adding digraph exporter

function-contrib-gollum/digraph_exporter.textile

@@ -0,0 +1,10 @@
+h1. Exporting to an Erlang digraph
+
++Contributed By:+ [[Ryan Maclear|https://github.com/ryanmaclear]]
+
+[[Source File on GitHub|https://github.com/basho/riak_function_contrib/blob/master/other/erlang/digraph_export.erl]] 
+
+
+
+
+

function-contrib-gollum/digraph_importer.textile

@@ -11,11 +11,11 @@ digraph_importer:import_digraph(address of server, port, bucket, digraph, conten
 
 h3. Notes
 
-The function uses the Erlang PBC client, so the correct ip address and port must be specified.
+The function uses the Erlang Protocol Buffer client, so the correct ip address and port must be specified.
 
 There are currently some restrictions regarding the construction of the digraph:
-The vertices should be created with digraph:add_vertex/2 or digraph:add_vertex/3
-and the edges need to be created with digraph:add_edge/5
+#The vertices should be created with digraph:add_vertex/2 or digraph:add_vertex/3
+#and the edges need to be created with digraph:add_edge/5
 
 h3. Examples
 

function-contrib-gollum/other-functions.textile

@@ -16,5 +16,6 @@ h2. Contributed Functions or Scripts
 [[Read Repair Bucket (Erlang)|bucket_inspector]]
 [[YAML Data Importer (Ruby)|yaml_importer]]
 [[Digraph Importer (Erlang)|digraph_importer]]
+[[Digraph Exporter (Erlang)|digraph_exporter]]
 
 

other/erlang/digraph_exporter.erl

@@ -0,0 +1,88 @@
+%%
+%%
+%% This file is provided to you under the Apache License,
+%% Version 2.0 (the "License"); you may not use this file
+%% except in compliance with the License.  You may obtain
+%% a copy of the License at
+%%
+%%  http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing,
+%% software distributed under the License is distributed on an
+%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+%% KIND, either express or implied.  See the License for the
+%% specific language governing permissions and limitations
+%% under the License.
+%%
+%% -------------------------------------------------------------------
+
+-module(digraph_exporter).
+
+-export([export_digraph/6]).
+
+export_digraph(Server, Port, Bucket, FilterList, Ref, UseValue) ->
+  {ok, Client} = riakc_pb_socket:start(Server, Port),
+
+  Input = {Bucket, [FilterList]},
+
+  MapFun = build_map_fun(),
+
+  MapPhase = {map, {qfun, MapFun}, notused, true},
+  Query    = [MapPhase],
+
+  {ok, [{_, Data}]} = riakc_pb_socket:mapred(Client, Input, Query),
+
+  build_vertices(Ref, UseValue, Data),
+  add_edges(Ref, Data).
+
+
+build_vertices(_Ref, _UseValue, []) -> ok;
+build_vertices(Ref, UseValue, [{Key, Value, ContentType, _}|T]) ->
+  Label = 
+          case UseValue of 
+            true ->
+              case ContentType of
+                "application/x-erlang-binary" ->
+                  binary_to_term(Value);
+                _ ->
+                  binary_to_list(Value)
+              end;
+            false -> ""
+          end,
+
+  Vertex = binary_to_list(Key),
+
+  digraph:add_vertex(Ref, Vertex, Label),
+  build_vertices(Ref, UseValue, T).
+
+
+add_edges(_Ref, []) -> ok;
+add_edges(Ref, [{Key, _, _, Links}|T]) ->
+  lists:foreach(fun({{_, Dest}, Tag}) ->
+                  Edge  = binary_to_list(Tag),
+                  VSrc  = binary_to_list(Key),
+                  VDest = binary_to_list(Dest),
+                  digraph:add_edge(Ref, Edge, VSrc, VDest, "")
+                end, Links),
+  add_edges(Ref, T).
+
+
+build_map_fun() ->
+  MapFun = "fun(Object, _KeyData, _Args) ->
+              [{MetaDataDict, Value}] = riak_object:get_contents(Object),
+              
+              MetaData    = dict:to_list(MetaDataDict),
+
+              ContentType = proplists:get_value(<<\"content-type\">>, MetaData, \"\"),
+              Links       = proplists:get_value(<<\"Links\">>, MetaData, []),
+              
+              [{riak_object:key(Object), Value, ContentType, Links}]
+            end.",
+
+  {ok, Tokens, _} = erl_scan:string(MapFun),
+  {ok, [Form]}    = erl_parse:parse_exprs(Tokens),
+  Bindings        = erl_eval:new_bindings(),
+  {value, Fun, _} = erl_eval:expr(Form, Bindings),
+  Fun.
+
+%%% EOF