Windows Chrome扩展本地消息只能接收第一个响应 [英] Windows Chrome extension native messaging can only receive the first response

问题描述

我试图使用本地消息发送一些数据到我的本地windows应用程序。它适用于runtime.sendNativeMessage（）方法。当我尝试使用使用端口的长期连接时，它也可以将数据从chrome传递到我的应用程序。但是，Chrome扩展只能从我的应用程序接收第一个响应。我相信端口仍然是开放的，因为我的应用程序仍然可以从chrome接收数据。以下是我的代码：

Chrome扩展脚本：

  var port = chrome.runtime.connectNative（'com.mydomain.app1'）; 
 
 port.onMessage.addListener（function（msg）{
 console.log（Received from port：，msg）; 
}）; 
 
 port.onDisconnect.addListener（function（）{
 console.log（Disconnected）; 
}）; 
 
 chrome.tabs.onUpdated.addListener（
函数（tabId，changeInfo，tab）{
 var param = {}; 
 param ['url'] = tab.url; 
 port.postMessage（param）; 
} 
} 
  

$ p
$ b

  int _tmain（int argc，_TCHAR * argv []）
 {
 while（true）
 {
 //读取前四个字节（=>长度）
 unsigned int length = 0; 
 for（int i = 0; i <4; i ++）
 {
 char c; 
 if（（c = getchar（））！= EOF）
 length + = c< i * 8; 
 else返回0; 
} 
 
 //读取json-message 
 std :: string msg =; 
 for int i = 0; i< length; i ++）
 {
 msg + = getchar（）; 
} 
 
 // ....做某事
 
 //发送回复消息
 std :: string message ={\text \：\这是一个响应信息\}; 
 unsigned int len = message.length（）; 
 //我们需要发送4个字节的长度信息
 std :: cout<< char（（（len>> 0）& 0xFF））
<< char（（（len>> 8）& 0xFF））
<< char（（（len>> 16）& 0xFF））
<< char（（（len>> 24）& 0xFF））; 
 //现在我们可以输出我们的消息
 std :: cout<< message.c_str（）; 
 std :: cout.flush（）; 
 
 
 
 
 
 
注意最后一行 strong> std :: cout.flush（）; ，如果我注释掉它，即使第一个响应也不会显示在chrome中。我只是无法弄清楚chrome如何从应用程序的stdout中读取数据。
      试着用自动刷新 -   std :: cout.setf（std :: ios_base :: unitbuf） 
 
 
 
另外，读/写输入/输出的方式消息长度不正确，并且会在长消息中失败。
 
 
 
这段代码适用于我： 
 
 
  int main（int argc，char * argv []）
 {
 std :: cout.setf（std :: ios_base :: unitbuf）; 
 
 while（true）
 {
 unsigned int ch，inMsgLen = 0，outMsgLen = 0; 
 std :: string input =，response =; 
 
 //为数据长度读取4个字节
 std :: cin.read（（char *）& inMsgLen，4）; 
 
 if（inMsgLen == 0）
 {
 break; 
} 
 else 
 {
 //循环getchar来拉取消息，直到达到所提供的总长度。 
 for（int i = 0; i< inMsgLen; i ++）
 {
 ch = getchar（）; 
 input + = ch; 
 
 
 
 response.append（{\echo \：）。append（input）.append（}）; 
 
 outMsgLen = response.length（）; 
 
 //发送4字节的数据长度
 std :: cout.write（（char *）& outMsgLen，4）; 
 
 //发送数据
 std :: cout<<响应; 
} 
 
返回0; 
} 
  
 
I am trying to use native messaging to send some data to my native windows application. It works well with the runtime.sendNativeMessage() method. When I am trying to use long lived connections which uses a port, it also can pass data from chrome to my app. However,  chrome extension can only receive the first response from my app. I am sure that the port is still open because my app can still receive data from chrome. Following are my code:


Chrome Extension Script:
var port = chrome.runtime.connectNative('com.mydomain.app1');

port.onMessage.addListener(function(msg) {
  console.log("Received from port:", msg);
});

port.onDisconnect.addListener(function() {
   console.log("Disconnected");
});

chrome.tabs.onUpdated.addListener(
   function(tabId, changeInfo, tab) {  
      var param = {};
      param['url'] = tab.url; 
      port.postMessage( param);   
   }
}
My windows app in c++:
int _tmain(int argc, _TCHAR* argv[])
{
    while( true )
    {
         //read the first four bytes (=> Length)
         unsigned int length = 0;
         for (int i = 0; i < 4; i++)
         {
              char c;
              if( ( c=getchar()) != EOF) 
                  length += c<<i*8;
              else return 0;
          }

          //read the json-message
          std::string msg = "";
          for (int i = 0; i < length; i++)
          {
              msg += getchar();
          } 

          //.... do something

          //send a response message
          std::string message = "{\"text\": \"This is a response message\"}";
          unsigned int len = message.length();
          // We need to send the 4 bytes of length information
          std::cout << char(((len>>0) & 0xFF))
                    << char(((len>>8) & 0xFF))
                    << char(((len>>16) & 0xFF))
                    << char(((len>>24) & 0xFF));
           // Now we can output our message
           std::cout << message.c_str();
           std::cout.flush();

     }
}   
Notice that the last line "std::cout.flush();", if I comment it out, even the first response won't be shown in chrome. I just couldn't figure out how chrome reads from the app's stdout.
解决方案
Try with automatic flushing - std::cout.setf( std::ios_base::unitbuf )

Also, the way you read/write the input/output messages length is incorrect and will fail on long messages.

This code works well for me:
int main(int argc, char* argv[])
{
    std::cout.setf( std::ios_base::unitbuf );

    while (true)
    {
        unsigned int ch, inMsgLen = 0, outMsgLen = 0;
        std::string input = "", response = "";

        // Read 4 bytes for data length
        std::cin.read((char*)&inMsgLen, 4);

        if (inMsgLen == 0)
        {
            break;
        }
        else
        {
            // Loop getchar to pull in the message until we reach the total length provided.
            for (int i=0; i < inMsgLen; i++)
            {
                ch = getchar();
                input += ch;
            }
        }

        response.append("{\"echo\":").append(input).append("}");

        outMsgLen = response.length();

        // Send 4 bytes of data length
        std::cout.write((char*)&outMsgLen, 4);

        // Send the data
        std::cout << response;
    }

    return 0;
}


                        
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