gracefully detect and handle when user declines authorization

lib/modules/tumblr.js

@@ -1,7 +1,8 @@
 var oauthModule = require('./oauth')
-  , Parser = require('xml2js').Parser;
+  , Parser = require('xml2js').Parser
+  , url = require('url');
 
-var twitter = module.exports =
+var tumblr = module.exports =
 oauthModule.submodule('tumblr')
   .apiHost('http://www.tumblr.com/api')
   .oauthHost('http://www.tumblr.com')
@@ -21,6 +22,20 @@ oauthModule.submodule('tumblr')
     });
     return promise;
   })
+  .authCallbackDidErr( function (req) {
+    var parsedUrl = url.parse(req.url, true);
+    return !parsedUrl.query || !parsedUrl.query.oauth_token;
+  })
+  .handleAuthCallbackError( function (req, res) {
+    if (res.render) {
+      res.render(__dirname + '/../views/auth-fail.jade', {
+        errorDescription: 'The user denied your request'
+      });
+    } else {
+      // TODO Replace this with a nice fallback
+      throw new Error("You must configure handleAuthCallbackError if you are not using express");
+    }
+  })
   .convertErr( function (data) {
-    return data.data;
-  });
+    return new Error(data.data);
+  });