Terminate mongodb connection in a callback

Question

I'm just learning mongojs and nodejs so I'm still trying to get used to programming asynchronously. What my program should do is take input from a file ('list'), read each line and pass the line to a parse function which writes data to a file and writes data to the database.

Here is my 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

And finally 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;

Hopefully that makes sense and is readable, my first post here.

Everything executes as I expect it to, except the program will not terminate (must do it with ctrl+c). How can I change the program so I can close the connection in a callback, or am I missing the point and going about this the wrong way?

score 0 · Answer 1 · answered Jul 01 '13 at 22:03

0

It looks like you have db.close() being called if an error happens but you don't call it after you're done with the connection.

While nodejs has active connections or is waiting for connections on a port/socket it will stay running.

Hope this helps!

answered Jul 01 '13 at 22:03

John Steel

324
1
7

I realized what my problem was. I need to have a callback parameter in my called function and then call it when the function is done. Thanks for the answer though! – Monkeyulize Jul 02 '13 at 18:29

Terminate mongodb connection in a callback

1 Answers1