added multi-key requests to _view, _temp_view, and _all_docs (with help from davisp)

git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@701814 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 456 insertions, 88 deletions

diff --git a/share/www/script/couch.js b/share/www/script/couch.js
index cf26bb2e..87bba88a 100644
--- a/share/www/script/couch.js
+++ b/share/www/script/couch.js
@@ -112,8 +112,11 @@ function CouchDB(name) {
   }
 
   // Applies the map function to the contents of database and returns the results.
-  this.query = function(mapFun, reduceFun, options) {
+  this.query = function(mapFun, reduceFun, options, keys) {
     var body = {language: "javascript"};
+    if(keys) {
+      body.keys = keys ;      
+    }
     if (typeof(mapFun) != "string")
       mapFun = mapFun.toSource ? mapFun.toSource() : "(" + mapFun.toString() + ")";
     body.map = mapFun;
@@ -132,8 +135,16 @@ function CouchDB(name) {
     return result;
   }
 
-  this.view = function(viewname, options) {
-    var req = request("GET", this.uri + "_view/" + viewname + encodeOptions(options));
+  this.view = function(viewname, options, keys) {
+    var req = null ;
+    if(!keys) {
+      req = request("GET", this.uri + "_view/" + viewname + encodeOptions(options));      
+    } else {
+      req = request("POST", this.uri + "_view/" + viewname + encodeOptions(options), {
+        headers: {"Content-Type": "application/json"},
+        body: JSON.stringify({keys:keys})
+      });      
+    }
     if (req.status == 404)
       return null;
     var result = JSON.parse(req.responseText);
@@ -151,8 +162,16 @@ function CouchDB(name) {
     return result;
   }
 
-  this.allDocs = function(options) {
-    var req = request("GET", this.uri + "_all_docs" + encodeOptions(options));
+  this.allDocs = function(options,keys) {
+    var req = null;
+    if(!keys) {
+      req = request("GET", this.uri + "_all_docs" + encodeOptions(options));      
+    } else {
+      req = request("POST", this.uri + "_all_docs" + encodeOptions(options), {
+        headers: {"Content-Type": "application/json"},
+        body: JSON.stringify({keys:keys})
+      });      
+    }
     var result = JSON.parse(req.responseText);
     if (req.status != 200)
       throw result;
diff --git a/share/www/script/couch_tests.js b/share/www/script/couch_tests.js
index 3abd570e..b2b0bbb1 100644
--- a/share/www/script/couch_tests.js
+++ b/share/www/script/couch_tests.js
@@ -1089,6 +1089,187 @@ var tests = {
     T(results.total_rows == 0);
   },
 
+  view_multi_key_all_docs: function(debug) {
+    var db = new CouchDB("test_suite_db");
+    db.deleteDb();
+    db.createDb();
+    if (debug) debugger;
+
+    var docs = makeDocs(0, 100);
+    T(db.bulkSave(docs).ok);
+
+    var keys = ["10","15","30","37","50"];
+    var rows = db.allDocs({},keys).rows;
+    T(rows.length == keys.length);
+    for(var i=0; i<rows.length; i++)
+      T(rows[i].id == keys[i]);
+
+    rows = db.allDocs({count: 1}, keys).rows;
+    T(rows.length == 1);
+    T(rows[0].id == keys[0]);
+
+    rows = db.allDocs({skip: 2}, keys).rows;
+    T(rows.length == 3);
+    for(var i=0; i<rows.length; i++)
+        T(rows[i].id == keys[i+2]);
+
+    rows = db.allDocs({descending: "true"}, keys).rows;
+    T(rows.length == keys.length);
+    for(var i=0; i<rows.length; i++)
+        T(rows[i].id == keys[keys.length-i-1]);
+
+    rows = db.allDocs({descending: "true", skip: 3, count:1}, keys).rows;
+    T(rows.length == 1);
+    T(rows[0].id == keys[1]);
+
+    // Check we get invalid rows when the key doesn't exist
+    rows = db.allDocs({}, [1, "i_dont_exist", "0"]).rows;
+    T(rows.length == 3);
+    T(rows[0].error == "not_found");
+    T(rows[1].error == "not_found");
+    T(rows[2].id == rows[2].key && rows[2].key == "0");
+  },
+
+  view_multi_key_design: function(debug) {
+    var db = new CouchDB("test_suite_db");
+    db.deleteDb();
+    db.createDb();
+    if (debug) debugger;
+
+    var docs = makeDocs(0, 100);
+    T(db.bulkSave(docs).ok);
+
+    var designDoc = {
+      _id:"_design/test",
+      language: "javascript",
+      views: {
+        all_docs: {
+          map: "function(doc) { emit(doc.integer, doc.string) }"
+        },
+        multi_emit: {
+          map: "function(doc) {for(var i = 0 ; i < 3 ; i++) { emit(i, doc.integer) ; } }"
+        },
+        summate: {
+          map:"function (doc) {emit(doc.integer, doc.integer)};",
+          reduce:"function (keys, values) { return sum(values); };"
+        }
+      }
+    }
+    T(db.save(designDoc).ok);
+
+    // First, the goods:
+    var keys = [10,15,30,37,50];
+    var rows = db.view("test/all_docs",{},keys).rows;
+    for(var i=0; i<rows.length; i++) {
+      T(keys.indexOf(rows[i].key) != -1);
+      T(rows[i].key == rows[i].value);
+    }
+    
+    var reduce = db.view("test/summate",{group:true},keys).rows;
+    T(reduce.length == keys.length);
+    for(var i=0; i<reduce.length; i++) {
+      T(keys.indexOf(reduce[i].key) != -1);
+      T(rows[i].key == rows[i].value);
+    }
+
+    // Test that invalid parameter combinations get rejected
+    var badargs = [{startkey:0}, {endkey:0}, {key: 0}, {group_level: 2}];
+    for(var i in badargs)
+    {
+        try {
+            db.view("test/all_docs",badargs[i],keys);
+            T(0==1);
+        } catch (e) {
+            T(e.error == "query_parse_error");
+        }
+    }
+
+    try {
+        db.view("test/summate",{},keys);
+        T(0==1);
+    } catch (e) {
+        T(e.error == "query_parse_error");
+    }
+
+    // Check that limiting by startkey_docid and endkey_docid get applied
+    // as expected.
+    var curr = db.view("test/multi_emit", {startkey_docid: 21, endkey_docid: 23}, [0, 2]).rows;
+    var exp_key = [ 0,  0,  0,  2,  2,  2] ;
+    var exp_val = [21, 22, 23, 21, 22, 23] ;
+    T(curr.length == 6);
+    for( var i = 0 ; i < 6 ; i++)
+    {
+        T(curr[i].key == exp_key[i]);
+        T(curr[i].value == exp_val[i]);
+    }
+
+    // Check count works
+    curr = db.view("test/all_docs", {count: 1}, keys).rows;
+    T(curr.length == 1);
+    T(curr[0].key == 10);
+
+    // Check offset works
+    curr = db.view("test/multi_emit", {skip: 1}, [0]).rows;
+    T(curr.length == 99);
+    T(curr[0].value == 1);
+
+    // Check that dir works
+    curr = db.view("test/multi_emit", {descending: "true"}, [1]).rows;
+    T(curr.length == 100);
+    T(curr[0].value == 99);
+    T(curr[99].value == 0);
+
+    // Check a couple combinations
+    curr = db.view("test/multi_emit", {descending: "true", skip: 3, count: 2}, [2]).rows;
+    T(curr.length, 2);
+    T(curr[0].value == 96);
+    T(curr[1].value == 95);
+
+    curr = db.view("test/multi_emit", {skip: 2, count: 3, startkey_docid: "13"}, [0]).rows;
+    T(curr.length == 3);
+    T(curr[0].value == 15);
+    T(curr[1].value == 16);
+    T(curr[2].value == 17);
+
+    curr = db.view("test/multi_emit",
+            {skip: 1, count: 5, startkey_docid: "25", endkey_docid: "27"}, [1]).rows;
+    T(curr.length == 2);
+    T(curr[0].value == 26);
+    T(curr[1].value == 27);
+
+    curr = db.view("test/multi_emit",
+            {skip: 1, count: 5, startkey_docid: "28", endkey_docid: "26", descending: "true"}, [1]).rows;
+    T(curr.length == 2);
+    T(curr[0].value == 27);
+    T(curr[1].value == 26);
+  },
+
+  view_multi_key_temp: function(debug) {
+    var db = new CouchDB("test_suite_db");
+    db.deleteDb();
+    db.createDb();
+    if (debug) debugger;
+
+    var docs = makeDocs(0, 100);
+    T(db.bulkSave(docs).ok);
+
+    var queryFun = function(doc) { emit(doc.integer, doc.integer) };
+    var reduceFun = function (keys, values) { return sum(values); };
+
+    var keys = [10,15,30,37,50];
+    var rows = db.query(queryFun, null, {}, keys).rows;
+    for(var i=0; i<rows.length; i++) {
+      T(keys.indexOf(rows[i].key) != -1);
+      T(rows[i].key == rows[i].value);
+    }
+    
+    var reduce = db.query(queryFun, reduceFun, {group:true}, keys).rows;
+    for(var i=0; i<reduce.length; i++) {
+      T(keys.indexOf(reduce[i].key) != -1);
+      T(reduce[i].key == reduce[i].value);
+    }
+  },
+
   view_pagination: function(debug) {
     var db = new CouchDB("test_suite_db");
     db.deleteDb();
diff --git a/src/couchdb/couch_httpd_db.erl b/src/couchdb/couch_httpd_db.erl
index ff3d8125..20805c85 100644
--- a/src/couchdb/couch_httpd_db.erl
+++ b/src/couchdb/couch_httpd_db.erl
@@ -156,38 +156,17 @@ db_req(#httpd{method='POST',path_parts=[_,<<"_purge">>]}=Req, Db) ->
 
 db_req(#httpd{path_parts=[_,<<"_purge">>]}=Req, _Db) ->
     send_method_not_allowed(Req, "POST");
-
+   
 db_req(#httpd{method='GET',path_parts=[_,<<"_all_docs">>]}=Req, Db) ->
-    #view_query_args{
-        start_key = StartKey,
-        start_docid = StartDocId,
-        count = Count,
-        skip = SkipCount,
-        direction = Dir
-    } = QueryArgs = couch_httpd_view:parse_view_query(Req),
-    {ok, Info} = couch_db:get_db_info(Db),
-    TotalRowCount = proplists:get_value(doc_count, Info),
+    all_docs_view(Req, Db, nil);
 
-    StartId = if is_binary(StartKey) -> StartKey;
-    true -> StartDocId
-    end,
-
-    FoldlFun = couch_httpd_view:make_view_fold_fun(Req, QueryArgs, TotalRowCount,
-        fun couch_db:enum_docs_reduce_to_count/1),
-    AdapterFun = fun(#full_doc_info{id=Id}=FullDocInfo, Offset, Acc) ->
-        case couch_doc:to_doc_info(FullDocInfo) of
-        #doc_info{deleted=false, rev=Rev} ->
-            FoldlFun({{Id, Id}, {[{rev, Rev}]}}, Offset, Acc);
-        #doc_info{deleted=true} ->
-            {ok, Acc}
-        end
-    end,
-    {ok, FoldResult} = couch_db:enum_docs(Db, StartId, Dir, AdapterFun,
-            {Count, SkipCount, undefined, []}),
-    couch_httpd_view:finish_view_fold(Req, TotalRowCount, {ok, FoldResult});
+db_req(#httpd{method='POST',path_parts=[_,<<"_all_docs">>]}=Req, Db) ->
+    {Props} = couch_httpd:json_body(Req),
+    Keys = proplists:get_value(<<"keys">>, Props, nil),
+    all_docs_view(Req, Db, Keys);
 
 db_req(#httpd{path_parts=[_,<<"_all_docs">>]}=Req, _Db) ->
-    send_method_not_allowed(Req, "GET,HEAD");
+    send_method_not_allowed(Req, "GET,HEAD,POST");
 
 db_req(#httpd{method='GET',path_parts=[_,<<"_all_docs_by_seq">>]}=Req, Db) ->
     #view_query_args{
@@ -261,6 +240,72 @@ db_req(#httpd{path_parts=[_, DocId]}=Req, Db) ->
 db_req(#httpd{path_parts=[_, DocId, FileName]}=Req, Db) ->
     db_attachment_req(Req, Db, DocId, FileName).
 
+all_docs_view(Req, Db, Keys) -> 
+    #view_query_args{
+        start_key = StartKey,
+        start_docid = StartDocId,
+        count = Count,
+        skip = SkipCount,
+        direction = Dir
+    } = QueryArgs = couch_httpd_view:parse_view_query(Req, Keys),
+    {ok, Info} = couch_db:get_db_info(Db),
+    TotalRowCount = proplists:get_value(doc_count, Info),
+    StartId = if is_binary(StartKey) -> StartKey;
+    true -> StartDocId
+    end,
+    FoldAccInit = {Count, SkipCount, undefined, []},
+    
+    case Keys of
+    nil ->
+        FoldlFun = couch_httpd_view:make_view_fold_fun(Req, QueryArgs, 
+            TotalRowCount, fun couch_db:enum_docs_reduce_to_count/1),
+        AdapterFun = fun(#full_doc_info{id=Id}=FullDocInfo, Offset, Acc) ->
+            case couch_doc:to_doc_info(FullDocInfo) of
+            #doc_info{deleted=false, rev=Rev} ->
+                FoldlFun({{Id, Id}, {[{rev, Rev}]}}, Offset, Acc);
+            #doc_info{deleted=true} ->
+                {ok, Acc}
+            end
+        end,
+        {ok, FoldResult} = couch_db:enum_docs(Db, StartId, Dir, 
+            AdapterFun, FoldAccInit),
+        couch_httpd_view:finish_view_fold(Req, TotalRowCount, {ok, FoldResult});
+    _ ->
+        FoldlFun = couch_httpd_view:make_view_fold_fun(Req, QueryArgs, 
+            TotalRowCount, fun(Offset) -> Offset end),
+        KeyFoldFun = case Dir of
+        fwd ->
+            fun lists:foldl/3;
+        rev ->
+            fun lists:foldr/3
+        end,
+        {ok, FoldResult} = KeyFoldFun(
+            fun(Key, {ok, FoldAcc}) ->
+                DocInfo = (catch couch_db:get_doc_info(Db, Key)),
+                Doc = case DocInfo of
+                {ok, #doc_info{id=Id, rev=Rev, deleted=false}} = DocInfo ->
+                    {{Id, Id}, {[{rev, Rev}]}};
+                {ok, #doc_info{id=Id, rev=Rev, deleted=true}} = DocInfo ->
+                    {{Id, Id}, {[{rev, Rev}, {deleted, true}]}};
+                not_found ->
+                    {{Key, error}, not_found};
+                _ ->
+                    ?LOG_ERROR("Invalid DocInfo: ~p", [DocInfo]),
+                    throw({error, invalid_doc_info})
+                end,
+                Acc = (catch FoldlFun(Doc, 0, FoldAcc)),
+                case Acc of
+                {stop, Acc2} ->
+                    {ok, Acc2};
+                _ ->
+                    Acc
+                end
+            end, {ok, FoldAccInit}, Keys),
+        couch_httpd_view:finish_view_fold(Req, TotalRowCount, {ok, FoldResult})        
+    end.
+
+
+
 
 
 db_doc_req(#httpd{method='DELETE'}=Req, Db, DocId) ->
diff --git a/src/couchdb/couch_httpd_view.erl b/src/couchdb/couch_httpd_view.erl
index c513e750..de6a6af7 100644
--- a/src/couchdb/couch_httpd_view.erl
+++ b/src/couchdb/couch_httpd_view.erl
@@ -15,40 +15,47 @@
 
 -export([handle_view_req/2,handle_temp_view_req/2]).
 
--export([parse_view_query/1,make_view_fold_fun/4,finish_view_fold/3]).
+-export([parse_view_query/1,parse_view_query/2,make_view_fold_fun/4,finish_view_fold/3]).
 
 -import(couch_httpd,
     [send_json/2,send_json/3,send_json/4,send_method_not_allowed/2,
     start_json_response/2,send_chunk/2,end_json_response/1]).
 
-
-handle_view_req(#httpd{method='GET',path_parts=[_,_, Id, ViewName]}=Req, Db) ->
-    #view_query_args{
-        reduce = Reduce
-    } = QueryArgs = parse_view_query(Req),
-    
+design_doc_view(Req, Db, Id, ViewName, Keys) ->
     case couch_view:get_map_view({couch_db:name(Db), 
             <<"_design/", Id/binary>>, ViewName}) of
     {ok, View} ->    
-        output_map_view(Req, View, QueryArgs);
+        QueryArgs = parse_view_query(Req, Keys),
+        output_map_view(Req, View, QueryArgs, Keys);
     {not_found, Reason} ->
         case couch_view:get_reduce_view({couch_db:name(Db),
                 <<"_design/", Id/binary>>, ViewName}) of
         {ok, View} ->
+            #view_query_args{
+                reduce = Reduce
+            } = QueryArgs = parse_view_query(Req, Keys, true),
             case Reduce of
             false ->
                 {reduce, _N, _Lang, MapView} = View,
-                output_map_view(Req, MapView, QueryArgs);
+                output_map_view(Req, MapView, QueryArgs, Keys);
             _ ->
-                output_reduce_view(Req, View)
+                output_reduce_view(Req, View, QueryArgs, Keys)
             end;
         _ ->
             throw({not_found, Reason})
         end
-    end;
+    end.
+
+handle_view_req(#httpd{method='GET',path_parts=[_,_, Id, ViewName]}=Req, Db) ->
+    design_doc_view(Req, Db, Id, ViewName, nil);
+
+handle_view_req(#httpd{method='POST',path_parts=[_,_, Id, ViewName]}=Req, Db) ->
+    {Props} = couch_httpd:json_body(Req),
+    Keys = proplists:get_value(<<"keys">>, Props, nil),
+    design_doc_view(Req, Db, Id, ViewName, Keys);
 
 handle_view_req(Req, _Db) ->
-    send_method_not_allowed(Req, "GET,HEAD").
+    send_method_not_allowed(Req, "GET,POST,HEAD").
 
 handle_temp_view_req(#httpd{method='POST'}=Req, Db) ->
     QueryArgs = parse_view_query(Req),
@@ -61,20 +68,21 @@ handle_temp_view_req(#httpd{method='POST'}=Req, Db) ->
     {Props} = couch_httpd:json_body(Req),
     Language = proplists:get_value(<<"language">>, Props, <<"javascript">>),
     MapSrc = proplists:get_value(<<"map">>, Props),
+    Keys = proplists:get_value(<<"keys">>, Props, nil),
     case proplists:get_value(<<"reduce">>, Props, null) of
     null ->
         {ok, View} = couch_view:get_map_view({temp, couch_db:name(Db), Language, MapSrc}),
-        output_map_view(Req, View, QueryArgs);
+        output_map_view(Req, View, QueryArgs, Keys);
     RedSrc ->
         {ok, View} = couch_view:get_reduce_view(
                 {temp,  couch_db:name(Db), Language, MapSrc, RedSrc}),
-        output_reduce_view(Req, View)
+        output_reduce_view(Req, View, QueryArgs, Keys)
     end;
 
 handle_temp_view_req(Req, _Db) ->
     send_method_not_allowed(Req, "POST").
 
-output_map_view(Req, View, QueryArgs) ->
+output_map_view(Req, View, QueryArgs, nil) ->
     #view_query_args{
         count = Count,
         direction = Dir,
@@ -88,9 +96,30 @@ output_map_view(Req, View, QueryArgs) ->
             fun couch_view:reduce_to_count/1),
     FoldAccInit = {Count, SkipCount, undefined, []},
     FoldResult = couch_view:fold(View, Start, Dir, FoldlFun, FoldAccInit),
+    finish_view_fold(Req, RowCount, FoldResult);
+    
+output_map_view(Req, View, QueryArgs, Keys) ->
+    #view_query_args{
+        count = Count,
+        direction = Dir,
+        skip = SkipCount,
+        start_docid = StartDocId
+    } = QueryArgs,
+    {ok, RowCount} = couch_view:get_row_count(View),
+    FoldAccInit = {Count, SkipCount, undefined, []},
+    FoldResult = lists:foldl(
+        fun(Key, {ok, FoldAcc}) ->
+            Start = {Key, StartDocId},
+            FoldlFun = make_view_fold_fun(Req,
+                QueryArgs#view_query_args{
+                    start_key = Key,
+                    end_key = Key
+                }, RowCount, fun couch_view:reduce_to_count/1),
+            couch_view:fold(View, Start, Dir, FoldlFun, FoldAcc)
+        end, {ok, FoldAccInit}, Keys),
     finish_view_fold(Req, RowCount, FoldResult).
 
-output_reduce_view(Req, View) ->
+output_reduce_view(Req, View, QueryArgs, nil) ->
     #view_query_args{
         start_key = StartKey,
         end_key = EndKey,
@@ -100,7 +129,39 @@ output_reduce_view(Req, View) ->
         start_docid = StartDocId,
         end_docid = EndDocId,
         group_level = GroupLevel
-    } = parse_view_query(Req),
+    } = QueryArgs,
+    {ok, Resp} = start_json_response(Req, 200),
+    {ok, GroupRowsFun, RespFun} = make_reduce_fold_funs(Resp, GroupLevel),
+    send_chunk(Resp, "{\"rows\":["),
+    {ok, _} = couch_view:fold_reduce(View, Dir, {StartKey, StartDocId}, 
+        {EndKey, EndDocId}, GroupRowsFun, RespFun, {"", Skip, Count}),
+    send_chunk(Resp, "]}"),
+    end_json_response(Resp);
+    
+output_reduce_view(Req, View, QueryArgs, Keys) ->
+    #view_query_args{
+        count = Count,
+        skip = Skip,
+        direction = Dir,
+        start_docid = StartDocId,
+        end_docid = EndDocId,
+        group_level = GroupLevel
+    } = QueryArgs,
+    {ok, Resp} = start_json_response(Req, 200),
+    {ok, GroupRowsFun, RespFun} = make_reduce_fold_funs(Resp, GroupLevel),
+    send_chunk(Resp, "{\"rows\":["),
+    lists:foldl(
+        fun(Key, AccSeparator) ->
+            {ok, _} = couch_view:fold_reduce(View, Dir, {Key, StartDocId}, 
+                {Key, EndDocId}, GroupRowsFun, RespFun, 
+                {AccSeparator, Skip, Count}),
+            "," % Switch to comma
+        end,
+    "", Keys), % Start with no comma
+    send_chunk(Resp, "]}"),
+    end_json_response(Resp).
+    
+make_reduce_fold_funs(Resp, GroupLevel) ->
     GroupRowsFun =
         fun({_Key1,_}, {_Key2,_}) when GroupLevel == 0 ->
             true;
@@ -110,55 +171,76 @@ output_reduce_view(Req, View) ->
         ({Key1,_}, {Key2,_}) ->
             Key1 == Key2
         end,
-    {ok, Resp} = start_json_response(Req, 200),
-    send_chunk(Resp, "{\"rows\":["),
-    {ok, _} = couch_view:fold_reduce(View, Dir, {StartKey, StartDocId}, {EndKey, EndDocId},
-        GroupRowsFun,
-        fun(_Key, _Red, {AccSeparator,AccSkip,AccCount}) when AccSkip > 0 ->
-            {ok, {AccSeparator,AccSkip-1,AccCount}};
-        (_Key, _Red, {AccSeparator,0,AccCount}) when AccCount == 0 ->
-            {stop, {AccSeparator,0,AccCount}};
-        (_Key, Red, {AccSeparator,0,AccCount}) when GroupLevel == 0 ->
-            Json = ?JSON_ENCODE({[{key, null}, {value, Red}]}),
-            send_chunk(Resp, AccSeparator ++ Json),
-            {ok, {",",0,AccCount-1}};
-        (Key, Red, {AccSeparator,0,AccCount})
-                when is_integer(GroupLevel) 
-                andalso is_list(Key) ->
-            Json = ?JSON_ENCODE(
-                {[{key, lists:sublist(Key, GroupLevel)},{value, Red}]}),
-            send_chunk(Resp, AccSeparator ++ Json),
-            {ok, {",",0,AccCount-1}};
-        (Key, Red, {AccSeparator,0,AccCount}) ->
-            Json = ?JSON_ENCODE({[{key, Key}, {value, Red}]}),
-            send_chunk(Resp, AccSeparator ++ Json),
-            {ok, {",",0,AccCount-1}}
-        end, {"", Skip, Count}),
-    send_chunk(Resp, "]}"),
-    end_json_response(Resp).
+    RespFun = fun(_Key, _Red, {AccSeparator,AccSkip,AccCount}) when AccSkip > 0 ->
+        {ok, {AccSeparator,AccSkip-1,AccCount}};
+    (_Key, _Red, {AccSeparator,0,AccCount}) when AccCount == 0 ->
+        {stop, {AccSeparator,0,AccCount}};
+    (_Key, Red, {AccSeparator,0,AccCount}) when GroupLevel == 0 ->
+        Json = ?JSON_ENCODE({[{key, null}, {value, Red}]}),
+        send_chunk(Resp, AccSeparator ++ Json),
+        {ok, {",",0,AccCount-1}};
+    (Key, Red, {AccSeparator,0,AccCount})
+            when is_integer(GroupLevel) 
+            andalso is_list(Key) ->
+        Json = ?JSON_ENCODE(
+            {[{key, lists:sublist(Key, GroupLevel)},{value, Red}]}),
+        send_chunk(Resp, AccSeparator ++ Json),
+        {ok, {",",0,AccCount-1}};
+    (Key, Red, {AccSeparator,0,AccCount}) ->
+        Json = ?JSON_ENCODE({[{key, Key}, {value, Red}]}),
+        send_chunk(Resp, AccSeparator ++ Json),
+        {ok, {",",0,AccCount-1}}
+    end,
+    {ok, GroupRowsFun, RespFun}.
     
 
+
+
 reverse_key_default(nil) -> {};
 reverse_key_default({}) -> nil;
 reverse_key_default(Key) -> Key.
 
 parse_view_query(Req) ->
+    parse_view_query(Req, nil, nil).
+parse_view_query(Req, Keys) ->
+    parse_view_query(Req, Keys, nil).
+parse_view_query(Req, Keys, IsReduce) ->
     QueryList = couch_httpd:qs(Req),
-    lists:foldl(fun({Key,Value}, Args) ->
+    #view_query_args{
+        group_level = GroupLevel
+    } = QueryArgs = lists:foldl(fun({Key,Value}, Args) ->
         case {Key, Value} of
         {"", _} ->
             Args;
         {"key", Value} ->
-            JsonKey = ?JSON_DECODE(Value),
-            Args#view_query_args{start_key=JsonKey,end_key=JsonKey};
+            case Keys of
+            nil ->
+                JsonKey = ?JSON_DECODE(Value),
+                Args#view_query_args{start_key=JsonKey,end_key=JsonKey};
+            _ ->
+                Msg = io_lib:format("Query parameter \"~s\" not compatible with multi key mode.", [Key]),
+                throw({query_parse_error, Msg})
+            end;
         {"startkey_docid", DocId} ->
             Args#view_query_args{start_docid=list_to_binary(DocId)};
         {"endkey_docid", DocId} ->
             Args#view_query_args{end_docid=list_to_binary(DocId)};
         {"startkey", Value} ->
-            Args#view_query_args{start_key=?JSON_DECODE(Value)};
+            case Keys of
+            nil ->
+                Args#view_query_args{start_key=?JSON_DECODE(Value)};
+            _ ->
+                Msg = io_lib:format("Query parameter \"~s\" not compatible with multi key mode.", [Key]),
+                throw({query_parse_error, Msg})
+            end;
         {"endkey", Value} ->
-            Args#view_query_args{end_key=?JSON_DECODE(Value)};
+            case Keys of
+            nil ->
+                Args#view_query_args{end_key=?JSON_DECODE(Value)};
+            _ ->
+                Msg = io_lib:format("Query parameter \"~s\" not compatible with multi key mode.", [Key]),
+                throw({query_parse_error, Msg})
+            end;
         {"count", Value} ->
             case (catch list_to_integer(Value)) of
             Count when is_integer(Count) ->
@@ -201,10 +283,24 @@ parse_view_query(Req) ->
                 "Bad URL query value, number expected: skip=~s", [Value])),
                 throw({query_parse_error, Msg})
             end;
-        {"group", "true"} ->
-            Args#view_query_args{group_level=exact};
+        {"group", Value} ->
+            case Value of
+            "true" ->
+                Args#view_query_args{group_level=exact};
+            "false" ->
+                Args#view_query_args{group_level=0};
+            _ ->
+                Msg = "Bad URL query value for 'group' expected \"true\" or \"false\".",
+                throw({query_parse_error, Msg})
+            end;
         {"group_level", LevelStr} ->
-            Args#view_query_args{group_level=list_to_integer(LevelStr)};
+            case Keys of
+            nil ->
+                Args#view_query_args{group_level=list_to_integer(LevelStr)};
+            _ ->
+                Msg = lists:flatten(io_lib:format("Multi-key fetches for a reduce view must include group=true", [])),
+                throw({query_parse_error, Msg})
+            end;
         {"reduce", "true"} ->
             Args#view_query_args{reduce=true};
         {"reduce", "false"} ->
@@ -214,7 +310,25 @@ parse_view_query(Req) ->
                 "Bad URL query key:~s", [Key])),
             throw({query_parse_error, Msg})
         end
-    end, #view_query_args{}, QueryList).
+    end, #view_query_args{}, QueryList),
+    case Keys of
+    nil ->
+        QueryArgs;
+    _ ->
+        case IsReduce of
+        nil ->
+            QueryArgs;
+        _ ->
+            case GroupLevel of
+            exact ->
+                QueryArgs;
+            _ ->
+                Msg = lists:flatten(io_lib:format(
+                    "Multi-key fetches for a reduce view must include group=true", [])),
+                throw({query_parse_error, Msg})
+            end
+        end
+    end.
 
 
 make_view_fold_fun(Req, QueryArgs, TotalViewCount, ReduceCountFun) ->
@@ -253,12 +367,21 @@ make_view_fold_fun(Req, QueryArgs, TotalViewCount, ReduceCountFun) ->
             {ok, Resp2} = start_json_response(Req, 200),
             JsonBegin = io_lib:format("{\"total_rows\":~w,\"offset\":~w,\"rows\":[\r\n",
                     [TotalViewCount, Offset]),
-            JsonObj = {[{id, DocId}, {key, Key}, {value, Value}]},
-            
+            JsonObj = case DocId of
+            error ->
+                {[{key, Key}, {error, Value}]};
+            _ ->
+                {[{id, DocId}, {key, Key}, {value, Value}]}
+            end,            
             send_chunk(Resp2, JsonBegin ++ ?JSON_ENCODE(JsonObj)),
             {ok, {AccCount - 1, 0, Resp2, AccRevRows}};
         {_, AccCount, _, Resp} when (AccCount > 0) ->
-            JsonObj = {[{id, DocId}, {key, Key}, {value, Value}]},
+            JsonObj = case DocId of
+            error ->
+                {[{key, Key}, {error, Value}]};
+            _ ->
+                {[{id, DocId}, {key, Key}, {value, Value}]}
+            end,
             send_chunk(Resp, ",\r\n" ++  ?JSON_ENCODE(JsonObj)),
             {ok, {AccCount - 1, 0, Resp, AccRevRows}}
         end