Add telekom-digioss#9 to handle breaking change

Author: ebarajas

src/handler.lua

@@ -11,6 +11,7 @@ local validate_realm_roles = require("kong.plugins.jwt-keycloak.validators.roles
 local validate_client_roles = require("kong.plugins.jwt-keycloak.validators.roles").validate_client_roles
 
 local re_gmatch = ngx.re.gmatch
+local decode_base64 = ngx.decode_base64
 
 local JwtKeycloakHandler = {
     VERSION = "1.2.1"
@@ -27,6 +28,24 @@ kong.log.debug('JWT_KEYCLOAK_PRIORITY: ' .. priority)
 
 JwtKeycloakHandler.PRIORITY = priority
 
+-------------------------------------------------------------------------------
+-- custom helper function of the extended plugin "jwt-keycloak"
+-- --> this is contained in jwt_parser, but has a breaking change in 3.5
+-- https://github.com/telekom-digioss/kong-plugin-jwt-keycloak/pull/9
+-------------------------------------------------------------------------------
+local function custom_base64_decode(input)
+    local remainder = #input % 4
+    if remainder > 0 then
+      local padlen = 4 - remainder
+      input = input .. rep("=", padlen)
+    end
+  
+    input = input:gsub("-", "+"):gsub("_", "/")
+    return decode_base64(input)
+  end
+  
+  
+
 function table_to_string(tbl)
     local result = ""
     for k, v in pairs(tbl) do
@@ -239,7 +258,7 @@ local function get_keys(well_known_endpoint)
 
     local decoded_keys = {}
     for i, key in ipairs(keys) do
-        decoded_keys[i] = jwt_decoder:base64_decode(key)
+        decoded_keys[i] = custom_base64_decode(key)
     end
 
     kong.log.debug('Number of keys retrieved: ' .. table.getn(decoded_keys))