xamarin.forms - 来自 Xamarin Forms PCL 的 Azure ServiceBus

Question

如何通过 Azure 服务总线从 Xamarin Forms PCL 完成消息传递...是否有 SDK、库或插件？如果有一种方法可以手动滚动代理消息，我想它可以通过 HttpClient 和 REST API 来完成......

Answer 1

我终于有了一种从 Xamarin PCL 向 Azure 服务总线队列发布消息的工作方法!这样做的方法是通过 HttpClient。

使解决方案难以捉摸的问题:

Microsoft.ServiceBus.Messaging 的 nuget 包将很容易安装，但没有接触到可移植类。

WebClient 示例比比皆是，但在
PCL!

PCL 没有用于共享访问签名的 HMACSHA256 的 native 加密
token 。从 nuget 获取 PCLCrypto 包。

一些文档说 Content-Type 的请求 header :application/atom+xml;type=entry;charset=utf-8 和 BrokerProerties 是必需的。不是这样!

发布到的路径是:BaseServiceBusAddress + queue + "/messages"

public const string ServiceBusNamespace = [YOUR SERVICEBUS NAMESPACE];

public const string BaseServiceBusAddress = "https://" + ServiceBusNamespace + ".servicebus.windows.net/";

/// <summary>
/// The get shared access signature token.
/// </summary>
/// <param name="sasKeyName">
/// The shared access signature key name.
/// </param>
/// <param name="sasKeyValue">
/// The shared access signature key value.
/// </param>
/// <returns>
/// The <see cref="string"/>.
/// </returns>
public static string GetSasToken(string sasKeyName, string sasKeyValue)
{
    var expiry = GetExpiry();
    var stringToSign = WebUtility.UrlEncode(BaseServiceBusAddress ) + "\n" + expiry;

    var algorithm = WinRTCrypto.MacAlgorithmProvider.OpenAlgorithm(MacAlgorithm.HmacSha256);
    var hasher = algorithm.CreateHash(Encoding.UTF8.GetBytes(sasKeyValue));
    hasher.Append(Encoding.UTF8.GetBytes(stringToSign));
    var mac = hasher.GetValueAndReset();
    var signature = Convert.ToBase64String(mac);

    var sasToken = string.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}", WebUtility.UrlEncode(baseAddress), WebUtility.UrlEncode(signature), expiry, sasKeyName);
    return sasToken;
}

/// <summary>
/// Posts an order data transfer object to queue.
/// </summary>
/// <param name="orderDto">
/// The order data transfer object.
/// </param>
/// <param name="serviceBusNamespace">
/// The service bus namespace.
/// </param>
/// <param name="sasKeyName">
/// The shared access signature key name.
/// </param>
/// <param name="sasKey">
/// The shared access signature key.
/// </param>
/// <param name="queue">
/// The queue.
/// </param>
/// <returns>
/// The <see cref="Task"/>.
/// </returns>
public static async Task<HttpResponseMessage> PostOrderDtoToQueue(OrderDto orderDto, string serviceBusNamespace, string sasKeyName, string sasKey, string queue)
{
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(BaseServiceBusAddress);
        client.DefaultRequestHeaders.Accept.Clear();

        var token = GetSasToken(sasKeyName, sasKey);
        client.DefaultRequestHeaders.Add("Authorization", token);

        HttpContent content = new StringContent(JsonConvert.SerializeObject(orderDto), Encoding.UTF8);
        content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

        var path = BaseServiceBusAddress + queue + "/messages";

        return await client.PostAsync(path, content);
    }
}

/// <summary>
///     Gets the expiry for a shared access signature token
/// </summary>
/// <returns>
///     The <see cref="string" /> expiry.
/// </returns>
private static string GetExpiry()
{
    var sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);
    return Convert.ToString((int)sinceEpoch.TotalSeconds + 3600);
}

}