From 8e812635d7f70e748ea829e3714650a279f70f88 Mon Sep 17 00:00:00 2001
From: Paul Carey <paul.p.carey@gmail.com>
Date: Wed, 10 Sep 2008 11:31:25 +0100
Subject: [PATCH] Improved view API a little. Added merge method - used for
 merging different document types returned by a join view into a single
 ViewObject.

---
 lib/relaxdb/all_delegator.rb |  4 +--
 lib/relaxdb/relaxdb.rb       | 38 ++++++++++++++++++++--------
 spec/denormalisation_spec.rb |  2 +-
 spec/relaxdb_spec.rb         | 48 ++++++++++++++++++++++++++++++++++--
 4 files changed, 77 insertions(+), 15 deletions(-)

diff --git a/lib/relaxdb/all_delegator.rb b/lib/relaxdb/all_delegator.rb
index 115896a..87ff75f 100644
--- a/lib/relaxdb/all_delegator.rb
+++ b/lib/relaxdb/all_delegator.rb
@@ -18,7 +18,7 @@ def __getobj__
       view_path = "_view/#{@klass}/all"
       map_function = ViewCreator.all(@klass)
       
-      @all = RelaxDB::retrieve(view_path, @klass, "all", map_function)      
+      @all = RelaxDB.retrieve(view_path, @klass, "all", map_function)      
     end
 
     def sorted_by(*atts)
@@ -27,7 +27,7 @@ def sorted_by(*atts)
       q = Query.new(@klass.name, v.view_name)
       yield q if block_given?
       
-      RelaxDB::retrieve(q.view_path, @klass, v.view_name, v.map_function)      
+      RelaxDB.retrieve(q.view_path, @klass, v.view_name, v.map_function)      
     end
     
     # Note that this method leaves the corresponding DesignDoc for the associated class intact
diff --git a/lib/relaxdb/relaxdb.rb b/lib/relaxdb/relaxdb.rb
index bc0e891..cfbf6b3 100644
--- a/lib/relaxdb/relaxdb.rb
+++ b/lib/relaxdb/relaxdb.rb
@@ -49,6 +49,7 @@ def load(id)
       create_object(data)
     end
     
+    # Used internally by RelaxDB
     def retrieve(view_path, design_doc, view_name, map_function)
       begin
         resp = db.get(view_path)
@@ -61,21 +62,38 @@ def retrieve(view_path, design_doc, view_name, map_function)
       create_from_hash(data)      
     end
       
-    def view(design_doc, view_name, default_ret_val=[])
+    # Requests the given view from CouchDB and returns a hash.
+    # This method should typically be wrapped in one of merge, instantiate, or reduce_result.
+    def view(design_doc, view_name)
       q = Query.new(design_doc, view_name)
       yield q if block_given?
       
       resp = db.get(q.view_path)
-      data = JSON.parse(resp.body)
-
-      # presence of total_rows tells us a map function was invoked
-      # if it's absent a map reduce invocation occured
-      if data["total_rows"]
-        create_from_hash(data)
-      else
-        obj = data["rows"][0] && data["rows"][0]["value"]
-        obj ? ViewObject.create(obj) : default_ret_val
+      JSON.parse(resp.body)      
+    end
+    
+    # Should be invoked on the result of a join view
+    # Merges all rows based on merge_key and returns an array of ViewOject
+    def merge(data, merge_key)
+      merged = {}
+      data["rows"].each do |row|
+        value = row["value"]
+        merged[value[merge_key]] ||= {}
+        merged[value[merge_key]].merge!(value)
       end
+      
+      merged.values.map { |v| ViewObject.create(v) }
+    end
+    
+    # Creates RelaxDB::Document objects from the result
+    def instantiate(data)
+      create_from_hash(data)
+    end
+    
+    # Returns a scalar, an object, or an Array of objects
+    def reduce_result(data)
+      obj = data["rows"][0] && data["rows"][0]["value"]
+      ViewObject.create(obj)      
     end
         
     def create_from_hash(data)
diff --git a/spec/denormalisation_spec.rb b/spec/denormalisation_spec.rb
index bd30f03..ae65c96 100644
--- a/spec/denormalisation_spec.rb
+++ b/spec/denormalisation_spec.rb
@@ -35,7 +35,7 @@ class Leaf < RelaxDB::Document
     it "should not interfere with normal belongs_to behaviour" do
       tree = Tree.new(:name => "sapling", :climate => "tropical").save
       leaf = Leaf.new(:tree => tree).save
-      leaf = RelaxDB.load(leaf._id)      
+      leaf = RelaxDB.load(leaf._id)
       leaf.tree.name.should == "sapling"
       leaf.tree.climate.should == "tropical"
     end
diff --git a/spec/relaxdb_spec.rb b/spec/relaxdb_spec.rb
index 4f84ebb..8a4fa28 100644
--- a/spec/relaxdb_spec.rb
+++ b/spec/relaxdb_spec.rb
@@ -58,8 +58,52 @@
     
   end
   
-  it "should offer an example where behaviour is different with caching enabled and caching disabled" do
-    # if caching is added
+  describe ".view" do
+    
+    map_func = %Q<
+      function (doc) {
+        emit(doc._id, doc);
+      }
+    >
+    
+    it "should request a view and return a hash" do
+      RelaxDB::DesignDocument.get("viewtest").add_view("simple", "map", map_func).save
+      data = RelaxDB.view("viewtest", "simple")
+      data.should be_instance_of(Hash)
+    end
+
+    it "may accept a block" do
+      RelaxDB::DesignDocument.get("viewtest").add_view("simple", "map", map_func).save
+      RelaxDB.db.put("x", {}.to_json)      
+      RelaxDB.db.put("y", {}.to_json)      
+      data = RelaxDB.view("viewtest", "simple") { |q| q.key("x") }
+      data["rows"].size.should == 1
+    end
+    
   end
+  
+  describe ".merge" do
+    
+    it "should merge rows sharing a common merge key into a single ViewObject" do
+      rows = [
+        {"value" => {"sculptor_id" => 1, "sculpture_name" => "strandbeesten"} },
+        {"value" => {"sculptor_id" => 1, "sculptor_name" => "hans"} },
+        {"value" => {"sculptor_id" => 2, "sculpture_name" => "parading dogs"} },
+        {"value" => {"sculptor_id" => 2, "sculptor_name" => "holmes"} }
+      ]
+      data = {"rows" => rows}
+      result = RelaxDB.merge(data, "sculptor_id")
+      result = result.sort { |a, b| a.sculptor_name <=> b.sculptor_name }      
+
+      result[0].sculptor_name.should == "hans"
+      result[0].sculpture_name.should == "strandbeesten"
+      result[1].sculptor_name.should == "holmes"
+      result[1].sculpture_name.should == "parading dogs"
+    end
+        
+  end
+  
+  # if caching is added
+  # it "should offer an example where behaviour is different with caching enabled and caching disabled"
             
 end