这是关于LearnYouNode的Node.js课程 这个挑战是：Juggling Async
这是我的代码：
var http = require('http')
var concat = require('concat-stream')
var urlHolder = [];
/*
function printResults()
{
for(var i = 0; i < 3; i++)
console.log(urlHolder[i]);
return;
}*/
function getURL(index) {
http.get(process.argv[2], function(err, response) {
if(err)
return console.error(err);
/*
response.pipe(concat(function (err, data) {
if(err)
return console.error(index);
urlHolder.push(data.toString());
if(index === 4)
{
printResults();
}
}))*/
})
}
getURL(9) //The 9 I'm putting as the parameter is random. It is just to pass to the function
/*
for(var index = 2; index < 5; index++){
getURL(index);
}*/
以下是我输入命令行的内容：
node juggleAsync.js http://www.google.com
我已经评论了大块的代码，试图调试它为什么返回err为true。起初，我认为这与我在命令行给出的参数上调用getURL的循环有关。
即使在评论出来之后，我仍然是错误的。我也尝试过不同的网站作为参数 - nada。希望有人可以帮我调试这段代码的精炼版本。
任何帮助将不胜感激。谢谢！
此外，因为我已经包含以下错误。这是非常长的，我不知道包括什么，不包括。我所理解的是，这就是吐出的东西。它超出了人物限制，所以我排出了一半身体。
node juggleAsync.js http://www.google.com
{ _readableState:
{ highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: false,
ended: false,
endEmitted: false,
reading: false,
calledRead: false,
sync: true,
needReadable: false,
emittedReadable: false,
readableListening: false,
objectMode: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events: { end: [Function: responseOnEnd] },
_maxListeners: 10,
socket:
{ _connecting: false,
_handle:
{ fd: 14,
writeQueueSize: 0,
owner: [Circular],
onread: [Function: onread],
reading: true },
_readableState:
{ highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: false,
ended: false,
endEmitted: false,
reading: true,
calledRead: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
objectMode: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
free: [Function],
close: [Object],
agentRemove: [Function],
drain: [Function: ondrain],
error: [Function: socketErrorListener] },
_maxListeners: 10,
_writableState:
{ highWaterMark: 16384,
objectMode: false,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
sync: false,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
buffer: [],
errorEmitted: false },
writable: true,
allowHalfOpen: false,
onend: [Function: socketOnEnd],
destroyed: false,
bytesRead: 1374,
_bytesDispatched: 64,
_pendingData: null,
_pendingEncoding: '',
parser:
{ _headers: [],
_url: '',
onHeaders: [Function: parserOnHeaders],
onHeadersComplete: [Function: parserOnHeadersComplete],
onBody: [Function: parserOnBody],
onMessageComplete: [Function: parserOnMessageComplete],
socket: [Circular],
incoming: [Circular],
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncomingClient] },
_httpMessage:
{ domain: null,
_events: {},
_maxListeners: 10,
output: [],
outputEncodings: [],
writable: true,
_last: true,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: false,
sendDate: false,
_headerSent: true,
_header: 'GET / HTTP/1.1\r\nHost: www.google.com\r\nConnection: keep-alive\r\n\r\n',
_hasBody: true,
_trailer: '',
finished: true,
_hangupClose: false,
socket: [Circular],
connection: [Circular],
agent: [Object],
socketPath: undefined,
method: 'GET',
path: '/',
_headers: [Object],
_headerNames: [Object],
parser: [Object],
res: [Circular] },
ondata: [Function: socketOnData] },
connection:
{ _connecting: false,
_handle:
{ fd: 14,
writeQueueSize: 0,
owner: [Circular],
onread: [Function: onread],
reading: true },
_readableState:
{ highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: false,
ended: false,
endEmitted: false,
reading: true,
calledRead: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
objectMode: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
free: [Function],
close: [Object],
agentRemove: [Function],
drain: [Function: ondrain],
error: [Function: socketErrorListener] },
_maxListeners: 10,
_writableState:
{ highWaterMark: 16384,
objectMode: false,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
sync: false,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
buffer: [],
errorEmitted: false },
writable: true,
allowHalfOpen: false,
onend: [Function: socketOnEnd],
destroyed: false,
bytesRead: 1374,
_bytesDispatched: 64,
_pendingData: null,
_pendingEncoding: '',
parser:
{ _headers: [],
_url: '',
onHeaders: [Function: parserOnHeaders],
onHeadersComplete: [Function: parserOnHeadersComplete],
onBody: [Function: parserOnBody],
onMessageComplete: [Function: parserOnMessageComplete],
socket: [Circular],
incoming: [Circular],
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncomingClient] },
_httpMessage:
{ domain: null,
_events: {},
_maxListeners: 10,
output: [],
outputEncodings: [],
writable: true,
_last: true,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: false,
sendDate: false,
_headerSent: true,
_header: 'GET / HTTP/1.1\r\nHost: www.google.com\r\nConnection: keep-alive\r\n\r\n',
_hasBody: true,
_trailer: '',
finished: true,
_hangupClose: false,
socket: [Circular],
connection: [Circular],
agent: [Object],
socketPath: undefined,
method: 'GET',
path: '/',
_headers: [Object],
_headerNames: [Object],
parser: [Object],
res: [Circular] },
ondata: [Function: socketOnData] },
httpVersion: '1.1',
complete: false,
headers:
{ date: 'Wed, 08 Oct 2014 02:57:46 GMT',
expires: '-1',
'cache-control': 'private, max-age=0',
'content-type': 'text/html; charset=ISO-8859-1',
'set-cookie':
[ 'PREF=ID=2d36a12041e95f4c:FF=0:TM=1412737066:LM=1412737066:S=DS6oLzPxyoZ6NZou; expires=Fri, 07-Oct-2016 02:57:46 GMT; path=/; domain=.google.com',
'NID=67=qj_qQhWU6YsBPYxf1szOnSENrlW_v27SkcoLTwXh-cRWB3MOtSfYX_v-ldvLCS06x4iMQ-7SJBTFhIMb8yR7lTso8dqAsvub0NJyZghv_xzpRI9YT0_c6rkSM_NmjeTG; expires=Thu, 09-Apr-2015 02:57:46 GMT; path=/; domain=.google.com; HttpOnly' ],
p3p: 'CP="This is not a P3P policy! See http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info."',
server: 'gws',
'x-xss-protection': '1; mode=block',
'x-frame-options': 'SAMEORIGIN',
'alternate-protocol': '80:quic,p=0.01',
'transfer-encoding': 'chunked' },
trailers: {},
_pendings: [],
_pendingIndex: 0,
url: '',
method: null,
statusCode: 200,
client:
{ _connecting: false,
_handle:
{ fd: 14,
writeQueueSize: 0,
owner: [Circular],
onread: [Function: onread],
reading: true },
_readableState:
{ highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: false,
ended: false,
endEmitted: false,
reading: true,
calledRead: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
objectMode: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
free: [Function],
close: [Object],
agentRemove: [Function],
drain: [Function: ondrain],
error: [Function: socketErrorListener] },
_maxListeners: 10,
_writableState:
{ highWaterMark: 16384,
objectMode: false,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
sync: false,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
buffer: [],
errorEmitted: false },
writable: true,
allowHalfOpen: false,
onend: [Function: socketOnEnd],
destroyed: false,
bytesRead: 1374,
_bytesDispatched: 64,
_pendingData: null,
_pendingEncoding: '',
parser:
{ _headers: [],
_url: '',
onHeaders: [Function: parserOnHeaders],
onHeadersComplete: [Function: parserOnHeadersComplete],
onBody: [Function: parserOnBody],
onMessageComplete: [Function: parserOnMessageComplete],
socket: [Circular],
incoming: [Circular],
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncomingClient] },
_httpMessage:
{ domain: null,
_events: {},
_maxListeners: 10,
output: [],
outputEncodings: [],
writable: true,
_last: true,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: false,
sendDate: false,
_headerSent: true,
_header: 'GET / HTTP/1.1\r\nHost: www.google.com\r\nConnection: keep-alive\r\n\r\n',
_hasBody: true,
_trailer: '',
finished: true,
_hangupClose: false,
socket: [Circular],
connection: [Circular],
agent: [Object],
socketPath: undefined,
method: 'GET',
path: '/',
_headers: [Object],
_headerNames: [Object],
parser: [Object],
res: [Circular] },
ondata: [Function: socketOnData] },
_consuming: false,
_dumped: false,
httpVersionMajor: 1,
httpVersionMinor: 1,
upgrade: false,
req:
{ domain: null,
_events: {},
_maxListeners: 10,
output: [],
outputEncodings: [],
writable: true,
_last: true,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: false,
sendDate: false,
_headerSent: true,
_header: 'GET / HTTP/1.1\r\nHost: www.google.com\r\nConnection: keep-alive\r\n\r\n',
_hasBody: true,
_trailer: '',
finished: true,
_hangupClose: false,
socket:
{ _connecting: false,
_handle: [Object],
_readableState: [Object],
readable: true,
domain: null,
_events: [Object],
_maxListeners: 10,
_writableState: [Object],
writable: true,
allowHalfOpen: false,
onend: [Function: socketOnEnd],
destroyed: false,
bytesRead: 1374,
_bytesDispatched: 64,
_pendingData: null,
_pendingEncoding: '',
parser: [Object],
_httpMessage: [Circular],
ondata: [Function: socketOnData] },
connection:
{ _connecting: false,
_handle: [Object],
_readableState: [Object],
readable: true,
domain: null,
_events: [Object],
_maxListeners: 10,
_writableState: [Object],
writable: true,
allowHalfOpen: false,
onend: [Function: socketOnEnd],
destroyed: false,
bytesRead: 1374,
_bytesDispatched: 64,
_pendingData: null,
_pendingEncoding: '',
parser: [Object],
_httpMessage: [Circular],
ondata: [Function: socketOnData] },
agent:
{ domain: null,
_events: [Object],
_maxListeners: 10,
options: {},
requests: {},
sockets: [Object],
maxSockets: 5,
createConnection: [Function] },
socketPath: undefined,
method: 'GET',
path: '/',
_headers: { host: 'www.google.com' },
_headerNames: { host: 'Host' },
parser:
{ _headers: [],
_url: '',
onHeaders: [Function: parserOnHeaders],
onHeadersComplete: [Function: parserOnHeadersComplete],
onBody: [Function: parserOnBody],
onMessageComplete: [Function: parserOnMessageComplete],
socket: [Object],
incoming: [Circular],
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncomingClient] },
res: [Circular] } }
答案 0 :(得分：0)
http.get返回一个响应对象，通过错误事件捕获错误：
http.get("http://www.google.com/index.html", function(res) {
console.log("Got response: " + res.statusCode);
}).on('error', function(e) {
console.log("Got error: " + e.message);
});
所以你的代码每次都会完美执行，除非你调用响应“错误”。
将function(err, response)更改为：function(response)
另外，对于评论部分，
res.pipe(concat(function (data) {
//
}));
res.on("error", callback);
答案 1 :(得分：0)
http.get的回调只获得一个参数，它是响应：
http.get("http://www.google.com/index.html", function(res) {
console.log("Got response: " + res.statusCode);
}).on('error', function(e) {
console.log("Got error: " + e.message);
});