Basic tag metadata returned. Now what to do about posts?...

app/controllers/api/v0/tags_controller.rb

+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
 class Api::V0::TagsController < ApplicationController
   def show
-    head :ok
+    render :json => Api::V0::Serializers::Tag.new(params[:name])
   end
 end

app/controllers/api/v0/users_controller.rb

+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
 class Api::V0::UsersController < ApplicationController
   def show
     if user = User.find_by_username(params[:username])

app/models/api/v0/serializers/tag.rb

+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
+class Api::V0::Serializers::Tag
+
+  def initialize(tag)
+    @stream = Stream::Tag.new(nil, tag)
+  end
+
+  def as_json(opts={})
+    {
+      "name" => @stream.tag_name,
+      "person_count" => @stream.people_count,
+      "followed_count" => @stream.tag_follow_count,
+      "posts" => []
+    }
+  end
+end

app/models/api/v0/serializers/user.rb

-class Api::V0::Serializers::User
-  attr_accessor :user
+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
 
+class Api::V0::Serializers::User
   def initialize(user)
-    @user = user
     @person = user.person
     @profile = @person.profile
   end

lib/stream/tag.rb

+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
 class Stream::Tag < Stream::Base
   attr_accessor :tag_name, :people_page
 

spec/lib/stream/tag_spec.rb

+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
 require 'spec_helper'
 require File.join(Rails.root, 'spec', 'shared_behaviors', 'stream')