【基本解决】用C#实现AWS的API中的ItemLookup

【背景】

需要折腾amazon产品信息的抓取,之前是通过网页直接抓取,

但是由于网页变数太多,所以代码实现起来,很麻烦,效率很低。

后来得知了Amazon有个API,AWS,后来叫做

Amazon Product Advertising API

,可以供使用,可以实现很多相关的产品信息的查询功能:

【未解决】通过Amazon的API查找某个产品的关键字

【已解决】查询AWS中某个产品还剩多少个数可买

所以,就打算去折腾折腾。

【折腾过程】

1.继续参考:

【未解决】通过Amazon的API查找某个产品的关键字

中提到的:

REST版本的:

Product Advertising API Signed Requests Sample Code – C# REST/QUERY

去下载看看。

2.参考了其中的介绍:

About this Sample

  • Based on the 2009-03-31 API version.
  • This sample shows how to send an authenticated REST request to the Amazon Product Advertising API using C#

Prerequisites

Reference Documentation

Quick Start

Sample comes with SignedRequestHelper with the signature logic and an ItemLookupSample C# class that uses the SignedRequestHelper to perform a simple ItemLookup operation. To get started with the sample, follow these steps:

  1. Log in to the AWS portal at http://aws.amazon.com/ and copy your AWS Access Key ID and your AWS Secret Key. You can find them under the Your Account -> Access Identifiers menu after you log in.
  2. Extract the zip file into a working directory.
  3. Open the solution in Visual Studio
  4. Open the ItemLookupSample.cs file in Visual Studio editor and change the MY_AWS_ACCESS_KEY_ID and MY_AWS_SECRET_KEY values to match the ones you obtained from AWS.
  5. The DESTINATION in the sample refers to the US endpoint for the service. Change it if needed to the endpoint if your choice. If you do, you may also want to change the ITEM_ID value since the value was selected for the US locale.
  6. Run the sample in Visual Studio.

Comments, Questions or Feedback

If you have any comments, questions or feedback on the library, please visit the Amazon Amazon Product Advertising API discussion forums.

先去:

http://aws.amazon.com/cn/

登陆,从:

https://portal.aws.amazon.com/gp/aws/securityCredentials

找到自己的ASW Access Key ID和Secret Key。

3.打开项目:

AmazonProductAdvtApiSample.sln

其中由于项目是旧版本的,所以还需要用当前新的VS2010,将项目转换一下。

找到ItemLookupSample.cs,将其中的

MY_AWS_ACCESS_KEY_ID

MY_AWS_SECRET_KEY

改为自己的值。

其他啥都不改:

/**********************************************************************************************
 * 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 MY_AWS_ACCESS_KEY_ID = "xxx";
        private const string MY_AWS_SECRET_KEY = "yyy";
        private const string DESTINATION          = "ecs.amazonaws.com";
        
        private const string NAMESPACE = "http://webservices.amazon.com/AWSECommerceService/2009-03-31";
        private const string ITEM_ID   = "0545010225";

        public static void Main()
        {
            SignedRequestHelper helper = new SignedRequestHelper(MY_AWS_ACCESS_KEY_ID, MY_AWS_SECRET_KEY, DESTINATION);

            /*
             * The helper supports two forms of requests - dictionary form and query string form.
             */
            String requestUrl;
            String title;

            /*
             * Here is an ItemLookup example where the request is stored as a dictionary.
             */
            IDictionary<string, string> r1 = new Dictionary<string, String>();
            r1["Service"] = "AWSECommerceService";
            r1["Version"] = "2009-03-31";
            r1["Operation"] = "ItemLookup";
            r1["ItemId"] = ITEM_ID;
            r1["ResponseGroup"] = "Small";

            /* Random params for testing */
            r1["AnUrl"] = "http://www.amazon.com/books";
            r1["AnEmailAddress"] = "foobar@nowhere.com";
            r1["AUnicodeString"] = "αβγδεٵٶٷٸٹٺチャーハン叉焼";
            r1["Latin1Chars"] = "ĀāĂ㥹ĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħĨĩĪīĬĭĮįİıIJij";

            requestUrl = helper.Sign(r1);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Method 1: ItemLookup Dictionary form.");
            System.Console.WriteLine("Title is \"" + title + "\"");
            System.Console.WriteLine();

            /*
             * Here is a CartCreate example where the request is stored as a dictionary.
             */
            IDictionary<string, string> r2 = new Dictionary<string, String>();
            r2["Service"] = "AWSECommerceService";
            r2["Version"] = "2009-03-31";
            r2["Operation"] = "CartCreate";
            r2["Item.1.OfferListingId"] = "Ho46Hryi78b4j6Qa4HdSDD0Jhan4MILFeRSa9mK+6ZTpeCBiw0mqMjOG7ZsrzvjqUdVqvwVp237ZWaoLqzY11w==";
            r2["Item.1.Quantity"] = "1";

            requestUrl = helper.Sign(r2);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Method 1: CartCreate Dictionary form.");
            System.Console.WriteLine("Cart Item Title is \"" + title + "\"");
            System.Console.WriteLine();

            /*
             * Here is an example where the request is stored as a query-string:
             */

            /*
             * string requestString = "Service=AWSECommerceService&Version=2009-03-31&Operation=ItemLookup&ResponseGroup=Small&ItemId=" + ITEM_ID;
             */
            System.Console.WriteLine("Method 2: Query String form.");

            String[] Keywords = new String[] {
                "surprise!",
                "café",
                "black~berry",
                "James (Jim) Collins",
                "münchen",
                "harry potter (paperback)",
                "black*berry",
                "finger lickin' good",
                "!\"#$%'()*+,-./:;<=>?@[\\]^_`{|}~",
                "αβγδε",
                "ٵٶٷٸٹٺ",
                "チャーハン",
                "叉焼",
            };

            foreach (String keyword in Keywords)
            {
                String requestString = "Service=AWSECommerceService" 
                    + "&Version=2009-03-31"
                    + "&Operation=ItemSearch"
                    + "&SearchIndex=Books"
                    + "&ResponseGroup=Small"
                    + "&Keywords=" + keyword
                    ;
                requestUrl = helper.Sign(requestString);
                title = FetchTitle(requestUrl);

                System.Console.WriteLine("Keyword=\"" + keyword + "\"; Title=\"" + title + "\"");
                System.Console.WriteLine();
            }

            String cartCreateRequestString = 
                "Service=AWSECommerceService"
                + "&Version=2009-03-31"
                + "&Operation=CartCreate"
                + "&Item.1.OfferListingId=Ho46Hryi78b4j6Qa4HdSDD0Jhan4MILFeRSa9mK%2B6ZTpeCBiw0mqMjOG7ZsrzvjqUdVqvwVp237ZWaoLqzY11w%3D%3D"
                + "&Item.1.Quantity=1"
                ;
            requestUrl = helper.Sign(cartCreateRequestString);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Cart Item Title=\"" + title + "\"");
            System.Console.WriteLine();


            System.Console.WriteLine("Hit Enter to end");
            System.Console.ReadLine();
        }

        private static string FetchTitle(string url)
        {
            try
            {
                WebRequest request = HttpWebRequest.Create(url);
                WebResponse response = request.GetResponse();
                XmlDocument doc = new XmlDocument();
                doc.Load(response.GetResponseStream());

                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;
                return title;
            }
            catch (Exception e)
            {
                System.Console.WriteLine("Caught Exception: " + e.Message);
                System.Console.WriteLine("Stack Trace: " + e.StackTrace);
            }

            return null;
        }
    }
}

先测试一把试试,结果返回错误,xml是:

<?xml version="1.0"?>
<ItemLookupResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2011-08-01">
    <OperationRequest>
        <RequestId>79b3b89b-6873-4d95-ba25-b5e782d1f41b</RequestId>
        <Arguments>
            <Argument Name="Operation" Value="ItemLookup"/>
            <Argument Name="Service" Value="AWSECommerceService"/>
            <Argument Name="AnUrl" Value="http://www.amazon.com/books"/>
            <Argument Name="Signature" Value="oFsMRP3SJqgjejBtPOCJVgNPoi8GRmwvQwFiRUYEbEw="/>
            <Argument Name="Latin1Chars" Value="ĀāĂ㥹ĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħĨĩĪīĬĭĮįİıIJij"/>
            <Argument Name="Version" Value="2009-03-31"/>
            <Argument Name="ItemId" Value="0545010225"/>
            <Argument Name="AWSAccessKeyId" Value="xxx"/>
            <Argument Name="AUnicodeString" Value="αβγδεٵٶٷٸٹٺチャーハン叉焼"/>
            <Argument Name="Timestamp" Value="2013-06-13T02:23:41Z"/>
            <Argument Name="ResponseGroup" Value="Small"/>
            <Argument Name="AnEmailAddress" Value="foobar@nowhere.com"/>
        </Arguments>
        <RequestProcessingTime>0.0029690000000000</RequestProcessingTime>
    </OperationRequest>
    <Items>
        <Request>
            <IsValid>False</IsValid>
            <ItemLookupRequest>
                <IdType>ASIN</IdType>
                <ItemId>0545010225</ItemId>
                <ResponseGroup>Small</ResponseGroup>
                <VariationPage>All</VariationPage>
            </ItemLookupRequest>
            <Errors>
                <Error>
                    <Code>AWS.MissingParameters</Code>
                    <Message>Your request is missing required parameters. Required parameters include AssociateTag.</Message>
                </Error>
            </Errors>
        </Request>
    </Items>
</ItemLookupResponse>

 

4.其中参考:

http://docs.aws.amazon.com/AWSECommerceService/latest/DG/CHAP_ResponseGroupsList.html

找到示例代码中的ResponseGroup的Small:

Small

5.剩下的,只有先去自己参考api说明,一点点改改内容,试试能否得到正确的结果了。

结果还是没法完全弄懂。

6.后来发现,貌似此处是纯的C#代码,没有像别人:

amazon product advertising api – item lookup request working example

那样,用到Amazon的库,所以,想起来,Amazon本身对应.NET,是有个库的,可以去试试:

AWS SDK for .NET

然后去下载:

http://sdk-for-net.amazonwebservices.com/latest/AWSToolsAndSDKForNet.msi

然后再安装:

aws sdk for dotnet

然后就是,尝试利用AWS SDK For .NET去实现ItemLookup了:

【记录】尝试使用AWS SDK for .NET去实现C#版本的ItemLookup

 

7.结果还是没搞定,即,

通过AWS的SDK,搞不定;

通过那个AWSECommerceServicePortTypeClient,也搞不定;

 

8.后来只好再回来,试了试之前的AmazonProductAdvtApiSample,然后用如下代码:

/**********************************************************************************************
 * 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 MY_AWS_ACCESS_KEY_ID = "xxx";
        private const string MY_AWS_SECRET_KEY = "yyy";
        private const string DESTINATION          = "ecs.amazonaws.com";
        
        //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 ITEM_ID   = "0545010225";
        private const string ITEM_ID = "B0083PWAPW";

        public static void Main()
        {
            SignedRequestHelper helper = new SignedRequestHelper(MY_AWS_ACCESS_KEY_ID, MY_AWS_SECRET_KEY, DESTINATION);

            /*
             * The helper supports two forms of requests - dictionary form and query string form.
             */
            String requestUrl;
            String title;

            /*
             * Here is an ItemLookup example where the request is stored as a dictionary.
             */
            IDictionary<string, string> r1 = new Dictionary<string, String>();
            r1["Service"] = "AWSECommerceService";
            //r1["Version"] = "2009-03-31";
            r1["Operation"] = "ItemLookup";
            r1["ItemId"] = ITEM_ID;
            r1["ResponseGroup"] = "Small";

            /* Random params for testing */
            r1["AnUrl"] = "http://www.amazon.com/books";
            r1["AnEmailAddress"] = "foobar@nowhere.com";
            r1["AUnicodeString"] = "αβγδεٵٶٷٸٹٺチャーハン叉焼";
            r1["Latin1Chars"] = "ĀāĂ㥹ĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħĨĩĪīĬĭĮįİıIJij";

            requestUrl = helper.Sign(r1);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Method 1: ItemLookup Dictionary form.");
            System.Console.WriteLine("Title is \"" + title + "\"");
            System.Console.WriteLine();

            /*
             * Here is a CartCreate example where the request is stored as a dictionary.
             */
            IDictionary<string, string> r2 = new Dictionary<string, String>();
            r2["Service"] = "AWSECommerceService";
            //r2["Version"] = "2009-03-31";
            r2["Operation"] = "CartCreate";
            r2["Item.1.OfferListingId"] = "Ho46Hryi78b4j6Qa4HdSDD0Jhan4MILFeRSa9mK+6ZTpeCBiw0mqMjOG7ZsrzvjqUdVqvwVp237ZWaoLqzY11w==";
            r2["Item.1.Quantity"] = "1";

            requestUrl = helper.Sign(r2);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Method 1: CartCreate Dictionary form.");
            System.Console.WriteLine("Cart Item Title is \"" + title + "\"");
            System.Console.WriteLine();

            /*
             * Here is an example where the request is stored as a query-string:
             */

            /*
             * string requestString = "Service=AWSECommerceService&Version=2009-03-31&Operation=ItemLookup&ResponseGroup=Small&ItemId=" + ITEM_ID;
             */
            System.Console.WriteLine("Method 2: Query String form.");

            String[] Keywords = new String[] {
                "surprise!",
                "café",
                "black~berry",
                "James (Jim) Collins",
                "münchen",
                "harry potter (paperback)",
                "black*berry",
                "finger lickin' good",
                "!\"#$%'()*+,-./:;<=>?@[\\]^_`{|}~",
                "αβγδε",
                "ٵٶٷٸٹٺ",
                "チャーハン",
                "叉焼",
            };

            foreach (String keyword in Keywords)
            {
                String requestString = "Service=AWSECommerceService" 
                    + "&Version=2009-03-31"
                    + "&Operation=ItemSearch"
                    + "&SearchIndex=Books"
                    + "&ResponseGroup=Small"
                    + "&Keywords=" + keyword
                    ;
                requestUrl = helper.Sign(requestString);
                title = FetchTitle(requestUrl);

                System.Console.WriteLine("Keyword=\"" + keyword + "\"; Title=\"" + title + "\"");
                System.Console.WriteLine();
            }

            String cartCreateRequestString = 
                "Service=AWSECommerceService"
                + "&Version=2009-03-31"
                + "&Operation=CartCreate"
                + "&Item.1.OfferListingId=Ho46Hryi78b4j6Qa4HdSDD0Jhan4MILFeRSa9mK%2B6ZTpeCBiw0mqMjOG7ZsrzvjqUdVqvwVp237ZWaoLqzY11w%3D%3D"
                + "&Item.1.Quantity=1"
                ;
            requestUrl = helper.Sign(cartCreateRequestString);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Cart Item Title=\"" + title + "\"");
            System.Console.WriteLine();


            System.Console.WriteLine("Hit Enter to end");
            System.Console.ReadLine();
        }

        private static string FetchTitle(string url)
        {
            try
            {
                WebRequest request = HttpWebRequest.Create(url);
                WebResponse response = request.GetResponse();
                XmlDocument doc = new XmlDocument();
                doc.Load(response.GetResponseStream());

                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;
                return title;
            }
            catch (Exception e)
            {
                System.Console.WriteLine("Caught Exception: " + e.Message);
                System.Console.WriteLine("Stack Trace: " + e.StackTrace);
            }

            return null;
        }
    }
}

返回结果xml是:

<?xml version="1.0"?>
<ItemLookupResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2011-08-01">
    <OperationRequest>
        <RequestId>ce920fcd-a1df-49d6-9ded-770f7168027d</RequestId>
        <Arguments>
            <Argument Name="Operation" Value="ItemLookup"/>
            <Argument Name="Service" Value="AWSECommerceService"/>
            <Argument Name="AnUrl" Value="http://www.amazon.com/books"/>
            <Argument Name="Signature" Value="PR9IL4SYJEE51RLKsppraFS3OFGLggaXaab8/zSF3sc="/>
            <Argument Name="Latin1Chars" Value="ĀāĂ㥹ĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħĨĩĪīĬĭĮįİıIJij"/>
            <Argument Name="ItemId" Value="B0083PWAPW"/>
            <Argument Name="AWSAccessKeyId" Value="xxx"/>
            <Argument Name="AUnicodeString" Value="αβγδεٵٶٷٸٹٺチャーハン叉焼"/>
            <Argument Name="Timestamp" Value="2013-06-13T06:53:07Z"/>
            <Argument Name="ResponseGroup" Value="Small"/>
            <Argument Name="AnEmailAddress" Value="foobar@nowhere.com"/>
        </Arguments>
        <RequestProcessingTime>0.0028030000000000</RequestProcessingTime>
    </OperationRequest>
    <Items>
        <Request>
            <IsValid>False</IsValid>
            <ItemLookupRequest>
                <IdType>ASIN</IdType>
                <ItemId>B0083PWAPW</ItemId>
                <ResponseGroup>Small</ResponseGroup>
                <VariationPage>All</VariationPage>
            </ItemLookupRequest>
            <Errors>
                <Error>
                    <Code>AWS.MissingParameters</Code>
                    <Message>Your request is missing required parameters. Required parameters include AssociateTag.</Message>
                </Error>
            </Errors>
        </Request>
    </Items>
</ItemLookupResponse>

说明,有戏,继续折腾那个Associate Tag。

9.然后改为:

(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 MY_AWS_ACCESS_KEY_ID = "xxx";
        private const string MY_AWS_SECRET_KEY = "yyy";
        private const string MY_AWS_ASSOCIATE_TAG = "zzz";
        private const string DESTINATION          = "ecs.amazonaws.com";
        
        //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 ITEM_ID   = "0545010225";
        private const string ITEM_ID = "B0083PWAPW";

        public static void Main()
        {
            SignedRequestHelper helper = new SignedRequestHelper(MY_AWS_ACCESS_KEY_ID, MY_AWS_SECRET_KEY, MY_AWS_ASSOCIATE_TAG, DESTINATION);

            /*
             * The helper supports two forms of requests - dictionary form and query string form.
             */
            String requestUrl;
            String title;

            /*
             * Here is an ItemLookup example where the request is stored as a dictionary.
             */
            IDictionary<string, string> r1 = new Dictionary<string, String>();
            r1["Service"] = "AWSECommerceService";
            //r1["Version"] = "2009-03-31";
            r1["Operation"] = "ItemLookup";
            r1["ItemId"] = ITEM_ID;
            r1["ResponseGroup"] = "Small";

            /* Random params for testing */
            r1["AnUrl"] = "http://www.amazon.com/books";
            r1["AnEmailAddress"] = "foobar@nowhere.com";
            r1["AUnicodeString"] = "αβγδεٵٶٷٸٹٺチャーハン叉焼";
            r1["Latin1Chars"] = "ĀāĂ㥹ĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħĨĩĪīĬĭĮįİıIJij";

            requestUrl = helper.Sign(r1);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Method 1: ItemLookup Dictionary form.");
            System.Console.WriteLine("Title is \"" + title + "\"");
            System.Console.WriteLine();

            /*
             * Here is a CartCreate example where the request is stored as a dictionary.
             */
            IDictionary<string, string> r2 = new Dictionary<string, String>();
            r2["Service"] = "AWSECommerceService";
            //r2["Version"] = "2009-03-31";
            r2["Operation"] = "CartCreate";
            r2["Item.1.OfferListingId"] = "Ho46Hryi78b4j6Qa4HdSDD0Jhan4MILFeRSa9mK+6ZTpeCBiw0mqMjOG7ZsrzvjqUdVqvwVp237ZWaoLqzY11w==";
            r2["Item.1.Quantity"] = "1";

            requestUrl = helper.Sign(r2);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Method 1: CartCreate Dictionary form.");
            System.Console.WriteLine("Cart Item Title is \"" + title + "\"");
            System.Console.WriteLine();

            /*
             * Here is an example where the request is stored as a query-string:
             */

            /*
             * string requestString = "Service=AWSECommerceService&Version=2009-03-31&Operation=ItemLookup&ResponseGroup=Small&ItemId=" + ITEM_ID;
             */
            System.Console.WriteLine("Method 2: Query String form.");

            String[] Keywords = new String[] {
                "surprise!",
                "café",
                "black~berry",
                "James (Jim) Collins",
                "münchen",
                "harry potter (paperback)",
                "black*berry",
                "finger lickin' good",
                "!\"#$%'()*+,-./:;<=>?@[\\]^_`{|}~",
                "αβγδε",
                "ٵٶٷٸٹٺ",
                "チャーハン",
                "叉焼",
            };

            foreach (String keyword in Keywords)
            {
                String requestString = "Service=AWSECommerceService" 
                    + "&Version=2009-03-31"
                    + "&Operation=ItemSearch"
                    + "&SearchIndex=Books"
                    + "&ResponseGroup=Small"
                    + "&Keywords=" + keyword
                    ;
                requestUrl = helper.Sign(requestString);
                title = FetchTitle(requestUrl);

                System.Console.WriteLine("Keyword=\"" + keyword + "\"; Title=\"" + title + "\"");
                System.Console.WriteLine();
            }

            String cartCreateRequestString = 
                "Service=AWSECommerceService"
                + "&Version=2009-03-31"
                + "&Operation=CartCreate"
                + "&Item.1.OfferListingId=Ho46Hryi78b4j6Qa4HdSDD0Jhan4MILFeRSa9mK%2B6ZTpeCBiw0mqMjOG7ZsrzvjqUdVqvwVp237ZWaoLqzY11w%3D%3D"
                + "&Item.1.Quantity=1"
                ;
            requestUrl = helper.Sign(cartCreateRequestString);
            title = FetchTitle(requestUrl);

            System.Console.WriteLine("Cart Item Title=\"" + title + "\"");
            System.Console.WriteLine();


            System.Console.WriteLine("Hit Enter to end");
            System.Console.ReadLine();
        }

        private static string FetchTitle(string url)
        {
            try
            {
                WebRequest request = HttpWebRequest.Create(url);
                WebResponse response = request.GetResponse();
                XmlDocument doc = new XmlDocument();
                doc.Load(response.GetResponseStream());

                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;
                return title;
            }
            catch (Exception e)
            {
                System.Console.WriteLine("Caught Exception: " + e.Message);
                System.Console.WriteLine("Stack Trace: " + e.StackTrace);
            }

            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;
        //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
        //must add this Associate Tag
        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;
            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;
            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);
        }
    }
}

就可以获得返回结果了:

<?xml version="1.0"?>
<ItemLookupResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2011-08-01">
    <OperationRequest>
        <RequestId>5a3d38fc-d6bf-4a91-92c1-4e87df69a612</RequestId>
        <Arguments>
            <Argument Name="Operation" Value="ItemLookup"/>
            <Argument Name="Service" Value="AWSECommerceService"/>
            <Argument Name="Latin1Chars" Value="ĀāĂ㥹ĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħĨĩĪīĬĭĮįİıIJij"/>
            <Argument Name="AssociateTag" Value="xxx"/>
            <Argument Name="AUnicodeString" Value="αβγδεٵٶٷٸٹٺチャーハン叉焼"/>
            <Argument Name="AnUrl" Value="http://www.amazon.com/books"/>
            <Argument Name="Signature" Value="nqx7diOZknsj+gedZY7CuGkDnFtFPV+Sq3J1wkQy9pE="/>
            <Argument Name="ItemId" Value="B0083PWAPW"/>
            <Argument Name="AWSAccessKeyId" Value="xxx"/>
            <Argument Name="Timestamp" Value="2013-06-13T07:02:50Z"/>
            <Argument Name="ResponseGroup" Value="Small"/>
            <Argument Name="AnEmailAddress" Value="foobar@nowhere.com"/>
        </Arguments>
        <RequestProcessingTime>0.0085650000000000</RequestProcessingTime>
    </OperationRequest>
    <Items>
        <Request>
            <IsValid>True</IsValid>
            <ItemLookupRequest>
                <IdType>ASIN</IdType>
                <ItemId>B0083PWAPW</ItemId>
                <ResponseGroup>Small</ResponseGroup>
                <VariationPage>All</VariationPage>
            </ItemLookupRequest>
        </Request>
        <Item>
            <ASIN>B0083PWAPW</ASIN>
            <ParentASIN>B008GGCAVM</ParentASIN>
            <DetailPageURL>http://www.amazon.com/Kindle-Fire-HD/dp/B0083PWAPW%3FSubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB0083PWAPW</DetailPageURL>
            <ItemLinks>
                <ItemLink>
                    <Description>Technical Details</Description>
                    <URL>http://www.amazon.com/Kindle-Fire-HD/dp/tech-data/B0083PWAPW%3FSubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
                <ItemLink>
                    <Description>Add To Baby Registry</Description>
                    <URL>http://www.amazon.com/gp/registry/baby/add-item.html%3Fasin.0%3DB0083PWAPW%26SubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
                <ItemLink>
                    <Description>Add To Wedding Registry</Description>
                    <URL>http://www.amazon.com/gp/registry/wedding/add-item.html%3Fasin.0%3DB0083PWAPW%26SubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
                <ItemLink>
                    <Description>Add To Wishlist</Description>
                    <URL>http://www.amazon.com/gp/registry/wishlist/add-item.html%3Fasin.0%3DB0083PWAPW%26SubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
                <ItemLink>
                    <Description>Tell A Friend</Description>
                    <URL>http://www.amazon.com/gp/pdp/taf/B0083PWAPW%3FSubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
                <ItemLink>
                    <Description>All Customer Reviews</Description>
                    <URL>http://www.amazon.com/review/product/B0083PWAPW%3FSubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
                <ItemLink>
                    <Description>All Offers</Description>
                    <URL>http://www.amazon.com/gp/offer-listing/B0083PWAPW%3FSubscriptionId%3Dxxx%26tag%3Dxxx%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB0083PWAPW</URL>
                </ItemLink>
            </ItemLinks>
            <ItemAttributes>
                <Manufacturer>Amazon Digital Services, Inc</Manufacturer>
                <ProductGroup>Amazon Devices</ProductGroup>
                <Title>Kindle Fire HD 7", Dolby Audio, Dual-Band Wi-Fi, 16 GB - Includes Special Offers</Title>
            </ItemAttributes>
        </Item>
    </Items>
</ItemLookupResponse>

其中,cmd中打印出来的,第一个title就是对应的:

Kindle Fire HD 7", Dolby Audio, Dual-Band Wi-Fi, 16 GB – Includes Special Offers

 

【总结】

至此,算是至少让整个流程跑通了。接下来,就是如何分析返回的xml数据。

以及去增强整个AWS的函数和功能了。


后续折腾,参见:

【记录】继续优化C#版的AWS的ItemLookup接口



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