configuration: take into account POST URI params when matching mappin…

…g rules

Suppose we have this mapping rule:
POST /test?key={value}

Before this change, `curl -XPOST "http://localhost:8080/test?key=hello"
-d "another=parameter"` did not match, but `curl -XPOST
"http://localhost:8080/test" -d "key=hello&another=parameter"` did.

That's because in POST requests, body params were taken into account,
but URI params were not. This commit changes that inconsistent
behavior, now both body & URI params are checked.

apicast/src/configuration.lua

@@ -66,16 +66,23 @@ local function check_rule(req, rule, usage_t, matched_rules, params)
 end
 
 local function get_auth_params(method)
-  local params
+  local params = ngx.req.get_uri_args()
 
   if method == "GET" then
-    params = ngx.req.get_uri_args()
+    return params
   else
     ngx.req.read_body()
-    params = ngx.req.get_post_args()
-  end
+    local body_params = ngx.req.get_post_args()
+
+    -- Adds to body_params URI params that are not included in the body. Doing
+    -- the reverse would be more expensive, because in general, we expect the
+    -- size of body_params to be larger than the size of params.
+    for k, v in pairs(params) do
+      if not body_params[k] then body_params[k] = v end
+    end
 
-  return params
+    return body_params
+  end
 end
 
 local regex_variable = '\\{[-\\w_]+\\}'