google-app-engine - 如何签署来自 python 应用程序引擎的亚马逊网络服务请求？

Question

我在我的 Google 应用引擎应用程序中使用 Amazon 网络服务 API。亚马逊表示他们只接受从 2009 年 8 月 15 日起签名的请求。虽然他们给出了简单的 instructions对于签名，我不太了解 SHA256 的 Python 库。应用引擎文档 says它支持 pycrypto 但我只是想知道(懒惰)是否有人已经这样做了。您可以分享任何代码片段吗？我可能在这里遗漏了任何问题吗？

Answer 1

这是一个基于较低级别(当时为 boto )库的 REST 请求示例。解决方案取自 http://cloudcarpenters.com/blog/amazon_products_api_request_signing .

您只需要 AWS_ACCESS_KEY_ID、AWS_SECRET_ACCESS_KEY 的有效条目

def amazon_test_url():
    import base64, hashlib, hmac, time
    from urllib import urlencode, quote_plus

    AWS_ACCESS_KEY_ID = 'YOUR_KEY'
    AWS_SECRET_ACCESS_KEY = 'YOUR_SECRET_KEY'  
    TEST_ISBN = '9780735619678' #http://stackoverflow.com/questions/1711/what-is-the-single-most-influential-book-every-programmer-should-read

    base_url = "http://ecs.amazonaws.com/onca/xml"
    url_params = dict(
        Service='AWSECommerceService', 
        Operation='ItemLookup', 
        IdType='ISBN', 
        ItemId=TEST_ISBN,
        SearchIndex='Books',
        AWSAccessKeyId=AWS_ACCESS_KEY_ID,  
        ResponseGroup='Images,ItemAttributes,EditorialReview,SalesRank')

    #Can add Version='2009-01-06'. What is it BTW? API version?


    # Add a ISO 8601 compliant timestamp (in GMT)
    url_params['Timestamp'] = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())

    # Sort the URL parameters by key
    keys = url_params.keys()
    keys.sort()
    # Get the values in the same order of the sorted keys
    values = map(url_params.get, keys)

    # Reconstruct the URL parameters and encode them
    url_string = urlencode(zip(keys,values))

    #Construct the string to sign
    string_to_sign = "GET\necs.amazonaws.com\n/onca/xml\n%s" % url_string

    # Sign the request
    signature = hmac.new(
        key=AWS_SECRET_ACCESS_KEY,
        msg=string_to_sign,
        digestmod=hashlib.sha256).digest()

    # Base64 encode the signature
    signature = base64.encodestring(signature).strip()

    # Make the signature URL safe
    urlencoded_signature = quote_plus(signature)
    url_string += "&Signature=%s" % urlencoded_signature

    print "%s?%s\n\n%s\n\n%s" % (base_url, url_string, urlencoded_signature, signature)