What is the exact command or openService be called when user open a file in the file explorer

Previovely I’ve asked a question about what happend when user open a file in the file explorer in Theia. A nice contributor answered my question and said that

and uses the OpenerService to determine what is the best opener for the given resource.
I follow the suggestion to see the source code, I found that when open a file, the program will execute a open function in the openHandler.

But I just find an interface, not the implementation of it. So in the default implementaion when a file in the browser be clicked, what command will be called when execute the open function?
I want to do this because in my senario the file is actually empty, I want to intercept the open command and download the file from the file server(Which has been already implemented) after the user click the file in the file explorer. Thanks~

@LamYunfu you should take a look at who implements OpenHandler and see who has the highest canHandle for the given uri passed. As mentioned, we use the OpenerService to determine the best handler for the uri and use it to open.

For example, in the case that the editor is opened from the navigator (without a preview) it will use the following opener (traced with a simple log):

root INFO opener: { id: code-editor-opener, uri: file:///home/vince/workspaces/theia/package.json }

In this case it uses the EditorManager to open the file:

This may be different if the editor is opened as a preview or we have a handler with a higher priority for different file-types.