c# - 亚马逊产品广告 API ItemSearch 返回空值

Question

我花了一整天的时间尝试解决 Amazon ECS(电子商务服务)API 的问题。

我已经在他们的站点上下载了使用 .NET 4.0 和 WCF 发送 SOAP 请求的示例

http://aws.amazon.com/code/Product-Advertising-API/3941

除了配置文件中的 AccessKeyID 和 SecretyKeyID 之外，我没有更改示例代码中的任何内容。

调用代码如下所示:

        // Instantiate Amazon ProductAdvertisingAPI client
        AWSECommerceServicePortTypeClient amazonClient = new AWSECommerceServicePortTypeClient();

        // prepare an ItemSearch request
        ItemSearchRequest request = new ItemSearchRequest();
        request.SearchIndex = "Books";
        request.Title = "WCF";
        request.ResponseGroup = new string[] { "Medium"};

        ItemSearch itemSearch = new ItemSearch();
        itemSearch.Request = new ItemSearchRequest[] { request };
        request.Condition = Condition.All;
        itemSearch.AssociateTag = "";
        itemSearch.AWSAccessKeyId = ConfigurationManager.AppSettings["accessKeyId"];

        // send the ItemSearch request
        ItemSearchResponse response = amazonClient.ItemSearch(itemSearch);
        if (response != null)
        {
            // write out the results from the ItemSearch request
            foreach (var item in response.Items[0].Item)
            {
                Console.WriteLine(item.ItemAttributes.Title);
            }
        }
        Console.WriteLine("done...enter any key to continue>");
        Console.ReadLine();

对 ItemSearch() 的调用返回一个空对象。我进一步研究了这一点，发现在 AmazongSigningMessageInspector 类中，AfterReceiveReply() 方法显示正在返回正确的 SOAP XML 响应和结果，所以我知道它正在调用服务并正确返回。出于某种原因，尽管我留下了 NULL ItemSearch 对象。

我的类(class)代码如下:

class AmazonSigningBehaviorExtensionElement : BehaviorExtensionElement
{
    public AmazonSigningBehaviorExtensionElement()
    {
    }

    public override Type BehaviorType
    {
        get
        {
            return typeof(AmazonSigningEndpointBehavior);
        }
    }

    protected override object CreateBehavior()
    {
        return new AmazonSigningEndpointBehavior(AccessKeyId, SecretKey);
    }

    [ConfigurationProperty("accessKeyId", IsRequired = true)]
    public string AccessKeyId
    {
        get { return (string)base["accessKeyId"]; }
        set { base["accessKeyId"] = value; }
    }

    [ConfigurationProperty("secretKey", IsRequired = true)]
    public string SecretKey
    {
        get { return (string)base["secretKey"]; }
        set { base["secretKey"] = value; }
    }
}


public class AmazonSigningEndpointBehavior : IEndpointBehavior {
    private string  _accessKeyId    = "";
    private string  _secretKey  = "";

    public AmazonSigningEndpointBehavior()
    {
        this._accessKeyId = ConfigurationManager.AppSettings["accessKeyId"];
        this._secretKey = ConfigurationManager.AppSettings["secretKey"];
    }

    public AmazonSigningEndpointBehavior(string accessKeyId, string secretKey) {
        this._accessKeyId   = accessKeyId;
        this._secretKey     = secretKey;
    }

    public void ApplyClientBehavior(ServiceEndpoint serviceEndpoint, ClientRuntime clientRuntime) {
        clientRuntime.MessageInspectors.Add(new AmazonSigningMessageInspector(_accessKeyId, _secretKey));
    }

    public void ApplyDispatchBehavior(ServiceEndpoint serviceEndpoint, EndpointDispatcher endpointDispatcher) { return; }
    public void Validate(ServiceEndpoint serviceEndpoint) { return; }
    public void AddBindingParameters(ServiceEndpoint serviceEndpoint, BindingParameterCollection bindingParameters) { return; }
}

public class AmazonSigningMessageInspector : IClientMessageInspector {
    private string  _accessKeyId    = "";
    private string  _secretKey  = "";

    public AmazonSigningMessageInspector(string accessKeyId, string secretKey) {
        this._accessKeyId   = accessKeyId;
        this._secretKey     = secretKey;
    }

    public object BeforeSendRequest(ref Message request, IClientChannel channel) {
        // prepare the data to sign
        string      operation       = Regex.Match(request.Headers.Action, "[^/]+$").ToString();
        DateTime    now             = DateTime.UtcNow;
        string      timestamp       = now.ToString("yyyy-MM-ddTHH:mm:ssZ");
        string      signMe          = operation + timestamp;
        byte[]      bytesToSign     = Encoding.UTF8.GetBytes(signMe);

        // sign the data
        byte[]      secretKeyBytes  = Encoding.UTF8.GetBytes(_secretKey);
        HMAC        hmacSha256      = new HMACSHA256(secretKeyBytes);
        byte[]      hashBytes       = hmacSha256.ComputeHash(bytesToSign);
        string      signature       = Convert.ToBase64String(hashBytes);

        // add the signature information to the request headers
        request.Headers.Add(new AmazonHeader("AWSAccessKeyId", _accessKeyId));
        request.Headers.Add(new AmazonHeader("Timestamp", timestamp));
        request.Headers.Add(new AmazonHeader("Signature", signature));

        return null;
    }

    public void AfterReceiveReply(ref Message reply, object correlationState)
    {


    }
}

我到处都看到这个问题，但没有人在任何地方发布修复程序。有人请帮我解决这个问题。

Answer 1

我的问题是我缺少关联标签。

itemSearch.AssociateTag = "213";

生成的代码肯定有问题，ItemSearchResponse 包含一个代码未公开的错误集合。正是通过查看检查器中的原始消息为我指明了正确的方向。