Reading XML file in Node.js

Question

I'm learning how to use Node. At this time, I have an XML file that looks like this:

sitemap.xml

<?xml version="1.0" encoding="utf-8"?>

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
  <url>
    <loc>http://www.example.com</loc>
    <lastmod>2015-10-01</lastmod>
    <changefreq>monthly</changefreq>
  </url>

  <url>
    <loc>http://www.example.com/about</loc>
    <lastmod>2015-10-01</lastmod>
    <changefreq>never</changefreq>
  </url>

  <url>
    <loc>http://www.example.com/articles/tips-and-tricks</loc>
    <lastmod>2015-10-01</lastmod>
    <changefreq>never</changefreq>
    <article:title>Tips and Tricks</blog:title>
    <article:description>Learn some of the tips-and-tricks of the trade</article:description>
  </url>
</urlset>

I am trying to load this XML in my Node app. When loaded, I want to only get the url elements that include the use of the <article: elements. At this time, I'm stuck though. Right now, I'm using XML2JS via the following:

var parser = new xml2js.Parser();
fs.readFile(__dirname + '/../public/sitemap.xml', function(err, data) {
    if (!err) {
        console.log(JSON.stringify(data));
    }
});

When the console.log statement is executed, I just see a bunch of numbers in the console window. Something like this:

{"type":"Buffer","data":[60,63,120, ...]}

What am I missing?

Any other reason to convert it to JSON? Using XMLDOM, XPAth for node since you know it's XML and can use XPath would be another route to consider. — Marvin Smit
– Marvin Smit, Commented Dec 12, 2019 at 23:05

Sajith Mantharath · Accepted Answer · 2017-02-02 06:44:38Z

51

use xml2json

https://www.npmjs.com/package/xml2json

fs = require('fs');
var parser = require('xml2json');

fs.readFile( './data.xml', function(err, data) {
    var json = parser.toJson(data);
    console.log("to json ->", json);
 });

answered Feb 2, 2017 at 6:44

Sajith Mantharath

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5 Comments

Alex Goncharenko Over a year ago

Small heads-up for everyone looking into XML-to-JSON transformations: xml2json library indeed worked much better for me rather than xml2js.

Sandburg Over a year ago

An other lib such as xml-js is able to convert in both directions. It's not when you will need this that you can. Because the inner representation in javascript is always specific in such libs. (xml -> javascript -> proper json)

BradGreens Over a year ago

It's worth noting that parse.toJson(data) returns a JSON string. If you want to access the results of parse.toJson(data) as a Javascript object you need to take one more step by calling JSON.parse. const json = JSON.parse(parser.toJson(data)); gives you a primitive object so you can do console.log(json.myPropertyKey).

user24950814234 Over a year ago

xml2json requires Python, no thanks.

letie Over a year ago

xml2json is no longer maintained. and as @user2867288 says, it uses python...

Quentin · Accepted Answer · 2015-09-30 18:23:22Z

18

From the documentation.

The callback is passed two arguments (err, data), where data is the contents of the file.

If no encoding is specified, then the raw buffer is returned.

If options is a string, then it specifies the encoding. Example:
fs.readFile('/etc/passwd', 'utf8', callback);

You didn't specify an encoding, so you get the raw buffer.

answered Sep 30, 2015 at 18:23

Quentin

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Comments

chrisbyte · Accepted Answer · 2020-04-16 13:33:47Z

@Sandburg mentioned xml-js in a comment and it worked best for me (several years after this question was asked). The others I tried were: xml2json which required some Windows Sdk that I did not want to deal with, and xml2js that did not provide an easy enough OTB way to search through attributes.

I had to pull out a specific attribute in an xml file 3 nodes deep and xml-js did it with ease.

https://www.npmjs.com/package/xml-js

With the following example file stats.xml

<stats>
  <runs>
    <latest date="2019-12-12" success="100" fail="2" />
    <latest date="2019-12-11" success="99" fail="3" />
    <latest date="2019-12-10" success="102" fail="0" />
    <latest date="2019-12-09" success="102" fail="0" />
  </runs>
</stats>

I used xml-js to find the element /stats/runs/latest with attribute @date='2019-12-12' like so

const convert = require('xml-js');
const fs = require('fs');

// read file
const xmlFile = fs.readFileSync('stats.xml', 'utf8');

// parse xml file as a json object
const jsonData = JSON.parse(convert.xml2json(xmlFile, {compact: true, spaces: 2}));

const targetNode = 

    // element '/stats/runs/latest'
    jsonData.stats.runs.latest

    .find(x => 

        // attribute '@date'
        x._attributes.date === '2019-12-12'
    );

// targetNode has the 'latest' node we want
// now output the 'fail' attribute from that node
console.log(targetNode._attributes.fail);  // outputs: 2

Nate · Accepted Answer · 2019-08-14 23:04:26Z

5

fs.readFile has an optional second parameter: encoding. If you do not include this parameter it will automatically return you a Buffer object.

https://nodejs.org/api/fs.html#fs_fs_readfile_filename_options_callback

If you know the encoding just use:

fs.readFile(__dirname + '/../public/sitemap.xml', 'utf8', function(err, data) {
    if (!err) {
        console.log(data);
    }
});

edited Aug 14, 2019 at 23:04

answered Sep 30, 2015 at 18:23

Nate

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3 Comments

rollingcodes Over a year ago

your parser variable is never used?

Nate Over a year ago

The parser variable was from the original question, I did not know how it was intended to be used from their code. Removed.

mewc Over a year ago

I was spending a bit of time trying to turn an xml into a string, but this is the better option. Alternatively use readFileSync()

mewc · Accepted Answer · 2021-02-21 22:22:14Z

4

For an express server:

  app.get('/api/rss/', (_request: Request, response: Response) => {
    const rssFile = fs.readFileSync(__dirname + '/rssFeeds/guardian.xml', { encoding: 'utf8' })

    console.log('FILE', rssFile)

    response.set('Content-Type', 'text/xml')
    response.send(rssFile)
  })

Take request
Read File
Set xml header
Return file

answered Feb 21, 2021 at 22:22

mewc

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Comments

TheChetan · Accepted Answer · 2023-07-11 04:33:42Z

4

Install xml2js using: npm install xml2js --save.

const xml2js = require('xml2js');
const fs = require('fs');
const parser = new xml2js.Parser({ attrkey: "ATTR" });

// this example reads the file synchronously
// you can read it asynchronously also
let xml_string = fs.readFileSync("data.xml", "utf8");

parser.parseString(xml_string, function(error, result) {
  if (error === null) {
    console.log(result);
  } else {
    console.log(error);
  }
});

edited Jul 11, 2023 at 4:33

TheChetan

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answered Aug 10, 2020 at 11:38

Reaper

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Comments

Atul Kr Dey · Accepted Answer · 2018-06-05 04:22:39Z

You can try this

npm install express-xml-bodyparser --save

at Client side:-

 $scope.getResp = function(){
     var posting = $http({
           method: 'POST',
           dataType: 'XML',
           url: '/getResp/'+$scope.user.BindData,//other bind variable
           data: $scope.project.XmlData,//xmlData passed by user
           headers: {
              "Content-Type" :'application/xml'
            },
           processData: true
           });
       posting.success(function(response){
       $scope.resp1 =  response;
       });
   };

on Server side:-

xmlparser = require('express-xml-bodyparser');
app.use(xmlparser());
app.post('/getResp/:BindData', function(req, res,next){
  var tid=req.params.BindData;
  var reqs=req.rawBody;
  console.log('Your XML '+reqs);
});

Daphoque · Accepted Answer · 2017-08-08 17:18:19Z

You can also use regex before parsing to remove elements not matching your conditions :

var parser = new xml2js.Parser();
fs.readFile(__dirname + '/../public/sitemap.xml', "utf8",function(err, data) {
    // handle err...

    var re = new RegExp("<url>(?:(?!<article)[\\s\\S])*</url>", "gmi")
    data = data.replace(re, ""); // remove node not containing article node
    console.log(data);
    //... parse data ...



});

Example :

   var str = "<data><url><hello>abc</hello><moto>abc</moto></url><url><hello>bcd</hello></url><url><hello>efd</hello><moto>poi</moto></url></data>";
   var re = new RegExp("<url>(?:(?!<moto>)[\\s\\S])*</url>", "gmi")
   str = str.replace(re, "")

   // "<data><url><hello>abc</hello><moto>abc</moto></url><url><hello>efd</hello><moto>poi</moto></url></data>"

Chad Campbell · Accepted Answer · 2016-02-17 14:56:44Z

0

In order to read an XML file in Node, I like the XML2JS package. This package lets me easily work with the XML in JavaScript then.

var parser = new xml2js.Parser();       
parser.parseString(fileData.substring(0, fileData.length), function (err, result) {
  var json = JSON.stringify(result);
});

answered Feb 17, 2016 at 14:56

Chad Campbell

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1 Comment

TacB0sS Over a year ago

This module is too limited... can't event handle nested nodes, and returns nodes with the same tag in an array regardless of their order... WTF?

KuN · Accepted Answer · 2017-01-18 23:24:43Z

0

coming late to this thread, just to add one simple tip here, if you plan to use parsed data in js or save it as json file, be sure to set explicitArray to false. The output will be more js-friendly

so it will look like,
letparser=newxml2js.Parser({explicitArray:false})

Ref: https://github.com/Leonidas-from-XIV/node-xml2js

answered Jan 18, 2017 at 23:24

KuN

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Comments

Cleardd · Accepted Answer · 2023-08-07 00:43:36Z

I like to use xml-js

var fs = require('fs');
var convert = require('xml-js');
var xml =
'<?xml version="1.0" encoding="utf-8"?>' +
'<note importance="high" logged="true">' +
'    <title>Happy</title>' +
'    <todo>Work</todo>' +
'    <todo>Play</todo>' +
'</note>';
fs.writeFileSync(`./file.xml`,xml);
var result1 = convert.xml2js(fs.readFileSync(`./file.xml`).toString());
console.log(JSON.stringify(result1,null,4));
/*
{
    "declaration": {
        "attributes": {
            "version": "1.0",
            "encoding": "utf-8"
        }
    },
    "elements": [
        {
            "type": "element",
            "name": "note",
            "attributes": {
                "importance": "high",
                "logged": "true"
            },
            "elements": [
                {
                    "type": "element",
                    "name": "title",
                    "elements": [
                        {
                            "type": "text",
                            "text": "Happy"
                        }
                    ]
                },
                {
                    "type": "element",
                    "name": "todo",
                    "elements": [
                        {
                            "type": "text",
                            "text": "Work"
                        }
                    ]
                },
                {
                    "type": "element",
                    "name": "todo",
                    "elements": [
                        {
                            "type": "text",
                            "text": "Play"
                        }
                    ]
                }
            ]
        }
    ]
}

*/

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