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Always try and show pre rendered preview 

Currently if the following situation happens

Server generates preview
Server has command removed which allows a preview to be shown
Client asks for preview, gets a 404 error when preview exists
(Mime checked before preview)

This happens more often with documents, or video as the commands are not
native PHP, they require a binary on the server.

After the fix the following would happen

Server generates preview
Server has command removed which allows a preview to be shown
Client asks for preview, gets preview which has been generated
(Mime checked after preview)

This would also allow offline generation (for example a docker image
containing the extra binaries), allowing a reduction in attack surface
of the instance serving the preview data.

Signed-off-by: Scott Dutton <scott@exussum.co.uk>
This commit is contained in:
Scott Dutton 2020-04-12 16:38:59 +01:00 committed by Morris Jobke
parent e9f5c7f649
commit b12a390220
No known key found for this signature in database
GPG Key ID: FE03C3A163FEDE68
1 changed files with 5 additions and 4 deletions
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9
lib/private/Preview/Generator.php
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@ -126,9 +126,6 @@ class Generator {
if ($mimeType === null) {
$mimeType = $file->getMimeType();
}
if (!$this->previewManager->isMimeSupported($mimeType)) {
throw new NotFoundException();
}
$previewFolder = $this->getPreviewFolder($file);
@ -155,7 +152,7 @@ class Generator {
$crop = $specification['crop'] ?? false;
$mode = $specification['mode'] ?? IPreview::MODE_FILL;
// If both width and heigth are -1 we just want the max preview
// If both width and height are -1 we just want the max preview
if ($width === -1 && $height === -1) {
$width = $maxWidth;
$height = $maxHeight;
@ -176,6 +173,10 @@ class Generator {
try {
$preview = $this->getCachedPreview($previewFolder, $width, $height, $crop, $maxPreview->getMimeType(), $previewVersion);
} catch (NotFoundException $e) {
if (!$this->previewManager->isMimeSupported($mimeType)) {
throw new NotFoundException();
}
if ($maxPreviewImage === null) {
$maxPreviewImage = $this->helper->getImage($maxPreview);
}