奇怪的 node.js 错误:TypeError: Object #
我正在尝试在 node.js 中运行一个简单的屏幕抓取应用程序。代码发布在这里: https://github.com/anismiles/jsdom-based-screen-scraper http://anismiles.wordpress。 com/2010/11/29/node-js-and-jquery-to-scrape-websites/
服务器启动正常,但是当我对其运行查询时,出现以下错误。有谁知道这是为什么?
TypeError: Object #<Object> has no method 'on'
at Object.<anonymous> (/Users/avishai/Downloads/anismiles-jsdom-based-screen-scraper-f0c79d3/searcher-server.js:9:10)
at param (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:146:21)
at param (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:157:15)
at pass (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:162:10)
at Object.router [as handle] (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:168:6)
at next (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/index.js:218:15)
at Server.handle (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/index.js:231:3)
at Server.emit (events.js:45:17)
at HTTPParser.onIncoming (http.js:1078:12)
at HTTPParser.onHeadersComplete (http.js:87:31)
似乎抛出错误的函数是:
function books(app){
app.get('/:query', function(req, res, next) {
res.writeHead(200, { 'Content-Type': 'text/html' });
var rediff = require('./searcher-rediff');
rediff.on('on_book', function(item){
res.write(item + "<br/>");
});
rediff.on('completed', function(){
res.end();
});
rediff.search(escape(req.params.query));
});
}
UPDATE
现在我注意到在第一个请求中,我得到了这个:
SyntaxError: Unexpected strict mode reserved word
at Module._compile (module.js:369:25)
at Object..js (module.js:380:10)
at Module.load (module.js:306:31)
at Function._load (module.js:272:10)
at require (module.js:318:19)
at Object.<anonymous> (/Users/avishai/Downloads/anismiles-jsdom-based-screen-scraper-f0c79d3/searcher.js:2:15)
at Module._compile (module.js:374:26)
at Object..js (module.js:380:10)
at Module.load (module.js:306:31)
at Function._load (module.js:272:10)
I'm trying to run a simple screen scraping app in node.js. The code is posted here:
https://github.com/anismiles/jsdom-based-screen-scraper
http://anismiles.wordpress.com/2010/11/29/node-js-and-jquery-to-scrape-websites/
The server starts up fine, but then when I run a query on it, I get the following error. Does anyone know why that is?
TypeError: Object #<Object> has no method 'on'
at Object.<anonymous> (/Users/avishai/Downloads/anismiles-jsdom-based-screen-scraper-f0c79d3/searcher-server.js:9:10)
at param (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:146:21)
at param (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:157:15)
at pass (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:162:10)
at Object.router [as handle] (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:168:6)
at next (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/index.js:218:15)
at Server.handle (/Users/avishai/.node_libraries/.npm/connect/0.5.10/package/lib/connect/index.js:231:3)
at Server.emit (events.js:45:17)
at HTTPParser.onIncoming (http.js:1078:12)
at HTTPParser.onHeadersComplete (http.js:87:31)
The function that appears to be throwing the error is:
function books(app){
app.get('/:query', function(req, res, next) {
res.writeHead(200, { 'Content-Type': 'text/html' });
var rediff = require('./searcher-rediff');
rediff.on('on_book', function(item){
res.write(item + "<br/>");
});
rediff.on('completed', function(){
res.end();
});
rediff.search(escape(req.params.query));
});
}
UPDATE
Now I noticed that on the first request, I get this:
SyntaxError: Unexpected strict mode reserved word
at Module._compile (module.js:369:25)
at Object..js (module.js:380:10)
at Module.load (module.js:306:31)
at Function._load (module.js:272:10)
at require (module.js:318:19)
at Object.<anonymous> (/Users/avishai/Downloads/anismiles-jsdom-based-screen-scraper-f0c79d3/searcher.js:2:15)
at Module._compile (module.js:374:26)
at Object..js (module.js:380:10)
at Module.load (module.js:306:31)
at Function._load (module.js:272:10)
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我想到的唯一解释是所需的模块不是 EventEmmiter 实例。因此,它没有“on”方法。
The only explanation that comes to mind is that the required module is not an EventEmmiter instance. Therefore, it does not have an 'on' method.
此错误背后的根本原因应该与
EventEmittter
有关。请允许我解释一下,searcher.js
继承自EventEmitter
(第 26 行)
Searcher.prototype = new process.EventEmitter
;searcher-rediff.js
、searcher-flipkart.js
和searcher-landmarkonthenet.js
扩展自searcher.js< /code>,因此它们也继承自
EventEmitter
。'on'方法实际上是在
EventEmitter
中定义的。因此,我认为,由于某种原因,
searcher.js
无法从EventEmitter
继承,因此缺少“on”方法。Fundamental reason behind this bug should be something to do with the
EventEmittter
. Allow me to explain,searcher.js
inherits fromEventEmitter
(Line-26)
Searcher.prototype = new process.EventEmitter
;searcher-rediff.js
,searcher-flipkart.js
andsearcher-landmarkonthenet.js
extend fromsearcher.js
, so they also inherit fromEventEmitter
.‘on’ method is actually defined in
EventEmitter
.So, I think, for some reason,
searcher.js
is not able to inherit fromEventEmitter
and hence the method ‘on’ is missing.您正在尝试在模块上设置侦听器而不是 EventEmitter。
require('./searcher-rediff');
返回一个 Javascript 模块。我想在searcher-rediff
模块中实际上有一个对象,它就是您正在寻找的 EventEmitter。查看
searcher-rediff.js
代码以查看定义和导出 EventEmitter 的位置,然后您需要引用它。最后你可能会得到类似的结果......
You are trying to setup a listener on a module instead of an EventEmitter.
require('./searcher-rediff');
returns a Javascript module. I imagine there is actually an object in thesearcher-rediff
module that is the EventEmitter you are looking for.Look through the
searcher-rediff.js
code to see where an EventEmitter is defined and exported, then you'll need to reference that.In the end you'll probably end up with something like...