Microsoft.Extensions.Caching.Postgres 1.1.0

Microsoft.Extensions.Caching.Postgres

A distributed cache implementation using PostgreSQL for .NET applications.

Installation

Install the NuGet package:

dotnet add package Microsoft.Extensions.Caching.Postgres

Configuration

1. Configure appsettings.json

Add the following configuration sections to your appsettings.json file. It's also recommended to configure your connection string to use connection pooling:

  "ConnectionStrings": {
    "PostgresCache": "Host=localhost;Port=5432;Username=postgres;Password=yourpassword;Database=yourdatabase;Pooling=true;MinPoolSize=0;MaxPoolSize=100;Timeout=15;"
  },
  "PostgresCache": {
    "SchemaName": "public",
    "TableName": "cache",
    "CreateIfNotExists": true,
    "UseWAL": false,
    "ExpiredItemsDeletionInterval": "00:30:00",
    "DefaultSlidingExpiration": "00:20:00"
  }

Configuration Options

2. Register the Service

Using Configuration Binding

using Microsoft.Extensions.DependencyInjection;

var builder = WebApplication.CreateBuilder(args);

// Register Postgres distributed cache
builder.Services.AddDistributedPostgresCache(options => {
    options.ConnectionString = builder.Configuration.GetConnectionString("PostgresCache");
    options.SchemaName = builder.Configuration.GetValue<string>("PostgresCache:SchemaName", "public");
    options.TableName = builder.Configuration.GetValue<string>("PostgresCache:TableName", "cache");
    options.CreateIfNotExists = builder.Configuration.GetValue<bool>("PostgresCache:CreateIfNotExists", true);
    options.UseWAL = builder.Configuration.GetValue<bool>("PostgresCache:UseWAL", false);
    
    // Optional: Configure expiration settings

    var expirationInterval = builder.Configuration.GetValue<string>("PostgresCache:ExpiredItemsDeletionInterval");
    if (!string.IsNullOrEmpty(expirationInterval) && TimeSpan.TryParse(expirationInterval, out var interval)) {
        options.ExpiredItemsDeletionInterval = interval;
    }
    
    var slidingExpiration = builder.Configuration.GetValue<string>("PostgresCache:DefaultSlidingExpiration");
    if (!string.IsNullOrEmpty(slidingExpiration) && TimeSpan.TryParse(slidingExpiration, out var sliding)) {
        options.DefaultSlidingExpiration = sliding;
    }
});

var app = builder.Build();

3. Using the Cache

Once configured, you can inject and use IDistributedCache in your services: using Microsoft.Extensions.Caching.Distributed;

public class MyService {
    private readonly IDistributedCache _cache; 

    public MyService(IDistributedCache cache) {
        _cache = cache;
    }

    public async Task<string> GetDataAsync(string key) {
        var cachedData = await _cache.GetStringAsync(key);
        
        if (cachedData == null) {
            // Fetch data from source
            var data = await FetchDataFromSource();
            
            // Cache the data with options
            var options = new DistributedCacheEntryOptions {
                AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(30),
                SlidingExpiration = TimeSpan.FromMinutes(5)
            };
            
            await _cache.SetStringAsync(key, data, options);
            return data;
        }
        
        return cachedData;
    }
}

Environment Variables

You can also configure the cache using environment variables with the prefix PostgresCache__:

PostgresCache__ConnectionString="Host=localhost;Port=5432;Username=postgres;Password=yourpassword;Database=yourdatabase"
PostgresCache__SchemaName="public"
PostgresCache__TableName="cache"
PostgresCache__CreateIfNotExists="true"