Below is a code sample showing how to write text in file(data.txt) in your extension's folder.
- You need to change the value of var id variable to match the id of your extension.
- The code below doesn't write correctly non-ASCII characters. If you need to write non-ASCII, see Writing_textual_data.
- The location of the file created is stored in file.path. You can use
alert(file.path);to view the location.
- Each time you reinstall/update your extension, your extension's folder will be deleted. Therefore, your saved file in there is also deleted. It is not safe to save data in your extension's folder.
/* * Get the path of your extension's folder. */ var id = "youExtId@openwritings.net";// The extension's id from install.rdf(i.e. <em:id>) var ext = Components.classes["@mozilla.org/extensions/manager;1"] .getService(Components.interfaces.nsIExtensionManager) .getInstallLocation(id) .getItemLocation(id); /* * Setting up the full path of the file. */ var file = Components.classes["@mozilla.org/file/local;1"] .createInstance(Components.interfaces.nsILocalFile); file.initWithPath(ext.path); // The path passed to initWithPath() should be in "native" form. file.append("data.txt"); // Use append() so you don't have to handle folder separator(e.g. / or \). /* * Writing data to the file. */ var foStream = Components.classes["@mozilla.org/network/file-output-stream;1"] .createInstance(Components.interfaces.nsIFileOutputStream); // See https://developer.mozilla.org/en/PR_Open#Parameters for the description of each octal constant. foStream.init(file, 0x02 | 0x08 | 0x20, 0666, 0); var data = "text to write in the file."; foStream.write(data, data.length); foStream.close();