New numlab exercises filter.

Exercises Filter-Plugin.
This filter masquerades the response of an request to
/numlab/exercises/<id>. With a query string the request only contain
toplevel properties with simple string type. For now these toplevel
properties are:

  * postTime
  * identifier
  * comment
  * name
  * description
  * environment

The querystring parameter is known as: properties. You're allowed to
note multiple toplevel properties, spaced by comma. Please be patient
not to include any spaces in the list.

Working ressource notations are:

http://ecs.uni-stuttgart.de/numlab/exercises/27?properties=name
http://ecs.uni-stuttgart.de/numlab/exercises/27?properties=name,description
http://ecs.uni-stuttgart.de/numlab/exercises/27?properties=name,description,comment,identifier

Problematic/forbidden notations are:

http://ecs.uni-stuttgart.de/numlab/exercises/27?properties= name
http://ecs.uni-stuttgart.de/numlab/exercises/27?properties=name ,description
http://ecs.uni-stuttgart.de/numlab/exercises/27?properties =name,description,comment , identifier

1 files changed, 25 insertions, 0 deletions

diff --git a/filter/numlab/exercises/show/extract_properties/filter.rb b/filter/numlab/exercises/show/extract_properties/filter.rb
new file mode 100644
index 0000000..d2a767a
--- /dev/null
+++ b/filter/numlab/exercises/show/extract_properties/filter.rb
@@ -0,0 +1,25 @@
+module Filter
+  def self.start
+    properties=FILTER_API.params[:properties]
+    return if properties.nil?
+    properties= properties.split(",")
+    properties_length= properties.length
+    obj= JSON.parse(FILTER_API.record.body)
+    i=0
+    body= ERB.new <<-'EOF',0,">"
+{ "Exercise" :
+  {
+<% properties.each do |e| %>
+<% i += 1 %>
+  "<%= e %>" : "<%= obj["Exercise"][e] %>"<% if i!=properties_length %>,
+<% end %>
+<% end %>
+
+  }
+} 
+EOF
+
+    FILTER_API.record.body= body.result(binding)
+    #Message.destroy_msg(FILTER_API.record)
+  end
+end