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我只是在学习mongojs和nodejs,所以我仍然试图习惯编程异步。我的程序应该做的是从一个文件('list')获取输入,读取每行并将行传递给解析函数,该函数将数据写入文件并将数据写入数据库。终止在回调中的mongodb连接
这里是我的index.js:
var read_list = require('./read_list').read_list;
var parse = require('./parse');
var databaseUrl = "mydb";
var collections = ["patents"]
var db = require("mongojs").connect(databaseUrl, collections);
read_list(filename, array, parse, database, function(err) {
if(err) throw err;
db.close();
});
read_list.js:
var fs = require('fs');
var tmp = "http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1="
function read_list(file_name, pat_array, parse, db) {
fs.readFile(file_name, function(err, data) {
if(err) throw err;
else {
pat_array = data.toString().split("\n");
for(var i = 0; i < pat_array.length; i++) {
parse(tmp+pat_array[i]+".PN.&OS=PN/"+pat_array[i]+"&RS=PN/"+pat_array[i], pat_array[i], db);
}
}
});
}
exports.read_list = read_list
最后parse.js:
var fs = require('fs');
var cheerio = require('cheerio');
var request = require('request');
function parse(url, filename, db) {
request(url, function(err, response, body) {
if (err)
throw err;
body = body.substring(body.indexOf("United States Patent", 43), body.indexOf("* * * * *"));
$ = cheerio.load(body);
var elems = new Array();
$("TD").each(function() {
if($(this).text())
{
elems.push($(this).text().trim());
}
})
var pat_title = $("font").text().trim();
var pat_abs = $("P").first().text().trim();
var pat_num = elems[0];
var pat_auth = elems[1];
var pat_date = elems[2];
var temp = "Title: " + pat_title + "\nNumber: " + pat_num + "\nAuthor: " + pat_auth + "\nDate: " + pat_date + "\nAbstract: " + pat_abs;
db.patents.save(
{
_id: filename.trim(),
Title: pat_title,
Number: pat_num,
Author: pat_auth,
Date: pat_date,
Abstract: pat_abs
},
function(err, saved)
{
if(err || !saved) console.log("Patent not saved");
else console.log("Patent saved");
});
fs.writeFile(filename.trim(), temp, function(err) {
if(err) {
console.log(err);
} else {
console.log("The file was saved!");
}
});
});
}
exports.parse = parse;
希望这是有道理的,是可读的,我的第一篇文章。
一切都按我期望的那样执行,除了程序不会终止(必须用ctrl + c来完成)。我怎样才能改变程序,所以我可以在回调中关闭连接,或者我错过了这一点,并以错误的方式去做这件事?
我意识到我的问题是什么。我需要在被调用的函数中有一个回调参数,然后在函数完成时调用它。尽管谢谢你的回答! – Monkeyulize