src/Microsoft.Azure.SignalR/EndpointProvider/ServiceEndpointProvider.cs

// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Collections.Generic;
using System.Net;
using System.Security.Claims;
using System.Threading.Tasks;

namespace Microsoft.Azure.SignalR;

internal class ServiceEndpointProvider : IServiceEndpointProvider
{
    public const string ConnectionStringNotFound =
        "No connection string was specified. " +
        $"Please specify a configuration entry for {Constants.Keys.ConnectionStringDefaultKey}, " +
        "or explicitly pass one using IServiceCollection.AddAzureSignalR(connectionString) in Startup.ConfigureServices.";

    private readonly IAccessKey _accessKey;

    private readonly string _appName;

    private readonly TimeSpan _accessTokenLifetime;

    private readonly IServiceEndpointGenerator _generator;

    private readonly AccessTokenAlgorithm _algorithm;

    public IWebProxy Proxy { get; }

    public ServiceEndpointProvider(ServiceEndpoint endpoint, ServiceOptions serviceOptions)
    {
        _accessTokenLifetime = serviceOptions.AccessTokenLifetime;
        _accessKey = endpoint.AccessKey;
        _appName = serviceOptions.ApplicationName;
        _algorithm = serviceOptions.AccessTokenAlgorithm;

        Proxy = serviceOptions.Proxy;

        _generator = new DefaultServiceEndpointGenerator(endpoint);
    }

    public Task<string> GenerateClientAccessTokenAsync(string hubName, IEnumerable<Claim> claims = null, TimeSpan? lifetime = null)
    {
        if (string.IsNullOrEmpty(hubName))
        {
            throw new ArgumentNullException(nameof(hubName));
        }

        var audience = _generator.GetClientAudience(hubName, _appName);

        return _accessKey.GenerateAccessTokenAsync(audience, claims, lifetime ?? _accessTokenLifetime, _algorithm);
    }

    public string GetClientEndpoint(string hubName, string originalPath, string queryString)
    {
        return string.IsNullOrEmpty(hubName)
            ? throw new ArgumentNullException(nameof(hubName))
            : _generator.GetClientEndpoint(hubName, _appName, originalPath, queryString);
    }

    public IAccessTokenProvider GetServerAccessTokenProvider(string hubName, string serverId)
    {
        if (_accessKey is MicrosoftEntraAccessKey key)
        {
            return new MicrosoftEntraTokenProvider(key);
        }
        else if (_accessKey is AccessKey key2)
        {
            var audience = _generator.GetServerAudience(hubName, _appName);
            var claims = serverId != null ? new[] { new Claim(ClaimTypes.NameIdentifier, serverId) } : null;
            return new LocalTokenProvider(key2, audience, claims, _algorithm, _accessTokenLifetime);
        }
        else
        {
            throw new NotSupportedException("Access key cannot be null.");
        }
    }

    public string GetServerEndpoint(string hubName)
    {
        return string.IsNullOrEmpty(hubName)
            ? throw new ArgumentNullException(nameof(hubName))
            : _generator.GetServerEndpoint(hubName, _appName);
    }
}