aws.a5xbm

FUNCTION lf AS C (count AS N = 1)
	dim return as c = ""
	while count
		*concat(return,chr(10))
		count = count - 1
	end while
	lf = return
END FUNCTION

function hmacsha256 as b (message as c, key as b)
	dim Encoding as p = new ::System::Text::Encoding::UTF8
	dim kha as ::System::Security::Cryptography::KeyedHashAlgorithm = new ::System::Security::Cryptography::KeyedHashAlgorithm::Create("HMACSHA256")
	'Set the key
	kha.Key = key

	hmacsha256 = kha.ComputeHash(Encoding.GetBytes(message))
end function

function getSignatureKey as b (key as c, dateStamp as c, regionName as c, serviceName as c)
	dim test as l = .f.
	if test then
		key = "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY"
		dateStamp = "20120215"
		regionName = "us-east-1"
		serviceName= "iam"
		'*to_hex()
		'kSecret  = '41575334774a616c725855746e46454d492f4b374d44454e472b62507852666943594558414d504c454b4559'
		'kDate    = '969fbb94feb542b71ede6f87fe4d5fa29c789342b0f407474670f0c2489e0a0d'
		'kRegion  = '69daa0209cd9c5ff5c8ced464a696fd4252e981430b10e3d3fd8e2f197d7a70c'
		'kService = 'f72cfd46f26bc4643f06a11eabb6c0ba18780c19a8da0c31ace671265e3c87fa'
		'kSigning = 'f4780e2d9f65fa895f9c67b32ce1baf0b0d8a43505a000a1a9e090d414db404d'
	end if
	
	dim Encoding as p = new ::System::Text::Encoding::UTF8
	dim kSecret as b = Encoding.GetBytes("AWS4"+key)
	dim kDate as b = hmacsha256(dateStamp,kSecret)
	dim kRegion as b = hmacsha256(regionName,kDate)
	dim kService as b = hmacsha256(serviceName,kRegion)
	dim kSigning as b = hmacsha256("aws4_request",kService)
	getSignatureKey = kSigning
end function

function sha256 as c (string as c)
	dim Encoding as p = new ::System::Text::Encoding::UTF8
	dim sham as ::System::Security::Cryptography::SHA256Managed = new ::System::Security::Cryptography::SHA256Managed()
	sha256 = *to_hex(sham.ComputeHash(Encoding.GetBytes(string)))
end function

function getAccessKey as c ()
	getAccessKey = ""
end function 
function getSecretKey as c ()
	getSecretKey = ""
end function 

function getSignature as c (verb as c, method as c, query as p, payload as c = "", serviceName as c = "ses", regionName as c = "us-east-1")
	'# ************* TASK 1: CREATE A CANONICAL REQUEST *************
	'http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
	
	dim datetime as t = now(.t.)
	dim amzdate as c = time("yyyyMMddT0h0m0sZ",datetime)
	dim datestamp as c = time("yyyyMMdd",datetime)
	dim access_key as c = getAccessKey()
	dim secret_key as c = getSecretKey()
	dim host as c = "email."+regionName+".amazonaws.com"
	
	dim test as l = .f.
	
	if test then
		amzdate = "20150830T123600Z"
		datestamp = "20150830"
		access_key = "AKIDEXAMPLE"
		secret_key = "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY"
		host = "example.amazonaws.com"
		serviceName = "service"
		regionName = "us-east-1"
		delete query
		dim query as p
		query.Param1 = "value1"
		query.Param2 = "value2"
		debug(1)
	end if
	
	'Step 1 is to define the verb (GET, POST, etc.)--already done by passing verb.
	
	'Step 2: Create canonical URI--the part of the URI from domain to query 
	' string (use '/' if no path)
	dim uri as c = method
	
	'Step 3: Create the canonical query string. In this example (a GET request),
	' request parameters are in the query string. Query string values must
	' be URL-encoded (space=%20). The parameters must be sorted by name.
	' For this example, the query string is pre-formatted in the request_parameters variable.
	dim queryString as c = property_to_url(query,"S")
	
	'Step 4: Create the canonical headers and signed headers. Header names
	' and value must be trimmed and lowercase, and sorted in ASCII order.
	' Note that there is a trailing \n.
	dim headers as c = "host:"+host+lf()+"x-amz-date:"+amzdate+lf()
	
	'Step 5: Create the list of signed headers. This lists the headers
	' in the canonical_headers list, delimited with ";" and in alpha order.
	' Note: The request can include any headers; canonical_headers and
	' signed_headers lists those that you want to be included in the 
	' hash of the request. "Host" and "x-amz-date" are always required.
	dim signedHeaders as c = "host;x-amz-date"
	
	'Step 6: Create payload hash (hash of the request body content). For GET
	' requests, the payload is an empty string ("").
	if verb == "GET" then
		dim payloadHash as c = sha256("")
	else
		dim payloadHash as c = sha256(payload)
	end if

	' Step 7: Combine elements to create create canonical request
	dim canonical_request as c  = alltrim(verb) + lf() + alltrim(uri) + lf()
	if queryString <> "" then
		 *concat(canonical_request,alltrim(queryString) + lf())
	end if
	*concat(canonical_request,alltrim(headers) + lf(2) + alltrim(signedHeaders) + lf() + alltrim(payloadHash))

	'# ************* TASK 2: CREATE THE STRING TO SIGN*************
	'Match the algorithm to the hashing algorithm you use, either SHA-1 or
	' SHA-256 (recommended)
	dim algorithm as c = "AWS4-HMAC-SHA256"
	dim credentialScope as c = datestamp + "/" + regionName + "/" + serviceName + "/aws4_request"
	dim canonicalHash as c = sha256(canonical_request)
	
	dim stringToSign as c = algorithm + lf() + amzdate + lf() + credentialScope + lf() + canonicalHash
	
	'# ************* TASK 3: CALCULATE THE SIGNATURE *************
	' Create the signing key using the function defined above.
	dim signingKey as b = getSignatureKey(secret_key, datestamp, regionName, serviceName)

	' Sign the string_to_sign using the signing_key
	dim signature as c = *to_hex(hmacsha256(stringToSign,signingKey))
	
	'# ************* TASK 4: ADD SIGNING INFORMATION TO THE REQUEST *************
	'# The signing information can be either in a query string value or in 
	'# a header named Authorization. This code shows how to use a header.
	'# Create authorization header and add to request headers
	dim authorization_header as c = algorithm + " " + "Credential=" + access_key + "/" + credentialScope + ", SignedHeaders=" + signedHeaders + ", Signature=" + signature
	
	'# The request can include any headers, but MUST include "host", "x-amz-date", 
	'# and (for this scenario) "Authorization". "host" and "x-amz-date" must
	'# be included in the canonical_headers and signed_headers, as noted
	'# earlier. Order here is not significant.
	'# Python note: The 'host' header is added automatically by the Python 'requests' library.
	'headers = {'x-amz-date':amzdate, 'Authorization':authorization_header}
	
	getSignature = "{'x-amz-date':'"+amzdate+"','Authorization':'"+authorization_header+"','Host':'"+host+"'}"

end function