how to distinguish rpc called from which peer

[ahczbhht1989]

pub trait FileSystem {
    type Metadata;
    fn new() -> Self;
    #[rpc(name = "open_file")]
    fn open_file(&self, file_name: String) -> Result<OpenFileResult>;
}

I have the rpc method open_file，I want to know which peer called open_file，and do somthing. How to do it.

[tomusdrw]

You can use Metadata to get information about the client. It would be necessary to implement MetaExtractor and use some of the data available in RequestContext.

[ahczbhht1989]

Thank you.Can you give me a example?