CODEWITHSUNDEEP
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Brian Oh
Brian Oh

Reputation: 10720

Console application - StringDecoder stdin

The following or similar was shown for terminal input, however terminating input with ctl-d is not good. Is there another way to exit from this "loop"?

import "dart:io";

void main() {
  stdout.write("Enter Data : ");
  new StringDecoder().bind(stdin).listen((String sInput){});
////  Do something with sInput ............
}

Upvotes: 0

Views: 236

Answers (2)

Darshan Rivka Whittle
Darshan Rivka Whittle

Reputation: 34031

A few options come to mind. First, you could use takeWhile() to set a 'done' condition:

new StringDecoder().bind(stdin)
  .takeWhile((s) => s.trim() != 'exit')
  .listen((sInput) {

That will use the same onDone handler (if one is set) when the user inputs the EOF character or types exit followed by the enter key. You can have more flexibility by cancelling the subscription with cancel():

void main() {
  stdout.write("Enter Data : ");
  var sub;
  sub = new StringDecoder().bind(stdin).listen((String sInput) {
    if (sInput.trim() == 'exit' || sInput.trim() == 'bye')
      sub.cancel();
    // Do something with sInput ............
  });

Cancelling the subscription doesn't close the Stream, so any onDone handler isn't called.

Of course, if you've got nothing left to do, you can always terminate with exit(0) [1].

Upvotes: 1

Benjamin Gruenbaum
Benjamin Gruenbaum

Reputation: 276306

You can terminate a dart program by running the exit method when using dart:io

void exit(int status)
Exit the Dart VM process immediately with the given status code.

This does not wait for any asynchronous operations to terminate.
Using exit is therefore very likely to lose data.

From the docs

That code would go inside a check in the event handler in listen

Upvotes: 1

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