.go#L52
for {
_, message, err := c.ws.ReadMessage()
if err != nil {
break
}
h.broadcast <- message
}
数据
所以上述代码适用于单个字符串,因为服务器所做的只是将任何客户端的传入消息传递给所有客户端。但是,我想要能够保存用户,并将活动用户列表与新消息一起发送回客户端。
为了做到这一点,在我看来,我将需要以不同的方式处理不同的传入消息。我尝试对传入的“message”进行解组,但是当我打印出类型时,它是这样的:
2015/11/24 20:03:10 []uint8
问题
我如何读取此输入流并将其解组为JSON?这是我在该部分添加的调试信息:
for {
_, dataString, err := c.ws.ReadMessage()
if err != nil {
break
}
log.Println(reflect.TypeOf(dataString))
var data MessageData
err = json.Unmarshal(dataString, &data)
log.Println(data.Type)
log.Println(data.Value)
if err != nil {
log.Println(err)
}
h.broadcast <- dataString
}
返回结果
2015/11/24 20:03:10 []uint8
2015/11/24 20:03:10
2015/11/24 20:03:10
英文:
The Problem
I need some help working with types in Golang, I get super confused. I am trying to alter the websocket chat example from Gorilla, and I want to pass in JSON and process it accordingly. I need to be able to set for example a user, and send a message to the websocket.
In the current implementation all it does is receive a string, and relays it back by broadcasting it to all connected clients.
For example I want to be able to set a data structure as follows and process it differently.
Incoming user would be:
{
'type': "user",
'value': "John Doe"
}
Incomming message would be:
{
'type': "message",
'value': "Hi There, how are you?"
}
Please refer to the following code:
https://github.com/gorilla/websocket/blob/master/examples/chat/conn.go#L52
for {
_, message, err := c.ws.ReadMessage()
if err != nil {
break
}
h.broadcast <- message
}
Data
So the above code works for single strings, because all the server does is pass the incoming message from any client to all. But I want to be able to save users, and send the list of active users back to the client along with the new message.
To do this, in my mind I will need to handle the different incoming messages differently. I tried to unmarchal the incomming message
, but when I print out the type it's this:
2015/11/24 20:03:10 []uint8
THE QUESTION
How do I go about reading this input stream, and unmarshal it to JSON? This is the debugging I added to the section:
for {
_, dataString, err := c.ws.ReadMessage()
if err != nil {
break
}
log.Println(reflect.TypeOf(dataString))
var data MessageData
err = json.Unmarshal(dataString, &data)
log.Println(data.Type)
log.Println(data.Value)
if err != nil {
log.Println(err)
}
h.broadcast <- dataString
}
Which Returns
2015/11/24 20:03:10 []uint8
2015/11/24 20:03:10
2015/11/24 20:03:10
答案1
得分: 3
抱歉,我在这方面有点愚蠢。message
已经是一个字节类型的接口。我在将数据发送到后端之前,没有正确地对HTML / JavaScript前端进行编码。
以下是在前端对其进行字符串化的方法:
var data = {};
data.type = "user";
data.value = user.val();
conn.send(JSON.stringify(data));
JSON.stringify(data);
然后,我可以解析JSON数据:
2015/11/24 20:36:04 {user fhgfhg}
2015/11/24 20:36:04 user
2015/11/24 20:36:04 fhgfhg
英文:
Sorry, I was being a bit stupid with this. The message
is already a byte type interface. I didn't properly encode the data on the HTML / JavaScript frontend before sending it to the backend.
What worked was stringifying it in the frontend:
var data = {};
data.type = "user";
data.value = user.val();
conn.send(JSON.stringify(data));
JSON.stringify(data)
Then I was able to unmarshall the JSON:
2015/11/24 20:36:04 {user fhgfhg}
2015/11/24 20:36:04 user
2015/11/24 20:36:04 fhgfhg
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