edit google document remotely - google-apps-script

Question

I'm trying to add a feature to my website as follows:
Clicking a button appends text to a Google document.
Obviously I will need to create an Apps Script in the drive. The question is how to trigger the Apps Script from my website. You can assume that I am the owner of the drive/document and so have permissions to edit it in any way I like.
I have looked at these topics:
Workarounds : How to edit native google documents programatcally?item
How to programmatically manipulate native google doc files
It seems they are all actions performed from the drive itself and not triggered remotely.
I have also looked up the Apps Script API in Google but have not found a way to do this. Is it even possible?

Answer 1

Yes, it is possible.
First write an Apps script that changes your desired document. Then deploy it as a web-app running as you that anyone has access, even anonymous. Check out the guides at Apps Script page to see how to write your script as a web-app.
Your script will then have a public url, which you can call from your website and have it run "remotely" normally.

Answer 2

To provide an example of what Henrique suggests, here is a small webapp that adds text to a publicly viewable document I own (it doesn't need to be public except for anyone here to check it works !)
I wrote it using UiApp but you could of course use HTMLService if you prefer...
The app runs as me but is accessible to anyone even anonymous.
// publicly viewable test doc url : https://docs.google.com/document/d/1THzBTURxGr2CdUmcZ7i2zD-RM8I3im2JCSHI3BHlkeM/edit
function doGet(){
var app = UiApp.createApplication().setTitle('docEdit');
var panel = app.createAbsolutePanel().setSize('100%','100%').setStyleAttributes({'padding':'40px','backgroundColor':'lightBlue'});
var text = app.createTextArea().setName('text').setPixelSize(500,300);
var grid = app.createFlexTable().setId('grid');
grid.setText(0,0,'Add your text').setWidget(1,0,text);
var handler = app.createServerHandler('writeText').addCallbackElement(panel);
grid.setWidget(2,0,app.createButton('update document',handler).setId('btn'));
app.add(panel.add(grid));
return app;
}
function writeText(e){
var doc = DocumentApp.openById('1THzBTURxGr2CdUmcZ7i2zD-RM8I3im2JCSHI3BHlkeM');
var now = Utilities.formatDate(new Date(),Session.getScriptTimeZone(),'MMM/dd/yyyy # hh:mm:ss');
var body = doc.getBody();
body.appendParagraph('Append text on '+now+' : '+e.parameter.text);
doc.saveAndClose();
var app = UiApp.getActiveApplication();
var grid = app.getElementById('grid');
grid.setWidget(3,0,app.createHTML('Thanks,<br>Your text has been added to the document'));
app.getElementById('btn').setEnabled(false).setHTML('Button disabled');
return app;
}