Forum Discussion

Qrew Trainee

3 years ago

Thumbnail pictures refreshing slowly

My thumbnail pictures created with this: If(Length([Attachment File])=0,"","<img width=\"30\" src=\""&URLRoot()&"up/"&Dbid()&"/a/r"&[Attachment ID#]&"/e7/v0\"/>") refresh unbearably slowly. When...

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MarkShnier__You
3 years ago
OK, try this and see if it eliminates the caching issue. I was able to test this and change the file attachment and the "old" way stayed cached, but the new way immediately used the new image.

"<img src=" & URLRoot() & "up/" & Dbid()
& "/g/r" & QB32Encode([Record ID#])
& "/e" & QB32Encode(12) // 12 is the fid of the file attachment field
& "/va/" & URLEncode([Picture]) // my file field is called [picture]
& " width=30>"

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Mark Shnier (YQC)
mark.shnier@gmail.com
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SimonH

Qrew Cadet

I did some more poking around.
It seems like cache control is setting the cache time tp 2 minutes, so your assessment of "longer then a minute" is spot on.
A solution you can implement on your end is something to referred to as "cache busting"
This is where you append a useless query parameter to the end of the URL so that the browser then sees is as a new url and requests the image anew without loading from the cache.
I experimented with a formula that appends the last modified time to the url, however a simple update of the image does not actually set the last modified time so unless your users are also changing something else it won't work.

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Simon H
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LaszloM

Qrew Trainee

3 years ago

Thank You Simon H for the interesting answers!

On the desktop - I tried - hard refresh helps. Still it is a question for me how to initiate it from QB... if this is possible at all...
But what can I do for my mobile users using the QB app on their devices? I have a form on my tablet before me with a thumbnail not refreshed for an hour or so...
I feel on mobile - have to forget edited files' thumbnails.

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Laszlo M
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SimonH
Qrew Cadet
3 years ago
Yeah, different devices/browsers can behave differently with regards to caching.

What you can try on your end is to append a parameter at the end of the url in your formula. I tried using a a parameter based on the last modified time but that doesn't work if the only change to the record is the file attachment, as that doesn't seem to trigger an actual modification. If any other field are being changed then you cna try the formula below to see if it works

If(Length([Attachment File])=0,"","<img width=\"30\" src=\""&URLRoot()&"up/"&Dbid()&"/a/r"&[Attachment ID#]&"/e7/v0?"& ToText([Date Modified])& "\"/>")

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Simon H
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- MarkShnier__You
  Qrew Legend
  3 years ago
  I have a partial answer to avoid caching when the image file name has changed.
  
  The format we all use is this
  
  URLRoot() & "up/" & Dbid() & "/a/r" & [Record ID#] & "/e15/v0/
  
  but if you click an attachment it ill open up with this as the URL
  
  h t t p s://mycompany.quickbase.com/up/xxxxxx/g/rd/ei/va/Mark%20Ski%20Pix.jpeg
  
  I have a theory that
  the g is a constant
  The rd is r plus the Base32 Encode of the [Record ID#]
  The ei is e plus the Base32 encode of the field ID# of the file attachment
  the va is a constant
  The last part is the URLEncode of the file name.
  
  I will try that when I get a chance, maybe later tonight if i get my real work done first.
  
  If the file path changes then the image would not be cached.
  
  ------------------------------
  Mark Shnier (YQC)
  mark.shnier@gmail.com
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  - MarkShnier__You
    Qrew Legend
    3 years ago
    OK, try this and see if it eliminates the caching issue. I was able to test this and change the file attachment and the "old" way stayed cached, but the new way immediately used the new image.
    
    "<img src=" & URLRoot() & "up/" & Dbid()
    & "/g/r" & QB32Encode([Record ID#])
    & "/e" & QB32Encode(12) // 12 is the fid of the file attachment field
    & "/va/" & URLEncode([Picture]) // my file field is called [picture]
    & " width=30>"
    
    ------------------------------
    Mark Shnier (YQC)
    mark.shnier@gmail.com
    ------------------------------