Parse XML Feed via Google Apps Script (Cannot read property 'getChildren' of undefined")

Question

I need to parse a Google Alert RSS Feed with Google Apps Script. Google Alerts RSS-Feed

I found a script which should do the job but I cant get it working with Google's RSS Feed:

The feed looks like this:

<feed xmlns="http://www.w3.org/2005/Atom" xmlns:idx="urn:atom-extension:indexing">
<id>tag:google.com,2005:reader/user/06807031914929345698/state/com.google/alerts/10604166159629661594</id>
<title>Google Alert – garbe industrial real estate</title>
<link href="https://www.google.com/alerts/feeds/06807031914929345698/10604166159629661594" rel="self"/>
<updated>2022-03-17T19:34:28Z</updated>
<entry>
<id>tag:google.com,2013:googlealerts/feed:10523743457612307958</id>
<title type="html"><b>Garbe Industrial</b> plant Multi-User-Immobilie in Ludwigsfelde - <b>Property</b> Magazine</title>
<link href="https://www.google.com/url?rct=j&sa=t&url=https://www.property-magazine.de/garbe-industrial-plant-multi-user-immobilie-in-ludwigsfelde-117551.html&ct=ga&cd=CAIyGWRmNjU0ZGNkMzJiZTRkOWY6ZGU6ZGU6REU&usg=AFQjCNENveXYlfrPc7pZTltgXY8lEAPe4A"/>
<published>2022-03-17T19:34:28Z</published>
<updated>2022-03-17T19:34:28Z</updated>
<content type="html">Die <b>Garbe Industrial Real Estate</b> GmbH startet ihr drittes Neubauprojekt in der Metropolregion Berlin/Brandenburg. Der Projektentwickler hat sich&nbsp;...</content>
<author>

...
</feed>

I want to extract entry -> id, title, link, updated, content.

I used this script:

function ImportFeed(url, n) {
  var res = UrlFetchApp.fetch(url).getContentText();
  var xml = XmlService.parse(res);

  //var item = xml.getRootElement().getChild("channel").getChildren("item")[n - 1].getChildren();
  var item = xml.getRootElement().getChildren("entry")[n - 1].getChildren();

  var values = item.reduce(function(obj, e) {

    obj[e.getName()] = e.getValue();
    return obj;
    }, {});
  
  return [[values.id, values.title, values.link, values.updated, values.content]];  
}

I modified this part, but all i got was "TypeError: Cannot read property 'getChildren' of undefined"

//var item = xml.getRootElement().getChild("channel").getChildren("item")[n - 1].getChildren();
  var item = xml.getRootElement().getChildren("entry")[n - 1].getChildren();

Any idea is welcome!

In order to confirm your current issue, can you provide the sample URL for testing your script? — Tanaike
– Tanaike, Commented Mar 19, 2022 at 0:20
@Cooper, thanks for your reply. I cant manipulate the feed. Or should I modify the script and ask for the "rss" element? But there is no element named "rss" in the feed. — s.Panse
– s.Panse, Commented Mar 19, 2022 at 9:18
Hey @Tanaike, thanks for your reply! Thats actally your script I was trying to modify :D I added the RSS feed URL as well a link to your solution. — s.Panse
– s.Panse, Commented Mar 19, 2022 at 9:23
Thank you for replying. From your reply, I proposed a modified script as an answer. Could you please confirm it? If that was not useful, I apologize. — Tanaike
– Tanaike, Commented Mar 19, 2022 at 12:55

Tanaike · Accepted Answer · 2022-03-19 13:33:07Z

3

In your situation, how about the following modified script?

Modified script:

function SAMPLE(url, n = 1) {
  var res = UrlFetchApp.fetch(url).getContentText();
  var root = XmlService.parse(res.replace(/&/g, "&amp;")).getRootElement();
  var ns = root.getNamespace();
  var entries = root.getChildren("entry", ns);
  if (!entries || entries.length == 0) return "No values";
  var header = ["id", "title", "link", "updated", "content"];
  var values = header.map(f => f == "link" ? entries[n - 1].getChild(f, ns).getAttribute("href").getValue().trim() : entries[n - 1].getChild(f, ns).getValue().trim());
  return [values];
}

In this case, when you use getChild and getChildren, please use the name space. I thought that this might be the reason of your issue.
From your script, I guessed that you might use your script as the custom function. In that case, please modify the function name from ImportFeed to others, because IMPORTFEED is a built-in function of Google Spreadsheet. In this sample, SAMPLE is used.
If you want to change the columns, please modify header.
In this sample, the default value of n is 1. In this case, the 1st entry is retrieved.
In this script, for example, you can put =SAMPLE("URL", 1) to a cell as the custom function. By this, the result value is returned.

Note:

If the above-modified script was not the direct solution of your issue, can you provide the sample value of res? By this, I would like to modify the script.

As the additional information, when you want to put all values by executing the script with the script editor, you can also use the following script.

  function myFunction() {
    var url = "###"; // Please set URL.

    var res = UrlFetchApp.fetch(url).getContentText();
    var root = XmlService.parse(res.replace(/&/g, "&amp;")).getRootElement();
    var ns = root.getNamespace();
    var entries = root.getChildren("entry", ns);
    if (!entries || entries.length == 0) return "No values";
    var header = ["id", "title", "link", "updated", "content"];
    var values = entries.map(e => header.map(f => f == "link" ? e.getChild(f, ns).getAttribute("href").getValue().trim() : e.getChild(f, ns).getValue().trim()));

    var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Sheet1"); // Please set the sheet name.
    sheet.getRange(sheet.getLastRow() + 1, 1, values.length, values[0].length).setValues(values);
  }

References:

edited Mar 19, 2022 at 13:33

answered Mar 19, 2022 at 12:54

Tanaike

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3 Comments

s.Panse Over a year ago

Hi There @Tanaike, thank you very much for your help! I opened a new Google Apps Script and called the function "SAMPLE("RSS-URL", 10)" from a Google Spreadsheet. I got me a response indeed! Is there a way I can use "n" as a limiter and not as a selector? It would be great to have the first "n" rss-feed-entries, not "numer n" only. I'm sorry - this was not clear from my description!

s.Panse Over a year ago

Wow! Works now: I can call and write the complete RSS feed to Spreadsheet. Awesome, thanks a lot @Tanaike!

s.Panse Over a year ago

I came over one thing @tanaike, i had to change this var root = XmlService.parse(res.replace(/&/g, "&")).getRootElement(); to var root = XmlService.parse(res).getRootElement(); becaus I need the URLs without the modification. I did not see problems resulting from this modification.

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