How can I open an external app from Firefox addon? (Eg: default text editor)

Question

I need my addon will be capable of editing some files with an external tool. Any ideas?

Answer 1

This snippet reveals or launches a file when provided with a path:

var localFile = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
localFile.initWithPath("C:\\some-directory\\some-file.png");

if(localFile.exists()){
    // localFile.reveal();       // open the containing folder of the file
    // localFile.launch();       // launch the file
}

However you might need to use nsIProcess in order to run an executable with parameters (such as the filepath you're trying to open with the executable).

var exeFile = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
exeFile.initWithPath("C:\\Program Files\\...\\app.exe");
var parameter="C:\\some-directory\\some-file.txt";
if(exeFile.exists()){
    var process = Cc["@mozilla.org/process/util;1"].createInstance(Ci.nsIProcess);  
    process.init(exeFile);
    process.run(false,[parameter],1);  // launch the executable with another file as parameter.
}

documentation:

https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIFile https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsILocalFile https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIProcess https://developer.mozilla.org/en-US/docs/Code_snippets/File_I_O