From 15096ed20f918d585f7b49610f89deefda0a20b3 Mon Sep 17 00:00:00 2001 From: hellekin Date: Mon, 22 Mar 2021 15:30:45 +0100 Subject: Add UUIDResolver The UUIDResolver adds a route at `/by-uuid/:uuid` that enables applications to request information about a given UUID. The UUID must be a Random UUID (version 4, see RFC 4122). If an invalid UUID is given, the controller will return 422 Unprocessable Entity. If a valid UUID is given: - 404 indicates that the UUID is not assigned to anything known to the system. - 302 indicates that the UUID was assigned to a record, and the User-Agent will be redirected to that record's Location as indicated in the response header. - 200 indicates that the UUID was assigned to more than one record (which is unlikely) and will list those records. --- app/controllers/uuid_resolver_controller.rb | 65 +++++++++++++++++++++++++++++ app/helpers/uuid_resolver_helper.rb | 2 + app/lib/uuid_resolver.rb | 55 ++++++++++++++++++++++++ app/views/uuid_resolver/new.html.erb | 15 +++++++ 4 files changed, 137 insertions(+) create mode 100644 app/controllers/uuid_resolver_controller.rb create mode 100644 app/helpers/uuid_resolver_helper.rb create mode 100644 app/lib/uuid_resolver.rb create mode 100644 app/views/uuid_resolver/new.html.erb (limited to 'app') diff --git a/app/controllers/uuid_resolver_controller.rb b/app/controllers/uuid_resolver_controller.rb new file mode 100644 index 0000000..095d26d --- /dev/null +++ b/app/controllers/uuid_resolver_controller.rb @@ -0,0 +1,65 @@ +# == UUIDResolverController +# +# This controller enables applications to retrieve information about a given UUID. + +# It can be used to verify the availability of this UUID in the database, e.g., +# when a remote Agent assigns an UUID to a record, or when it looks up the +# record for that UUID. +# +# Usually it would either find no matching record (and can thus safely assign +# the UUID) or a single one (and be redirected to the matching resource.). +# +# It's also possible, but unlikely, that the UUID matches more than one record +# (e.g., a Map and a Resource), given the construction of UUIDs. In that case, +# the controller will return the list of matching records. +# +# === Verifying the availability of an UUID +# +# When the call is made to verify an UUID is not yet assigned, a 404 (Not Found) +# response means the UUID is available. +# +# === Identifying an existing record +# +# When the call is made to verify the existence of a record matching this UUID, +# a 302 (Found) response means a single record was found, and the Location +# header gives its URL. If a GET request was made, then the User-Agent will be +# redirected to that Location. +class UUIDResolverController < ApplicationController + # GET /by-uuid/:uuid + def new + @resolver = UUIDResolver.new(params[:uuid]) + + case @resolver.count + when 0 + render json: { + status: :not_found, + message: "UUID %s is unknown to the system." % { uuid: @resolver.uuid }, + uuid: @resolver.uuid + }, + status: :not_found + when 1 + respond_to do |format| + format.html { redirect_to @resolver.record } + format.json { + render json: { + status: :found, + message: "UUID %s was found at %s." % { + uuid: @resolver.uuid, + url: url_for(@resolver.record) + }, + uuid: @resolver.uuid, + location: url_for(@resolver.record) + } + } + end + else + render json: { + status: :ok, + message: @resolver.records.to_json + }, + status: :ok + end + rescue ArgumentError => e + render plain: e.message, status: :unprocessable_entity + end +end diff --git a/app/helpers/uuid_resolver_helper.rb b/app/helpers/uuid_resolver_helper.rb new file mode 100644 index 0000000..59f0aef --- /dev/null +++ b/app/helpers/uuid_resolver_helper.rb @@ -0,0 +1,2 @@ +module UUIDResolverHelper +end diff --git a/app/lib/uuid_resolver.rb b/app/lib/uuid_resolver.rb new file mode 100644 index 0000000..acca494 --- /dev/null +++ b/app/lib/uuid_resolver.rb @@ -0,0 +1,55 @@ +class UUIDResolver + # Note the static '4' in the third group: that's the UUID version. + UUID_V4_REGEX = %r[\A[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[0-9a-f]{4}-[0-9a-f]{12}\z] + + attr_reader :records, :count, :record, :uuid + + def initialize(uuid) + @uuid = validate!(uuid) + @records, @count = resolve! + + end + + def record + case @count + when 0 + nil + else + records.first + end + end + + private + + # List models that have UUIDs + def public_record_types + [ + ::Agent, + ::Map, + ::Resource, + ::Taxonomy + ].freeze + end + + # Find records with this UUID + def resolve! + records = [] + + public_record_types.each do |model| + records << model.find_by(uuid: @uuid) + end + + [records.compact, records.compact.size] + end + + # Ensure the passed UUID is correct + def validate!(uuid) + validate_uuid_v4(uuid) || raise(ArgumentError.new("You must pass a valid random UUID (https://tools.ietf.org/html/rfc4122)")) + end + + # Validate a UUID version 4 (random) + def validate_uuid_v4(uuid) + uuid = uuid.to_s.downcase + uuid.match?(UUID_V4_REGEX) ? uuid : false + end +end diff --git a/app/views/uuid_resolver/new.html.erb b/app/views/uuid_resolver/new.html.erb new file mode 100644 index 0000000..1cefbfc --- /dev/null +++ b/app/views/uuid_resolver/new.html.erb @@ -0,0 +1,15 @@ +

Resolving <%= @resolver.uuid %>

+

Found <%= pluralize(@resolver.count, "result") %>.

+ +<% if @resolver.count == 1 %> + <%= render @resolver.record %> +<% elsif @resolver.count > 1 %> + <% @resolver.records.each do |rec| %> + <%= render rec %> + <% end %> +<% end %> + +<% content_for :debug do %> + <%= h @resolver.records.inspect %> +<% end %> + -- cgit v1.2.3