157 lines
3.8 KiB
Ruby
157 lines
3.8 KiB
Ruby
require_dependency "mobile_detection"
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require_dependency "crawler_detection"
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require_dependency "guardian"
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module Middleware
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class AnonymousCache
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def self.anon_cache(env, duration)
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env["ANON_CACHE_DURATION"] = duration
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end
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class Helper
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USER_AGENT = "HTTP_USER_AGENT".freeze
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RACK_SESSION = "rack.session".freeze
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ACCEPT_ENCODING = "HTTP_ACCEPT_ENCODING".freeze
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def initialize(env)
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@env = env
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@request = Rack::Request.new(@env)
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end
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def is_mobile=(val)
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@is_mobile = val ? :true : :false
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end
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def is_mobile?
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@is_mobile ||=
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begin
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session = @env[RACK_SESSION]
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# don't initialize params until later otherwise
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# you get a broken params on the request
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params = {}
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user_agent = @env[USER_AGENT]
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MobileDetection.resolve_mobile_view!(user_agent, params, session) ? :true : :false
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end
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@is_mobile == :true
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end
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def has_brotli?
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@has_brotli ||=
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begin
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@env[ACCEPT_ENCODING].to_s =~ /br/ ? :true : :false
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end
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@has_brotli == :true
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end
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def is_crawler?
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@is_crawler ||=
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begin
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user_agent = @env[USER_AGENT]
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CrawlerDetection.crawler?(user_agent) ? :true : :false
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end
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@is_crawler == :true
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end
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def cache_key
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@cache_key ||= "ANON_CACHE_#{@env["HTTP_ACCEPT"]}_#{@env["HTTP_HOST"]}#{@env["REQUEST_URI"]}|m=#{is_mobile?}|c=#{is_crawler?}|b=#{has_brotli?}|t=#{theme_key}"
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end
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def theme_key
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key, _ = @request.cookies['theme_key']&.split(',')
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if key && Guardian.new.allow_theme?(key)
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key
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else
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nil
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end
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end
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def cache_key_body
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@cache_key_body ||= "#{cache_key}_body"
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end
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def cache_key_other
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@cache_key_other || "#{cache_key}_other"
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end
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def get?
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@env["REQUEST_METHOD"] == "GET"
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end
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def has_auth_cookie?
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CurrentUser.has_auth_cookie?(@env)
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end
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def no_cache_bypass
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request = Rack::Request.new(@env)
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request.cookies['_bypass_cache'].nil?
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end
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def cacheable?
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!!(!has_auth_cookie? && get? && no_cache_bypass)
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end
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def cached
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if body = $redis.get(cache_key_body)
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if other = $redis.get(cache_key_other)
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other = JSON.parse(other)
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[other[0], other[1], [body]]
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end
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end
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end
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def cache_duration
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@env["ANON_CACHE_DURATION"]
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end
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# NOTE in an ideal world cache still serves out cached content except for one magic worker
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# that fills it up, this avoids a herd killing you, we can probably do this using a job or redis tricks
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# but coordinating this is tricky
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def cache(result)
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status, headers, response = result
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if status == 200 && cache_duration
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headers_stripped = headers.dup.delete_if { |k, _| ["Set-Cookie", "X-MiniProfiler-Ids"].include? k }
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headers_stripped["X-Discourse-Cached"] = "true"
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parts = []
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response.each do |part|
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parts << part
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end
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$redis.setex(cache_key_body, cache_duration, parts.join)
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$redis.setex(cache_key_other, cache_duration, [status, headers_stripped].to_json)
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else
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parts = response
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end
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[status, headers, parts]
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end
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def clear_cache
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$redis.del(cache_key_body)
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$redis.del(cache_key_other)
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end
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end
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def initialize(app, settings = {})
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@app = app
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end
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def call(env)
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helper = Helper.new(env)
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if helper.cacheable?
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helper.cached || helper.cache(@app.call(env))
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else
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@app.call(env)
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end
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end
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end
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end
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