Abstract
This article regards the question "Is it possible (let's say depending on the user name
calling the script) to redirect to another URL in a Google script as web app view?"
Objective
The objective is already contained in the question:
Depending on the username, a script as web app view should redirect to another page.
This implementation is needed in the Hotline Planner. Only one link for the My Personal View
should be implemented on the Google Site, while three separate systems exists. The
My Persional View should redirect the user to the correct system according the user id
that is calling the script. A definition (dictionary) from user to system has to be provided.
Techniques
To redirect to different page, the follwing techniques can be used:
- Metatag
<meta http-equiv="refresh"
content="0; url=https://example.com/" />
Redirect works but browser keeps the initial URL.
- JavaScript 1
window.location.href = "https://example.com"
Redirect works but browser keeps the initial URL.
- JavaScript 2
// window.open(URL, name, specs, replace)
window.open('https://consulity.de', '_top')
Redirect works perfectly and the new URL is displayed in the browser's address bar correctly.
- Link
<a target="_top"
href="https://consulity.de">go to consulity.de</a>
According to this article,
links have to be used with target="_top" or target="_blank".
- Workaround
After some research, the following solution for GAS was found on stackoverflow
function doGet() {
return HtmlService.createHtmlOutput(
"<form action='https://www.google.com' method='get' id='foo'></form>" +
"<script>document.getElementById('foo').submit();</script>");
}
Result
If HTMLService is used with SandboxMode NATIVE
or EMULATED, none of the above mentioned techniques work at all.
The results above are described for SandboxMode IFRAME.
Source Code
Code.gs
var url = "";
function doGet() {
var uid = Session.getActiveUser().getEmail();
if (uid == "dn@consulity.com")
{
url = 'https://consulity.de';
}
else {
url = 'https://google.de';
}
return HtmlService.createTemplateFromFile('Index').evaluate().setSandboxMode(HtmlService.SandboxMode.IFRAME);
}
Index.html
<!DOCTYPE html>
<html>
<head>
<script src="https://consulity.de/scripts/jquery-1.9.1.min.js"></script>
</head>
<body>
<input id="url"
type="hidden" value="<?!= url ?>"/>
<p><button
onclick="go1()">redirect via location href</button></p>
<p><button
onclick="go2()">redirect via window.open</button></p>
<p><a
target="_top" href="https://consulity.de">go
to consulity (_top)</a></p>
<p><a
target="_blank" href="https://consulity.de">go
to consulity (_blank)</a></p>
</body>
<script>
//<!-- redirect via meta tag after 0 seconds-->
//<meta http-equiv="refresh" content="0; url=https://consulity.de/"/>
$(function(){
console.log('script ran');
var url=$('#url').val();
console.log(url);
window.open(url,'_top')
});
function go1(){
window.location.href='https://consulity.de';
console.log('script ran');
}
function go2(){
window.open('https://consulity.de','_top')
console.log('script ran');
}
</script>
</html>
Conclusion
The window.open command works perfect when called with "_top" or "_blank" (target).
Here is the solution
and the source (access restricted).
The user id "dn@consulity.com" will be redirected to consulity, while all other users will be redirected to google.
Please note:
It is important to use
return HtmlService.createTemplateFromFile('Index').evaluate().setSandboxMode(HtmlService.SandboxMode.IFRAME);
and not to use
return HtmlService.createHtmlOutputFromFile('Index').setSandboxMode(HtmlService.SandboxMode.IFRAME);
because in the latter case, server variables <?!=?> cannot be evaluated in the HTML context.
Note: The script needs to retrieve the user ID from the session and therefore needs the following rights/scope:
