Help. I can't get the right signature using the test parameters provided by Amazon and Go.
My signature hash function is as follows. I use SHA-256 and base64 encoding as per Amazon documentation.
func HashSignature(str string, secret string) string {
mac := hmac.New(sha256.New, []byte(secret))
_, err := mac.Write([]byte(str))
if err != nil { return "" }
hash := base64.StdEncoding.EncodeToString(mac.Sum(nil))
hash = url.QueryEscape(hash)
return hash
}
My signature test function is as follows. I use the canonical string below in Ruby code and it generates the correct expected signature. So the problem seems to be with the output of my HashSignature() function, but I don't see what I'm doing wrong there.
func TestAmazonSignature(t *testing.T) {
/* here is the canonical string from Amazon documentation which should yield the expected signature below
GET
webservices.amazon.com
/onca/xml
AWSAccessKeyId=AKIAIOSFODNN7EXAMPLE&AssociateTag=mytag-20&ItemId=0679722769&Operation=ItemLookup&ResponseGroup=Images%2CItemAttributes%2COffers%2CReviews&Service=AWSECommerceService&Timestamp=2014-08-18T12%3A00%3A00Z&Version=2013-08-01
*/
SECRET_KEY := "1234567890"
CANONICAL_STR := "GET
webservices.amazon.com
/onca/xml
AWSAccessKeyId=AKIAIOSFODNN7EXAMPLE&AssociateTag=mytag-20&ItemId=0679722769&Operation=ItemLookup&ResponseGroup=Images%2CItemAttributes%2COffers%2CReviews&Service=AWSECommerceService&Timestamp=2014-08-18T12%3A00%3A00Z&Version=2013-08-01"
EXPECTED := "j7bZM0LXZ9eXeZruTqWm2DIvDYVUU3wxPPpp%2BiXxzQc%3D"
if RESULT := HashSignature(CANONICAL_STR, SECRET_KEY); RESULT != EXPECTED {
t.Errorf("
EXPECTED:
%v
RESULT:
%v", EXPECTED, RESULT)
} else { fmt.Println("TestAmazonSignature: Signature: OK") }
}
Here's a playground link with all this code.
