Support for pre-caching belongs_to associations

Author: evanmiller

src/boss_db.erl

@@ -12,7 +12,6 @@
         find_first/3,
         find_last/2,
         find_last/3,
-        get/1,
         count/1,
         count/2,
         counter/1, 
@@ -65,25 +64,20 @@ db_call(Msg) ->
             Reply
     end.
 
-%% @spec find(Id::string()) -> BossRecord | {error, Reason}
-%% @doc Find a BossRecord with the specified `Id'.
+%% @spec find(Id::string()) -> Value | {error, Reason}
+%% @doc Find a BossRecord with the specified `Id' (e.g. "employee-42") or a value described
+%% by a dot-separated path (e.g. "employee-42.manager.name").
 find("") -> undefined;
 find(Key) when is_list(Key) ->
-    db_call({find, Key});
+    [IdToken|Rest] = string:tokens(Key, "."),
+    case db_call({find, IdToken}) of
+        undefined -> undefined;
+        {error, Reason} -> {error, Reason};
+        BossRecord -> BossRecord:get(string:join(Rest, "."))
+    end;
 find(_) ->
     {error, invalid_id}.
 
-%% @spec get(Path::string()) -> Value | {error, Reason} | undefined
-%% @doc Find a BossRecord or value described by the dot-separated `Path' (e.g., "employee-42.manager.name").
-get(Path) when is_list(Path) ->
-    [IdToken|Rest] = string:tokens(Path, "."),
-    case find(IdToken) of
-        {error, Reason} ->
-            {error, Reason};
-        BossRecord ->
-            BossRecord:get(string:join(Rest, "."))
-    end.
-
 %% @spec find(Type::atom(), Conditions) -> [ BossRecord ]
 %% @doc Query for BossRecords. Returns all BossRecords of type
 %% `Type' matching all of the given `Conditions'
@@ -94,8 +88,9 @@ find(Type, Conditions) ->
 %% @doc Query for BossRecords. Returns BossRecords of type
 %% `Type' matching all of the given `Conditions'. Options may include
 %% `limit' (maximum number of records to return), `offset' (number of records
-%% to skip), `order_by' (attribute to sort on), and `descending' (whether to
-%% sort the values from highest to lowest)
+%% to skip), `order_by' (attribute to sort on), `descending' (whether to
+%% sort the values from highest to lowest), and `include' (list of belongs_to
+%% associations to pre-cache)
 find(Type, Conditions, Options) ->
     Max = proplists:get_value(limit, Options, all),
     Skip = proplists:get_value(offset, Options, 0),
@@ -104,7 +99,8 @@ find(Type, Conditions, Options) ->
         true -> descending;
         _ -> ascending
     end,
-    db_call({find, Type, normalize_conditions(Conditions), Max, Skip, Sort, SortOrder}).
+    Include = proplists:get_value(include, Options, []),
+    db_call({find, Type, normalize_conditions(Conditions), Max, Skip, Sort, SortOrder, Include}).
 
 %% @spec find_first( Type::atom(), Conditions ) -> Record | undefined
 %% @doc Query for the first BossRecord of type `Type' matching all of the given `Conditions'

src/boss_db_controller.erl

@@ -71,14 +71,32 @@ handle_call({find, Key}, _From, #state{ cache_enable = false } = State) ->
     {Adapter, Conn} = db_for_key(Key, State),
     {reply, Adapter:find(Conn, Key), State};
 
-handle_call({find, Type, Conditions, Max, Skip, Sort, SortOrder} = Cmd, From, 
+handle_call({find, Type, Conditions, Max, Skip, Sort, SortOrder, Include} = Cmd, From, 
     #state{ cache_enable = true, cache_prefix = Prefix } = State) ->
     Key = {Type, Conditions, Max, Skip, Sort, SortOrder},
     case boss_cache:get(Prefix, Key) of
         undefined ->
             {reply, Res, _} = handle_call(Cmd, From, State#state{ cache_enable = false }),
             case is_list(Res) of
                 true ->
+                    DummyRecord = boss_record_lib:dummy_record(Type),
+                    BelongsToNames = DummyRecord:belongs_to_names(),
+                    IncludedRecords = lists:foldl(fun
+                            ({RelationshipName, InnerInclude}, Acc) ->
+                                RecordList = case lists:member(RelationshipName, BelongsToNames) of
+                                    true ->
+                                        IdList = lists:map(fun(Record) -> Record:id() end, Res),
+                                        handle_call({find, RelationshipName, 
+                                                [{'id', 'in', IdList}], all, 0, id, ascending,
+                                                InnerInclude}, From, State);
+                                    _ ->
+                                        []
+                                end,
+                                RecordList ++ Acc
+                        end, [], lists:map(fun({R, I}) -> {R, I}; (R) -> {R, []} end, Include)),
+                    lists:map(fun(Rec) ->
+                                boss_cache:set(Prefix, Rec:id(), Rec, State#state.cache_ttl)
+                        end, IncludedRecords),
                     boss_cache:set(Prefix, Key, Res, State#state.cache_ttl),
                     WatchString = lists:concat([inflector:pluralize(atom_to_list(Type)), ", ", Type, "-*.*"]), 
                     boss_news:set_watch(Key, WatchString, fun boss_db_cache:handle_collection_news/3, 
@@ -90,7 +108,7 @@ handle_call({find, Type, Conditions, Max, Skip, Sort, SortOrder} = Cmd, From,
             boss_news:extend_watch(Key),
             {reply, CachedValue, State}
     end;
-handle_call({find, Type, Conditions, Max, Skip, Sort, SortOrder}, _From, #state{ cache_enable = false } = State) ->
+handle_call({find, Type, Conditions, Max, Skip, Sort, SortOrder, _}, _From, #state{ cache_enable = false } = State) ->
     {Adapter, Conn} = db_for_type(Type, State),
     {reply, Adapter:find(Conn, Type, Conditions, Max, Skip, Sort, SortOrder), State};
 

src/boss_record_compiler.erl

@@ -379,14 +379,15 @@ attribute_names_forms(ModuleName, Parameters) ->
 has_one_forms(HasOne, ModuleName, Opts) ->
     Type = proplists:get_value(module, Opts, HasOne),
     ForeignKey = proplists:get_value(foreign_key, Opts, atom_to_list(ModuleName) ++ "_id"),
+    Include = proplists:get_value(include, Opts, []),
     [erl_syntax:add_precomments([erl_syntax:comment(
                     [lists:concat(["% @spec ", HasOne, "() -> ", Type, " | undefined"]),
                         lists:concat(["% @doc Retrieves the `", Type, "' with `", ForeignKey, "' ",
                                 "set to the `Id' of this `", ModuleName, "'"])])],
             erl_syntax:function(erl_syntax:atom(HasOne),
                 [erl_syntax:clause([], none, [
                             first_or_undefined_forms(
-                                has_many_application_forms(Type, ForeignKey, 1, id, false)
+                                has_many_application_forms(Type, ForeignKey, 1, id, false, Include)
                             )
                         ])]))
     ].
@@ -398,6 +399,7 @@ has_many_forms(HasMany, ModuleName, Limit, Opts) ->
     IsDescending = proplists:get_value(descending, Opts, false),
     Singular = inflector:singularize(atom_to_list(HasMany)),
     Type = proplists:get_value(module, Opts, Singular),
+    Include = proplists:get_value(include, Opts, []),
     ForeignKey = proplists:get_value(foreign_key, Opts, atom_to_list(ModuleName) ++ "_id"),
     [erl_syntax:add_precomments([erl_syntax:comment(
                     [
@@ -406,7 +408,7 @@ has_many_forms(HasMany, ModuleName, Limit, Opts) ->
                                 "set to the `Id' of this `", ModuleName, "'"])])],
             erl_syntax:function(erl_syntax:atom(HasMany),
                 [erl_syntax:clause([], none, [
-                            has_many_application_forms(Type, ForeignKey, Limit, Sort, IsDescending)
+                            has_many_application_forms(Type, ForeignKey, Limit, Sort, IsDescending, Include)
                         ])])),
         erl_syntax:add_precomments([erl_syntax:comment(
                     [
@@ -416,7 +418,7 @@ has_many_forms(HasMany, ModuleName, Limit, Opts) ->
             erl_syntax:function(erl_syntax:atom("first_"++Singular),
                 [erl_syntax:clause([], none, [
                             first_or_undefined_forms(
-                                has_many_application_forms(Type, ForeignKey, 1, Sort, IsDescending)
+                                has_many_application_forms(Type, ForeignKey, 1, Sort, IsDescending, Include)
                             )
                         ])])),
         erl_syntax:add_precomments([erl_syntax:comment(
@@ -427,7 +429,7 @@ has_many_forms(HasMany, ModuleName, Limit, Opts) ->
             erl_syntax:function(erl_syntax:atom("last_"++Singular),
                 [erl_syntax:clause([], none, [
                             first_or_undefined_forms(
-                                    has_many_application_forms(Type, ForeignKey, 1, Sort, not IsDescending)
+                                    has_many_application_forms(Type, ForeignKey, 1, Sort, not IsDescending, Include)
                                 )
                         ])]))
     ].
@@ -438,7 +440,7 @@ first_or_undefined_forms(Forms) ->
                 [erl_syntax:variable(?PREFIX++"Record")]),
             erl_syntax:clause([erl_syntax:underscore()], none, [erl_syntax:atom(undefined)])]).
 
-has_many_application_forms(Type, ForeignKey, Limit, Sort, IsDescending) ->
+has_many_application_forms(Type, ForeignKey, Limit, Sort, IsDescending, Include) ->
     erl_syntax:application(
         erl_syntax:atom(?DATABASE_MODULE), 
         erl_syntax:atom(find),
@@ -457,7 +459,10 @@ has_many_application_forms(Type, ForeignKey, Limit, Sort, IsDescending) ->
                             erl_syntax:atom(Sort)]),
                     erl_syntax:tuple([
                             erl_syntax:atom(descending),
-                            erl_syntax:atom(IsDescending)])
+                            erl_syntax:atom(IsDescending)]),
+                    erl_syntax:tuple([
+                            erl_syntax:atom(include),
+                            erl_syntax:list(lists:map(fun erl_syntax:atom/1, Include))])
                 ])
         ]).