fix(pdk): response.set_header support header argument with table arra…

…y of string (#12164)

This PR lets response.set_header support setting a header with an array of strings. It also fixes a type error issue in the response-header-transformer plugin when manipulating multiple headers with the same name.

FTI-5585

changelog/unreleased/kong/fix-pdk-response-set-header-with-table.yml

@@ -0,0 +1,3 @@
+message: "response.set_header support header argument with table array of string"
+type: bugfix
+scope: PDK

kong/pdk/private/checks.lua

@@ -51,11 +51,19 @@ function checks.validate_header(name, value)
 
   local tvalue = type(value)
   if tvalue ~= "string" then
-    if tvalue == "number" or tvalue == "boolean" then
+    if tvalue == "table" then
+      for _, vv in ipairs(value) do
+        local tvv = type(vv)
+        if tvv ~= "string" then
+          error(fmt("invalid header value in array %q: got %s, " ..
+                              "expected string", name, tvv), 3)
+        end
+      end
+    elseif tvalue == "number" or tvalue == "boolean" then
       value = tostring(value)
     else
       error(fmt("invalid header value for %q: got %s, expected " ..
-                          "string, number or boolean", name, tvalue), 3)
+                          "array of string, string, number or boolean", name, tvalue), 3)
     end
   end
   return value

kong/pdk/response.lua

@@ -31,7 +31,6 @@ local error = error
 local pairs = pairs
 local coroutine = coroutine
 local cjson_encode = cjson.encode
-local normalize_header = checks.normalize_header
 local normalize_multi_header = checks.normalize_multi_header
 local validate_header = checks.validate_header
 local validate_headers = checks.validate_headers
@@ -431,7 +430,7 @@ local function new(self, major_version)
       return
     end
 
-    ngx.header[name] = normalize_header(value)
+    ngx.header[name] = normalize_multi_header(value)
   end
 
 
@@ -463,7 +462,7 @@ local function new(self, major_version)
 
     validate_header(name, value)
 
-    add_header(name, normalize_header(value))
+    add_header(name, normalize_multi_header(value))
   end
 
 

kong/pdk/service/request.lua

@@ -18,7 +18,6 @@ local string_find = string.find
 local string_sub = string.sub
 local string_byte = string.byte
 local string_lower = string.lower
-local normalize_header = checks.normalize_header
 local normalize_multi_header = checks.normalize_multi_header
 local validate_header = checks.validate_header
 local validate_headers = checks.validate_headers
@@ -312,7 +311,7 @@ local function new(self)
       end
     end
 
-    ngx.req.set_header(header, normalize_header(value))
+    ngx.req.set_header(header, normalize_multi_header(value))
   end
 
   ---
@@ -343,7 +342,7 @@ local function new(self)
       headers = { headers }
     end
 
-    table_insert(headers, normalize_header(value))
+    table_insert(headers, normalize_multi_header(value))
 
     ngx.req.set_header(header, headers)
   end

spec/03-plugins/15-response-transformer/01-header_transformer_spec.lua

@@ -148,6 +148,11 @@ describe("Plugin: response-transformer", function()
         header_transformer.transform_headers(conf, headers)
         assert.same({}, headers)
       end)
+      it("header rename when same header being set twice", function()
+        local headers = get_headers({ h1 = { "v1", "v2"}})
+        header_transformer.transform_headers(conf, headers)
+        assert.same({h2 = { "v1", "v2" }}, headers)
+      end)
     end)
     describe("replace", function()
       local conf  = {

t/01-pdk/06-service-request/09-set_header.t

@@ -68,7 +68,7 @@ invalid header name "127001": got number, expected string
 --- request
 GET /t
 --- response_body
-invalid header value for "foo": got function, expected string, number or boolean
+invalid header value for "foo": got function, expected array of string, string, number or boolean
 --- no_error_log
 [error]
 
@@ -89,7 +89,7 @@ invalid header value for "foo": got function, expected string, number or boolean
 --- request
 GET /t
 --- response_body
-invalid header value for "foo": got nil, expected string, number or boolean
+invalid header value for "foo": got nil, expected array of string, string, number or boolean
 --- no_error_log
 [error]
 

t/01-pdk/06-service-request/10-add_header.t

@@ -68,7 +68,7 @@ invalid header name "127001": got number, expected string
 --- request
 GET /t
 --- response_body
-invalid header value for "foo": got function, expected string, number or boolean
+invalid header value for "foo": got function, expected array of string, string, number or boolean
 --- no_error_log
 [error]
 
@@ -89,7 +89,7 @@ invalid header value for "foo": got function, expected string, number or boolean
 --- request
 GET /t
 --- response_body
-invalid header value for "foo": got nil, expected string, number or boolean
+invalid header value for "foo": got nil, expected array of string, string, number or boolean
 --- no_error_log
 [error]
 

t/01-pdk/08-response/05-set_header.t

@@ -77,7 +77,7 @@ invalid header name "127001": got number, expected string
 
 
 
-=== TEST 3: response.set_header() errors if value is not a string
+=== TEST 3: response.set_header() errors if value is not a table contain array of string 
 --- http_config eval: $t::Util::HttpConfig
 --- config
     location = /t {
@@ -89,8 +89,9 @@ invalid header name "127001": got number, expected string
 
             local PDK = require "kong.pdk"
             local pdk = PDK.new()
+            local set_header = { {} }
 
-            local ok, err = pcall(pdk.response.set_header, "foo", {})
+            local ok, err = pcall(pdk.response.set_header, "foo", set_header)
             if not ok then
                 ngx.ctx.err = err
             end
@@ -104,7 +105,7 @@ invalid header name "127001": got number, expected string
 --- request
 GET /t
 --- response_body chop
-invalid header value for "foo": got table, expected string, number or boolean
+invalid header value in array "foo": got table, expected string
 --- no_error_log
 [error]
 
@@ -137,7 +138,7 @@ invalid header value for "foo": got table, expected string, number or boolean
 --- request
 GET /t
 --- response_body chop
-invalid header value for "foo": got nil, expected string, number or boolean
+invalid header value for "foo": got nil, expected array of string, string, number or boolean
 --- no_error_log
 [error]
 
@@ -277,3 +278,37 @@ GET /t
 Transfer-Encoding: chunked
 --- error_log
 manually setting Transfer-Encoding. Ignored.
+
+
+=== TEST 8: response.set_header() with header table
+--- http_config eval: $t::Util::HttpConfig
+--- config
+    location = /t {
+        content_by_lua_block {
+        }
+
+        header_filter_by_lua_block {
+            ngx.header.content_length = nil
+
+            local PDK = require "kong.pdk"
+            local pdk = PDK.new()
+            local set_header = {"a", "b"}
+
+            pdk.response.set_header("X-Foo", set_header)
+        }
+
+        body_filter_by_lua_block {
+            local new_headers = ngx.resp.get_headers()
+
+            local cjson = require("cjson")
+            ngx.arg[1] = "X-Foo: {" ..  new_headers["X-Foo"][1] .. "," .. new_headers["X-Foo"][2] .. "}"
+
+            ngx.arg[2] = true
+        }
+    }
+--- request
+GET /t
+--- response_body chop
+X-Foo: {a,b}
+--- no_error_log
+[error]

t/01-pdk/08-response/06-add_header.t

@@ -90,7 +90,7 @@ invalid header name "127001": got number, expected string
             local PDK = require "kong.pdk"
             local pdk = PDK.new()
 
-            local ok, err = pcall(pdk.response.add_header, "foo", {})
+            local ok, err = pcall(pdk.response.add_header, "foo", {{}})
             if not ok then
                 ngx.ctx.err = err
             end
@@ -104,7 +104,7 @@ invalid header name "127001": got number, expected string
 --- request
 GET /t
 --- response_body chop
-invalid header value for "foo": got table, expected string, number or boolean
+invalid header value in array "foo": got table, expected string
 --- no_error_log
 [error]
 
@@ -137,7 +137,7 @@ invalid header value for "foo": got table, expected string, number or boolean
 --- request
 GET /t
 --- response_body chop
-invalid header value for "foo": got nil, expected string, number or boolean
+invalid header value for "foo": got nil, expected array of string, string, number or boolean
 --- no_error_log
 [error]