ExpoPushNotifications 1.0.2

expo-push-notifications-dotnet

Server-side library for sending Expo push notifications from .NET applications.

Installation

dotnet add package ExpoPushNotifications

Quick Start

Basic Usage

using ExpoPushNotifications;
using ExpoPushNotifications.Models;

// Create a client
var expo = new Expo(new ExpoClientOptions
{
    AccessToken = Environment.GetEnvironmentVariable("EXPO_ACCESS_TOKEN")
});

// Build messages
var messages = new List<ExpoPushMessage>();

foreach (var pushToken in somePushTokens)
{
    // Validate the token
    if (!Expo.IsExpoPushToken(pushToken))
    {
        Console.WriteLine($"Invalid push token: {pushToken}");
        continue;
    }

    messages.Add(new ExpoPushMessage
    {
        To = [pushToken],
        Title = "Hello",
        Body = "World",
        Sound = "default",
        Data = new Dictionary<string, object> { ["key"] = "value" }
    });
}

// Send notifications in chunks
foreach (var chunk in expo.ChunkPushNotifications(messages))
{
    try
    {
        var tickets = await expo.SendPushNotificationsAsync(chunk);

        foreach (var ticket in tickets)
        {
            if (ticket is ExpoPushErrorTicket errorTicket)
            {
                Console.WriteLine($"Error: {errorTicket.Message}");
            }
        }
    }
    catch (ExpoApiException ex)
    {
        Console.WriteLine($"API error: {ex.Message}");
    }
}

With Dependency Injection (ASP.NET Core)

// In Program.cs
builder.Services.AddExpoClient(options =>
{
    options.AccessToken = builder.Configuration["Expo:AccessToken"];
    options.MaxConcurrentRequests = 6;
    options.AttemptTimeout = TimeSpan.FromSeconds(10);
    options.TotalRequestTimeout = TimeSpan.FromSeconds(100);
});

// In your service
public class NotificationService
{
    private readonly IExpoClient _expo;

    public NotificationService(IExpoClient expo)
    {
        _expo = expo;
    }

    public async Task SendNotificationAsync(string token, string title, string body)
    {
        var messages = new[]
        {
            new ExpoPushMessage
            {
                To = [token],
                Title = title,
                Body = body,
                Sound = "default"
            }
        };

        var tickets = await _expo.SendPushNotificationsAsync(messages);
        // Process tickets...
    }
}

Checking Delivery Receipts

// Collect receipt IDs from successful tickets
var receiptIds = tickets
    .OfType<ExpoPushSuccessTicket>()
    .Select(t => t.Id)
    .ToList();

// Wait some time for delivery (15+ minutes recommended)
await Task.Delay(TimeSpan.FromMinutes(15));

// Retrieve receipts
foreach (var chunk in expo.ChunkPushNotificationReceiptIds(receiptIds))
{
    var receipts = await expo.GetPushNotificationReceiptsAsync(chunk);

    foreach (var (id, receipt) in receipts)
    {
        if (receipt is ExpoPushErrorReceipt errorReceipt)
        {
            Console.WriteLine($"Failed to deliver {id}: {errorReceipt.Message}");

            if (errorReceipt.Details?.Error == PushErrorCode.DeviceNotRegistered)
            {
                // Remove the token from your database
            }
        }
    }
}

API Reference

Expo Class

Configuration Options

Push Message Properties

Error Codes

Error Handling

The SDK automatically retries rate-limited requests (HTTP 429) with exponential backoff.

try
{
    var tickets = await expo.SendPushNotificationsAsync(messages);
}
catch (ExpoApiException ex) when (ex.IsRateLimitError)
{
    // All retries exhausted
    Console.WriteLine("Rate limited after retries");
}
catch (ExpoApiException ex) when (ex.IsAuthenticationError)
{
    // Invalid access token
    Console.WriteLine("Authentication failed");
}
catch (ExpoApiException ex)
{
    Console.WriteLine($"API error: {ex.Message}, Code: {ex.ErrorCode}");
}

Requirements

• .NET 8.0, 9.0, or 10.0

Related Projects

• expo-server-sdk-node - Node.js SDK (official)
• Expo Documentation

License

MIT