How can I enable PDF preview

ℹ️ Support
1

Hello,

Thank you for your support.

Here are my installation info:

Nextcloud version: 19.0.1.1 (installed on user account via a PHP script from nextcloud website.)
OS: Ubuntu 20.04.1
Control Panel: Hestia CP v1.2.3
Apache version: 2.4.46
PHP version: 7.3

APCu Support: Enabled
memcache.local:none
memcache.distributed:none
memcache.locking: none

I have also installed the following requirements:
*imagemagick
*ghostscript

I am trying to activate PDF previews. Its looks like I have a multiple issues regarding cash, security and setting up the config.php file.

I tried to edit the config.php file by myself but I failed.
https://docs.nextcloud.com/server/latest/admin_manual/configuration_server/config_sample_php_parameters.html?highlight=pdf#previews

For more details check the logs below.

The output of my Nextcloud log

    [core] Error: ImagickException: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/408 at <<closure>>

     0. /home/XXXX/web/XXXX/public_html/lib/private/Preview/Bitmap.php line 87
    Imagick->readimage("/home/XXXX/w ... ]")
     1. /home/XXXX/web/XXXX/public_html/lib/private/Preview/Bitmap.php line 50
    OC\Preview\Bitmap->getResizedPreview("/home/XXXX/w ... f", 4096, 4096)
     2. /home/XXXX/web/XXXX/public_html/lib/private/Preview/GeneratorHelper.php line 63
    OC\Preview\Bitmap->getThumbnail(OC\Files\Node\File {}, 4096, 4096)
     3. /home/XXXX/web/XXXX/public_html/lib/private/Preview/Generator.php line 235
    OC\Preview\GeneratorHelper->getThumbnail(OC\Preview\PDF {}, OC\Files\Node\File {}, 4096, 4096)
     4. /home/XXXX/web/XXXX/public_html/lib/private/Preview/Generator.php line 141
    OC\Preview\Generator->getMaxPreview(OC\Files\SimpleFS\SimpleFolder {}, OC\Files\Node\File {}, "application/pdf", "")
     5. /home/XXXX/web/XXXX/public_html/lib/private/Preview/Generator.php line 107
    OC\Preview\Generator->generatePreviews(OC\Files\Node\File {}, [{width: 256,hei ... }], "application/pdf")
     6. /home/XXXX/web/XXXX/public_html/lib/private/PreviewManager.php line 190
    OC\Preview\Generator->getPreview(OC\Files\Node\File {}, 256, 256, true, "fill", null)
     7. /home/XXXX/web/XXXX/public_html/apps/files/lib/Controller/ApiController.php line 128
    OC\PreviewManager->getPreview(OC\Files\Node\File {}, 256, 256, true)
     8. /home/XXXX/web/XXXX/public_html/lib/private/AppFramework/Http/Dispatcher.php line 170
    OCA\Files\Controller\ApiController->getThumbnail(256, 256, OC\Files\Node\File {})
     9. /home/XXXX/web/XXXX/public_html/lib/private/AppFramework/Http/Dispatcher.php line 100
    OC\AppFramework\Http\Dispatcher->executeController(OCA\Files\Controller\ApiController {}, "getThumbnail")
    10. /home/XXXX/web/XXXX/public_html/lib/private/AppFramework/App.php line 137
    OC\AppFramework\Http\Dispatcher->dispatch(OCA\Files\Controller\ApiController {}, "getThumbnail")
    11. /home/XXXX/web/XXXX/public_html/lib/private/AppFramework/Routing/RouteActionHandler.php line 47
    OC\AppFramework\App::main("APIController", "getThumbnail", OC\AppFramework\ ... {}, {x: "256",y: "25 ... "})
    12. <<closure>>
    OC\AppFramework\Routing\RouteActionHandler->__invoke({x: "256",y: "25 ... "})
    13. /home/XXXX/web/XXXX/public_html/lib/private/Route/Router.php line 297
    call_user_func(OC\AppFramework\ ... {}, {x: "256",y: "25 ... "})
    14. /home/XXXX/web/XXXX/public_html/lib/base.php line 1007
    OC\Route\Router->match("/apps/files/api ... f")
    15. /home/XXXX/web/XXXX/public_html/index.php line 37
    OC::handleRequest()

    GET /index.php/apps/files/api/v1/thumbnail/256/256/1_5118352478428987514.pdf
    from 78.95.238.102 by XXXX at 2020-08-20T20:54:30+00:00

The output of my config.php:

    <?php
    $CONFIG = array (
      'instanceid' => 'XXXX',
      'passwordsalt' => 'XXXX',
      'secret' => 'XXXX',
      'trusted_domains' => 
      array (
        0 => 'XXXX.com',
      ),
      'datadirectory' => '/home/XXXX/web/XXXX.com/public_html/data',
      'dbtype' => 'mysql',
      'version' => '19.0.1.1',
      'overwrite.cli.url' => 'https://XXXX.com',
      'dbname' => 'XXXX',
      'dbhost' => 'localhost',
      'dbport' => '',
      'dbtableprefix' => 'oc_',
      'mysql.utf8mb4' => true,
      'dbuser' => 'XXXX',
      'dbpassword' => 'XXXX',
      'installed' => true,
    );

Can you kindly assist me fixing the issue and getting the PDF previews to work.

Best regards,
Nasser

1 Like
2

You find all information in the documentation, so please describe IN DETAIL what changes you’ve tried to apply to your configuration and what the DETAILED result was of your tests.

3

Hello,

Thank you for your support.

I manage to fix the PDF preview by editing the config.php file to the following:

<?php
$CONFIG = array (
  'instanceid' => 'XXXX',
  'passwordsalt' => 'XXXX',
  'secret' => 'XXXX',
  'trusted_domains' => 
  array (
    0 => 'XXXX',
  ),
  'datadirectory' => '/home/XXXX/web/XXXX/public_html/data',
  'dbtype' => 'mysql',
  'version' => '19.0.1.1',
  'overwrite.cli.url' => 'XXXX',
  'dbname' => 'XXXX',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'XXXX',
  'dbpassword' => 'XXXX',
  'installed' => true,
  'memcache.local' => '\OC\Memcache\APCu',
  'enable_previews' => true,
  'preview_max_x' => 4096,
  'preview_max_y' => 4096,
  'preview_max_filesize_image' => 50,
  'enabledPreviewProviders' => [
    'OC\Preview\PNG',
    'OC\Preview\JPEG',
    'OC\Preview\GIF',
    'OC\Preview\HEIC',
    'OC\Preview\BMP',
    'OC\Preview\XBitmap',
    'OC\Preview\MP3',
    'OC\Preview\TXT',
    'OC\Preview\MarkDown',
    'OC\Preview\OpenDocument',
    'OC\Preview\Krita',
    'OC\Preview\PDF',
  ],
);

I also edited “Imagemagick security policy” just before the end by wrapping it :

  <!-- <policy domain="coder" rights="none" pattern="PS" />
  <policy domain="coder" rights="none" pattern="PS2" />
  <policy domain="coder" rights="none" pattern="PS3" />
  <policy domain="coder" rights="none" pattern="EPS" />
  <policy domain="coder" rights="none" pattern="PDF" /> 
  <policy domain="coder" rights="none" pattern="XPS" /> -->

The file I edited is loacted at /etc/ImageMagick-6/policy.xml . Hope this solution help other members with the same issue.

Regards,
Nasser

4 Likes
4

To give rights for PDF in the policy, you can run, e.g. in Dockerfile:

sed -i 's/\(^ *<policy.*rights="\)\([^"]*\)\(".*PDF.*\/>\)/\1read|write\3/1' /etc/ImageMagick-6/policy.xml

Of course, sed is bad for XML…

6 Likes
5

Thanks - worked for me.