如何仅使用客户端 JavaScript 正确签署对亚马逊 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

这是我目前所拥有的:

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
"
    + "webservices.amazon.com
"
    + "/onca/xml
"
    + 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 amazonUrl 的值会导致来自亚马逊的以下响应:

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>

有用的链接:

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

我使用了你的代码并且我让它工作了.

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
" + "webservices.amazon.com
" + "/onca/xml
" + paramString

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

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

我用来参考的 Javascript 的 Header.

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>

您将需要修改其中的一部分，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.

我做了什么来修复它(根据我的记忆).

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

1. 参数必须按字母顺序排列.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.在它以小写形式返回十六进制之前，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.它返回一个纪元时间戳而不是字符串时间戳.我编写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.

此代码要求您还包含用于 CryptoJS 的 Base64 库.

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

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