Problem rendering images

[Harsimrat]

Our Images are on Azure Blob Storage and it needs a special SAS token to access (https://docs.microsoft.com/en-us/azure/storage/common/storage-dotnet-shared-access-signature-part-1).

We generate the Url on runtime and return it to the report viewer with valid SAS (proper Url), and sometimes the images render and other times it just gives 403.

An error has occurred while processing PictureBox 'Images':
Invalid image data.
------------- InnerException -------------
The remote server returned an error: (403) Forbidden.

Even if the images render in the viewer, when we go try to generate a PDF, it always throws the above error.

Harsimrat

 

[Neli]

Hi Harsimrat,

For the images that are not rendered correctly, I suspect that the SAS Token contains sequences of characters that are like URL encoded symbols, and our tool decodes them. For example: %2F is accepted as  "/", e.g. forward slash - check HTML URL Encoding Reference, and for that reason the exception is thrown because the link is not already the same. This is a known issue which is already resolved and the fix will be included in our Service Pack which will be released in the middle of June 2019.

As a workaround, you may implement a UserFunction which uses a custom logic to avoid this URL encoding, e.g. to take the URL to the image and resolve it to a Bitmap to be passed as a value to the PictureBox.

Regards,
Neli
Progress Telerik

[Harsimrat]

Thank you very much for the workaround, it worked successfully.

[Christine]

Hello, I just wanted to follow up on this question because I upgraded to v14.2.20.1021 and would like to use the Azure Blob Storage URL with SAS token (ideally without needing a user function). My understanding was that this was fixed in a 2019 version, however I am still seeing the following error for all of my PictureBoxes:

An error has occurred while processing PictureBox 'pictureBox3':

"The remote server returned an error: (400) Bad Request".

And interestingly enough, in the Telerik Report Designer, I can view the images 100% of the time.

 

I tried the URI config changes, but it didn't make a difference. I'm using .NET Framework 4.7.2.

Any ideas?

Thanks!

Christine

 

[Neli]

Hi Christine,

This seems to be an issue from the TLS version. The service is probably using a TLS 1.2 HTTPS connection. This makes sense since we have enabled this protocol in the Standalone designer. However, this should be enabled explicitly in order to connect to such secure web services. You may check the WebServiceDataSource failing to retrieve web resources on TLS 1.2 HTTPS connection KB article for details.

Please, test the approach from the KB  article and let us know if the issue is resolved.

Regards,
Neli
Progress Telerik

[Christine]

Fantastic. I was able to use the fix of calling "System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12" in my override method of SendAsync of the HttpDelegator in my Telerik reporting assembly. I'm able to view all blob images using the URL.

Thanks Neli.