fix(proxy-cache): set Header Accept-Encoding as default values of v…

…ary_headers

Currently, proxy-cache might mix the compression and uncompression
values while cacheing, and return runexpected compression response to
the request if users didn't specify the vary_headers.

kong/plugins/proxy-cache/schema.lua

@@ -72,6 +72,7 @@ return {
  elements = { type = "string" },
  }},
  { vary_headers = { description = "Relevant headers considered for the cache key. If undefined, none of the headers are taken into consideration.", type = "array",
+ default = { "Accept-Encoding" },
  elements = { type = "string" },
  }},
  { response_headers = {

spec/03-plugins/31-proxy-cache/01-schema_spec.lua

@@ -112,6 +112,13 @@ describe("proxy-cache schema", function()
  assert.is_truthy(entity)
  end)
 
+ it("defines default vary_headers values", function()
+ local config = { strategy = "memory" }
+ local entity, err = v(config, proxy_cache_schema)
+ assert.is_nil(err)
+ assert.is_truthy(entity)
+ assert.same(entity.config.vary_headers, { "Accept-Encoding" })
+ end)
  it("supports vary_headers values", function()
  local entity, err = v({
  strategy = "memory",

spec/03-plugins/31-proxy-cache/03-api_spec.lua

@@ -259,6 +259,17 @@ describe("Plugin: proxy-cache", function()
  assert.res_status(200, res)
  assert.same("Miss", res.headers["X-Cache-Status"])
  end)
+ it("miss if pass the Accept-Encoding", function()
+ local res = assert(proxy_client:get("/get", {
+ headers = {
+ host = "route-1.test",
+ ["kong-debug"] = 1,
+ ["Accept-Encoding"] = "gzip",
+ }
+ }))
+ assert.res_status(200, res)
+ assert.same("Miss", res.headers["X-Cache-Status"])
+ end)
  it("purge all the cache entries", function()
  -- make a `Hit` request to `route-1`
  local res = assert(proxy_client:get("/get", {