GDocs Script to fetch web info behind a form using UrlFetchApp - google-apps-script

Question

I want to fetch some web data using GDocs but the data is behind a form so I need to post some data to the form to get the result. (So I cant use ImportXML etc)
The function that I am trying to use is https://developers.google.com/apps-script/reference/url-fetch/url-fetch-app but I dont really know where to start since I don't have much java script experience.
Is there anyone that has a script that takes an url, form name & the data to post that can be used in GDocs?

Answer 1

There's an example of such a script here: How do I use Google Apps Script to change a CSS page to one with inline styles?.
It's a different application, but the method applies. Here's a skeleton function to get you started.
The payload object should contain the name / value pairs of the form data you want to simulate. The url should be changed to match the site you're submitting the form to. Once you've made the POST request by the call to UrlFetchApp.fetch(), you should be able to parse the response using the getElementByVal() utility from Does Google Apps Script have something like getElementById?.
function postForm() {
// Generate a POST request with form data.
var payload =
{
"name" : 'Anonymous Person', // Replace with relevant name / value pairs
"town" : "Springfield"
};
// Because payload is a JavaScript object, it will be interpreted as
// an HTML form. (We do not need to specify contentType; it will
// automatically default to either 'application/x-www-form-urlencoded'
// or 'multipart/form-data')
var options =
{
"method" : "post",
"payload" : payload,
"muteHttpExceptions" : true
};
var url = "http://form.somewhere.com"; // Replace as appropriate
var response = UrlFetchApp.fetch(url, options);
// Put the receieved xml response into XMLdocument format
var xml = response.getContentText();
var doc = XmlService.parse(xml);
// Extract the details you want...
var someData = getElementByVal( doc, 'textarea', 'name', 'text' );
...
}