would anyone have a working example of an amazon ITEMLOOKUP ?>
i have the following code but it does not seem to work:
string ISBN = "0393326381";
string ASIN = "";
if (!(string.IsNullOrEmpty(ISBN) && string.IsNullOrEmpty(ASIN)))
{
AWSECommerceServicePortTypeChannel service = new AWSECommerceServicePortTypeChannel();
ItemLookup lookup = new ItemLookup();
ItemLookupRequest request = new ItemLookupRequest();
lookup.AssociateTag = secretKey;
lookup.AWSAccessKeyId = accessKeyId;
if (string.IsNullOrEmpty(ASIN))
{
request.IdType = ItemLookupRequestIdType.ISBN;
request.ItemId = new string[] { ISBN.Replace("-", "") };
}
else
{
request.IdType = ItemLookupRequestIdType.ASIN;
request.ItemId = new string[] { ASIN };
}
request.ResponseGroup = new string[] { "OfferSummary" };
lookup.Request = new ItemLookupRequest[] { request };
response = service.ItemLookup(lookup);
if (response.Items.Length > 0 && response.Items[0].Item.Length > 0)
{
Item item = response.Items[0].Item[0];
if (item.MediumImage == null)
{
//bookImageHyperlink.Visible = false;
}
else
{
//bookImageHyperlink.ImageUrl = item.MediumImage.URL;
}
//bookImageHyperlink.NavigateUrl = item.DetailPageURL;
//bookTitleHyperlink.Text = item.ItemAttributes.Title;
//bookTitleHyperlink.NavigateUrl = item.DetailPageURL;
if (item.OfferSummary.LowestNewPrice == null)
{
if (item.OfferSummary.LowestUsedPrice == null)
{
//priceHyperlink.Visible = false;
}
else
{
//priceHyperlink.Text = string.Format("Buy used {0}", item.OfferSummary.LowestUsedPrice.FormattedPrice);
//priceHyperlink.NavigateUrl = item.DetailPageURL;
}
}
else
{
//priceHyperlink.Text = string.Format("Buy new {0}", item.OfferSummary.LowestNewPrice.FormattedPrice);
//priceHyperlink.NavigateUrl = item.DetailPageURL;
}
if (item.ItemAttributes.Author != null)
{
//authorLabel.Text = string.Format("By {0}", string.Join(", ", item.ItemAttributes.Author));
}
else
{
//authorLabel.Text = string.Format("By {0}", string.Join(", ", item.ItemAttributes.Creator.Select(c => c.Value).ToArray()));
}
/*
ItemLink link = item.ItemLinks.Where(i => i.Description.Contains("Wishlist")).FirstOrDefault();
if (link == null)
{
//wishListHyperlink.Visible = false;
}
else
{
//wishListHyperlink.NavigateUrl = link.URL;
}
* */
}
}
}
the problem is with this:
thisshould be defined differently but i do not know how AWSECommerceServicePortTypeChannel service = new AWSECommerceServicePortTypeChannel();
Say, that code looks awful familiar. You're missing the Endpoint signing piece from when they switched over to requiring that you add message signing. You need to add a behavior on your client. Here's the change to your code above:
if (!(string.IsNullOrEmpty(ISBN) && string.IsNullOrEmpty(ASIN)))
{
AWSECommerceServicePortTypeClient client = new AWSECommerceServicePortTypeClient();
client.ChannelFactory.Endpoint.Behaviors.Add(
new Amazon.AmazonSigningEndpointBehavior(
accessKeyId,
secretKey);
ItemLookup lookup = new ItemLookup();
ItemLookupRequest request = new ItemLookupRequest();
lookup.AssociateTag = accessKeyId;
lookup.AWSAccessKeyId = secretKey;
//... etc.
And here's the Endpoint (I can't take credit for this, I wish I could remember who should):
namespace Amazon
{
public class AmazonSigningEndpointBehavior : IEndpointBehavior {
private string accessKeyId = "";
private string 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; }
}
}
Oh. And you'll need the MessageInspector for that to work.
namespace Amazon
{
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) { }
}
}
And finally, the Header:
namespace Amazon
{
public class AmazonHeader : MessageHeader
{
private string name;
private string value;
public AmazonHeader(string name, string value)
{
this.name = name;
this.value = value;
}
public override string Name { get { return name; } }
public override string Namespace { get { return "http://security.amazonaws.com/doc/2007-01-01/"; } }
protected override void OnWriteHeaderContents(XmlDictionaryWriter xmlDictionaryWriter, MessageVersion messageVersion)
{
xmlDictionaryWriter.WriteString(value);
}
}
}
Yes, they made it complicated when they started requiring message signing...
A simple and easy library is available on nuget.
PM> Install-Package Nager.AmazonProductAdvertising
Example
var authentication = new AmazonAuthentication();
authentication.AccessKey = "accesskey";
authentication.SecretKey = "secretkey";
var wrapper = new AmazonWrapper(authentication, AmazonEndpoint.DE);
var result = wrapper.Lookup("0393326381", AmazonResponseGroup.OfferSummary);
To perform a lookup for anything other then an ASIN, you need to specify the "SearchIndex" property. You can simply set it to "All".
var request = new ItemLookupRequest();
request.ItemId = new[] {upcCode};
request.IdType = ItemLookupRequestIdType.UPC;
request.IdTypeSpecified = true;
request.SearchIndex = "All";
Here is a link to the documentation: http://docs.amazonwebservices.com/AWSECommerceService/2011-08-01/DG/index.html?ItemLookup.html. Note the description of the SearchIndex parameter:
Constraint:If ItemIdis an ASIN, a search index cannot be specified in the request. Required for non-ASIN ItemIds.
I actually built a little wrapper around it so it hands you back a handy object graph. I have the source up on BitBucket and a little more about it on the C# Amazon ItemLookup page.
You can make calls like:
var item = client.LookupByAsin("B0037X9N5U");
double? price = item.GetLowestPrice();
来源：https://stackoverflow.com/questions/6460936/amazon-product-advertising-api-item-lookup-request-working-example