【背景】
折腾：
过程中，想要试试ResponseGroup的VariationSummary。
【折腾过程】
1. 完整代码：
（1）ItemLookupSample.cs
/**********************************************************************************************
* Copyright 2009 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
* except in compliance with the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0/
*
* or in the "LICENSE.txt" file accompanying this file. This file is distributed on an "AS IS"
* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under the License.
*
* ********************************************************************************************
*
* Amazon Product Advertising API
* Signed Requests Sample Code
*
* API Version: 2009-03-31
*
*/
using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.IO;
using System.Xml;
using System.Xml.XPath;
namespace AmazonProductAdvtApi
{
class ItemLookupSample
{
private const string awsAccessKeyId = "xxx";
private const string awsSecretKey = "xxx";
private const string awsAssociateTag = "xxx";
private const string awsDestination = "ecs.amazonaws.com";
private const string awsApiVersion = "2011-08-02";
//private const string NAMESPACE = "http://webservices.amazon.com/AWSECommerceService/2009-03-31";
//private const string NAMESPACE = "http://webservices.amazon.com/AWSECommerceService/2011-08-01";
private const string NAMESPACE = "http://webservices.amazon.com/AWSECommerceService/" + awsApiVersion;
//private const string ITEM_ID = "0545010225";
private const string ITEM_ID = "B0083PWAPW";
//<Item>
// <ASIN>B0083PWAPW</ASIN>
// <ParentASIN>B008GGCAVM</ParentASIN>
//</Item>
//private const string ITEM_ID = "B008GGCAVM";
public static void Main()
{
SignedRequestHelper helper = new SignedRequestHelper(awsAccessKeyId, awsSecretKey, awsAssociateTag, awsDestination);
/*
* Here is an ItemLookup example where the request is stored as a dictionary.
*/
IDictionary<string, string> reqDict = new Dictionary<string, String>();
reqDict["Service"] = "AWSECommerceService";
//r1["Version"] = "2009-03-31";
//r1["Version"] = "2009-03-31";
reqDict["Version"] = "2011-08-02";
reqDict["Operation"] = "ItemLookup";
reqDict["IdType"] = "ASIN";
reqDict["ItemId"] = ITEM_ID;
//reqDict["ResponseGroup"] = "Small";
//reqDict["ResponseGroup"] = "OfferSummary";
//reqDict["ResponseGroup"] = "ItemAttributes";
reqDict["ResponseGroup"] = "VariationSummary";
//reqDict["ResponseGroup"] = "Variations";
/*
* The helper supports two forms of requests - dictionary form and query string form.
*/
String requestUrl;
String title;
requestUrl = helper.Sign(reqDict);
title = FetchTitle(requestUrl);
System.Console.WriteLine("Method 1: ItemLookup Dictionary form.");
System.Console.WriteLine("Title is \"" + title + "\"");
System.Console.WriteLine();
}
private static string FetchTitle(string url)
{
try
{
WebRequest request = HttpWebRequest.Create(url);
WebResponse response = request.GetResponse();
XmlDocument doc = new XmlDocument();
doc.Load(response.GetResponseStream());
//for debug
System.Console.WriteLine(doc.InnerXml);
XmlNodeList errorMessageNodes = doc.GetElementsByTagName("Message", NAMESPACE);
if (errorMessageNodes != null && errorMessageNodes.Count > 0)
{
String message = errorMessageNodes.Item(0).InnerText;
return "Error: " + message + " (but signature worked)";
}
XmlNode titleNode = doc.GetElementsByTagName("Title", NAMESPACE).Item(0);
string title = titleNode.InnerText;
response.Close();
return title;
}
catch (Exception e)
{
System.Console.WriteLine("Caught Exception: " + e.Message);
System.Console.WriteLine("Stack Trace: " + e.StackTrace);
}
finally
{
}
return null;
}
}
}（2）SignedRequestHelper.cs
/**********************************************************************************************
* Copyright 2009 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
* except in compliance with the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0/
*
* or in the "LICENSE.txt" file accompanying this file. This file is distributed on an "AS IS"
* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under the License.
*
* ********************************************************************************************
*
* Amazon Product Advertising API
* Signed Requests Sample Code
*
* API Version: 2009-03-31
*
*/
using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.Security.Cryptography;
namespace AmazonProductAdvtApi
{
class SignedRequestHelper
{
private string endPoint;
private string akid;
//added by Crifan Li
//https://affiliate-program.amazon.co.uk/gp/advertising/api/detail/api-changes.html?ie=UTF8&pf_rd_t=501&ref_=amb_link_83388313_2&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_p=&pf_rd_s=assoc-center-1&pf_rd_r=&pf_rd_i=assoc-api-detail-2-v2
//Product Advertising API Change Details
//Associate Tag Parameter: Every request made to the API should include a valid Associate Tag. Any request that does not contain a valid Associate Tag will be rejected with an appropriate error message. For details on the Associate Tag parameter, please refer to our Developer guide.
//-> must add this Associate Tag, otherwise will return:
//<Error>
// <Code>AWS.MissingParameters</Code>
// <Message>Your request is missing required parameters. Required parameters include AssociateTag.</Message>
//</Error>
private string associateTag;
private byte[] secret;
private HMAC signer;
private const string REQUEST_URI = "/onca/xml";
private const string REQUEST_METHOD = "GET";
/*
* Use this constructor to create the object. The AWS credentials are available on
* http://aws.amazon.com
*
* The destination is the service end-point for your application:
* US: ecs.amazonaws.com
* JP: ecs.amazonaws.jp
* UK: ecs.amazonaws.co.uk
* DE: ecs.amazonaws.de
* FR: ecs.amazonaws.fr
* CA: ecs.amazonaws.ca
*/
public SignedRequestHelper(string awsAccessKeyId, string awsSecretKey, string awsAssociateTag, string destination)
{
this.endPoint = destination.ToLower();
this.akid = awsAccessKeyId;
//added by Crifan Li
this.associateTag = awsAssociateTag;
this.secret = Encoding.UTF8.GetBytes(awsSecretKey);
this.signer = new HMACSHA256(this.secret);
}
/*
* Sign a request in the form of a Dictionary of name-value pairs.
*
* This method returns a complete URL to use. Modifying the returned URL
* in any way invalidates the signature and Amazon will reject the requests.
*/
public string Sign(IDictionary<string, string> request)
{
// Use a SortedDictionary to get the parameters in naturual byte order, as
// required by AWS.
ParamComparer pc = new ParamComparer();
SortedDictionary<string, string> sortedMap = new SortedDictionary<string, string>(request, pc);
// Add the AWSAccessKeyId and Timestamp to the requests.
sortedMap["AWSAccessKeyId"] = this.akid;
//added by Crifan Li
sortedMap["AssociateTag"] = this.associateTag;
sortedMap["Timestamp"] = this.GetTimestamp();
// Get the canonical query string
string canonicalQS = this.ConstructCanonicalQueryString(sortedMap);
// Derive the bytes needs to be signed.
StringBuilder builder = new StringBuilder();
builder.Append(REQUEST_METHOD)
.Append("\n")
.Append(this.endPoint)
.Append("\n")
.Append(REQUEST_URI)
.Append("\n")
.Append(canonicalQS);
string stringToSign = builder.ToString();
byte[] toSign = Encoding.UTF8.GetBytes(stringToSign);
// Compute the signature and convert to Base64.
byte[] sigBytes = signer.ComputeHash(toSign);
string signature = Convert.ToBase64String(sigBytes);
// now construct the complete URL and return to caller.
StringBuilder qsBuilder = new StringBuilder();
qsBuilder.Append("http://")
.Append(this.endPoint)
.Append(REQUEST_URI)
.Append("?")
.Append(canonicalQS)
.Append("&Signature=")
.Append(this.PercentEncodeRfc3986(signature));
return qsBuilder.ToString();
}
/*
* Sign a request in the form of a query string.
*
* This method returns a complete URL to use. Modifying the returned URL
* in any way invalidates the signature and Amazon will reject the requests.
*/
public string Sign(string queryString)
{
IDictionary<string, string> request = this.CreateDictionary(queryString);
return this.Sign(request);
}
/*
* Current time in IS0 8601 format as required by Amazon
*/
private string GetTimestamp()
{
DateTime currentTime = DateTime.UtcNow;
string timestamp = currentTime.ToString("yyyy-MM-ddTHH:mm:ssZ");
return timestamp;
}
/*
* Percent-encode (URL Encode) according to RFC 3986 as required by Amazon.
*
* This is necessary because .NET's HttpUtility.UrlEncode does not encode
* according to the above standard. Also, .NET returns lower-case encoding
* by default and Amazon requires upper-case encoding.
*/
private string PercentEncodeRfc3986(string str)
{
str = HttpUtility.UrlEncode(str, System.Text.Encoding.UTF8);
str = str.Replace("'", "%27").Replace("(", "%28").Replace(")", "%29").Replace("*", "%2A").Replace("!", "%21").Replace("%7e", "~").Replace("+", "%20");
StringBuilder sbuilder = new StringBuilder(str);
for (int i = 0; i < sbuilder.Length; i++)
{
if (sbuilder[i] == '%')
{
if (Char.IsLetter(sbuilder[i + 1]) || Char.IsLetter(sbuilder[i + 2]))
{
sbuilder[i + 1] = Char.ToUpper(sbuilder[i + 1]);
sbuilder[i + 2] = Char.ToUpper(sbuilder[i + 2]);
}
}
}
return sbuilder.ToString();
}
/*
* Convert a query string to corresponding dictionary of name-value pairs.
*/
private IDictionary<string, string> CreateDictionary(string queryString)
{
Dictionary<string, string> map = new Dictionary<string, string>();
string[] requestParams = queryString.Split('&');
for (int i = 0; i < requestParams.Length; i++)
{
if (requestParams[i].Length < 1)
{
continue;
}
char[] sep = { '=' };
string[] param = requestParams[i].Split(sep, 2);
for (int j = 0; j < param.Length; j++)
{
param[j] = HttpUtility.UrlDecode(param[j], System.Text.Encoding.UTF8);
}
switch (param.Length)
{
case 1:
{
if (requestParams[i].Length >= 1)
{
if (requestParams[i].ToCharArray()[0] == '=')
{
map[""] = param[0];
}
else
{
map[param[0]] = "";
}
}
break;
}
case 2:
{
if (!string.IsNullOrEmpty(param[0]))
{
map[param[0]] = param[1];
}
}
break;
}
}
return map;
}
/*
* Consttuct the canonical query string from the sorted parameter map.
*/
private string ConstructCanonicalQueryString(SortedDictionary<string, string> sortedParamMap)
{
StringBuilder builder = new StringBuilder();
if (sortedParamMap.Count == 0)
{
builder.Append("");
return builder.ToString();
}
foreach (KeyValuePair<string, string> kvp in sortedParamMap)
{
builder.Append(this.PercentEncodeRfc3986(kvp.Key));
builder.Append("=");
builder.Append(this.PercentEncodeRfc3986(kvp.Value));
builder.Append("&");
}
string canonicalString = builder.ToString();
canonicalString = canonicalString.Substring(0, canonicalString.Length - 1);
return canonicalString;
}
}
/*
* To help the SortedDictionary order the name-value pairs in the correct way.
*/
class ParamComparer : IComparer<string>
{
public int Compare(string p1, string p2)
{
return string.CompareOrdinal(p1, p2);
}
}
}返回的xml结果为：
<?xml version="1.0"?>
<ItemLookupResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2011-08-01">
<OperationRequest>
<RequestId>dae5b10b-e4c5-4ec7-9d6a-072ee3bcf9cc</RequestId>
<Arguments>
<Argument Name="Operation" Value="ItemLookup"/>
<Argument Name="Service" Value="AWSECommerceService"/>
<Argument Name="Signature" Value="zyGwjGxKto/TR4l9h2Wir0TFmP5nDE4+u79TziAgYFo="/>
<Argument Name="AssociateTag" Value="xxx"/>
<Argument Name="Version" Value="2011-08-02"/>
<Argument Name="ItemId" Value="B0083PWAPW"/>
<Argument Name="IdType" Value="ASIN"/>
<Argument Name="AWSAccessKeyId" Value="xxx"/>
<Argument Name="Timestamp" Value="2013-06-13T09:34:05Z"/>
<Argument Name="ResponseGroup" Value="VariationSummary"/>
</Arguments>
<RequestProcessingTime>0.0114470000000000</RequestProcessingTime>
</OperationRequest>
<Items>
<Request>
<IsValid>True</IsValid>
<ItemLookupRequest>
<IdType>ASIN</IdType>
<ItemId>B0083PWAPW</ItemId>
<ResponseGroup>VariationSummary</ResponseGroup>
<VariationPage>All</VariationPage>
</ItemLookupRequest>
</Request>
<Item>
<ASIN>B0083PWAPW</ASIN>
<ParentASIN>B008GGCAVM</ParentASIN>
</Item>
</Items>
</ItemLookupResponse>不是我们所想要的。
因为在
网页：
http://www.amazon.com/Kindle-Fire-HD/dp/B0083PWAPW/
中看到的2×2=4个variation：
16 GB或32 GB
With Special Offers或Without Special Offers
共4个，才对。
2.后来，发现，可以通过上述得到ParentASIN的值B008GGCAVM，去获得对应的我们所要的VariationSummary的信息
代码：
//private const string ITEM_ID = "B0083PWAPW";
//<Item>
// <ASIN>B0083PWAPW</ASIN>
// <ParentASIN>B008GGCAVM</ParentASIN>
//</Item>
private const string ITEM_ID = "B008GGCAVM";返回xml：
<?xml version="1.0"?>
<ItemLookupResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2011-08-01">
<OperationRequest>
<RequestId>725c039e-a79c-43e4-bf86-e61a0b683a45</RequestId>
<Arguments>
<Argument Name="Operation" Value="ItemLookup"/>
<Argument Name="Service" Value="AWSECommerceService"/>
<Argument Name="Signature" Value="K7O0rI0Vpn23Xva50Mv7s9Yx7tV+MQHvczDNyYdNV1E="/>
<Argument Name="AssociateTag" Value="xxx"/>
<Argument Name="Version" Value="2011-08-02"/>
<Argument Name="ItemId" Value="B008GGCAVM"/>
<Argument Name="IdType" Value="ASIN"/>
<Argument Name="AWSAccessKeyId" Value="xxx"/>
<Argument Name="Timestamp" Value="2013-06-13T09:38:10Z"/>
<Argument Name="ResponseGroup" Value="VariationSummary"/>
</Arguments>
<RequestProcessingTime>0.0182190000000000</RequestProcessingTime>
</OperationRequest>
<Items>
<Request>
<IsValid>True</IsValid>
<ItemLookupRequest>
<IdType>ASIN</IdType>
<ItemId>B008GGCAVM</ItemId>
<ResponseGroup>VariationSummary</ResponseGroup>
<VariationPage>All</VariationPage>
</ItemLookupRequest>
</Request>
<Item>
<ASIN>B008GGCAVM</ASIN>
<ParentASIN>B008GGCAVM</ParentASIN>
<VariationSummary>
<LowestPrice>
<Amount>19900</Amount>
<CurrencyCode>USD</CurrencyCode>
<FormattedPrice>$199.00</FormattedPrice>
</LowestPrice>
<HighestPrice>
<Amount>24400</Amount>
<CurrencyCode>USD</CurrencyCode>
<FormattedPrice>$244.00</FormattedPrice>
</HighestPrice>
</VariationSummary>
</Item>
</Items>
</ItemLookupResponse>
【总结】
如果一个variation的ASIN，不是个child的，则只能获得类似于：
<Item>
<ASIN>B0083PWAPW</ASIN>
<ParentASIN>B008GGCAVM</ParentASIN>
</Item>的信息，需要拿到其parent的ASIN，然后才能获得所需要的VariationSummary的信息：
<Item>
<ASIN>B008GGCAVM</ASIN>
<ParentASIN>B008GGCAVM</ParentASIN>
<VariationSummary>
<LowestPrice>
<Amount>19900</Amount>
<CurrencyCode>USD</CurrencyCode>
<FormattedPrice>$199.00</FormattedPrice>
</LowestPrice>
<HighestPrice>
<Amount>24400</Amount>
<CurrencyCode>USD</CurrencyCode>
<FormattedPrice>$244.00</FormattedPrice>
</HighestPrice>
</VariationSummary>
</Item>
更多细节可参考：
http://docs.aws.amazon.com/AWSECommerceService/latest/DG/RG_VariationSummary.html
相关参考：
【整理】C#版的AWS的ResponseGroup的Small示例代码
【整理】C#版的AWS的ResponseGroup的OfferSummary示例代码
【整理】C#版的AWS的ResponseGroup的ItemAttributes示例代码