Force reload (do not use browser cache) of PDF

[Theo Kusters]

Hi,
We have an application that shows pdf's in a URL widget. These pdf's can change but keep the same name. Now it seems that the browser keeps showing the old version until I clear my cache. Is there a way to tell the browser not to use the cached version?
Kind regards,
Theo

[Theo Kusters]

An option would be that I could add some html to the page presented, like:
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">

[Johnny Major]

Hi Theo,

You could also stop the cache a couple of other ways by adding a cache buster to the URL.

Example 1 - random number on the data source
Data Source SQL

select
cname,
rand() AS cachebust,

Then add that to the url via behaviors :

/myPath/index.html?dc_={CACHEBUST}

Example 2 - if you're using an app var linked to your URL

Before showing URL widget execute script to add the cache buster:

var url = getAppVar('URL');

// add cache buster
//
url += '?dc_=' + Math.random();

// set the app var
//
setAppVar('URL', url);
success();

[sean.lanktree]

Hi Theo -

You can add a parameter to the URL when you set it for the widget. For example, suppose the URL is:

/myPdfs/customers/acme/12345.pdf

Let's add a parameter named "cb" (short for cachebuster):

/myPdfs/customers/acme/12345.pdf?cb=20201030091510

In this case we are using a timestamp as the parameter value.

Does the path to your PDF come from a data source? If so, maybe just add a new field to your data source:

current_timestamp as tStamp

Then use this new field when you set the URL for the URL widget:

{MYPATH}?cb={TSTAMP}

[Theo Kusters]

Thanks, that worked and was much easier than I thought!