diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 6fe5b2e57a..3b18f72460 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -71,7 +71,7 @@ Metrics/ClassLength:
 # Offense count: 59
 # Configuration parameters: AllowedMethods, AllowedPatterns.
 Metrics/CyclomaticComplexity:
-  Max: 29
+  Max: 31
 
 # Offense count: 753
 # Configuration parameters: CountComments, CountAsOne, AllowedMethods, AllowedPatterns.
@@ -86,7 +86,7 @@ Metrics/ParameterLists:
 # Offense count: 56
 # Configuration parameters: AllowedMethods, AllowedPatterns.
 Metrics/PerceivedComplexity:
-  Max: 30
+  Max: 32
 
 # Offense count: 2394
 # This cop supports safe autocorrection (--autocorrect).
@@ -95,7 +95,7 @@ Minitest/EmptyLineBeforeAssertionMethods:
 
 # Offense count: 565
 Minitest/MultipleAssertions:
-  Max: 54
+  Max: 60
 
 # Offense count: 1
 # This cop supports unsafe autocorrection (--autocorrect-all).
diff --git a/app/abilities/api_capability.rb b/app/abilities/api_capability.rb
index f27dd2e63a..44e6763455 100644
--- a/app/abilities/api_capability.rb
+++ b/app/abilities/api_capability.rb
@@ -19,6 +19,8 @@ def initialize(token)
         can [:gpx_files], User if scope?(token, :read_gpx)
         can [:index, :show], UserPreference if scope?(token, :read_prefs)
         can [:update, :update_all, :destroy], UserPreference if scope?(token, :write_prefs)
+        can [:inbox, :outbox, :show, :update, :destroy], Message if scope?(token, :consume_messages)
+        can [:create], Message if scope?(token, :send_messages)
 
         if user.terms_agreed?
           can [:create, :update, :upload, :close, :subscribe, :unsubscribe], Changeset if scope?(token, :write_api)
diff --git a/app/controllers/api/messages_controller.rb b/app/controllers/api/messages_controller.rb
new file mode 100644
index 0000000000..074f873987
--- /dev/null
+++ b/app/controllers/api/messages_controller.rb
@@ -0,0 +1,149 @@
+# The MessagesController is the RESTful interface to Message objects
+
+module Api
+  class MessagesController < ApiController
+    before_action :authorize
+
+    before_action :check_api_writable, :only => [:create, :update, :destroy]
+    before_action :check_api_readable, :except => [:create, :update, :destroy]
+
+    authorize_resource
+
+    around_action :api_call_handle_error, :api_call_timeout
+
+    before_action :set_request_formats
+
+    def inbox
+      @skip_body = true
+      @messages = Message.includes(:sender, :recipient).where(:to_user_id => current_user.id)
+
+      show_messages
+    end
+
+    def outbox
+      @skip_body = true
+      @messages = Message.includes(:sender, :recipient).where(:from_user_id => current_user.id)
+
+      show_messages
+    end
+
+    # Dump the details on a message given in params[:id]
+    def show
+      @message = Message.includes(:sender, :recipient).find(params[:id])
+
+      raise OSM::APIAccessDenied if current_user.id != @message.from_user_id && current_user.id != @message.to_user_id
+
+      # Render the result
+      respond_to do |format|
+        format.xml
+        format.json
+      end
+    end
+
+    # Create a new message from current user
+    def create
+      # Check the arguments are sane
+      raise OSM::APIBadUserInput, "No title was given" if params[:title].blank?
+      raise OSM::APIBadUserInput, "No body was given" if params[:body].blank?
+
+      # Extract the arguments
+      if params[:recipient_id]
+        recipient_id = params[:recipient_id].to_i
+        recipient = User.find(recipient_id)
+      elsif params[:recipient]
+        recipient_display_name = params[:recipient]
+        recipient = User.find_by(:display_name => recipient_display_name)
+      else
+        raise OSM::APIBadUserInput, "No recipient was given"
+      end
+
+      raise OSM::APIRateLimitExceeded if current_user.sent_messages.where(:sent_on => Time.now.utc - 1.hour..).count >= current_user.max_messages_per_hour
+
+      @message = Message.new(:sender => current_user,
+                             :recipient => recipient,
+                             :sent_on => Time.now.utc,
+                             :title => params[:title],
+                             :body => params[:body],
+                             :body_format => "markdown")
+      @message.save!
+
+      UserMailer.message_notification(@message).deliver_later if @message.notify_recipient?
+
+      # Return a copy of the new message
+      respond_to do |format|
+        format.xml { render :action => :show }
+        format.json { render :action => :show }
+      end
+    end
+
+    # Update read status of a message
+    def update
+      @message = Message.find(params[:id])
+      read_status_idx = %w[true false].index params[:read_status]
+
+      raise OSM::APIBadUserInput, "Invalid value of `read_status` was given" if read_status_idx.nil?
+      raise OSM::APIAccessDenied unless current_user.id == @message.to_user_id
+
+      @message.message_read = read_status_idx.zero?
+      @message.save!
+
+      # Return a copy of the message
+      respond_to do |format|
+        format.xml { render :action => :show }
+        format.json { render :action => :show }
+      end
+    end
+
+    # Delete message by marking it as not visible for the current user
+    def destroy
+      @message = Message.find(params[:id])
+      if current_user.id == @message.from_user_id
+        @message.from_user_visible = false
+      elsif current_user.id == @message.to_user_id
+        @message.to_user_visible = false
+      else
+        raise OSM::APIAccessDenied
+      end
+
+      @message.save!
+
+      # Return a copy of the message
+      respond_to do |format|
+        format.xml { render :action => :show }
+        format.json { render :action => :show }
+      end
+    end
+
+    private
+
+    def show_messages
+      @messages = @messages.where(:muted => false)
+      if params[:order].nil? || params[:order] == "newest"
+        @messages = @messages.where(:id => ..params[:from_id]) unless params[:from_id].nil?
+        @messages = @messages.order(:id => :desc)
+      elsif params[:order] == "oldest"
+        @messages = @messages.where(:id => params[:from_id]..) unless params[:from_id].nil?
+        @messages = @messages.order(:id => :asc)
+      else
+        raise OSM::APIBadUserInput, "Invalid order specified"
+      end
+
+      limit = params[:limit]
+      if !limit
+        limit = Settings.default_message_query_limit
+      elsif !limit.to_i.positive? || limit.to_i > Settings.max_message_query_limit
+        raise OSM::APIBadUserInput, "Messages limit must be between 1 and #{Settings.max_message_query_limit}"
+      else
+        limit = limit.to_i
+      end
+
+      @messages = @messages.limit(limit)
+
+      # Render the result
+      respond_to do |format|
+        format.xml
+        format.json
+      end
+    end
+  end
+end
diff --git a/app/views/api/messages/_message.json.jbuilder b/app/views/api/messages/_message.json.jbuilder
new file mode 100644
index 0000000000..a04295d313
--- /dev/null
+++ b/app/views/api/messages/_message.json.jbuilder
@@ -0,0 +1,17 @@
+json.id message.id
+json.from_user_id message.from_user_id
+json.from_display_name message.sender.display_name
+json.to_user_id message.to_user_id
+json.to_display_name message.recipient.display_name
+json.title message.title
+json.sent_on message.sent_on.xmlschema
+
+if current_user.id == message.from_user_id
+  json.deleted !message.from_user_visible
+elsif current_user.id == message.to_user_id
+  json.message_read message.message_read
+  json.deleted !message.to_user_visible
+end
+
+json.body_format message.body_format
+json.body message.body unless @skip_body
diff --git a/app/views/api/messages/_message.xml.builder b/app/views/api/messages/_message.xml.builder
new file mode 100644
index 0000000000..64ac9e3bcc
--- /dev/null
+++ b/app/views/api/messages/_message.xml.builder
@@ -0,0 +1,21 @@
+attrs = {
+  "id" => message.id,
+  "from_user_id" => message.from_user_id,
+  "from_display_name" => message.sender.display_name,
+  "to_user_id" => message.to_user_id,
+  "to_display_name" => message.recipient.display_name,
+  "sent_on" => message.sent_on.xmlschema,
+  "body_format" => message.body_format
+}
+
+if current_user.id == message.from_user_id
+  attrs["deleted"] = !message.from_user_visible
+elsif current_user.id == message.to_user_id
+  attrs["message_read"] = message.message_read
+  attrs["deleted"] = !message.to_user_visible
+end
+
+xml.message(attrs) do |nd|
+  nd.title(message.title)
+  nd.body(message.body) unless @skip_body
+end
diff --git a/app/views/api/messages/inbox.json.jbuilder b/app/views/api/messages/inbox.json.jbuilder
new file mode 100644
index 0000000000..524006ded5
--- /dev/null
+++ b/app/views/api/messages/inbox.json.jbuilder
@@ -0,0 +1,5 @@
+json.partial! "api/root_attributes"
+
+json.messages(@messages) do |message|
+  json.partial! message
+end
diff --git a/app/views/api/messages/inbox.xml.builder b/app/views/api/messages/inbox.xml.builder
new file mode 100644
index 0000000000..0ef9003a92
--- /dev/null
+++ b/app/views/api/messages/inbox.xml.builder
@@ -0,0 +1,7 @@
+xml.instruct!
+
+xml.osm(OSM::API.new.xml_root_attributes) do |osm|
+  xml.tag! "messages" do
+    osm << (render(@messages) || "")
+  end
+end
diff --git a/app/views/api/messages/outbox.json.jbuilder b/app/views/api/messages/outbox.json.jbuilder
new file mode 100644
index 0000000000..524006ded5
--- /dev/null
+++ b/app/views/api/messages/outbox.json.jbuilder
@@ -0,0 +1,5 @@
+json.partial! "api/root_attributes"
+
+json.messages(@messages) do |message|
+  json.partial! message
+end
diff --git a/app/views/api/messages/outbox.xml.builder b/app/views/api/messages/outbox.xml.builder
new file mode 100644
index 0000000000..440e3429bd
--- /dev/null
+++ b/app/views/api/messages/outbox.xml.builder
@@ -0,0 +1,5 @@
+xml.instruct!
+
+xml.osm(OSM::API.new.xml_root_attributes) do |osm|
+  osm << (render(@messages) || "")
+end
diff --git a/app/views/api/messages/show.json.jbuilder b/app/views/api/messages/show.json.jbuilder
new file mode 100644
index 0000000000..d8f24e9580
--- /dev/null
+++ b/app/views/api/messages/show.json.jbuilder
@@ -0,0 +1,5 @@
+json.partial! "api/root_attributes"
+
+json.message do
+  json.partial! @message
+end
diff --git a/app/views/api/messages/show.xml.builder b/app/views/api/messages/show.xml.builder
new file mode 100644
index 0000000000..008d592498
--- /dev/null
+++ b/app/views/api/messages/show.xml.builder
@@ -0,0 +1,5 @@
+xml.instruct! :xml, :version => "1.0"
+
+xml.osm(OSM::API.new.xml_root_attributes) do |osm|
+  osm << render(@message)
+end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index dc7f1a1c0e..3f2e8a93b0 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -2641,6 +2641,8 @@ en:
       write_notes: Modify notes
       write_redactions: Redact map data
       read_email: Read user email address
+      consume_messages: Read, update status and delete user messages
+      send_messages: Send private messages to other users
       skip_authorization: Auto approve application
     for_roles:
       moderator: This permission is for actions available only to moderators
diff --git a/config/routes.rb b/config/routes.rb
index c832cbb358..650818d6fc 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -78,6 +78,15 @@
       end
     end
 
+    resources :messages, :path => "user/messages", :constraints => { :id => /\d+/ }, :only => [:create, :show, :destroy], :controller => "messages", :as => :api_messages do
+      collection do
+        get "inbox"
+        get "outbox"
+      end
+    end
+
+    post "/user/messages/:id" => "messages#update", :as => :api_message_update
+
     post "gpx/create" => "traces#create"
     get "gpx/:id" => "traces#show", :as => :api_trace, :id => /\d+/
     put "gpx/:id" => "traces#update", :id => /\d+/
diff --git a/config/settings.yml b/config/settings.yml
index fa7207721c..71df9ad3d7 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -59,6 +59,10 @@ user_block_periods: [0, 1, 3, 6, 12, 24, 48, 96, 168, 336, 731, 4383, 8766, 8766
 user_account_deletion_delay: null
 # Rate limit for message sending
 max_messages_per_hour: 60
+# Default limit on the number of messages returned by inbox and outbox message api
+default_message_query_limit: 100
+# Maximum number of messages returned by inbox and outbox message api
+max_message_query_limit: 100
 # Rate limit for friending
 max_friends_per_hour: 60
 # Rate limit for changeset comments
diff --git a/lib/oauth.rb b/lib/oauth.rb
index 88db38eb4b..a8f4976211 100644
--- a/lib/oauth.rb
+++ b/lib/oauth.rb
@@ -2,7 +2,7 @@ module Oauth
   SCOPES = %w[read_prefs write_prefs write_diary write_api read_gpx write_gpx write_notes].freeze
   PRIVILEGED_SCOPES = %w[read_email skip_authorization].freeze
   MODERATOR_SCOPES = %w[write_redactions].freeze
-  OAUTH2_SCOPES = %w[write_redactions openid].freeze
+  OAUTH2_SCOPES = %w[write_redactions consume_messages send_messages openid].freeze
 
   class Scope
     attr_reader :name
diff --git a/test/controllers/api/messages_controller_test.rb b/test/controllers/api/messages_controller_test.rb
new file mode 100644
index 0000000000..0b54be4dc2
--- /dev/null
+++ b/test/controllers/api/messages_controller_test.rb
@@ -0,0 +1,611 @@
+require "test_helper"
+
+module Api
+  class MessagesControllerTest < ActionDispatch::IntegrationTest
+    ##
+    # test all routes which lead to this controller
+    def test_routes
+      assert_routing(
+        { :path => "/api/0.6/user/messages/inbox", :method => :get },
+        { :controller => "api/messages", :action => "inbox" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/inbox.xml", :method => :get },
+        { :controller => "api/messages", :action => "inbox", :format => "xml" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/inbox.json", :method => :get },
+        { :controller => "api/messages", :action => "inbox", :format => "json" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/outbox", :method => :get },
+        { :controller => "api/messages", :action => "outbox" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/outbox.xml", :method => :get },
+        { :controller => "api/messages", :action => "outbox", :format => "xml" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/outbox.json", :method => :get },
+        { :controller => "api/messages", :action => "outbox", :format => "json" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/1", :method => :get },
+        { :controller => "api/messages", :action => "show", :id => "1" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/1.xml", :method => :get },
+        { :controller => "api/messages", :action => "show", :id => "1", :format => "xml" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/1.json", :method => :get },
+        { :controller => "api/messages", :action => "show", :id => "1", :format => "json" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages", :method => :post },
+        { :controller => "api/messages", :action => "create" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/1", :method => :post },
+        { :controller => "api/messages", :action => "update", :id => "1" }
+      )
+      assert_routing(
+        { :path => "/api/0.6/user/messages/1", :method => :delete },
+        { :controller => "api/messages", :action => "destroy", :id => "1" }
+      )
+    end
+
+    def test_create_success
+      recipient = create(:user)
+      sender = create(:user)
+
+      sender_token = create(:oauth_access_token,
+                            :resource_owner_id => sender.id,
+                            :scopes => %w[send_messages consume_messages])
+      sender_auth = bearer_authorization_header(sender_token.token)
+
+      msg = build(:message)
+
+      assert_difference "Message.count", 1 do
+        assert_difference "ActionMailer::Base.deliveries.size", 1 do
+          perform_enqueued_jobs do
+            post api_messages_path,
+                 :params => { :title => msg.title,
+                              :recipient_id => recipient.id,
+                              :body => msg.body,
+                              :format => "json" },
+                 :headers => sender_auth
+            assert_response :success
+          end
+        end
+      end
+
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_not_nil jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert_equal !msg.from_user_visible, jsm["deleted"]
+      assert_not jsm.key?("message_read")
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+    end
+
+    def test_create_fail
+      recipient = create(:user)
+
+      sender = create(:user)
+      sender_token = create(:oauth_access_token,
+                            :resource_owner_id => sender.id,
+                            :scopes => %w[send_messages consume_messages])
+      sender_auth = bearer_authorization_header(sender_token.token)
+
+      assert_no_difference "Message.count" do
+        assert_no_difference "ActionMailer::Base.deliveries.size" do
+          perform_enqueued_jobs do
+            post api_messages_path,
+                 :params => { :title => "Title",
+                              :recipient_id => recipient.id,
+                              :body => "body" }
+          end
+        end
+      end
+      assert_response :unauthorized
+
+      assert_no_difference "Message.count" do
+        assert_no_difference "ActionMailer::Base.deliveries.size" do
+          perform_enqueued_jobs do
+            post api_messages_path,
+                 :params => { :recipient_id => recipient.id,
+                              :body => "body" },
+                 :headers => sender_auth
+          end
+        end
+      end
+      assert_response :bad_request
+
+      assert_no_difference "Message.count" do
+        assert_no_difference "ActionMailer::Base.deliveries.size" do
+          perform_enqueued_jobs do
+            post api_messages_path,
+                 :params => { :title => "Title",
+                              :body => "body" },
+                 :headers => sender_auth
+          end
+        end
+      end
+      assert_response :bad_request
+
+      assert_no_difference "Message.count" do
+        assert_no_difference "ActionMailer::Base.deliveries.size" do
+          perform_enqueued_jobs do
+            post api_messages_path,
+                 :params => { :title => "Title",
+                              :recipient_id => recipient.id },
+                 :headers => sender_auth
+          end
+        end
+      end
+      assert_response :bad_request
+    end
+
+    def test_show
+      recipient = create(:user)
+      sender = create(:user)
+      user3 = create(:user)
+
+      sender_token = create(:oauth_access_token,
+                            :resource_owner_id => sender.id,
+                            :scopes => %w[consume_messages])
+      sender_auth = bearer_authorization_header(sender_token.token)
+
+      recipient_token = create(:oauth_access_token,
+                               :resource_owner_id => recipient.id,
+                               :scopes => %w[consume_messages])
+      recipient_auth = bearer_authorization_header(recipient_token.token)
+
+      user3_token = create(:oauth_access_token,
+                           :resource_owner_id => user3.id,
+                           :scopes => %w[send_messages consume_messages])
+      user3_auth = bearer_authorization_header(user3_token.token)
+
+      msg = create(:message, :unread, :sender => sender, :recipient => recipient)
+
+      # fail if not authorized
+      get api_message_path(:id => msg.id)
+      assert_response :unauthorized
+
+      # only recipient and sender can read the message
+      get api_message_path(:id => msg.id), :headers => user3_auth
+      assert_response :forbidden
+
+      # message does not exist
+      get api_message_path(:id => 99999), :headers => user3_auth
+      assert_response :not_found
+
+      # verify xml output
+      get api_message_path(:id => msg.id), :headers => recipient_auth
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 1 do
+        assert_select "[id='#{msg.id}']"
+        assert_select "[from_user_id='#{sender.id}']"
+        assert_select "[from_display_name='#{sender.display_name}']"
+        assert_select "[to_user_id='#{recipient.id}']"
+        assert_select "[to_display_name='#{recipient.display_name}']"
+        assert_select "[sent_on]"
+        assert_select "[deleted='#{!msg.to_user_visible}']"
+        assert_select "[message_read='#{msg.message_read}']"
+        assert_select "[body_format='markdown']"
+        assert_select "title", msg.title
+        assert_select "body", msg.body
+      end
+
+      # verify json output
+      get api_message_path(:id => msg.id, :format => "json"), :headers => recipient_auth
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_equal msg.id, jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert_equal msg.message_read, jsm["message_read"]
+      assert_equal !msg.to_user_visible, jsm["deleted"]
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+
+      get api_message_path(:id => msg.id), :headers => sender_auth
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 1 do
+        assert_select "[id='#{msg.id}']"
+        assert_select "[from_user_id='#{sender.id}']"
+        assert_select "[from_display_name='#{sender.display_name}']"
+        assert_select "[to_user_id='#{recipient.id}']"
+        assert_select "[to_display_name='#{recipient.display_name}']"
+        assert_select "[sent_on]"
+        assert_select "[deleted='#{!msg.from_user_visible}']"
+        assert_select "[message_read='#{msg.message_read}']", 0
+        assert_select "[body_format='markdown']"
+        assert_select "title", msg.title
+        assert_select "body", msg.body
+      end
+
+      # verify json output
+      get api_message_path(:id => msg.id, :format => "json"), :headers => sender_auth
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_equal msg.id, jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert_equal !msg.from_user_visible, jsm["deleted"]
+      assert_not jsm.key?("message_read")
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+    end
+
+    def test_update_status
+      recipient = create(:user)
+      sender = create(:user)
+      user3 = create(:user)
+
+      recipient_token = create(:oauth_access_token,
+                               :resource_owner_id => recipient.id,
+                               :scopes => %w[consume_messages])
+      recipient_auth = bearer_authorization_header(recipient_token.token)
+
+      user3_token = create(:oauth_access_token,
+                           :resource_owner_id => user3.id,
+                           :scopes => %w[send_messages consume_messages])
+      user3_auth = bearer_authorization_header(user3_token.token)
+
+      msg = create(:message, :unread, :sender => sender, :recipient => recipient)
+
+      # attempt to mark message as read by recipient, not authenticated
+      post api_message_path(:id => msg.id), :params => { :read_status => true }
+      assert_response :unauthorized
+
+      # attempt to mark message as read by recipient, not allowed
+      post api_message_path(:id => msg.id), :params => { :read_status => true }, :headers => user3_auth
+      assert_response :forbidden
+
+      # missing parameter
+      post api_message_path(:id => msg.id), :headers => recipient_auth
+      assert_response :bad_request
+
+      # wrong type of parameter
+      post api_message_path(:id => msg.id),
+           :params => { :read_status => "not a boolean" },
+           :headers => recipient_auth
+      assert_response :bad_request
+
+      # mark message as read by recipient
+      post api_message_path(:id => msg.id, :format => "json"),
+           :params => { :read_status => true },
+           :headers => recipient_auth
+      assert_response :success
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_equal msg.id, jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert jsm["message_read"]
+      assert_equal !msg.to_user_visible, jsm["deleted"]
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+
+      # mark message as unread by recipient
+      post api_message_path(:id => msg.id, :format => "json"),
+           :params => { :read_status => false },
+           :headers => recipient_auth
+      assert_response :success
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_equal msg.id, jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert_not jsm["message_read"]
+      assert_equal !msg.to_user_visible, jsm["deleted"]
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+    end
+
+    def test_delete
+      recipient = create(:user)
+      recipient_token = create(:oauth_access_token,
+                               :resource_owner_id => recipient.id,
+                               :scopes => %w[consume_messages])
+      recipient_auth = bearer_authorization_header(recipient_token.token)
+
+      sender = create(:user)
+      sender_token = create(:oauth_access_token,
+                            :resource_owner_id => sender.id,
+                            :scopes => %w[send_messages consume_messages])
+      sender_auth = bearer_authorization_header(sender_token.token)
+
+      user3 = create(:user)
+      user3_token = create(:oauth_access_token,
+                           :resource_owner_id => user3.id,
+                           :scopes => %w[send_messages consume_messages])
+      user3_auth = bearer_authorization_header(user3_token.token)
+
+      msg = create(:message, :read, :sender => sender, :recipient => recipient)
+
+      # attempt to delete message, not authenticated
+      delete api_message_path(:id => msg.id)
+      assert_response :unauthorized
+
+      # attempt to delete message, by user3
+      delete api_message_path(:id => msg.id), :headers => user3_auth
+      assert_response :forbidden
+
+      # delete message by recipient
+      delete api_message_path(:id => msg.id, :format => "json"), :headers => recipient_auth
+      assert_response :success
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_equal msg.id, jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert_equal msg.message_read, jsm["message_read"]
+      assert jsm["deleted"]
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+
+      # delete message by sender
+      delete api_message_path(:id => msg.id, :format => "json"), :headers => sender_auth
+      assert_response :success
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["message"]
+      assert_not_nil jsm
+      assert_equal msg.id, jsm["id"]
+      assert_equal sender.id, jsm["from_user_id"]
+      assert_equal sender.display_name, jsm["from_display_name"]
+      assert_equal recipient.id, jsm["to_user_id"]
+      assert_equal recipient.display_name, jsm["to_display_name"]
+      assert_equal msg.title, jsm["title"]
+      assert_not_nil jsm["sent_on"]
+      assert jsm["deleted"]
+      assert_not jsm.key?("message_read")
+      assert_equal "markdown", jsm["body_format"]
+      assert_equal msg.body, jsm["body"]
+    end
+
+    def test_list_messages
+      user1 = create(:user)
+      user1_token = create(:oauth_access_token,
+                           :resource_owner_id => user1.id,
+                           :scopes => %w[send_messages consume_messages])
+      user1_auth = bearer_authorization_header(user1_token.token)
+
+      user2 = create(:user)
+      user2_token = create(:oauth_access_token,
+                           :resource_owner_id => user2.id,
+                           :scopes => %w[send_messages consume_messages])
+      user2_auth = bearer_authorization_header(user2_token.token)
+
+      user3 = create(:user)
+      user3_token = create(:oauth_access_token,
+                           :resource_owner_id => user3.id,
+                           :scopes => %w[send_messages consume_messages])
+      user3_auth = bearer_authorization_header(user3_token.token)
+
+      # create some messages between users
+      # user | inbox | outbox
+      #   1  |   0   |   3
+      #   2  |   2   |   1
+      #   3  |   2   |   0
+      create(:message, :unread, :sender => user1, :recipient => user2)
+      create(:message, :unread, :sender => user1, :recipient => user2)
+      create(:message, :unread, :sender => user1, :recipient => user3)
+      create(:message, :unread, :sender => user2, :recipient => user3)
+
+      # only authorized users
+      get inbox_api_messages_path
+      assert_response :unauthorized
+      get outbox_api_messages_path
+      assert_response :unauthorized
+
+      # no messages in user1.inbox
+      get inbox_api_messages_path, :headers => user1_auth
+      assert_response :success
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 0
+
+      # 3 messages in user1.outbox
+      get outbox_api_messages_path, :headers => user1_auth
+      assert_response :success
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 3 do
+        assert_select "[from_user_id='#{user1.id}']"
+        assert_select "[from_display_name='#{user1.display_name}']"
+        assert_select "[to_user_id]"
+        assert_select "[to_display_name]"
+        assert_select "[sent_on]"
+        assert_select "[message_read]", 0
+        assert_select "[deleted='false']"
+        assert_select "[body_format]"
+        assert_select "body", false
+        assert_select "title"
+      end
+
+      # 2 messages in user2.inbox
+      get inbox_api_messages_path, :headers => user2_auth
+      assert_response :success
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 2 do
+        assert_select "[from_user_id]"
+        assert_select "[from_display_name]"
+        assert_select "[to_user_id='#{user2.id}']"
+        assert_select "[to_display_name='#{user2.display_name}']"
+        assert_select "[sent_on]"
+        assert_select "[message_read='false']"
+        assert_select "[deleted='false']"
+        assert_select "[body_format]"
+        assert_select "body", false
+        assert_select "title"
+      end
+
+      # 1 message in user2.outbox
+      get outbox_api_messages_path, :headers => user2_auth
+      assert_response :success
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 1 do
+        assert_select "[from_user_id='#{user2.id}']"
+        assert_select "[from_display_name='#{user2.display_name}']"
+        assert_select "[to_user_id]"
+        assert_select "[to_display_name]"
+        assert_select "[sent_on]"
+        assert_select "[deleted='false']"
+        assert_select "[message_read]", 0
+        assert_select "[body_format]"
+        assert_select "body", false
+        assert_select "title"
+      end
+
+      # 2 messages in user3.inbox
+      get inbox_api_messages_path, :headers => user3_auth
+      assert_response :success
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 2 do
+        assert_select "[from_user_id]"
+        assert_select "[from_display_name]"
+        assert_select "[to_user_id='#{user3.id}']"
+        assert_select "[to_display_name='#{user3.display_name}']"
+        assert_select "[sent_on]"
+        assert_select "[message_read='false']"
+        assert_select "[deleted='false']"
+        assert_select "[body_format]"
+        assert_select "body", false
+        assert_select "title"
+      end
+
+      # 0 messages in user3.outbox
+      get outbox_api_messages_path, :headers => user3_auth
+      assert_response :success
+      assert_equal "application/xml", response.media_type
+      assert_select "message", :count => 0
+    end
+
+    def test_paged_list_messages_asc
+      recipient = create(:user)
+      recipient_token = create(:oauth_access_token,
+                               :resource_owner_id => recipient.id,
+                               :scopes => %w[consume_messages])
+      recipient_auth = bearer_authorization_header(recipient_token.token)
+
+      sender = create(:user)
+
+      create_list(:message, 100, :unread, :sender => sender, :recipient => recipient)
+
+      msgs_read = {}
+      params = { :order => "oldest", :limit => 20 }
+      10.times do
+        get inbox_api_messages_path(:format => "json"),
+            :params => params,
+            :headers => recipient_auth
+        assert_response :success
+        assert_equal "application/json", response.media_type
+        js = ActiveSupport::JSON.decode(@response.body)
+        jsm = js["messages"]
+        assert_operator jsm.count, :<=, 20
+
+        break if jsm.nil? || jsm.count.zero?
+
+        assert_operator(jsm[0]["id"], :>=, params[:from_id]) unless params[:from_id].nil?
+        # ensure ascending order
+        (0..jsm.count - 1).each do |i|
+          assert_operator(jsm[i]["id"], :<, jsm[i + 1]["id"]) unless i == jsm.count - 1
+          msgs_read[jsm[i]["id"]] = jsm[i]
+        end
+        params[:from_id] = jsm[jsm.count - 1]["id"]
+      end
+      assert_equal 100, msgs_read.count
+    end
+
+    def test_paged_list_messages_desc
+      recipient = create(:user)
+      recipient_token = create(:oauth_access_token,
+                               :resource_owner_id => recipient.id,
+                               :scopes => %w[consume_messages])
+      recipient_auth = bearer_authorization_header(recipient_token.token)
+
+      sender = create(:user)
+
+      create_list(:message, 100, :unread, :sender => sender, :recipient => recipient)
+
+      real_max_id = -1
+      msgs_read = {}
+      params = { :order => "newest", :limit => 20 }
+      10.times do
+        get inbox_api_messages_path(:format => "json"),
+            :params => params,
+            :headers => recipient_auth
+        assert_response :success
+        assert_equal "application/json", response.media_type
+        js = ActiveSupport::JSON.decode(@response.body)
+        jsm = js["messages"]
+        assert_operator jsm.count, :<=, 20
+
+        break if jsm.nil? || jsm.count.zero?
+
+        if params[:from_id].nil?
+          real_max_id = jsm[0]["id"]
+        else
+          assert_operator jsm[0]["id"], :<=, params[:from_id]
+        end
+        # ensure descending order
+        (0..jsm.count - 1).each do |i|
+          assert_operator(jsm[i]["id"], :>, jsm[i + 1]["id"]) unless i == jsm.count - 1
+          msgs_read[jsm[i]["id"]] = jsm[i]
+        end
+        params[:from_id] = jsm[jsm.count - 1]["id"]
+      end
+      assert_equal 100, msgs_read.count
+      assert_not_equal(-1, real_max_id)
+
+      # invoke without min_id/max_id parameters, verify that we get the last batch
+      get inbox_api_messages_path(:format => "json"), :params => { :limit => 20 }, :headers => recipient_auth
+      assert_response :success
+      assert_equal "application/json", response.media_type
+      js = ActiveSupport::JSON.decode(@response.body)
+      jsm = js["messages"]
+      assert_not_nil jsm
+      assert_equal real_max_id, jsm[0]["id"]
+    end
+  end
+end