publish a message to Amazon SNS using python or ruby

publish_sns.rb

require 'openssl'
require "hmac-sha2"
require "cgi"
require 'time'
require 'net/https'
require 'base64'

$AWS_ID='<set aws id>'
$AWS_KEY='<set aws key>'
$SNS_ENDPOINT='sns.us-east-1.amazonaws.com'

def url_encode(string)
  # don't encode: ~_-, spaces must me %20
  CGI.escape(string.to_s).gsub("%7E", "~").gsub("+", "%20")
end

def canonical_query_string(params)
  #sort params by byte order
  params.keys.sort.collect {|key|  [url_encode(key), url_encode(params[key])].join("=") }.join("&")
end

def sign_request(params)
  hmac = HMAC::SHA256.new($AWS_KEY)
  hmac.update ['GET',$SNS_ENDPOINT,'/',canonical_query_string(params)].join("\n")
  signature = Base64.encode64(hmac.digest).chomp
end

def publish(arn, subject, msg)
  params = {
      'Subject' => subject,
      'TopicArn' => arn,
      'Message' => msg,
      'Action' => 'Publish',
      'SignatureMethod' => 'HmacSHA256',
      'SignatureVersion' => 2,
      'Timestamp' => Time.now.utc.iso8601,
      'AWSAccessKeyId' => $AWS_ID
  }
  params['Signature']=sign_request(params)
  query_string = canonical_query_string(params)

  response=Net::HTTP.get_response(URI.parse("http://#{$SNS_ENDPOINT}/?#{query_string}"))
  raise "SNS Publish failed #{response.code}\n#{response.body}" unless response.code=="200"
end

publishAmazonSnsMsg.py

from time import strftime,gmtime,time
import urllib2
import hmac
import hashlib
import base64
import string

def publishAmazonSnsMsg(Subject,TopicArn,Message,AWSAccessKeyId,privatekey):
  #http://docs.amazonwebservices.com/AWSSimpleQueueService/2008-01-01/SQSDeveloperGuide/
  amzsnshost = 'sns.us-east-1.amazonaws.com'
  params = {'Subject' : Subject,
            'TopicArn' : TopicArn,
            'Message' :Message,
            'Timestamp' : strftime("%Y-%m-%dT%H:%M:%S.000Z", gmtime(time())),
            'AWSAccessKeyId' : AWSAccessKeyId,
            'Action' : 'Publish',
            'SignatureVersion' : '2',
            'SignatureMethod' : 'HmacSHA256',
            }
  
  cannqs=string.join(["%s=%s"%(urllib2.quote(key),urllib2.quote(params[key], safe='-_~')) \
                                for key in sorted(params.keys())],'&')
  string_to_sign=string.join(["GET",amzsnshost,"/",cannqs],'\n')
  sig=base64.b64encode(hmac.new(privatekey,string_to_sign,digestmod=hashlib.sha256).digest())
  url="http://%s/?%s&Signature=%s"%(amzsnshost,cannqs,urllib2.quote(sig))
  
  try:
    return urllib2.urlopen(url).read()
  except urllib2.HTTPError, exception:
    return "Error %s (%s):\n%s"%(exception.code,exception.msg,exception.read())

Thanks, this was so useful, I had a horrible time with the documentation and C++

What if I wanted to send an sms message to a mobile device, so a phone number, via AWS SNS? I'm having hard time figuring out the connection.

IxayWolf, I was able to get that working by changing the params like such and providing the PhoneNumber in E.164 format (+[countrycode][phonenumber]), example +18005551212:

params = {'PhoneNumber' : Phone,
            'Message' :Message,
            'Timestamp' : strftime("%Y-%m-%dT%H:%M:%S.000Z", gmtime(time())),
            'AWSAccessKeyId' : AWSAccessKeyId,
            'Action' : 'Publish',
            'SignatureVersion' : '2',
            'SignatureMethod' : 'HmacSHA256',
            }

Enjoy!

As @kylefritz mentioned, better to use boto SNS client for this...

If you see 'dict' object has no attribute 'rstrip’, replace line 21 in publishAmazonSnsMsg.py with:

cannqs=string.join(["%s=%s"%(urllib2.quote(key),urllib2.quote(str(params[key]), safe='-_~')) for key in sorted(params.keys())],'&')

(convert params[key] to string)

As mentioned by others, boto3 is a nicer way of doing this. Here’s the code for that

import boto3

def publish(topic_arn, message_json, region):
    client = boto3.client('sns', region_name = region)
    return client.publish(TopicArn=topic_arn, Message=message_json)

Your AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY can be environment variables