Bad URI syntax exception when file name contains '%' percent character

[timar]

Bad URI syntax exception when file name contains '%' percent character. E.g. someone has a file in Nextcloud with the name test%.odt, then it won't open in Collabora Online. In the log we will find the "Bad URI syntax" exception.

We had this problem long ago, fixed it (cf. 898c47f), had protected the fix with unit test. But regression happened nevertheless.

[timar]

Local make run, I renamed writer-edit.fodt to writer-edit%.fodt.

• http://localhost:9980/browser/e729f7ed07/debug.html?file_path=/home/timar/MOVE/online/test/samples/writer-edit%.fodt -> error 400
• http://localhost:9980/browser/e729f7ed07/debug.html?file_path=/home/timar/MOVE/online/test/samples/writer-edit%25.fodt -> error 400
• http://localhost:9980/browser/e729f7ed07/debug.html?file_path=/home/timar/MOVE/online/test/samples/writer-edit%2525.fodt -> error 500, with this message:

Error: 500 - Internal Server Error!
Cannot process the request - Bad URI syntax: URI encoding: not a hex digit /browser/e729f7ed07/cool.html
Please contact your system administrator.

The "not a hex digit" message comes from poco, https://github.com/austinsc/Poco/blob/f459e1ddb12354edd5c9908b2d53ec129bdcfa98/Foundation/src/URI.cpp#L617