Reading static files under a library in Dart? - dart

Question

I am writing a library in Dart and I have static files under the library folder. I want to be able to read those files, but I'm not sure how to retrieve the path to it... there is not __FILE__ or $0 like in some other languages.
Update: It seems that I was not clear enough. Let this help you understand me:
test.dart
import 'foo.dart';
void main() {
print(Foo.getMyPath());
}
foo.dart
library asd;
class Foo {
static Path getMyPath() => new Path('resources/');
}
It gives me the wrong folder location. It gives me the path to test.dart + resources/, but I want the path to foo.dart + resources/.

Answer 1

As mentioned, you can use mirrors. Here's an example using what you wanted to achieve:
test.dart
import 'foo.dart';
void main() {
print(Foo.getMyPath());
}
foo.dart
library asd;
import 'dart:mirrors';
class Foo {
static Path getMyPath() => new Path('${currentMirrorSystem().libraries['asd'].url}/resources/');
}
It should output something like:
/Users/Kai/test/lib/resources/
There will probably be a better way to do this in a future release. I will update the answer when this is the case.
Update: You could also define a private method in the library:
/**
* Returns the path to the root of this library.
*/
_getRootPath() {
var pathString = new Path(currentMirrorSystem().libraries['LIBNAME'].url).directoryPath.toString().replaceFirst('file:///', '');
return pathString;
}

Answer 2

The dart mirrors API (still experimental, and not available on all platforms such as dart2js yet) exposes a url getter on the LibraryMirror. This should give you what you want.
I'm not aware of any other way to get this information on a library.
#import('dart:mirrors');
#import('package:mylib/mylib.dart');
main(){
final urlOfLib = currentMirrorSystem().libraries['myLibraryName'].url;
}

Answer 3

Generally the usual method of accessing resources which are located at a static position with your library is by use using a relative path.
#import('dart:io');
...
var filePath = new Path('resources/cool.txt');
var file = new File.fromPath(filePath);
// And if you really wanted, you can then get the full path
// Note: below is for example only. It is missing various
// integrity checks like error handling.
file.fullPath.then((path_str) {
print(path_str);
});
See addition API information on Path and on File
As an aside.. If you absolutely wanted to get the same type of output as __FILE__ you can do something like the following:
#import('dart:io');
...
var opts = new Options();
var path = new Path(opts.script);
var file = new File.fromPath(path);
file.fullPath().then((path_str) {
print(path_str);
});