load PFIs from known source and cache as shared preference #17
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I need to add to this the ability to quickly set a local DID for when using a local PFI |
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Amazing @michaelneale!!
This is a great idea! I was also thinking about maybe having a local version of pfis.json or something so we can try out new PFIs before officially releasing them to the pfi-providers-data repo. But this is a great start.
| return (json.decode(cachedData) as List).map((data) { | ||
| return Pfi( | ||
| id: data['id'] as String, | ||
| name: data['name'] as String, | ||
| didUri: data['didUri'] as String, | ||
| ); | ||
| }).toList(); |
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For this type of stuff, you can add toJson and fromJson to the type to centralize this logic. Then you can do Pfi.fromJson(data) in these 2 places here. That could might look like this in pfi.dart
Map<String, dynamic> toJson() {
return {
'id': id,
'name': name,
'didUri': didUri,
};
}
factory Pfi.fromJson(Map<String, dynamic> json) {
return Pfi(
id: json['id'],
name: json['name'],
didUri: json['didUri'],
);
}| List<Pfi> pfis = (json.decode(response.body) as List).map((data) { | ||
| return Pfi( | ||
| id: data['id'] as String, | ||
| name: data['name'] as String, | ||
| didUri: data['didUri'] as String, | ||
| ); | ||
| }).toList(); |
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With the serialization change below, you can update to this if you wanna:
final pfis = (json.decode(response.body) as List)
.map<Pfi>((p) => Pfi.fromJson(p))
.toList();| // Save the data to cache | ||
| final prefs = await SharedPreferences.getInstance(); | ||
| await prefs.setString(cacheKey, response.body); |
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We can add a provider for this as well so that any code can use SharedPreferences without having to get an instance. It will be similar to how we setup secureStorage:
https://github.com/TBD54566975/didpay/blob/main/frontend/lib/services/service_providers.dart#L4
Then initialize and override it in main.dart:
https://github.com/TBD54566975/didpay/blob/main/frontend/lib/main.dart#L13-L24
Then when you need prefs you can use ref.read(sharedPreferencesProvider).setString(...)
| ); | ||
| final pfisProvider = FutureProvider<List<Pfi>>((ref) async { | ||
| const url = 'https://raw.githubusercontent.com/TBD54566975/pfi-providers-data/main/pfis.json'; | ||
| const cacheKey = 'pfis_cache'; |
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super nit: We can make this private to the file to avoid having to pass it to the _loadFromCache function below.
| } else { | ||
| // If server returns an unsuccessful response, try loading from cache | ||
| return await _loadFromCache(cacheKey); | ||
| } | ||
| } catch (e) { | ||
| // In case of an error, try loading from cache | ||
| return await _loadFromCache(cacheKey); | ||
| } |
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Another approach I like to use on mobile, to keep things snappy is to always load cache first, then always load from network. That way the users gets the list right away from cache and we can refresh from network after. This would require another provider/notifier which is a bit more complicated. Happy to show how that might work as well if you're interested.
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good idea - did that.
| ), | ||
| ) | ||
| ], | ||
| body: pfisAsyncValue.when( |
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nit: but you can use the ref directly here. This has the advantage that only this part of the widget tree will rebuild when the value changes.
ref.watch(pfisProvider).when(....
We can add some configs for prod, staging, and local etc. |
This will load the PFIs from an open github repo, caching them: TBD54566975/pfi-providers-data
It even shows a spinny circle the first time it is loading, which is kind of neat. Great typo on the branch name.