How to enable copy limitation in swift/kotlin?

[mane1603]

Hi, I am trying to set limits for users - 3000 max character copy limit. But no success with what exists in codebase. Anybody has done this? or something similar?

now, I am trying with this, but no log or something else is shown.

`private func handleCopyEvent(text: String, length: Int) async {

#if LCP
// Check LCP license information
guard let lcpLicense = publication.lcpLicense else {
  print(TAG, "📋 No LCP license found - copy allowed without restrictions")
  return
}

// Get license information
if let charactersLeft = lcpLicense.charactersToCopyLeft {
  print(TAG, "📋 LCP License Info:")
  print(TAG, "   - Characters remaining: \(charactersLeft)")
  
  if let user = lcpLicense.license.user.name {
    print(TAG, "   - User: \(user)")
  }
  
  if let endDate = lcpLicense.license.rights.end {
    print(TAG, "   - Loan expires: \(endDate)")
  }
  
  // Consume the copy quota
  if length > 0 {
    do {
      try await lcpLicense.copy(count: length)
      print(TAG, "✅ Successfully consumed \(length) characters from LCP license")
      
      // Get updated quota
      if let updatedCharactersLeft = lcpLicense.charactersToCopyLeft {
        print(TAG, "📋 Updated characters remaining: \(updatedCharactersLeft)")
      }
    } catch {
      print(TAG, "❌ Failed to consume copy quota: \(error)")
    }
  }
} else {
  print(TAG, "📋 No copy restriction in LCP license")
}
#else
print(TAG, "📋 LCP not available - copy allowed without restrictions")
#endif

}`

[mickael-menu]

The 3000 character limit must be set by the content provider in the LCP License Document's rights.copy field. The reading app cannot set arbitrary limits, it only enforces what the license specifies.

If you use the EPUB navigator view controller with the default editing actions menu, the copy limitations are automatically enforced by the toolkit when the publication is protected with LCP. You don't need to manually check or consume quota.

If you implement your own custom "Copy" action, which it looks like you're doing with this handleCopyEvent() function, then you do need to call the APIs yourself.

I don't know why you don't see any logs. Do you actually call handleCopyEvent() somewhere? It's not part of the toolkit. The code also seems incomplete since it doesn't copy to the pasteboard (UIPasteboard.general.string = text). But one big issue is that lcpLicense.copy(count: length) doesn't exist. The correct API is lcpLicense.copy(text: text). I'm not sure how this code compiles.

As for the Kotlin toolkit, Copy rights enforcement is not implemented. You need to disable Copy altogether when the publication is protected with LCP. If you use the EPUB navigator from the Kotlin toolkit with the default selection menu, this is already handled.

[mane1603]

we use 3.2.0 version

no, we do not override the func navigator(_ navigator: SelectableNavigator, shouldShowMenuForSelection selection: Selection) -> Bool

[mickael-menu]

This looks correct. What did you observe that shows that the copy is not prevented after reaching the limit? I checked and it works in the latest Test App.

• Check that the license has a character limit and it decreases when you Copy text, using navigator.publication.lcpLicense?.charactersToCopyLeft().
• Check that you override NavigatorDelegate.navigator(_ navigator: any Navigator, presentError error: NavigatorError), this is where the "copy forbidden" error will be forwarded to your app.

[mane1603]

User is still able to copy more, even the limit is reached.

[mickael-menu]

Did you check that the license has a character limit and it decreases when you Copy text, using navigator.publication.lcpLicense?.charactersToCopyLeft()?

[mane1603]

yes, it has the limit
no, it's not being decreased

[DavitAsatryan]

Hi Mickael
aboout this issue....
when I select text and copy it, the value does not decrease.
It stays the same even after multiple copy actions, and I’m still able to copy text beyond the limit.

So it seems like the copy quota is not being consumed when the user copies text.

Let me know if I might be missing a required delegate or callback that should be triggered on copy.

[DavitAsatryan]

We do LCP decrypt manually and then open the decrypted file, so publication.lcpLicense is nil and we don't get a value from charactersToCopyLeft(). Can this manual encrypt/decrypt flow still connect with the copy-limit functionality, or do we have to open via the toolkit’s LCP for that to work?

[DavitAsatryan]

{"provider":"https://www.edrlab.org","id":"52d2fca0-8113-4f4a-a284-2bdeb9710438","issued":"2019-04-17T12:56:16Z","encryption":{"profile":"http://readium.org/lcp/profile-1.0","content_key":{"algorithm":"http://www.w3.org/2001/04/xmlenc#aes256-cbc","encrypted_value":"t0h8Ew5aH/TiW7UIqpEDcwSaALSR30kXGx0eLgLs8d3hJM3NIl9WyhG/Kk3J1ZMKllH2dFd7zaLukFxWG7+8AQ=="},"user_key":{"algorithm":"http://www.w3.org/2001/04/xmlenc#sha256","text_hint":"One passphrase","key_check":"tKYonIBR9/0wl5KbVaovW0OsLpHRyv+StukCjYeddy2YwsY3KA6fUQxaQp7Cy5f4o4fxq8VtzqCZnrpgRctNfw=="}},"links":[{"rel":"status","href":"https://lsd-prod.edrlab.org/licenses/52d2fca0-8113-4f4a-a284-2bdeb9710438/status","type":"application/vnd.readium.license.status.v1.0+json"},{"rel":"publication","href":"https://lcp-prod.edrlab.org/contents/6fbca352-13f7-424c-b93d-0d752df738bc","type":"application/epub+zip","title":"moby-dick","length":1646451,"hash":"33a41df3ae98c40fc4cc16e96052bd41db207c45fbfe7439009795f7e3c0df7c"},{"rel":"hint","href":"https://front-prod.edrlab.org"}],"user":{"id":"7b61b202-33b3-4129-b2b5-16eac65c70bf","email":"WyckqOe4nDiuDZPfDva5o9t3YQVfolV1YC2eksipBh3u0L4wuNugDx6dPryj8TlZ","name":"v++cWselhj4I0SGpV71S+0DcJCTekEJbwN8Fj86uk6Q=","encrypted":["email","name"]},"rights":{"print":2,"copy":50},"signature":{"certificate":"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","value":"AQjZ00NLV7Bu15ctjyZFcDPFTwt5vCMQoUhMuYKTEAaXgVxnFxwDynlWRHXydFzShoXvxTrXYbL8gudrKmnLo7E7AePScJKbnhs0QY2o8HqbRb72TNQ88sP54MW5FPjAvm1LcisBhxOnNq220NoC6DHe113780t32M3h7d57TIRqAxkb","algorithm":"http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256"}}

36a018aa-98e7-419b-9238-27f12eb73d95

[mickael-menu]

We do LCP decrypt manually and then open the decrypted file, so publication.lcpLicense is nil

Ha but this changes everything! That's the reason the copy rights is not working in the EPUB navigator, it's using publication.lcpLicense.

What do you mean exactly by doing the LCP decrypt manually? Are you decrypting the EPUB on the disk, and then opening the unencrypted EPUBs with Readium?
Why don't you open the encrypted EPUBs directly with Readium?

[mane1603]

What do you mean encrypted EPUB directly with Readium?

[mickael-menu]

Did you look at the documentation? https://github.com/readium/swift-toolkit/blob/develop/docs/Guides/Readium%20LCP.md#supporting-readium-lcp
You don't need to do anything else to support LCP with Readium

But I need to know what you meant by decrypting LCP manually?