如何仅使用客户端JavaScript正确签署对Amazon的ItemLookup的GET请求？ [英] How to properly sign a GET request to Amazon's ItemLookup using client-side JavaScript only?

问题描述

这是我到目前为止所拥有的：

Here's what I have so far:

function sha256(stringToSign, secretKey) {
  return CryptoJS.HmacSHA256(stringToSign, secretKey);
} 

function getAmazonItemInfo(barcode) {

  var parameters = 
    "Service=AWSECommerceService&"
    + "AWSAccessKeyId=" + appSettings.amazon.accessKey + "&"
    + "Operation=ItemLookup&"
    + "ItemId=" + barcode
    + "&Timestamp=" + Date.now().toString();

  var stringToSign =
    "GET\n"
    + "webservices.amazon.com\n"
    + "/onca/xml\n"
    + parameters;

  var signature = "&Signature=" + encodeURIComponent(sha256(stringToSign, appSettings.amazon.secretKey));

  var amazonUrl =  
    "http://webservices.amazon.com/onca/xml?"
    + parameters
    + signature;

  // perform a GET request with amazonUrl and do other stuff

}

当作为HTTP GET请求执行时，上述代码中的 amazonUrl 的值会导致亚马逊的以下响应：

When executed as an HTTP GET request, the value of amazonUrl in the above code results in the following response from Amazon:

<?xml version="1.0"?> 
  <ItemLookupErrorResponse xmlns="http://ecs.amazonaws.com/doc/2005-10-05/">
    <Error>
      <Code>SignatureDoesNotMatch</Code>
      <Message>
        The request signature we calculated does not match the signature you provided. 
        Check your AWS Secret Access Key and signing method. Consult the service 
        documentation for details.
      </Message>
   </Error>
   <RequestId>[REMOVED]</RequestId>
  </ItemLookupErrorResponse>

有用链接：

ItemLookup - 产品广告API亚马逊文档

REST请求示例

AWS身份验证流程

CryptoJS

推荐答案

我用你的代码破解了我的工作。

I hacked around with your code and I got it working.

function sha256(stringToSign, secretKey) {
  var hex = CryptoJS.HmacSHA256(stringToSign, secretKey);
  return hex.toString(CryptoJS.enc.Base64);
} 

function timestamp() {
    var date = new Date();
    var y = date.getUTCFullYear().toString();
    var m = (date.getUTCMonth() + 1).toString();
    var d = date.getUTCDate().toString();
    var h = date.getUTCHours().toString();
    var min = date.getUTCMinutes().toString();
    var s = date.getUTCSeconds().toString();

    if(m.length < 2) { m = "0" + m; }
    if(d.length < 2) { d = "0" + d; }
    if(h.length < 2) { h = "0" + h; }
    if(min.length < 2) { min = "0" + min; }
    if(s.length < 2) { s = "0" + s}

    var date = y + "-" + m + "-" + d;
    var time = h + ":" + min + ":" + s;
    return date + "T" + time + "Z";
}

function getAmazonItemInfo(barcode) {
    var PrivateKey = "";
    var PublicKey = "";
    var AssociateTag = "";

    var parameters = [];
    parameters.push("AWSAccessKeyId=" + PublicKey);
    parameters.push("ItemId=" + barcode);
    parameters.push("Operation=ItemLookup");
    parameters.push("Service=AWSECommerceService");
    parameters.push("Timestamp=" + encodeURIComponent(timestamp()));
    parameters.push("Version=2011-08-01");
parameters.push("AssociateTag=" + AssociateTag);

    parameters.sort();
    var paramString = parameters.join('&');

    var signingKey = "GET\n" + "webservices.amazon.com\n" + "/onca/xml\n" + paramString

    var signature = sha256(signingKey,PrivateKey);
        signature = encodeURIComponent(signature);

    var amazonUrl =  "http://webservices.amazon.com/onca/xml?" + paramString + "&Signature=" + signature;
    console.log(amazonUrl);
}

我用过的Javascript标题供参考。

The Header of the Javascript I used for some reference.

<script src="hmac-sha256.js"></script>
<script src="http://crypto-js.googlecode.com/svn/tags/3.0.2/build/components/enc-base64-min.js"></script>
<script src="amazon.js"></script>

您需要修改部分内容，因为我更改了一些参数并且没有引用您的应用程序对象。

You will need to modify parts of it because I changed some parameters around and don't reference your "app" object.

我做了什么来解决它（从我记忆中）。

For what I did to fix it (from what I can recall).

1. 参数必须是按字母顺序排列的。我把它们放在一个数组中，然后对它们进行排序。我通过与&符号的连接来跟进。

1. The parameters have to be alphabetical. I placed them in an array and then sort them. I follow this up by a join with the ampersand.

我修改了sha256函数以返回RAW sha256的base64。之前它以小写形式返回六角形，这是不正确的。

I modified the sha256 function to return the base64 of the RAW sha256. Before it was returning the hexbits in lowercase, which isn't correct.

我打算在编码之前添加一个base64，但sha256现在处理所有签名。

I was going to add a base64 before encoding, but the sha256 now handles all of the signing.

日期格式不正确。它返回了一个纪元时间戳而不是一个字符串时间戳。我一起攻击了一个简单的时间戳选项。

The date format was incorrect. It was returning a epoch timestamp instead of a string timestamp. I hacked together a simple timestamp option.

此代码要求您也包括Cry64toJS的Base64库。

This code requires you to include the Base64 Library for CryptoJS also.

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