Some Fetch Block URLs Fail, Citing "Upgrade Your Browser"

[Dan-Peck]

References
Ticket 47376

Describe the bug
When using a public URL to fetch basic textual data into a Fetch block, the result is an error message indicating the browser should be upgraded. In this particular scenario, we were using a Dropbox URL pointing to a text file, and it returned a "409" error, stating "Your current browser is not supported. We support the latest versions of the following browsers:"

To Reproduce
Steps to reproduce the behavior:

1. Create a Dropbox (or other site that serves files/data content) text file.
2. Use its "Sharing" functionality to retrieve a Public URL to the file.
3. On DAKboard, create a Fetch block and enter this Public URL into its configuration.
4. Notice the error shows after it runs a test-fetch on it.

Expected behavior
The text file should show as a result of the fetch.

Desktop (please complete the following information):
Any/all

Smartphone (please complete the following information):
Any/all

[Dan-Peck]

After some analysis with the team, we have found this is the result of an older User-Agent header string that we pass during the call to retrieve the URL content.

Updating the User-Agent string in these requests to report as a more modern browser should increase compatibility with most URLs, and allow them to work as expected moving forward.

[Dan-Peck]

Merged in @ 681dcea and added to the queue for upcoming release to the live site.