556 lines
17 KiB
Ruby
556 lines
17 KiB
Ruby
# frozen_string_literal: true
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require "method_profiler"
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require "middleware/anonymous_cache"
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require "http_user_agent_encoder"
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class Middleware::RequestTracker
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@@detailed_request_loggers = nil
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@@ip_skipper = nil
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# You can add exceptions to our app rate limiter in the app.yml ENV section.
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# example:
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#
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# env:
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# DISCOURSE_MAX_REQS_PER_IP_EXCEPTIONS: >-
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# 14.15.16.32/27
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# 216.148.1.2
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#
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STATIC_IP_SKIPPER =
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ENV["DISCOURSE_MAX_REQS_PER_IP_EXCEPTIONS"]&.split&.map { |ip| IPAddr.new(ip) }
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# register callbacks for detailed request loggers called on every request
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# example:
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#
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# Middleware::RequestTracker.detailed_request_logger(->|env, data| do
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# # do stuff with env and data
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# end
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def self.register_detailed_request_logger(callback)
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MethodProfiler.ensure_discourse_instrumentation!
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(@@detailed_request_loggers ||= []) << callback
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end
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def self.unregister_detailed_request_logger(callback)
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@@detailed_request_loggers.delete(callback)
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@detailed_request_loggers = nil if @@detailed_request_loggers.length == 0
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end
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# used for testing
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def self.unregister_ip_skipper
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@@ip_skipper = nil
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end
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# Register a custom `ip_skipper`, a function that will skip rate limiting
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# for any IP that returns true.
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#
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# For example, if you never wanted to rate limit 1.2.3.4
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#
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# ```
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# Middleware::RequestTracker.register_ip_skipper do |ip|
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# ip == "1.2.3.4"
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# end
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# ```
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def self.register_ip_skipper(&blk)
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raise "IP skipper is already registered!" if @@ip_skipper
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@@ip_skipper = blk
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end
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def self.ip_skipper
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@@ip_skipper
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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 self.log_request(data)
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if data[:is_api]
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ApplicationRequest.increment!(:api)
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elsif data[:is_user_api]
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ApplicationRequest.increment!(:user_api)
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elsif data[:track_view]
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if data[:is_crawler]
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ApplicationRequest.increment!(:page_view_crawler)
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WebCrawlerRequest.increment!(data[:user_agent])
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elsif data[:has_auth_cookie]
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ApplicationRequest.increment!(:page_view_logged_in)
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ApplicationRequest.increment!(:page_view_logged_in_mobile) if data[:is_mobile]
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if data[:explicit_track_view]
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# Must be a browser if it had this header from our ajax implementation
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ApplicationRequest.increment!(:page_view_logged_in_browser)
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ApplicationRequest.increment!(:page_view_logged_in_browser_mobile) if data[:is_mobile]
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if data[:topic_id].present? && data[:current_user_id].present?
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TopicsController.defer_topic_view(
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data[:topic_id],
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data[:request_remote_ip],
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data[:current_user_id],
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)
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end
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end
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elsif !SiteSetting.login_required
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ApplicationRequest.increment!(:page_view_anon)
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ApplicationRequest.increment!(:page_view_anon_mobile) if data[:is_mobile]
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if data[:explicit_track_view]
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# Must be a browser if it had this header from our ajax implementation
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ApplicationRequest.increment!(:page_view_anon_browser)
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ApplicationRequest.increment!(:page_view_anon_browser_mobile) if data[:is_mobile]
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if data[:topic_id].present?
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TopicsController.defer_topic_view(data[:topic_id], data[:request_remote_ip])
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end
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end
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end
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end
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# Message-bus requests may include this 'deferred track' header which we use to detect
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# 'real browser' views.
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if data[:deferred_track] && !data[:is_crawler]
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if data[:has_auth_cookie]
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ApplicationRequest.increment!(:page_view_logged_in_browser)
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ApplicationRequest.increment!(:page_view_logged_in_browser_mobile) if data[:is_mobile]
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if data[:topic_id].present? && data[:current_user_id].present?
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TopicsController.defer_topic_view(
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data[:topic_id],
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data[:request_remote_ip],
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data[:current_user_id],
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)
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end
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elsif !SiteSetting.login_required
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ApplicationRequest.increment!(:page_view_anon_browser)
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ApplicationRequest.increment!(:page_view_anon_browser_mobile) if data[:is_mobile]
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if data[:topic_id].present?
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TopicsController.defer_topic_view(data[:topic_id], data[:request_remote_ip])
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end
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end
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end
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ApplicationRequest.increment!(:http_total)
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status = data[:status]
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if status >= 500
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ApplicationRequest.increment!(:http_5xx)
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elsif data[:is_background]
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ApplicationRequest.increment!(:http_background)
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elsif status >= 400
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ApplicationRequest.increment!(:http_4xx)
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elsif status >= 300
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ApplicationRequest.increment!(:http_3xx)
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elsif status >= 200
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ApplicationRequest.increment!(:http_2xx)
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end
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end
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def self.get_data(env, result, timing, request = nil)
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status, headers = result
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# result may be nil if the downstream app raised an exception
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status = status.to_i
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headers ||= {}
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request ||= Rack::Request.new(env)
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helper = Middleware::AnonymousCache::Helper.new(env, request)
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# Since ActionDispatch::RemoteIp middleware is run before this middleware,
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# we have access to the normalised remote IP based on ActionDispatch::RemoteIp::GetIp
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#
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# NOTE: Locally with MessageBus requests, the remote IP ends up as ::1 because
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# of the X-Forwarded-For header set...somewhere, whereas all other requests
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# end up as 127.0.0.1.
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request_remote_ip = env["action_dispatch.remote_ip"].to_s
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# Value of the discourse-track-view request header, set in `lib/ajax.js`
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env_track_view = env["HTTP_DISCOURSE_TRACK_VIEW"]
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# Was the discourse-track-view request header set to true? Likely
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# set by our ajax library to indicate a page view.
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explicit_track_view = status == 200 && %w[1 true].include?(env_track_view)
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# An HTML response to a GET request is tracked implicitly
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implicit_track_view =
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status == 200 && !%w[0 false].include?(env_track_view) && request.get? && !request.xhr? &&
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headers["Content-Type"] =~ %r{text/html}
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# This header is sent on a follow-up request after a real browser loads up a page
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# see `scripts/pageview.js` and `instance-initializers/page-tracking.js`
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deferred_track_view = %w[1 true].include?(env["HTTP_DISCOURSE_DEFERRED_TRACK_VIEW"])
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# This is treated separately from deferred tracking in #log_request, this is
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# why deferred_track_view is not counted here.
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track_view = !!(explicit_track_view || implicit_track_view)
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# These are set in the same place as the respective track view headers in the client.
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topic_id =
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if deferred_track_view
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env["HTTP_DISCOURSE_DEFERRED_TRACK_VIEW_TOPIC_ID"]
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elsif explicit_track_view || implicit_track_view
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env["HTTP_DISCOURSE_TRACK_VIEW_TOPIC_ID"]
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end
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auth_cookie = Auth::DefaultCurrentUserProvider.find_v0_auth_cookie(request)
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auth_cookie ||= Auth::DefaultCurrentUserProvider.find_v1_auth_cookie(env)
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has_auth_cookie = auth_cookie.present?
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is_api ||= !!env[Auth::DefaultCurrentUserProvider::API_KEY_ENV]
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is_user_api ||= !!env[Auth::DefaultCurrentUserProvider::USER_API_KEY_ENV]
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is_message_bus = request.path.start_with?("#{Discourse.base_path}/message-bus/")
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is_topic_timings = request.path.start_with?("#{Discourse.base_path}/topics/timings")
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# Auth cookie can be used to find the ID for logged in users, but API calls must look up the
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# current user based on env variables.
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#
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# We only care about this for topic views, other pageviews it's enough to know if the user is
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# logged in or not, and we have separate pageview tracking for API views.
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current_user_id =
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if topic_id.present?
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begin
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(auth_cookie&.[](:user_id) || CurrentUser.lookup_from_env(env)&.id)
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rescue Discourse::InvalidAccess => err
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# This error is raised when the API key is invalid, no need to stop the show.
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Discourse.warn_exception(
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err,
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message: "RequestTracker.get_data failed with an invalid API key error",
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)
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nil
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end
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end
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h = {
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status: status,
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is_crawler: helper.is_crawler?,
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has_auth_cookie: has_auth_cookie,
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current_user_id: current_user_id,
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topic_id: topic_id,
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is_api: is_api,
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is_user_api: is_user_api,
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is_background: is_message_bus || is_topic_timings,
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is_mobile: helper.is_mobile?,
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track_view: track_view,
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timing: timing,
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queue_seconds: env["REQUEST_QUEUE_SECONDS"],
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explicit_track_view: explicit_track_view,
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deferred_track: deferred_track_view,
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request_remote_ip: request_remote_ip,
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}
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if h[:is_background]
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h[:background_type] = if is_message_bus
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if request.query_string.include?("dlp=t")
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"message-bus-dlp"
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elsif env["HTTP_DONT_CHUNK"]
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"message-bus-dontchunk"
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else
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"message-bus"
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end
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else
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"topic-timings"
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end
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end
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if h[:is_crawler]
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user_agent = env["HTTP_USER_AGENT"]
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user_agent = HttpUserAgentEncoder.ensure_utf8(user_agent) if user_agent
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h[:user_agent] = user_agent
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end
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if cache = headers["X-Discourse-Cached"]
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h[:cache] = cache
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end
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h
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end
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def log_request_info(env, result, info, request = nil)
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# We've got to skip this on error ... its just logging
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data =
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begin
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self.class.get_data(env, result, info, request)
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rescue StandardError => err
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Discourse.warn_exception(err, message: "RequestTracker.get_data failed")
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# This is super hard to find if in testing, we should still raise in this case.
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raise err if Rails.env.test?
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nil
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end
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if data
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if result && (headers = result[1])
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headers["X-Discourse-TrackView"] = "1" if data[:track_view]
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end
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if @@detailed_request_loggers
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@@detailed_request_loggers.each { |logger| logger.call(env, data) }
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end
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log_later(data)
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end
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end
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def self.populate_request_queue_seconds!(env)
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if !env["REQUEST_QUEUE_SECONDS"]
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if queue_start = env["HTTP_X_REQUEST_START"]
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queue_start =
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if queue_start.start_with?("t=")
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queue_start.split("t=")[1].to_f
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else
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queue_start.to_f / 1000.0
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end
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queue_time = (Time.now.to_f - queue_start)
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env["REQUEST_QUEUE_SECONDS"] = queue_time
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end
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end
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end
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def call(env)
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result = nil
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info = nil
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gc_stat_timing = nil
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# doing this as early as possible so we have an
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# accurate counter
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::Middleware::RequestTracker.populate_request_queue_seconds!(env)
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request = Rack::Request.new(env)
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cookie = find_auth_cookie(env)
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if error_details = rate_limit(request, cookie)
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available_in, error_code, limit_on_id = error_details
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message = <<~TEXT
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Slow down, too many requests from this #{limit_on_id ? "user" : "IP address"}.
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Please retry again in #{available_in} seconds.
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Error code: #{error_code}.
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TEXT
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headers = {
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"Content-Type" => "text/plain",
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"Retry-After" => available_in.to_s,
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"Discourse-Rate-Limit-Error-Code" => error_code,
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}
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if username = cookie&.[](:username)
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headers["X-Discourse-Username"] = username
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end
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return 429, headers, [message]
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end
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if !cookie
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if error_details = check_crawler_limits(env)
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available_in, error_code = error_details
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message = "Too many crawling requests. Error code: #{error_code}."
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headers = {
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"Content-Type" => "text/plain",
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"Retry-After" => available_in.to_s,
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"Discourse-Rate-Limit-Error-Code" => error_code,
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}
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return 429, headers, [message]
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end
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end
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env["discourse.request_tracker"] = self
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MethodProfiler.start
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if SiteSetting.instrument_gc_stat_per_request
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gc_stat_timing = GCStatInstrumenter.instrument { result = @app.call(env) }
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else
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result = @app.call(env)
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end
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info = MethodProfiler.stop
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# possibly transferred?
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if info && (headers = result[1])
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headers["X-Runtime"] = "%0.6f" % info[:total_duration]
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if GlobalSetting.enable_performance_http_headers
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if redis = info[:redis]
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headers["X-Redis-Calls"] = redis[:calls].to_s
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headers["X-Redis-Time"] = "%0.6f" % redis[:duration]
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end
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if sql = info[:sql]
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headers["X-Sql-Calls"] = sql[:calls].to_s
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headers["X-Sql-Time"] = "%0.6f" % sql[:duration]
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end
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if queue = env["REQUEST_QUEUE_SECONDS"]
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headers["X-Queue-Time"] = "%0.6f" % queue
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end
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end
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end
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if env[Auth::DefaultCurrentUserProvider::BAD_TOKEN] && (headers = result[1])
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headers["Discourse-Logged-Out"] = "1"
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end
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result
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ensure
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if (limiters = env["DISCOURSE_RATE_LIMITERS"]) && env["DISCOURSE_IS_ASSET_PATH"]
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limiters.each(&:rollback!)
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env["DISCOURSE_ASSET_RATE_LIMITERS"].each do |limiter|
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begin
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limiter.performed!
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rescue RateLimiter::LimitExceeded
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# skip
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end
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end
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end
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if !env["discourse.request_tracker.skip"]
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info.merge!(gc_stat_timing) if gc_stat_timing
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log_request_info(env, result, info, request)
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end
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end
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def log_later(data)
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Scheduler::Defer.later("Track view") do
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self.class.log_request(data) unless Discourse.pg_readonly_mode?
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end
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end
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def find_auth_cookie(env)
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min_allowed_timestamp = Time.now.to_i - (UserAuthToken::ROTATE_TIME_MINS + 1) * 60
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cookie = Auth::DefaultCurrentUserProvider.find_v1_auth_cookie(env)
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cookie if cookie && cookie[:issued_at] >= min_allowed_timestamp
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end
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def is_private_ip?(ip)
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ip = IPAddr.new(ip)
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!!(ip && (ip.private? || ip.loopback?))
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rescue IPAddr::AddressFamilyError, IPAddr::InvalidAddressError
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false
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end
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def rate_limit(request, cookie)
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warn =
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GlobalSetting.max_reqs_per_ip_mode == "warn" ||
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GlobalSetting.max_reqs_per_ip_mode == "warn+block"
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block =
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GlobalSetting.max_reqs_per_ip_mode == "block" ||
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GlobalSetting.max_reqs_per_ip_mode == "warn+block"
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return if !block && !warn
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ip = request.ip
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if !GlobalSetting.max_reqs_rate_limit_on_private
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return if is_private_ip?(ip)
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end
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return if @@ip_skipper&.call(ip)
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return if STATIC_IP_SKIPPER&.any? { |entry| entry.include?(ip) }
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ip_or_id = ip
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limit_on_id = false
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if cookie && cookie[:user_id] && cookie[:trust_level] &&
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cookie[:trust_level] >= GlobalSetting.skip_per_ip_rate_limit_trust_level
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ip_or_id = cookie[:user_id]
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limit_on_id = true
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end
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limiter10 =
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RateLimiter.new(
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nil,
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"global_limit_10_#{ip_or_id}",
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GlobalSetting.max_reqs_per_ip_per_10_seconds,
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10,
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global: !limit_on_id,
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aggressive: true,
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error_code: limit_on_id ? "id_10_secs_limit" : "ip_10_secs_limit",
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)
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limiter60 =
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RateLimiter.new(
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nil,
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"global_limit_60_#{ip_or_id}",
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GlobalSetting.max_reqs_per_ip_per_minute,
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60,
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global: !limit_on_id,
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error_code: limit_on_id ? "id_60_secs_limit" : "ip_60_secs_limit",
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aggressive: true,
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)
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limiter_assets10 =
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RateLimiter.new(
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nil,
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"global_limit_10_assets_#{ip_or_id}",
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GlobalSetting.max_asset_reqs_per_ip_per_10_seconds,
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10,
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error_code: limit_on_id ? "id_assets_10_secs_limit" : "ip_assets_10_secs_limit",
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global: !limit_on_id,
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)
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request.env["DISCOURSE_RATE_LIMITERS"] = [limiter10, limiter60]
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request.env["DISCOURSE_ASSET_RATE_LIMITERS"] = [limiter_assets10]
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if !limiter_assets10.can_perform?
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if warn
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limited_on = limit_on_id ? "user_id" : "ip"
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Discourse.warn(
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"Global asset rate limit exceeded for #{limited_on}: #{ip}: 10 second rate limit",
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uri: request.env["REQUEST_URI"],
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)
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end
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if block
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return [
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limiter_assets10.seconds_to_wait(Time.now.to_i),
|
|
limiter_assets10.error_code,
|
|
limit_on_id
|
|
]
|
|
end
|
|
end
|
|
|
|
begin
|
|
type = 10
|
|
limiter10.performed!
|
|
|
|
type = 60
|
|
limiter60.performed!
|
|
|
|
nil
|
|
rescue RateLimiter::LimitExceeded => e
|
|
if warn
|
|
limited_on = limit_on_id ? "user_id" : "ip"
|
|
Discourse.warn(
|
|
"Global rate limit exceeded for #{limited_on}: #{ip}: #{type} second rate limit",
|
|
uri: request.env["REQUEST_URI"],
|
|
)
|
|
end
|
|
if block
|
|
[e.available_in, e.error_code, limit_on_id]
|
|
else
|
|
nil
|
|
end
|
|
end
|
|
end
|
|
|
|
def check_crawler_limits(env)
|
|
slow_down_agents = SiteSetting.slow_down_crawler_user_agents
|
|
return if slow_down_agents.blank?
|
|
|
|
user_agent = HttpUserAgentEncoder.ensure_utf8(env["HTTP_USER_AGENT"])&.downcase
|
|
return if user_agent.blank?
|
|
|
|
return if !CrawlerDetection.crawler?(user_agent)
|
|
|
|
slow_down_agents
|
|
.downcase
|
|
.split("|")
|
|
.each do |crawler|
|
|
if user_agent.include?(crawler)
|
|
key = "#{crawler}_crawler_rate_limit"
|
|
limiter =
|
|
RateLimiter.new(nil, key, 1, SiteSetting.slow_down_crawler_rate, error_code: key)
|
|
limiter.performed!
|
|
break
|
|
end
|
|
end
|
|
nil
|
|
rescue RateLimiter::LimitExceeded => e
|
|
[e.available_in, e.error_code]
|
|
end
|
|
end
|