IVONA CreateSpeech test based on AWS example

ivona.py

# AWS Version 4 signing example

# EC2 API (DescribeRegions)

# See: http://docs.aws.amazon.com/general/latest/gr/sigv4_signing.html
# This version makes a GET request and passes the signature
# in the Authorization header.
import sys, os, base64, datetime, hashlib, hmac 
import requests # pip install requests
import urllib
# import pdb; pdb.set_trace() # debugger

# ************* REQUEST VALUES *************
method = 'GET'
service = 'tts'
host = 'tts.us-east-1.ivonacloud.com'
region = 'us-east-1'
endpoint = 'https://tts.us-east-1.ivonacloud.com'

# Key derivation functions. See:
# http://docs.aws.amazon.com/general/latest/gr/signature-v4-examples.html#signature-v4-examples-python
def base_sign(key, msg):
    return hmac.new(key, msg.encode('utf-8'), hashlib.sha256)

def sign(key, msg):
    return base_sign(key, msg).digest()

def hex_sign(key, msg):
    return base_sign(key, msg).hexdigest()

def getSignatureKey(key, dateStamp, regionName, serviceName):
    kDate = sign(('AWS4' + key).encode('utf-8'), dateStamp)
    kRegion = sign(kDate, regionName)
    kService = sign(kRegion, serviceName)
    kSigning = sign(kService, 'aws4_request')
    return kSigning

# Read AWS access key from env. variables or configuration file. Best practice is NOT
# to embed credentials in code.
access_key = os.environ.get('AWS_ACCESS_KEY_ID')
secret_key = os.environ.get('AWS_SECRET_ACCESS_KEY')
if access_key is None or secret_key is None:
    print 'No access key is available.'
    sys.exit()

# Create a date for headers and the credential string
t = datetime.datetime.utcnow()
amzdate = t.strftime('%Y%m%dT%H%M%SZ')
datestamp = t.strftime('%Y%m%d') # Date w/o time, used in credential scope

# ************* TASK 1: CREATE A CANONICAL REQUEST *************
# http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html

# Step 1 is to define the verb (GET, POST, etc.)--already done.

# Step 2: Create canonical URI--the part of the URI from domain to query 
# string (use '/' if no path)
canonical_uri = '/CreateSpeech' 

# 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.
# canonical_querystring = 'Input.Data=' + urllib.quote("Oi, mundo.") + '&Voice.Name=Vit%C3%B3ria&Voice.Language=pt-BR&Voice.Gender=Female'
canonical_querystring = "" # request_parameters


payload = '{"Input":{"Data":"Hello world"}}'

# Step 6: Create payload hash (hash of the request body content). For GET
# requests, the payload is an empty string ("").
payload_hash = hashlib.sha256(payload).hexdigest()

# 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.
canonical_headers = 'content-type:application/json' + '\n' + 'host:' + host + '\n' + 'x-amz-content-sha256:' + payload_hash + '\n' + 'x-amz-date:' + amzdate + '\n' + 'Content-Length:' + str(len(payload))

# 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.
# signed_headers = 'host;x-amz-date'
signed_headers = 'content-type;host;x-amz-content-sha256;x-amz-date'

# Step 7: Combine elements to create create canonical request
canonical_request = method + '\n' + canonical_uri + '\n' + canonical_querystring + '\n' + canonical_headers + '\n\n' + signed_headers + '\n' + payload_hash + '\n'

# ************* TASK 2: CREATE THE STRING TO SIGN*************
# Match the algorithm to the hashing algorithm you use, either SHA-1 or
# SHA-256 (recommended)
algorithm = 'AWS4-HMAC-SHA256'
credential_scope = datestamp + '/' + region + '/' + service + '/' + 'aws4_request'

request_parameters = 'Input.Data=Does%20Mary%20have%20a%20little%20lamb%3F&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=' + urllib.quote(credential_scope) + '&X-Amz-Date=' + urllib.quote(amzdate) + '&X-Amz-SignedHeaders=host'

string_to_sign = algorithm + '\n' +  amzdate + '\n' +  credential_scope + '\n' +  hashlib.sha256(canonical_request).hexdigest()

# ************* TASK 3: CALCULATE THE SIGNATURE *************
# Create the signing key using the function defined above.
signing_key = getSignatureKey(secret_key, datestamp, region, service)

# Sign the string_to_sign using the signing_key
signature = hex_sign(signing_key, string_to_sign)

# ************* 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
authorization_header = algorithm + ' ' + 'Credential=' + access_key + '/' + credential_scope + ', ' +  'SignedHeaders=' + signed_headers + ', ' + '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}
headers = {'content-type':'application/json', 'host':host, 'x-amz-content-sha256':payload_hash, 'x-amz-date':amzdate, 'Content-Length':str(len(payload)), 'Authorization':authorization_header}

# ************* SEND THE REQUEST *************
request_url = endpoint + canonical_uri
if canonical_querystring:
  request_url += '?' + canonical_querystring

# import ipdb; ipdb.set_trace() # debugger

print '\nBEGIN REQUEST++++++++++++++++++++++++++++++++++++'
print 'Request URL = ' + request_url
r = requests.post(request_url, headers=headers, data=payload)
# r = requests.get(request_url, headers=headers)

print '\nRESPONSE++++++++++++++++++++++++++++++++++++'
print 'Response code: %d\n' % r.status_code
print r.text