redis #

Redis-enabled services for the Angel framework. RedisService can be used alone, or as the backend of a CacheService, and thereby cache the results of calling an upstream database.

Installation #

package:angel_redis requires Angel 2.

In your pubspec.yaml:

dependencies:
    angel_framework: ^2.0.0-alpha
    angel_redis: ^1.0.0

Usage #

Pass an instance of RespCommands (from package:resp_client) to the RedisService constructor. You can also pass an optional prefix, which is recommended if you are using angel_redis for multiple logically-separate collections. Redis is a flat key-value store; by prefixing the keys used, angel_redis can provide the experience of using separate stores, rather than a single node.

Without a prefix, there's a chance that different collections can overwrite one another's data.

Notes #

• Neither index, nor modify is atomic; each performs two separate queries.angel_redis stores data as JSON strings, rather than as Redis hashes, so an update-in-place is impossible.
• index uses Redis' KEYS functionality, so use it sparingly in production, if at all. In a larger database, it can quickly become a bottleneck.
• remove uses MULTI+EXEC in a transaction.
• Prefer using update, rather than modify. The former only performs one query, though it does overwrite the current contents for a given key.
• When calling create, it's possible that you may already have an id in mind to insert into the store. For example, when caching another database, you'll preserve the ID or primary key of an item. angel_redis heeds this. If no id is present, then an ID will be created via an INCR call.

Example #

Also present at example/main.dart:

import 'package:angel_redis/angel_redis.dart';
import 'package:resp_client/resp_client.dart';
import 'package:resp_client/resp_commands.dart';

main() async {
  var connection = await connectSocket('localhost');
  var client = new RespClient(connection);
  var service = new RedisService(new RespCommands(client), prefix: 'example');

  // Create an object
  await service.create({'id': 'a', 'hello': 'world'});

  // Read it...
  var read = await service.read('a');
  print(read['hello']);

  // Delete it.
  await service.remove('a');

  // Close the connection.
  await connection.close();
}