Web Page Card Refresh (stale the cache)

[ttreker]

One huge drawback of Home Assistant's presentation capabilities is the inability to display any kind of dynamic data with length and structure in some sort of card (or dashboard) where templates have insufficient capabilities to provide the dynamic data.

The canonical answer to this conundrum is often to define Shell Command actions or use File Notifications to generate files in the web directory and then display these files using a local URL in a Web Page card (or a Web Dashboard).

However, this is a less-than-ideal solution at best as the Web Page card (and the Web Dashboard) caches the page and so when the data updates in the file the cache doesn't get marked stale and so instead the page becomes stale and remains that way making it very difficult to see the updated data and potentially leading to misinterpretations of important information!

There are potentially some solutions to this conundrum currently that are rather kludgy. The one that I use is to use my browser-of-choice's context menu to update the iFrame. This solution is just far from ideal! Non-technically-inclined users will just be completely confused by this esoteric approach.

I have read posts addressing this issue that claim that there is some sort of complexity behind why this can't be done possibly being related to an insecurity. Frankly, these arguments sound like weak tea. I don't buy it. If differing external browsers can do it then Home Assistant should be able to do it. If nothing else it seems that they should be able to do it securely if it is a local URL used in a Navigate Interaction. (I am not sure this is exactly the way to characterize a possible approach but I hope you get the picture; i'm just throwing out ideas here.)

Home Assistant is aiming to be a power user's home automation system. Its aim is toward end users that are not assumed to have development skills. There is a host of solutions a power user could implement were this simple problem resolved.

Here is a use case that (among many others which I can come up with) that demonstrates how a power user might use this.:

The power user wants a page that displays a custom log in a non-standard format. Here is how they should be able to do it:

1. Create a File Notification to a file in the www subfolder.
2. Output their log info using the Notification Action.
3. Display the results in Web Page card or a Web Dashboard.

This is a straight forward solution that could be used over and over again where templating in a Markdown card falls short. However, without a page reload capability it is profoundly convoluted at best.

So far all of my solutions along this line have required me, in order to get it to work in the Companion App have a button to open the text file accompanied by a Markdown card with explicit instructions for each type of browser on how to go about reloading the frame! Further, once used the user has to go back to the Home Assistant app, which they just left, to further investigate things. This is a confusing mess to the end user which happen to be non-technically inclined family members.

It just seems that this is a simple problem that really needs to be addressed where, if it is addressed, dramatically expands what information can be presented quickly in the Home Assistant UI.