bwalker99

Problem creating LTI Tool Consumer

Blog Post created by bwalker99 on Aug 25, 2016

In the past, I've successfully created java LTI Tool Providers (using Blackboard's BLTI-Sandwich) which have been working nicely for a few years.  The TPs are an integral part of our BB courses, and are called from many places.

Now I'm trying to create a java-based LTI Tool Consumer with the same library, but the signature process doesn't seem to be working.

 

BLTIMessage msg = new BLTIMessage( "ConsumerKey" );

// fill in parameters...

BLTIConsumer consumer = new BLTIConsumer( "POST", launchsite,msg );

consumer.sign(mysecret);

List<Map.Entry<String, String>> launchParams = consumer.getParameters();

// then autopost a form with the parameters embedded.

 

The error on the TP webserver is: 

net.oauth.OAuthProblemException: signature_invalid

        at net.oauth.signature.OAuthSignatureMethod.validate(OAuthSignatureMethod.java:65)

        at net.oauth.SimpleOAuthValidator.validateSignature(SimpleOAuthValidator.java:103)

        at net.oauth.SimpleOAuthValidator.validateMessage(SimpleOAuthValidator.java:68) 

...

(I've double checked everything, and can connect to the TP from other TCs, including Blackboard).

Any ideas?

Thanks, bob

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