我尝试在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-scraperhttp://anismiles.wordpress.com/2010/11/29/node-js-and-jquery-to-scrape-websites/
服务器启动正常,但是当我在上面运行查询时,我得到以下错误。有人知道为什么吗?
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)
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));
});
}
更新
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)
3条答案
按热度按时间bq9c1y661#
想到的唯一解释是所需的模块不是EventEmmiter示例。因此,它没有“on”方法。
8oomwypt2#
这个bug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
从searcher.js
扩展而来,因此它们也继承自EventEmitter
。1.'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,因此缺少方法'on'。xuo3flqw3#
您正在尝试在模块而不是EventEmitter上设置侦听器。
require('./searcher-rediff');
返回Javascript模块。我想在searcher-rediff
模块中实际上有一个对象,它就是您要查找的EventEmitter。查看
searcher-rediff.js
代码,查看EventEmitter定义和导出的位置,然后需要引用它。最后你可能会得到这样的东西...