我四处寻找,要么找不到我想要回答的确切问题,要么我需要有人像我5岁一样向我解释。
基本上,我有一个使用Net库的Node.js脚本。我正在连接多个主机,发送命令,并侦听返回数据。
var net = require('net');
var nodes = [
'HOST1,192.168.179.8',
'HOST2,192.168.179.9',
'HOST3,192.168.179.10',
'HOST4,192.168.179.11'
];
function connectToServer(tid, ip) {
var conn = net.createConnection(23, ip);
conn.on('connect', function() {
conn.write (login_string); // login string hidden in pretend variable
});
conn.on('data', function(data) {
var read = data.toString();
if (read.match(/Login Successful/)) {
console.log ("Connected to " + ip);
conn.write(command_string);
}
else if (read.match(/Command OK/)) { // command_string returned successful,
// read until /rnENDrn/
// First part of data comes in here
console.log("Got a response from " + ip + ':' + read);
}
else {
//rest of data comes in here
console.log("Atonomous message from " + ip + ':' + read);
}
});
conn.on('end', function() {
console.log("Lost conncection to " + ip + "!!");
});
conn.on('error', function(err) {
console.log("Connection error: " + err + " for ip " + ip);
});
}
nodes.forEach(function(node) {
var nodeinfo = node.split(",");
connectToServer(nodeinfo[0], nodeinfo[1]);
});
数据最终被分成两块。即使我将数据存储在哈希中,并在读取/\r\nEND\r\n/分隔符时将第一部分附加到余数,中间也会缺少一个块。如何正确缓冲数据以确保从流中获得完整的消息?
编辑:好的,这似乎效果更好:
function connectToServer(tid, ip) {
var conn = net.createConnection(23, ip);
var completeData = '';
conn.on('connect', function() {
conn.write (login_string);
});
conn.on('data', function(data) {
var read = data.toString();
if (read.match(/Login Successful/)) {
console.log ("Connected to " + ip);
conn.write(command_string);
}
else {
completeData += read;
}
if (completeData.match(/Command OK/)) {
if (completeData.match(/rnENDrn/)) {
console.log("Response: " + completeData);
}
}
});
conn.on('end', function() {
console.log("Connection closed to " + ip );
});
conn.on('error', function(err) {
console.log("Connection error: " + err + " for ip " + ip);
});
}
我最大的问题显然是逻辑错误。我要么在等待开始回复的大块,要么在等待结束回复的大块。
我想,如果我想了解它的所有节点信息,我应该在收到完整消息时触发一个事件(以空行开始,单独一行以"END"结束),并在那里进行处理。
在收到结束事件之前,不应该对收到的数据执行任何操作。结束回调意味着所有数据块都已通过流发送到回调。如果数据出现在多个区块中,则需要在函数闭包中创建一个变量来存储这些数据。忽略这一事实,大多数程序都可以正常工作,因为数据通常出现在一个区块中。但有时情况并非如此。它甚至不一定取决于数据量。如果你正处于这种情况下,我创建了一个示例来演示如何处理它。我基本上使用了你的代码,但删除了所有的错误。。。这只是演示您需要收集所有数据并对其进行处理的逻辑。
function connectToServer(tid, ip) {
var conn = net.createConnection(23, ip);
var completeData = '';
conn.on('connect', function() {
conn.write (login_string); // login string hidden in pretend variable
});
conn.on('data', function(data) {
completeData += data;
var dataArray = completeData.split('your delimiter');
if(dataArray.size > 1) { //If our data was split into several pieces, we have a complete chunk saved in the 0th position in the array
doWorkOnTheFirstHalfOfData(dataArray[0]);
completeData = dataArray[1];// The second portion of data may yet be incomplete, thise may need to be more complete logic if you can get more than one delimeter at a time...
}
});
conn.on('end', function() {
//do stuff with the "completeData" variable in here.
});
}
我的问题是一个逻辑问题。我要么在寻找开始消息的区块,要么在寻找结束消息的区块。我想我预计整个回复会分成一两块。
这是从上面粘贴的工作代码。可能有一种更像Node的方法(我真的应该为每一块信息发出一个事件),但我会把它标记为答案,除非明天这个时候有人发布更好的版本。
function connectToServer(tid, ip) {
var conn = net.createConnection(23, ip);
var completeData = '';
conn.on('connect', function() {
conn.write (login_string);
});
conn.on('data', function(data) {
var read = data.toString();
if (read.match(/Login Successful/)) {
console.log ("Connected to " + ip);
conn.write(command_string);
}
else {
completeData += read;
}
if (completeData.match(/Command OK/)) {
if (completeData.match(/rnENDrn/)) {
console.log("Response: " + completeData);
}
}
});
conn.on('end', function() {
console.log("Connection closed to " + ip );
});
conn.on('error', function(err) {
console.log("Connection error: " + err + " for ip " + ip);
});
}