feat: Add Public APIs for API Channel (#2375)

app/controllers/public/api/v1/inboxes/contacts_controller.rb

@@ -0,0 +1,48 @@
+class Public::Api::V1::Inboxes::ContactsController < Public::Api::V1::InboxesController
+  before_action :contact_inbox, except: [:create]
+  before_action :process_hmac
+
+  def create
+    source_id = params[:source_id] || SecureRandom.uuid
+    @contact_inbox = ::ContactBuilder.new(
+      source_id: source_id,
+      inbox: @inbox_channel.inbox,
+      contact_attributes: permitted_params.except(:identifier, :identifier_hash)
+    ).perform
+  end
+
+  def show; end
+
+  def update
+    contact_identify_action = ContactIdentifyAction.new(
+      contact: @contact_inbox.contact,
+      params: permitted_params.to_h.deep_symbolize_keys.except(:identifier)
+    )
+    render json: contact_identify_action.perform
+  end
+
+  private
+
+  def contact_inbox
+    @contact_inbox = @inbox_channel.inbox.contact_inboxes.find_by!(source_id: params[:id])
+  end
+
+  def process_hmac
+    return if params[:identifier_hash].blank? && !@inbox_channel.hmac_mandatory
+    raise StandardError, 'HMAC failed: Invalid Identifier Hash Provided' unless valid_hmac?
+
+    @contact_inbox.update(hmac_verified: true) if @contact_inbox.present?
+  end
+
+  def valid_hmac?
+    params[:identifier_hash] == OpenSSL::HMAC.hexdigest(
+      'sha256',
+      @inbox_channel.hmac_token,
+      params[:identifier].to_s
+    )
+  end
+
+  def permitted_params
+    params.permit(:identifier, :identifier_hash, :email, :name, :avatar_url, custom_attributes: {})
+  end
+end