Flow to Return varbinary as Image or PDF

[stephenkln]

Hi all,

I'm trying to figure out if my problem I'm trying to solve requires a Flow, and if so, how I would set it up.

I'm trying to add a feature in my PowerApp that allows the user to do two things. 

1) attach a file and save as varbinary in on premise sql database (finished this part)

2) view that varbinary as an img or pdf in powerapps (need help)

Context-- so the app I've built is basically a user friendly gui to add employee data to an on prem sql dB. The client requested functionality to upload scanned copies of employee records via the app and also view uploaded docs based on the selected employee. I'm at a loss on how to actually return the varbinary from the dB, back to the app as an image or pdf so the user can view it.

To add the image/doc to the dB as varbinary I'm using Shane Young's method here https://www.youtube.com/watch?v=Pa-pYEkLH-U but with a slight change in that instead of using the AzureBlobStorage.CreateFile function, I'm simply using Patch to insert a new record into the dB with the file contents as varbinary. Each blob is also related to the relevant employee via foreign key. 

Any ideas on how I would then fetch the relevant blob back from the dB and display it as an image or pdf?

I'm assuming Flow would be involved. I've also asked this on the PowerApps forums and received no responses, so I thought I'd see if anyone here has any ideas.

Thanks!

[Pstork1]

Take a look at this video on how to view PDFs from SharePoint in the PDF viewer using Power Automate.  I think you can probably do something similar with your varBinary from SQL

https://www.youtube.com/watch?reload=9&v=s3PC7tqqoI4

[v-alzhan-msft · Accepted solution]

Hi @stephenkln ,

Sorry for I'm afraid that the requirement to return varbinary as image or pdf couldn't be achieved with Microsoft flow currently.

Best Regards,

Alice

Community Support Team _ Alice Zhang
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[stephenkln]

@Pstork1 @v-alzhan-msft Thanks for the responses. I think I've found a round about way to do it, but I've hit a snag.

So basically, my idea to get this to work was to first create a gallery in my app that displays all the relevant file names stored in the dB for a particular employee. On selection of an item in the gallery, it will run this flow:

So this takes the varbinary from sql and saves it to sharepoint with the appropriate file type based on the filename. I realized that if the filename saved in the dB contains the extension, then when I save the varbinary to sharepoint with the filename, I can download it and it will be the correct file type. My problem is that I now have an error when trying to pass a sharing link back to powerapps...

The problem is that I'm getting this error: 

Flow save failed with code 'InvalidWorkflowRunAction' and message 'The workflow run action 'Respond_to_a_PowerApp_or_flow' has type 'Response' that could not be nested under an action of type 'foreach'.'.

I guess even though the Get Rows step is only returning one record, it's returning it into a collection. How do I handle this so I can return the download link to Powerapps?

[Pstork1]

The problem is the sharing link is a URI.  I suspect you'll need to use a function to make it text and then send that back to Power Apps.  Once you have it in Power Apps as Text then you can convert it back to a URI.

[stephenkln]

@Pstork1 Thanks for the response. That doesn't appear to solve the problem though.

The error appears to have something to do with the "Apply to each"

[Pstork1]

Sorry, I went right past that part.  The error is pointing out that you can only send one return from the flow to Power apps.  Since you have it inside a loop you are trying to return each time the apply to each loops.  I think you are doing this one file at a time, but the actions you are using are returning a collection.  You can only return one thing, one time so you'll need to store the URL in a variable and then send the variable as a return after the loop closes.

[CliveMM]

Hello it’s now 2024 can power automate no resolve a pdf out of a varbinary field? 

[Pstork1]

You can't use the Respond to Power Apps inside an Apply to Each and you can't use it to return an array. you need to build an array of files in the Apply to each and then return that to the Power App using the HTTP response Action.  You can capture the output in a Collection.  Make sure to add an appropriate Schema under the advanced properties.