Fl-Query
Asynchronous data caching, refetching & invalidation library for Flutter. FL-Query lets you manage & distribute your async data without touching any global state
Fl-Query makes asynchronous server state management a breeze in flutter
# Features
- Async data caching & management
- Smart + effective refetching
- Optimistic updates
- Automatically cached data invalidation & unneeded query/mutation garbage collection
- Easy to write & understand code. Follows DRY (Don't repeat yourself) convention
- Compatible with both vanilla Flutter & elite [flutter_hooks](https://pub.dev/packages/flutter_hooks)
# Installation
Regular installation:
```bash
$ flutter pub add fl_query
```
For elite flutter_hooks user:
```bash
$ flutter pub add flutter_hooks
$ flutter pub add fl_query_hooks
```
# Docs
You can find the documentation (WIP) of fl-query at https://fl-query.vercel.app/
# Basic Usage
First wrap your `MaterialApp` with with `QueryBowlScope` widget
```dart
Widget build(BuildContext context) {
return QueryBowlScope(
child: MaterialApp(
title: 'Fl-Query Example App',
theme: ThemeData(
useMaterial3: true,
primarySwatch: Colors.blue,
),
home: const MyHomePage(),
),
);
}
```
Fl-Query has two types of jobs
- `QueryJob`: Used for storing GET requests or for storing changeable yet readonly async data
- `MutationJob`: Used for POST/PUT/DELETE requests or for mutating/changing data in services or a store asynchronously
You can write all your query or mutation logic a method parameter named `task` & identify the query uniquely by passing a unique `queryKey`
Example of a QueryJob:
```dart
final exampleQueryJob = QueryJob(
queryKey: "example", // have to be unique
task: (queryKey, externalData) async {
final res = await http.get("/api/example-data");
return jsonDecode(res.body);
}
);
```
Store the `QueryJob` somewhere globally accessible in your project so you can reuse it later
Now you can use this `QueryJob` anywhere inside your flutter app inside the build method using a `QueryBuilder` widget
```dart
Widget build(BuildContext context){
return QueryBuilder(
job: exampleQueryJob,
externalData: null,
builder: (context, query) {
if (!query.hasData || query.isLoading) {
return const CircularProgressIndicator();
}
return Row(
children: [
Text(query.data!),
ElevatedButton(
child: const Text("Refetch"),
onPressed: () async {
// refetches the query
await query.refetch();
},
),
],
);
},
);
}
```
Or if you're an elite **flutter_hooks** user you can use the `useQuery` hook which is exported from the `package:fl_query_hooks/fl_query_hooks.dart` to do the same thing as above
```dart
/* other imports */
import 'package:flutter_hooks/flutter_hooks.dart';
import 'package:fl_query_hooks/fl_query_hooks.dart'; // importing the fl-query hook package
class Example extends HookWidget{
Example(super.key);
Widget build(BuildContext context) {
final query = useQuery(job: exampleQueryJob, externalData: null);
if (!query.hasData || query.isLoading) {
return const CircularProgressIndicator();
}
return Row(
children: [
Text(query.data!),
ElevatedButton(
child: const Text("Refetch"),
onPressed: () async {
// refetches the query
await query.refetch();
},
),
],
);
}
}
```
# Why?
The main purpose of Fl-Query is providing the easiest way to manage the messy server-state part requiring the least amount of code with code reusability & performance
**Isn't `FutureBuilder` good?**
Yes but it is only if your commercial server has huge load of power & you're made of money or your app is simple or mostly offline & barely requires internet connection
`FutureBuilder` isn't good for data persistency & its impossible to share data across the entire application using it
**So `FutureProvider` from riverpod or provider not enough?**
Yeah, indeed its more than enough for many applications but what if your app needs Optimistic Updates & proper server-state synchronization or simply want a custom `cacheTime`? Although `FutureProvider` is a viable solution most of the `Future` related stuff, why not kick it up a notch with smart refetching capabilities with proper server-state synchronization?
Riverpod is definitely a inspiration for Fl-Query & the `QueryJob` is actually inspired by riverpod & imo is the best state management solution any library has ever provided but that's still a client state manager just like other client state manager or synchronous data manager
# Notice Board
This project is currently under heavy development & not yet production ready. There are lot of features to cover. If anyone encounters any unintended behavior or any bug please report it. Also we're open to improvement suggestions & feature requests
**Important!:** The project needs Dart-Flutter developers who are willing to contribute to the project by writing Tests. (I'm the worst example for tester)