Add Metadata request (#6)

* Provide api to request tag metadata

Why:
In order to make this information visible to the applications using scrub

How:
add new public api and corresponding queries in the session.ex application

* Fix return tuple from from read_metadata to includ :ok and data

* Add template data filter

Why:
Scrub.session appends template data to the metadata map. This data contains information about templates for structured types
not needed currently

How:
Filtering items whose structure map key is not set to :atomic

* Remove incorrectly uncommented code

* Increase Version Number

* Including mix format changes

lib/scrub.ex

@@ -38,6 +38,16 @@ defmodule Scrub do
     Scrub.Session.close(session)
   end
 
+  def read_metadata(session) do
+    case Session.get_tags_metadata(session) do
+      {:ok, metadata} ->
+        {:ok, filter_template_data(metadata)}
+
+      error ->
+        error
+    end
+  end
+
   def read_tag(session, tag) when is_binary(tag) do
     case Session.get_tag_metadata(session, tag) do
       {:ok, tag} ->
@@ -81,6 +91,21 @@ defmodule Scrub do
     end
   end
 
+  def filter_template_data(tags) do
+    tags
+    |> Enum.reject(fn item ->
+      is_structure_type(item)
+    end)
+  end
+
+  def is_structure_type(%{structure: :atomic}) do
+    false
+  end
+
+  def is_structure_type(_x) do
+    true
+  end
+
   # def read_tag(host, tag) when is_binary(host) do
   #   open_conn(host)
   #   |> read_tag(tag)

lib/scrub/session.ex

@@ -49,6 +49,19 @@ defmodule Scrub.Session do
     DBConnection.start_link(__MODULE__, opts)
   end
 
+  def get_tags_metadata(session) do
+    case DBConnection.execute(session, %Query{query: :get_all_tags_metadata}, <<>>) do
+      {:ok, _query, {:error, err}} ->
+        {:error, err}
+
+      {:ok, _query, result} ->
+        {:ok, result}
+
+      {:error, _} = err ->
+        err
+    end
+  end
+
   def get_tag_metadata(session, tag) do
     case DBConnection.execute(session, %Query{query: :get_tag_metadata}, tag) do
       {:ok, _query, {:error, err}} ->
@@ -229,6 +242,16 @@ defmodule Scrub.Session do
     end
   end
 
+  @impl true
+  def handle_execute(
+        %Query{query: :get_all_tags_metadata} = query,
+        _data,
+        _opts,
+        %{tag_metadata: reply} = state
+      ) do
+    {:ok, query, reply, state}
+  end
+
   @impl true
   def handle_execute(
         %Query{query: :get_tag_metadata} = query,
@@ -477,7 +500,13 @@ defmodule Scrub.Session do
     end
 
     def encode(%Query{query: tag}, data, _s)
-        when tag in [:send_rr_data, :close, :get_tag_metadata, :send_unit_data] do
+        when tag in [
+               :send_rr_data,
+               :close,
+               :get_tag_metadata,
+               :get_all_tags_metadata,
+               :send_unit_data
+             ] do
       data
     end
 

mix.exs

@@ -4,7 +4,7 @@ defmodule Scrub.MixProject do
   def project do
     [
       app: :scrub,
-      version: "0.1.2",
+      version: "0.1.3",
       elixir: "~> 1.8",
       start_permanent: Mix.env() == :prod,
       deps: deps()