Initial commit

.gitignore

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+lib-cov
+*.seed
+*.log
+*.csv
+*.dat
+*.out
+*.pid
+*.gz
+
+pids
+logs
+results
+
+node_modules
+npm-debug.log

README.md

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+# node-snsclient
+

index.js

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+module.exports = require('./lib/snsclient');

lib/snsclient.js

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+var https = require('https')
+  , crypto = require('crypto');
+  , url = require('url');
+
+var pem_cache = {}
+  , REQUIRED_KEYS = [
+        'Type', 'MessageId', 'TopicArn', 'Message', 'Timestamp'
+      , 'SignatureVersion', 'Signature', 'SigningCertURL', 'UnsubscribeURL'
+  ];
+
+function validateRequest(opts, message, cb) {
+    // Let's make sure all keys actually exist to avoid
+    // future errors
+    for(var key in REQUIRED_KEYS) {
+        if(!(key in message)) {
+            return cb(new Error('Invalid request'));
+        }
+    }
+    // short circuit to be able to bypass validation
+    if('verify' in opts && opts.verify === false) cb();
+
+    var host = url.parse(message.SigningCertURL).host,
+      , arn = message.TopicArn
+
+    var next = validateMessage;
+    if(message.SigningCertURL in pem_cache) {
+        var pem = pem_cache[message.SigningCertURL];
+        return next(pem, message, cb);
+    } else {
+        https.get(url.parse(message.SigningCertURL), function(res) {
+            var chunks = [];
+            res.on('data', function(chunk) {
+                chunks.push(chunk);
+            });
+            res.on('end', function() {
+                var pem = chunks.join('');
+                pem_cache[message.SigningCertURL] = pem;
+                return next(pem, message, cb);
+            });
+        })
+    }
+}
+
+function validateMessage(pem, message, cb) {
+    !buildSignatureString(message) && return cb(new Error('Invalid request'));
+
+    var verifier = crypto.createVerify('RSA-SHA1');
+    verifier.update(request);
+    verifier.verify(pem, message.Signature, 'base64') && return cb();
+    return cb(new Error('Invalid request'));
+}
+
+function buildSignatureString(message) {
+    var chunks = [];
+    if(message.Type === 'Notification') {
+        chunks.push('Message');
+        chunks.push(message.Message);
+        chunks.push('MessageId');
+        chunks.push(message.MessageId);
+        if(message.Subject) {
+            chunks.push('Subject');
+            chunks.push(message.Subject);
+        }
+        chunks.push('Timestamp');
+        chunks.push(message.Timestamp);
+        chunks.push('TopicArn');
+        chunks.push(message.TopicArn);
+        chunks.push('Type');
+        chunks.push(message.Type);
+    } else if(message.Type === 'SubscriptionConfirmation') {
+        chunks.push('Message');
+        chunks.push(message.Message);
+        chunks.push('MessageId');
+        chunks.push(message.MessageId);
+        chunks.push('SubscribeURL');
+        chunks.push(message.SubscribeURL);
+        chunks.push('Timestamp');
+        chunks.push(message.Timestamp);
+        chunks.push('Token');
+        chunks.push(message.Token);
+        chunks.push('TopicArn');
+        chunks.push(message.TopicArn);
+        chunks.push('Type');
+        chunks.push(message.Type);
+    } else { return false; }
+
+    return chunks.join('\n')+'\n';
+}
+
+function SNSClient(opts, cb) {
+    if(typeof opt === 'function') {
+        cb = opt;
+        opt = {};
+    }
+    return function SNSClient(req, res) {
+        var chunks = [];
+        req.on('data', function(chunk) {
+            chunks.push(chunk);
+        });
+        req.on('end', function() {
+            try {
+                var message = JSON.parse(chunks.join(''));
+            catch(e) {
+                // catch a JSON parsing error
+                return;
+            }
+            console.log(message);
+            validateRequest(opts, message, function(err){
+                err && return;
+                if(message.Type === 'SubscriptionConfirmation') {
+                    return https.get(url.parse(message.SubscribeURL));
+                }
+                if(message.Type === 'Notification') {
+                    return cb(message);
+                }
+            });
+        });
+        res.end();
+    }
+}
+
+module.exports = SNSClient;