Added a convenience function to pull a desired claim value out of the token

hosts/proxy/default/nginx/conf/nginx.conf

@@ -24,6 +24,22 @@ http {
             proxy_pass http://backend:5000/secure;
         }
 
+        location /secure/secretUser {
+            access_by_lua '
+                -- this endpoint will only allow users whose jwt contains a claim
+                -- of "customerId" with a value of "customer1"
+                local jwt = require("nginx-jwt")
+                jwt.auth()
+
+                local customerId = jwt.get_claim("customerId")
+                if customerId == nil or customerId ~= "customer1" then
+                    ngx.exit(ngx.HTTP_UNAUTHORIZED)
+                end
+            ';
+
+            proxy_pass http://backend:5000/secure;
+        }
+
         location /secure/admin {
             access_by_lua '
                 local jwt = require("nginx-jwt")

nginx-jwt.lua

@@ -20,9 +20,7 @@ if os.getenv("JWT_SECRET_IS_BASE64_ENCODED") == 'true' then
     secret = basexx.from_base64(secret)
 end
 
-local M = {}
-
-function M.auth(claim_specs)
+function getJwt()
     -- require Authorization request header
     local auth_header = ngx.var.http_Authorization
 
@@ -35,6 +33,13 @@ function M.auth(claim_specs)
 
     -- require Bearer token
     local _, _, token = string.find(auth_header, "Bearer%s+(.+)")
+    return token
+end
+
+local M = {}
+
+function M.auth(claim_specs)
+    local token = getJwt()
 
     if token == nil then
         ngx.log(ngx.WARN, "Missing token")
@@ -121,4 +126,10 @@ function M.table_contains(table, item)
     return false
 end
 
+function M.get_claim(claim)
+    local jwt_obj = jwt:verify(secret, getJwt())
+
+    return jwt_obj.payload[claim]
+end
+
 return M

test/test_integration.js

@@ -106,6 +106,32 @@ describe('proxy', function () {
             });
         });
 
+        describe("GET /secure/secretUser", function() {
+            it("should return a 401 for a a user with the wrong customerId value", function() {
+                var token = jwt.sign(
+                    { customerId: 'customer2' },
+                    secret);
+
+                return request(url)
+                    .get('/secure/secretUser')
+                    .headers({'Authorization': 'Bearer ' + token})
+                    .expect(401)
+                    .end();
+            });
+
+            it("should return a 200 for a user with the correct customerId value", function() {
+                var token = jwt.sign(
+                    { customerId: 'customer1' },
+                    secret);
+
+                return request(url)
+                    .get('/secure/secretUser')
+                    .headers({'Authorization': 'Bearer ' + token})
+                    .expect(200)
+                    .end();
+            });
+        });
+
         describe("GET /secure/admin", function () {
             it("should return 401 when an authenticated user is missing a required claim", function () {
                 var token = jwt.sign(