discourse/lib/middleware/anonymous_cache.rb

93 lines
2.1 KiB
Ruby

module Middleware
class AnonymousCache
def self.anon_cache(env, duration)
env["ANON_CACHE_DURATION"] = duration
end
class Helper
def initialize(env)
@env = env
end
def cache_key
@cache_key ||= "ANON_CACHE_#{@env["HTTP_HOST"]}#{@env["REQUEST_URI"]}"
end
def cache_key_body
@cache_key_body ||= "#{cache_key}_body"
end
def cache_key_other
@cache_key_other || "#{cache_key}_other"
end
def get?
@env["REQUEST_METHOD"] == "GET"
end
def cacheable?
!!(!CurrentUser.has_auth_cookie?(@env) && get?)
end
def cached
if body = $redis.get(cache_key_body)
if other = $redis.get(cache_key_other)
other = JSON.parse(other)
[other[0], other[1], [body]]
end
end
end
def cache_duration
@env["ANON_CACHE_DURATION"]
end
# NOTE in an ideal world cache still serves out cached content except for one magic worker
# that fills it up, this avoids a herd killing you, we can probably do this using a job or redis tricks
# but coordinating this is tricky
def cache(result)
status,headers,response = result
if status == 200 && cache_duration
headers_stripped = headers.dup.delete_if{|k,v| ["Set-Cookie","X-MiniProfiler-Ids"].include? k}
parts = []
response.each do |part|
parts << part
end
$redis.setex(cache_key_body, cache_duration, parts.join)
$redis.setex(cache_key_other, cache_duration, [status,headers_stripped].to_json)
else
parts = response
end
[status,headers,parts]
end
def clear_cache
$redis.del(cache_key_body)
$redis.del(cache_key_other)
end
end
def initialize(app, settings={})
@app = app
end
def call(env)
helper = Helper.new(env)
if helper.cacheable?
helper.cached or helper.cache(@app.call(env))
else
@app.call(env)
end
end
end
end