I am attempting to make a Facebook application with node.js, however I'm having trouble in checking signed requests. Every time I make a request, the program throws a SyntaxError: Unexpected token ILLEGAL as such:
undefined:1
":"721599476"}
^^
SyntaxError: Unexpected token ILLEGAL
The culprit function is below:
function parse_signed_request(signed_request, secret) {
encoded_data = signed_request.split('.',2);
// decode the data
sig = encoded_data[0];
json = base64url.decode(encoded_data[1]);
data = JSON.parse(json); // ERROR Occurs Here!
// check algorithm - not relevant to error
if (!data.algorithm || data.algorithm.toUpperCase() != 'HMAC-SHA256') {
console.error('Unknown algorithm. Expected HMAC-SHA256');
return null;
}
// check sig - not relevant to error
expected_sig = crypto.createHmac('sha256',secret).update(encoded_data[1]).digest('base64').replace(/\+/g,'-').replace(/\//g,'_').replace('=','');
if (sig !== expected_sig) {
console.error('Bad signed JSON Signature!');
return null;
}
return data;
}
Just for testing, a valid signed_request would be
WGvK-mUKB_Utg0l8gSPvf6smzacp46977pTtcRx0puE.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImV4cGlyZXMiOjEyOTI4MjEyMDAsImlzc3VlZF9hdCI6MTI5MjgxNDgyMCwib2F1dGhfdG9rZW4iOiIxNTI1NDk2ODQ3NzczMDJ8Mi5ZV2NxV2k2T0k0U0h4Y2JwTWJRaDdBX18uMzYwMC4xMjkyODIxMjAwLTcyMTU5OTQ3NnxQaDRmb2t6S1IyamozQWlxVldqNXp2cTBmeFEiLCJ1c2VyIjp7ImxvY2FsZSI6ImVuX0dCIiwiY291bnRyeSI6ImF1In0sInVzZXJfaWQiOiI3MjE1OTk0NzYifQ
Why am I getting this error when it is valid JSON and simply using a static string of JSON will work fine, and are there any tips to fix this?
Thanks.
