Fetch with ReadableStream as Request Body
We’re working on making this work, see https://github.com/whatwg/fetch/pull/425 for the PR to the Fetch Standard. Once that is done you can expect this to make its way into browsers (slowly).
stream
Dart: How do you make a Future wait for a Stream?
You can use the Stream method firstWhere to create a future that resolves when your Stream emits a true value. Future<bool> whenTrue(Stream<bool> source) { return source.firstWhere((bool item) => item); } An alternative implementation without the stream method could use the await for syntax on the Stream. Future<bool> whenTrue(Stream<bool> source) async { await for (bool value … Read more
Difference between await for and listen in Dart
Given: Stream<String> stream = new Stream<String>.fromIterable([‘mene’, ‘mene’, ‘tekel’, ‘parsin’]); then: print(‘BEFORE’); stream.listen((s) { print(s); }); print(‘AFTER’); yields: BEFORE AFTER mene mene tekel parsin whereas: print(‘BEFORE’); await for(String s in stream) { print(s); } print(‘AFTER’); yields: BEFORE mene mene tekel parsin AFTER stream.listen() sets up code that will be put on the event queue when an … Read more
Flutter : stream two Streams into a single screen?
You can nest StreamBuilder if needed. Nothing prevents you from doing the following: StreamBuilder( stream: stream1, builder: (context, snapshot1) { return StreamBuilder( stream: stream2, builder: (context, snapshot2) { // do some stuff with both streams here }, ); }, ) Another solution if this makes sense for you is: Streams are designed to be mergeable/transformed. … Read more
How to reset a BehaviorSubject
I assume you want to clear the BehaviorSubject (because otherwise don’t call onComplete on it). That is not supported but you can achieve a similar effect by having a current value that is ignored by consumers: public static final Object EMPTY = new Object(); BehaviorSubject<Object> subject = BehaviorSubject.createDefault(EMPTY); Observable<YourType> obs = subject.filter(v -> v != … Read more
What is the difference between Sink and Stream in Flutter?
Sink and Stream both are parts of the StreamController. You add a data to the StreamController using Sink which can be listened via the Stream. Example: final _user = StreamController<User>(); Sink get updateUser => _user.sink; Stream<User> get user => _user.stream; Usage: updateUser.add(yourUserObject); // This will add data to the stream. Whenever a data is added … Read more
Dart: Do I have to cancel Stream subscriptions and close StreamSinks?
Short-answer: no, but you should. Nothing in the contract of either StreamSubscription or StreamSink requires closing the resources, but some use cases can lead to memory leaks if you don’t close them, even though in some cases, doing so might be confusing. Part of the confusion around these classes is that they are overloaded, and … Read more
Events vs Streams vs Observables vs Async Iterators
There are roughly two categories of APIs here: pull and push. Pull Async pull APIs are a good fit for cases where data is pulled from a source. This source might be a file, or a network socket, or a directory listing, or anything else. The key is that work is done to pull or … Read more
Difference between stream processing and message processing
In traditional message processing, you apply simple computations on the messages — in most cases individually per message. In stream processing, you apply complex operations on multiple input streams and multiple records (ie, messages) at the same time (like aggregations and joins). Furthermore, traditional messaging systems cannot go “back in time” — ie, they automatically … Read more