topic Re: Null Reference Exception in File Management Extended C# in Digital Exchange

Null Reference Exception in File Management Extended C#

BohyonHwang — Fri, 15 Apr 2022 08:11:53 GMT

I'd tried to get an internet image file in the binary data item directly.
Utility - File Management [Extended C#] seemed to have the right action as 'Download File as Binary'.
But the action returned False Success even if HTTP Status Code equals 200 - OK.

What's wrong with my code?
A screenshot is attached.
Thanks in advance.

Re: Null Reference Exception in File Management Extended C#

BohyonHwang — Fri, 15 Apr 2022 08:24:53 GMT

Image is attached again.

Re: Null Reference Exception in File Management Extended C#

GeoffHirst — Thu, 12 May 2022 14:27:29 GMT

Hi @Bohyon Hwang,

Thank you for using Blue Prism.

The problem seems to be that the code in the download elements is relying on a response header called Content-Disposition. Now, it seems that its null, hence the null exception you are getting when the process tries to retrieve the filename.

Now, if you are familiar with C#, you could just edit the code as shown below:

if (responseMessage.Content.Headers.ContentDisposition != null)

{

fileName = responseMessage.Content.Headers.ContentDisposition.FileNameStar;

}

This code can be found on the code page of the Download File As Binary action. The downside is that in this example the filename will not be returned. I will need to spend more time to see how this might be resolved in full. In the interim, I hope this helps.

Once again, thank you for being an SS&C Blue Prism user.

regards

Geoff HIrst

SR DX Engineer, Integration and Enablement, Blue Prism Digital Exchange

-- Further Note. The problem may actually be that the website isn't responding how it should be. This link explains the header that is the issue here https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition.

If you try to download from another site, do you get the same problem?

Re: Null Reference Exception in File Management Extended C#

BohyonHwang — Fri, 13 May 2022 02:07:00 GMT

The problem is solved with the help of Mr Geoff Hirst.
The data item can be filled with the correct data I wanted.
It also works for downloading another website.
Thank you so much.