PushServiceClient bindings for Azure Functions

The PushServiceClient extensions for Azure Functions supports input binding.

Packages

The PushServiceClient extensions for Azure Functions are provided in the Lib.Azure.WebJobs.Extensions.WebPush (in-process model) and Lib.Azure.Functions.Worker.Extensions.WebPush (isolated worker model) NuGet packages.

PM>  Install-Package Lib.Azure.WebJobs.Extensions.WebPush

PM>  Install-Package Lib.Azure.Functions.Worker.Extensions.WebPush

Input

The PushServiceClient input binding uses HttpClientFactory to retrieve PushServiceClient instance and passes it to the input parameter of the function.

Input - language-specific examples

Input - C# examples

Isolated Worker Model

In the isolated worker model functions, use the PushServiceInput attribute.

The attribute's constructor takes the application server public key and application server private key. For information about those settings and other properties that you can configure, see Input - configuration.

Azure Cosmos DB trigger, subscriptions from Azure Cosmos DB

The following example shows a C# function that broadcasts a notification to all known subscriptions. The function is triggered by a change in Azure Cosmos DB collection and retrieves subscriptions also from Azure Cosmos DB.

...

namespace Demo.Azure.Functions.Worker.PushNotifications
{
    public class SendNotificationFunction
    {
        private readonly ILogger _logger;

        public SendNotificationFunction(ILoggerFactory loggerFactory)
        {
            _logger = loggerFactory.CreateLogger<SendNotificationFunction>();
        }

        [Function("SendNotificationFunction")]
        public async Task Run([CosmosDBTrigger(
            databaseName: "PushNotifications",
            containerName: "Notifications",
            Connection = "CosmosDBConnection",
            LeaseContainerName = "NotificationsLeaseCollection",
            CreateLeaseContainerIfNotExists = true)] IReadOnlyList<Notification> notifications,
            [CosmosDBInput(
            databaseName: "PushNotifications",
            containerName: "Subscriptions",
            Connection = "CosmosDBConnection")] CosmosClient cosmosClient,
            [PushServiceInput(
            PublicKeySetting = "ApplicationServerPublicKey",
            PrivateKeySetting = "ApplicationServerPrivateKey",
            SubjectSetting = "ApplicationServerSubject")] PushServiceClient pushServiceClient)
        {
            if (notifications != null)
            {
                Container subscriptionsContainer = cosmosClient.GetDatabase("PushNotifications").GetContainer("Subscriptions");
                using (FeedIterator<PushSubscription> subscriptionsIterator = subscriptionsContainer.GetItemQueryIterator<PushSubscription>())
                {
                    while (subscriptionsIterator.HasMoreResults)
                    {
                        foreach (PushSubscription subscription in await subscriptionsIterator.ReadNextAsync())
                        {
                            foreach (Notification notification in notifications)
                            {
                                // Fire-and-forget
                                pushServiceClient.RequestPushMessageDeliveryAsync(subscription, new PushMessage(notification.Content)
                                {
                                    Topic = notification.Topic,
                                    TimeToLive = notification.TimeToLive,
                                    Urgency = notification.Urgency
                                });
                            }
                        }
                    }
                }
            }
        }
    }

    public class Notification
    {
        public string? Topic { get; set; }

        public string Content { get; set; } = String.Empty;

        public int? TimeToLive { get; set; }

        public PushMessageUrgency Urgency { get; set; }
    }
}

In-process Model

In C# class libraries, use the PushService attribute.

The attribute's constructor takes the application server public key and application server private key. For information about those settings and other properties that you can configure, see Input - configuration.

Azure Cosmos DB trigger, subscriptions from Azure Cosmos DB

The following example shows a C# function that broadcasts a notification to all known subscriptions. The function is triggered by a change in Azure Cosmos DB collection and retrieves subscriptions also from Azure Cosmos DB.

...

namespace Demo.Azure.Funtions.PushNotifications
{
    public class Notification
    {
        public string Topic { get; set; }

        public string Content {  get; set; }

        public int? TimeToLive { get; set; }

        public PushMessageUrgency Urgency { get; set; }
    }

    public static class SendNotificationFunction
    {
        [FunctionName("SendNotification")]
        public static async Task Run([CosmosDBTrigger(
            databaseName: "PushNotifications",
            containerName: "Notifications",
            Connection = "CosmosDBConnection",
            LeaseContainerName = "NotificationsLeaseCollection",
            CreateLeaseContainerIfNotExists = true)]IReadOnlyList<Notification> notifications,
            [CosmosDB(
            databaseName: "PushNotifications",
            containerName: "Subscriptions",
            Connection = "CosmosDBConnection")]CosmosClient cosmosClient,
            [PushService(
            PublicKeySetting = "ApplicationServerPublicKey",
            PrivateKeySetting = "ApplicationServerPrivateKey",
            SubjectSetting = "ApplicationServerSubject")]PushServiceClient pushServiceClient)
        {
            if (notifications != null)
            {
                Container subscriptionsContainer = cosmosClient.GetDatabase("PushNotifications").GetContainer("Subscriptions");
                using (FeedIterator<PushSubscription> subscriptionsIterator = subscriptionsContainer.GetItemQueryIterator<PushSubscription>())
                {
                    while (subscriptionsIterator.HasMoreResults)
                    {
                        foreach (PushSubscription subscription in await subscriptionsIterator.ReadNextAsync())
                        {
                            foreach (Notification notification in notifications)
                            {
                                // Fire-and-forget
                                pushServiceClient.RequestPushMessageDeliveryAsync(subscription, new PushMessage(notification.Content)
                                {
                                    Topic = notification.Topic,
                                    TimeToLive = notification.TimeToLive,
                                    Urgency = notification.Urgency
                                });
                            }
                        }
                    }
                }
            }
        }
    }
}

Input - configuration

The following table explains the binding configuration properties that you set in the function.json file and the PushService attribute.

function.json property	Attribute property	Description
type		Must be set to pushService.
direction		Must be set to in.
publicKeySetting	PublicKeySetting	The name of an app setting that contains the application server public key.
privateKeySetting	PrivateKeySetting	The name of an app setting that contains the application server private key.
subjectSetting	SubjectSetting	The name of an app setting that contains the contact information for the application server.