discourse/lib/discourse_hub.rb

# frozen_string_literal: true

module DiscourseHub
  STATS_FETCHED_AT_KEY = "stats_fetched_at"

  class Error < StandardError
    attr_reader :status, :body

    def initialize(rel_url, status, body)
      @status = status
      @body = body
      super("Discourse Hub (#{rel_url}) returned status #{status}")
    end
  end

  def self.version_check_payload
    default_payload = { installed_version: Discourse::VERSION::STRING }.merge!(
      Discourse.git_branch == "unknown" && !Rails.env.test? ? {} : { branch: Discourse.git_branch },
    )
    default_payload.merge!(get_payload)
  end

  def self.discourse_version_check
    get("/version_check", version_check_payload)
  end

  def self.discover_enrollment_payload
    {
      include_in_discourse_discover: SiteSetting.include_in_discourse_discover?,
      forum_url: Discourse.base_url,
      forum_title: SiteSetting.title,
      locale: I18n.locale,
    }
  end

  def self.discover_enrollment
    post("/discover/enroll", discover_enrollment_payload)
  end

  def self.stats_fetched_at=(time_with_zone)
    Discourse.redis.set STATS_FETCHED_AT_KEY, time_with_zone.to_i
  end

  def self.get_payload
    if SiteSetting.share_anonymized_statistics && stats_fetched_at < 7.days.ago
      About.fetch_cached_stats.symbolize_keys
    else
      {}
    end
  end

  def self.get(rel_url, params = {}, raise_on_error: false)
    singular_action :get, rel_url, params, raise_on_error: raise_on_error
  end

  def self.post(rel_url, params = {}, raise_on_error: false)
    collection_action :post, rel_url, params, raise_on_error: raise_on_error
  end

  def self.put(rel_url, params = {}, raise_on_error: false)
    collection_action :put, rel_url, params, raise_on_error: raise_on_error
  end

  def self.delete(rel_url, params = {}, raise_on_error: false)
    singular_action :delete, rel_url, params, raise_on_error: raise_on_error
  end

  def self.singular_action(action, rel_url, params = {}, raise_on_error: false)
    connect_opts = connect_opts(params)

    response =
      Excon.public_send(
        action,
        "#{hub_base_url}#{rel_url}",
        { headers: { "Referer" => referer, "Accept" => accepts.join(", ") }, query: params }.merge(
          connect_opts,
        ),
      )

    if raise_on_error && response.status != 200
      raise Error.new(rel_url, response.status, parse_body(response.body))
    end

    JSON.parse(response.body)
  end

  def self.collection_action(action, rel_url, params = {}, raise_on_error: false)
    connect_opts = connect_opts(params)

    response =
      Excon.public_send(
        action,
        "#{hub_base_url}#{rel_url}",
        {
          body: JSON[params],
          headers: {
            "Referer" => referer,
            "Accept" => accepts.join(", "),
            "Content-Type" => "application/json",
          },
        }.merge(connect_opts),
      )

    if (status = response.status) != 200
      Rails.logger.warn(response_status_log_message(rel_url, status))
    end

    body = parse_body(response.body)

    raise Error.new(rel_url, status, body) if raise_on_error && status != 200

    body
  end

  def self.parse_body(raw)
    JSON.parse(raw)
  rescue JSON::ParserError
    Rails.logger.error(response_body_log_message(raw))
    nil
  end

  def self.response_status_log_message(rel_url, status)
    "Discourse Hub (#{hub_base_url}#{rel_url}) returned a bad status #{status}."
  end

  def self.response_body_log_message(body)
    "Discourse Hub returned a bad response body: #{body}"
  end

  def self.connect_opts(params = {})
    params.delete(:connect_opts)&.except(:body, :headers, :query) || {}
  end

  def self.hub_base_url
    if Rails.env.production?
      ENV["HUB_BASE_URL"] || "https://api.discourse.org/api"
    else
      ENV["HUB_BASE_URL"] || "http://local.hub:3000/api"
    end
  end

  def self.accepts
    %w[application/json application/vnd.discoursehub.v1]
  end

  def self.referer
    Discourse.base_url
  end

  def self.stats_fetched_at
    t = Discourse.redis.get(STATS_FETCHED_AT_KEY)
    t ? Time.zone.at(t.to_i) : 1.year.ago
  end
end