Hello evreyone … There is any way to decrease uploading files formats?? By default user can upload any types of format files … I mean I want to be able upload only multimedia files(ex. .mp3,mp4,png,jpeg)
Take a look at the file access control-app, in the docs there is only an example how to block an extension but you probably can write a rule to do it the other way round:
https://docs.nextcloud.com/server/13/admin_manual/file_workflows/access_control.html?highlight=file%20access%20control#prevent-uploading-of-specific-files
Thanks very much… But there is any way to change this from source code , not from admin panel???
Sure the project is open source: Issues · nextcloud/server · GitHub
There is even a blacklist for .htaccess-files, this can perhaps help you to implement your idea: server/apps/files/lib/Capabilities.php at b4f36d44c43aac0efdc6c70ff8e46473341a9bfe · nextcloud/server · GitHub
Thank you very much 
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I try their example for zip files, It’s work for me , but a can’t write another reg.expression for a few types
Can you help me to write reg.expression for a few files?? ,
P.S , Sorry for a bad English!!!
Regular expressions are a bit cryptic in the beginning but there are a lot of tutorials. There are also many editors, where you can test your expressions against a number of strings (it takes some time, but I’d have to do that as well):
https://regexr.com/