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NodeJS: 一起代码引发的杯具

热度:1162   发布时间:2013-12-16 23:49:16.0
NodeJS: 一行代码引发的杯具

这几天有点儿小空,寻思着看看Node JS 方面的东东。

在网上东搜搜西搜搜,找到如下网站:

http://www.nodebeginner.org/index-zh-cn.html

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主题是node 入门。

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于是乎就照着上面的代码敲下来, 一路行来倒是没有怎么遇到困难。

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唯独最后在引入fs 模块和 formidable模块尝试完成文件上传功能时,出问题了。

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报错如下:

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?fs.renameSync(files.upload.path, "C:/sap/java/nodejs/examples/testUpload/test.png"

? ? ? ? ? ? ? ? ? ? ? ? ? ? ?^ ? ? ? ? ? ? ? ? ? ??

TypeError: Cannot read property 'path' of undefined

? ? at c:\sap\java\nodejs\examples\hello\requestHandlers.js:30:30

? ? at IncomingForm.<anonymous> (c:\sap\java\nodejs\examples\hello\node_modules\

formidable\lib\incoming_form.js:89:9)

? ? at IncomingForm.EventEmitter.emit (events.js:95:17)

? ? at IncomingForm._error (c:\sap\java\nodejs\examples\hello\node_modules\formi

dable\lib\incoming_form.js:272:8)

? ? at IncomingMessage.<anonymous> (c:\sap\java\nodejs\examples\hello\node_modul

es\formidable\lib\incoming_form.js:119:14)

? ? at IncomingMessage.EventEmitter.emit (events.js:92:17)

? ? at _stream_readable.js:920:16

? ? at process._tickCallback (node.js:415:13)

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我的代码如下

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server.js

var http = require("http");

var url = require("url");

//var formidable = require("formidable");

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function start(route,handle) {

http.createServer(function(request, response){

var postData="";

var pathName = url.parse(request.url).pathname;

console.log("Request for " + pathName + " received");

request.setEncoding("utf8");

route(handle, pathName, response, request);

}).listen(8081);

console.log("Server has started");

}

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exports.start = start;

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requestHandlers.js:

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var queryString = require("querystring");

var formidable = require("formidable");

var fs = require("fs");

function start(response, request) {

console.log("Request handler 'start' is called");

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var content = '<html>' +

'<head>' +

'<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />' +

'</head>' +

'<body>' +

'<form action="/upload" enctype="multipart/form-data" method="post">' +

'<input type="file" name="upload"/>' +

'<input type="submit" value="Upload file" />' +

'</form>' +

'</body>' +

'</html>';

response.writeHead(200,{"Content-Type": "Text/html"});

response.write(content);

response.end();

}

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function upload(response, request) {

console.log("Request handler 'upload' is called");

var form = new formidable.IncomingForm();

console.log("About to parse");

form.parse(request, function(error, fields, files) {

console.log("parse done");

//try{

fs.renameSync(files.upload.path, "C:/sap/java/nodejs/examples/testUpload/test.png");

/*}catch(e){

console.log(e);

}*/

response.writeHead(200, {"Content-Type": "text/html"});

response.write("received image:<br/>");

response.write("<image src='/show' />");

response.end();

});

}

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function show(response, request) {

console.log("Requset handler 'show' is called");

fs.readFile("C:/sap/java/nodejs/examples/testUpload/test.png", "binary", function(error, file) {

if(error) {

response.writeHead(500, {"Content-Type": "text/plain"});

response.write(error + "\n");

response.end();

}else{

response.writeHead(200, {"Content-Type": "image/png"});

response.write(file, "binary");

response.end();

}

});

}

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exports.start = start;

exports.upload = upload;

exports.show = show;

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route.js:

?function route(handle, pathName, response, request) {

console.log("About to route a request for " + pathName);

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if(typeof(handle[pathName])==='function'){

return handle[pathName](response, request);

}else{

console.log("No request handler found for " + pathName);

response.writeHead(404,{"Content-Type": "Text/Plain"});

response.write("404 Not Found");

response.end();

}

}

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exports.route = route;

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index.js:

var server = require("./server.js");

var route = require("./router.js");

var requestHandlers = require("./requestHandlers.js");

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var handle = {};

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handle['/'] = requestHandlers.start;

handle['/start'] = requestHandlers.start;

handle['/upload'] = requestHandlers.upload;

handle['/show'] = requestHandlers.show;

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server.start(route.route, handle);

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?看到server.js中的红色高亮的那一行,去掉就一切OK了。。。

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因为request.setEncoding 这部分node-formidable自身会处理,在这个地方手动给设置一下貌似会有冲突,从而导致出错。

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另外,值得注意的两点,在requestHandlers.js中,

1.由于我的开发环境是:win7 64, 在fs.parse 和 fs.readFile的路径参数中,我都是直接给出的是绝对路径。

? 相对路径没有试过。

2.对应路径下的文件夹必须要存在(fs.renameSync 和 fs.readFile不会自动创建文件夹),否则还是会报错如下:

? fs.js:543

? return binding.rename(pathModule._makeLong(oldPath),

? ? ? ? ? ? ? ? ?^

Error: ENOENT, no such file or directory 'X:\...\ddcdf999d6b56cb30716f43e528e7eeb'

? ? at Object.fs.renameSync (fs.js:543:18)

? ? at c:\sap\java\nodejs\examples\hello\requestHandlers.js:30:7

? ? at IncomingForm.<anonymous> (c:\sap\java\nodejs\examples\hello\node_modules\

formidable\lib\incoming_form.js:92:9)

? ? at IncomingForm.EventEmitter.emit (events.js:92:17)

? ? at IncomingForm._maybeEnd (c:\sap\java\nodejs\examples\hello\node_modules\fo

rmidable\lib\incoming_form.js:533:8)

? ? at c:\sap\java\nodejs\examples\hello\node_modules\formidable\lib\incoming_fo

rm.js:211:12

? ? at WriteStream.<anonymous> (c:\sap\java\nodejs\examples\hello\node_modules\f

ormidable\lib\file.js:70:5)

? ? at WriteStream.g (events.js:175:14)

? ? at WriteStream.EventEmitter.emit (events.js:117:20)

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? ? at finishMaybe (_stream_writable.js:354:12)

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貌似有不少新人在做这个例子的时候都遇到了类似的问题, 如下两个网站中的楼主貌似也都是类似的问题:

http://cnodejs.org/topic/50234890f767cc9a51f88481

http://cnodejs.org/topic/4f2b9a04aa8e490b110bfae2