1 files changed, 44 insertions, 0 deletions
diff --git a/server/resty/http_headers.lua b/server/resty/http_headers.lua
new file mode 100644
index 0000000..97e8157
--- /dev/null
+++ b/server/resty/http_headers.lua
@@ -0,0 +1,44 @@
+local rawget, rawset, setmetatable =
+    rawget, rawset, setmetatable
+
+local str_lower = string.lower
+
+local _M = {
+    _VERSION = '0.17.0-beta.1',
+}
+
+
+-- Returns an empty headers table with internalised case normalisation.
+function _M.new()
+    local mt = {
+        normalised = {},
+    }
+
+    mt.__index = function(t, k)
+        return rawget(t, mt.normalised[str_lower(k)])
+    end
+
+    mt.__newindex = function(t, k, v)
+        local k_normalised = str_lower(k)
+
+        -- First time seeing this header field?
+        if not mt.normalised[k_normalised] then
+            -- Create a lowercased entry in the metatable proxy, with the value
+            -- of the given field case
+            mt.normalised[k_normalised] = k
+
+            -- Set the header using the given field case
+            rawset(t, k, v)
+        else
+            -- We're being updated just with a different field case. Use the
+            -- normalised metatable proxy to give us the original key case, and
+            -- perorm a rawset() to update the value.
+            rawset(t, mt.normalised[k_normalised], v)
+        end
+    end
+
+    return setmetatable({}, mt)
+end
+
+
+return _M