Soon I'll write up an

scott — Tue, 24 Apr 2007 10:43:28 -0400

Soon I'll write up an example implementation that uses this service within Drupal, to create a customized download process.

Is Pando Installed?

scott — Mon, 23 Apr 2007 16:06:40 -0400

Update: In most cases, the PandoAPI javascript method for detecting Pando's installed status would be preferable to this approach. Here is a detailed example using javascript.

In many cases, it's helpful to know whether a user has Pando installed or not, to determine what to display on a particular web page containing Pando downloads or channel subscriptions, for example; and to better explain to your sites visitors how to acquire Pando if they don't already have it.

The Pando "Installed" Cookie

For our own web sites, we use a browser cookie to track whether a user has Pando installed or not. This cookie gets set in a user's default browser when they install Pando, and is set to never expire. The cookie's key/name is "installed" and value is set to "yes"). Because this cookie is accessible to any pando.com URL, we can make use of it in many places. For example, when a user clicks a package URL, we look for the cookie and, if it's set, we send the user the Pando file. If it's not set, we redirect them to a page explaining how to installed Pando (example).

Unfortunately, because cookies can only be read by the domain that sets them (a good thing for security purposes), other web sites cannot tell if a user has Pando installed.

"Installed" Cookie Check Service

To get around this limitation, we've implemented a simple "installed" cookie checking service you may use to discover if your users have Pando installed. To use this service, you must redirect your users (using javascript or, preferably, a server side script) to the following URL: http://www.pando.com/installcheck/?returnURL=http://example.com/ where http://example.com is an URL on your server that can handle the resultant response.

When a user visits the above URL, the pando web server looks for the Pando "installed" cookie and redirects the user back to the specified returnURL with hasPando=yes or hasPando=no appended to the URL parameters. It is up to you to receive this response and handle it in a useful way. We recommend setting your own cookie to remember the result of this check, to minimize these redirect-heavy requests.

Caveat

It's important to note that this is an imperfect solution. If a privacy-minded user frequently clears her cookies or uses a browser other than her default, the "installed" cookie might not be set even when she has Pando installed. It is important to allow users a way around a cookie check and force the cookie to be set to cover these cases.

Pando Developer Tools - Is Pando Installed? - Comments

Soon I'll write up an

Is Pando Installed?

The Pando "Installed" Cookie

"Installed" Cookie Check Service

Caveat