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Viewing large (PDF) files

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Posted on by cssrt123

Hi community

My team has a requirement to build a internal staff app (for use on mobile and tablet) which can view a PDF (80-100Mb; ~1200pages) in-app.

Why don't we just download it?

Staff have previously used an externally created app which downloaded the file, but over a number of years/updates the device storage usage built up (plus other downloads on the device), which led to slowing devices and an increase in calls to the service desk (for them to remotely delete files).
The file is updated a number of times throughout the year, so it being loaded in-app would mean we have better control over which version they are looking at.

Ideally, we'd like the user to download (the content), and it to be viewable via the app; we'd love it to store the content locally (so it doesn't need to re-download every run) so was thinking the SaveData/LoadData (but I need the content accessible first), and then when we update the source file, the app would know it's been updated, and pickup the new version, and replace the current locally stored version.

Note that the users do require a local version to be available (it can't be 100% cloud accessed) - this is because there are a number of areas we cover where there's no/limited data connectivity, and the document must be available to staff at all times.

But none of the testing so far has yielded any positive results; the app can't download the content of a file that size to display in the PDF viewer, automate can't send/Power Apps can't receive content of that size, trying to get it in small sections would require an automate being called an unrealistic number of times.

Googling has resulting in a number of options on how to upload files/large files.....but has anyone managed to, or got any thoughts on, how to get Power Apps to download a large file....and retain control over it (rather than saving it to a Downloads folder).

Hoping someone out there has some ideas we can try.

Thanks

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Building Power Apps

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Michael E. Gernaey 53,335 Super User 2025 Season 2 on at

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Hi @cssrt123

As there are no pictures, no code, no errors nothing, just sort of... statements of not working, as feedback, it is almost positively why no one answered. Its too general

Its also very confusing. you went on a long explanation as to why they cannot download the file, then turned around and said it needs to be downloaded. very confusing.

What I will say ask, in your app, are you using the Download action to download the content and saying that fails?

if the answer is no or yes, you can see how hard it is to try to help with no details at all.

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ronaldwalcott 3,847 Super User 2025 Season 2 on at

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There are numerous available solutions which allow one to view PDFs therefore I would presume that isn't really what you need.

If these are technical documents provided to you by an external source which staff need access to on short notice hence the storage, access and versioning issues then Power Apps is probably not the solution needed. You could probably create a solution using a SharePoint library or OneDrive which maintains a list of the up-to-date versions of the PDFs. (One drive for business can probably have a shared folder which synchs to the users in a read only manner)

If these are internal PDFs containing whatever information needed for remote work then the content of the document should be available in a categorized manner related to the job being done.

I also don't understand your difficulties in managing the mobile and tablet devices used by your staff. There are solutions which can manage these devices. You can schedule uploads to add new versions and remove the old versions of the PDFs.

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cssrt123 23 on at

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Hi @Michael E. Gernaey

I don't really have any pictures, specific errors/codes etc at the moment, as it's very early stages of this section of the app and we're just trying to overcome this issue; so, the issue at the moment, is a very general one and namely, how to get a local (Power Apps) controlled copy of a large PDF.

What I will say ask, in your app, are you using the Download action to download the content and saying that fails?

No, I did explore the Download option, but that does just that, it'll download the file to the downloads area of the device in use; which isn't what we want. We have 2000+ users that would use this app, with a very wide range of technical ability, so we're looking for a method of standardising the access to the file.

I'd tried to cover what our requirements were, and what our limitations were....but it's easy when I know what I need....I'll try to simplify the keys points in the explanation / requirements....

We have an app that's going to be used by 2000+ staff to register that they read a recent copy of a weekly file (it just registers their name, date/time and their location against the file.

Periodically (2 or 3 times a year), there's a large PDF (80+Mb, ~1200pages) that they need to acknowledge; but they must keep a copy available to them offline (it used to paper!), so we need it stored on their device (either a mobile or tablet depending on their exact role).

Our issue is that if they just Download it (without clearing up old versions), when they need to refer to it, they risk looking at the wrong version. We also can't trust that they will all manually delete previous versions from the downloads area (some of them won't know how, and some of them won't want to do "extra work"), which will begin to take up large amounts of space over time - plus they'd need to only delete the old ones, not the most recent one.

So, what we'd (ideally) like to do is have the app just download the content, store it locally, and display it to the user (using SaveData/LoadData). Then, when it's out of date, we can refresh the local content. This way there are no local copies getting out of control, no accidental deletion of the most recent version, and they can view it quite easily, whenever they need, without an internet connection being required (as we cover areas with zero data signal possible.

The PDFs are (currently, for this testing) being held in a SP site; but the storage location isn't fixed, and we are more than happy to relocate them if required.

I've tested Download, but like I said that just puts an uncontrolled copy in the downloads folder

I've tried the PDF viewer, pointed directly to the file, but that gives me the option to open in a browser instead - looking to get it all in the app, and this wouldn't work offline

I've tried a flow, called from the app, to get the file content, and pass it back to the app, but the size of the content appears to be problematic and caused the app to crash (it gets the content in the flow fine, but it's passing it back that's unmanageable)

I've tried a flow that, using the download link (https://xxxx.sharepoint.com/sites/testsite/_layouts/15/download.aspx?UniqueId=669x5b64-1fc1-4ae9-ad8d-8f0a062abe3b&Translate=false&tempauth=v1.eyJzaXRlaWQiOiI5MWMzNjg0MC1mYjk0LTQyNGYtYjNhOC0xOWUwMDZkYjI5ZTQiLCJhcHBfZGlzcGxheW5hbWUiOiJBcHAgU2VydmljZS.........fk4RihHNWxlcy5yZWFkyAEB.mPhieJ_vuiVd49hvoUAQyct12TRdcrxqJ3VQuvQERXU&ApiVersion=2.0) , gets partial sections of the content (which does work, as below) and tries to pass it back to the app; but if I use a chunk that's too big, it crashes, and if it's too small, it becomes hundreds or thousands of calls to the flow per user.

{ "body": { "$content-type": "application/pdf", "$content": "JVBERi0.........DQwMTA5MzkNCiUlRU9GDQo=" } }

I will say that I did manage to get the GetContent flow > Power App > Collection > SaveData > LoadData process to work at one point (but not on a piece of code/demo I've currently got in front of me as it's changed about 20 times since).....but that was a very small file in comparison....so if you've any suggestions on how to overcome the file size issue it would be greatly appreciated

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cssrt123 23 on at

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Hi @ronaldwalcott

Appreciate the thoughts on this, and if it turns out that Power Apps can't do what we need, then we'll certainly look elsewhere. A previous incarnation of this system was done by an external company, and when it worked, there was a hefty annual charge to the company, and then it become unsupported due to third party changes....so we're left trying to consider an internal version instead.

A synced SP library could possibly work, and I'll have a discussion with my colleague about it tomorrow and explore the intune options, but the issues here would be:

use of two systems - we still need to get the documents signed off, so they'd use one system for that, and then have to go to the offline library for the actual document (unless we can reference the file from within Power Apps somehow)

actually trying to direct them to where it is locally on their device (some aren't the most tech savvy) (again, unless we can reference it)

adding / removing the sync from users if they join / leave a role that requires these (if we can get intune to handle this, it shouldn't be too bad for this one)

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stampcoin 5,058 Super User 2025 Season 2 on at

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I would try ( if must use power App) to split the PDF in somewhere. For example , id =1 map to Page 1.
Define a table in dataverse, for example, ID/PageNumber, VersionId, PageLocation. expireDate. publishedDate, etc.

each page has its own version, for a PDF file, which means the app only need get the updated page technically.

since I don't have full picture of your story, that's my draft thought, but I like my thought😊

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