iframe no picture refresh

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dear Pimatic friends,
Although i found the posts from @djmvt, 8 months old, there ist no solution yet.
My PiCam, controlled by application “motion”, generates Pictures (.jpg) dependent to changing environment. The name of picture-File ist constant. So newer overwrites the older. The picture is placed in the public Folder of “mobile-frontend”. So the picture is displayed in the pimatic-gui by iframe plugin.
This works fine.
But, this will be done one singe time, means, only the first picture is displayed.
@djmvt says this is the funktion of browser-cache.
i found this true, for blocking datacaching in browser, starts pictureupdate.
Because of serious restrictions in dialog, this is no solution.

would be glad to get it working
Joseph

as far as i see @djvmt got it working here https://forum.pimatic.org/topic/1439/iframe-device-won-t-refresh-picture-from-ip-camera/5 with the sysinfo cpu variable.

Do you try to attach the sysinfo cpu variable with a questionmark after the .jpg in the path like "picpath/picname.jpg?sysinfo cpu variable"
For the browser then it should a new picture every time the iframe reloads.

For reference see thread https://forum.pimatic.org/topic/1380/browser-cache referred to by “Iframe device won’t refresh picture from ip camera.”. May be we can add the refresh variable as a feature into the iframe plugin. I’ll have look into this soon.

Thank you very much for the quick response.
Iframe refresh now working fine.
Made a donation today.

I have developed an integrated solution which hopefully solves the refresh problem. It’d be great if someone can trial it. The package is mwittig/pimatic-iframe.
As part of the device configuration there is a new configuration property (see below). Setting it tur truewill make the iframe source URL unique for each update cycle.

refreshHack:                                                                                                                              
	description: "Add a _refresh URL param to make URL unique. This is to solve caching issues"     
	type: "boolean"
	default: false

Here are the results of fist test with iframe - Version 0.1.3 including refreshhack:

1. without “?sysinfo cpu variable” - suffix in URL-Parameter of iframe:
   refreshhack active, value: ja true Picture delivered
   refreshhack active, value: nein cache Picture delivered
   refreshhack inactive cache Picture delivered
2. with “?sysinfo cpu variable” - suffix in URL-Parameter of iframe:
   refreshhack active, value: ja true Picture delivered
   refreshhack active, value: nein true Picture delivered
   refreshhack inactive true Picture delivered
   No issue found.
   Warnings of npm installing iframe package ignored (license field, peer dependency).

@Joseph Thank you very much for testing this and excellent summary of test results!

If I interpret your results correctly, the refreshHack solves the “no picture refresh” problem and work-arounds like adding the “sysinfo cpu” variable to the URL are no longer required. I have filed a pull request and hopefully, the changes will land in a new release of pimatic-iframe soon.

@mwittig read your pull request. Do you mind to have a look @gitter?

I did solve this indeed with the variable trick.
Good to see an official solution now!

The option was renamed to “enforceReload” and published to npm.