Use public link previews for relative paths

[juliusknorr]

Follow up to #1057 to make sure inserted images are accessible if they are in the same or sub directory of a share link

• Wait for Fix images in public links #1057 to be merged
• Add tests

[azul]

I tested this as follows:

• I created a folder public and moved one of the images from Media into it.
• I inserted the image into Readme.md via the workspace menu bar.
• The image shows up fine on teh public share
• However the image fails to show for the logged in user.

The relevant part of the html source for the logged in user looks like this

<div data-v-336b1e4e="" data-src="photo-1495962637988-4be9db2af01f.jpeg?fileId=10#mimetype=image%2Fjpeg&amp;hasPreview=true" class="image" contenteditable="false" draggable="true">
  <div data-v-336b1e4e="" class="image__placeholder">
    <div data-v-336b1e4e="" class="image__main" style="">
      <a data-v-336b1e4e="" href="/index.php/f/10" target="_blank">
        <div data-v-336b1e4e="" class="icon-image" style="background-image: url(&quot;/index.php/apps/theming/img/core/filetypes/image.svg?v=0&quot;);"></div> 
        <!---->
      </a>
    </div>
    <div data-v-336b1e4e="" class="image__caption" style="">
      <input data-v-336b1e4e="" type="text">
    </div>
  </div>
</div>

So it looks like we ended up in the placeholder branch of the template. The main branch has
v-if="imageLoaded && isSupportedImage".
So either imageLoaded or isSupportedImage is false.

I suspect that imageLoaded does not turn true because for an authenticated user the shareToken remains unset and the image cannot be loaded without it.

[azul]

With the one adjustment mentioned above this works for me.

the imageUrl function is getting a bit complex and repetetive towards the end.
I suspect replacing the temp previewPath and f with a query / computed property would help here.

[azul]

looks like the preview.png is what is breaking jpegs for the authenticated user.
Befor i had a 200 request for

http://nextcloud.local/index.php/core/preview?fileId=10&x=1024&y=1024&a=true

now i get a 400 for

http://nextcloud.local/index.php/core/preview.png?fileId=10&x=1024&y=1024&a=true

Suggested change

	const previewPath = (!isPublic ? generateUrl('/core/preview.png') : generateUrl('/apps/files_sharing/publicpreview/' + sharingToken))
	const previewPath = (!isPublic ? generateUrl('/core/preview') : generateUrl('/apps/files_sharing/publicpreview/' + sharingToken))

[juliusknorr]

Obsolete through #1900