70 lines
2.9 KiB
Markdown
70 lines
2.9 KiB
Markdown
# Angel3 Redis
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[](https://dart.dev/null-safety)
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[](https://discord.gg/3X6bxTUdCM)
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[](https://github.com/dart-backend/angel/tree/master/packages/redis/LICENSE)
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**Forked from `angel_redis` to support NNBD**
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Redis-enabled services for the Angel3 framework. `RedisService` can be used alone, *or* as the backend of a [`CacheService`](https://pub.dev/packages/angel3_cache), and thereby cache the results of calling an upstream database.
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## Installation
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`package:angel3_redis` requires Angel3.
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In your `pubspec.yaml`:
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```yaml
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dependencies:
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angel3_framework: ^8.0.0
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angel3_redis: ^8.0.0
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```
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## Usage
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Pass an instance of `RespCommandsTier2` (from `package:resp_client`) to the `RedisService` constructor. You can also pass an optional prefix, which is recommended if you are using `angel3_redis` for multiple logically-separate collections. Redis is a flat key-value store; by prefixing the keys used, `angel3_redis` can provide the experience of using separate stores, rather than a single node.
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Without a prefix, there's a chance that different collections can overwrite one another's data.
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## Notes
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* Neither `index`, nor `modify` is atomic; each performs two separate queries.`angel3_redis` stores data as JSON strings, rather than as Redis hashes, so an update-in-place is impossible.
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* `index` uses Redis' `KEYS` functionality, so use it sparingly in production, if at all. In a larger database, it can quickly
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become a bottleneck.
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* `remove` uses `MULTI`+`EXEC` in a transaction.
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* Prefer using `update`, rather than `modify`. The former only performs one query, though it does overwrite the current
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contents for a given key.
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* When calling `create`, it's possible that you may already have an `id` in mind to insert into the store. For example,
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when caching another database, you'll preserve the ID or primary key of an item. `angel3_redis` heeds this. If no
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`id` is present, then an ID will be created via an `INCR` call.
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## Example
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Also present at `example/main.dart`:
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```dart
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import 'package:angel3_redis/angel3_redis.dart';
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import 'package:resp_client/resp_client.dart';
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import 'package:resp_client/resp_commands.dart';
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import 'package:resp_client/resp_server.dart';
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main() async {
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var connection = await connectSocket('localhost');
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var client = RespClient(connection);
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var service = RedisService(RespCommandsTier2(client), prefix: 'example');
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// Create an object
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await service.create({'id': 'a', 'hello': 'world'});
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// Read it...
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var read = await service.read('a');
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print(read['hello']);
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// Delete it.
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await service.remove('a');
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// Close the connection.
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await connection.close();
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}
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```
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