From 07e6c1834ef4ed01766235ebf2dba89431982c5c Mon Sep 17 00:00:00 2001
From: Klaus Trainer <klaus_trainer@apache.org>
Date: Mon, 2 Nov 2015 18:33:19 +0100
Subject: [PATCH] Don't set random ETag header for views

This fixes the issue that by setting a random ETag header, we implicitly
promised that there's a chance of a cache hit where there was no chance.

For 2.0, we simply remove the random ETag without replacement, in order
to not accidentally cause useless cache bloat in clients.

COUCHDB-2859
---
 src/chttpd_view.erl | 44 +++++++++++++-------------------------------
 1 file changed, 13 insertions(+), 31 deletions(-)

diff --git a/src/chttpd_view.erl b/src/chttpd_view.erl
index 8da557d..ea86095 100644
--- a/src/chttpd_view.erl
+++ b/src/chttpd_view.erl
@@ -24,41 +24,23 @@ multi_query_view(Req, Db, DDoc, ViewName, Queries) ->
         QueryArg = couch_mrview_http:parse_params(Query, undefined, Args1),
         couch_mrview_util:validate_args(QueryArg)
     end, Queries),
-    {ok, Resp2} = couch_httpd:etag_maybe(Req, fun() ->
-        VAcc0 = #vacc{db=Db, req=Req, prepend="\r\n"},
-        %% TODO: proper calculation of etag
-        Etag = [$", couch_uuids:new(), $"],
-        Headers = [{"ETag", Etag}],
-        FirstChunk = "{\"results\":[",
-        {ok, Resp0} = chttpd:start_delayed_json_response(VAcc0#vacc.req, 200, Headers, FirstChunk),
-        VAcc1 = VAcc0#vacc{resp=Resp0, etag=Etag},
-        VAcc2 = lists:foldl(fun(Args, Acc0) ->
-            {ok, Acc1} = fabric:query_view(Db, DDoc, ViewName, fun couch_mrview_http:view_cb/2, Acc0, Args),
-            Acc1
-        end, VAcc1, ArgQueries),
-        {ok, Resp1} = chttpd:send_delayed_chunk(VAcc2#vacc.resp, "\r\n]}"),
-        {ok, Resp2} = chttpd:end_delayed_json_response(Resp1),
-        {ok, VAcc2#vacc{resp=Resp2}}
-    end),
-    case is_record(Resp2, vacc) of
-        true -> {ok, Resp2#vacc.resp};
-        _ -> {ok, Resp2}
-    end.
+    VAcc0 = #vacc{db=Db, req=Req, prepend="\r\n"},
+    FirstChunk = "{\"results\":[",
+    {ok, Resp0} = chttpd:start_delayed_json_response(VAcc0#vacc.req, 200, [], FirstChunk),
+    VAcc1 = VAcc0#vacc{resp=Resp0},
+    VAcc2 = lists:foldl(fun(Args, Acc0) ->
+        {ok, Acc1} = fabric:query_view(Db, DDoc, ViewName, fun couch_mrview_http:view_cb/2, Acc0, Args),
+        Acc1
+    end, VAcc1, ArgQueries),
+    {ok, Resp1} = chttpd:send_delayed_chunk(VAcc2#vacc.resp, "\r\n]}"),
+    chttpd:end_delayed_json_response(Resp1).
 
 
 design_doc_view(Req, Db, DDoc, ViewName, Keys) ->
     Args = couch_mrview_http:parse_params(Req, Keys),
-    %% TODO: proper calculation of etag
-    Etag = [$", couch_uuids:new(), $"],
-    {ok, Resp} = couch_httpd:etag_maybe(Req, fun() ->
-        Max = chttpd:chunked_response_buffer_size(),
-        VAcc0 = #vacc{db=Db, req=Req, threshold=Max, etag=Etag},
-        fabric:query_view(Db, DDoc, ViewName, fun couch_mrview_http:view_cb/2, VAcc0, Args)
-    end),
-    case is_record(Resp, vacc) of
-        true -> {ok, Resp#vacc.resp};
-        _ -> {ok, Resp}
-    end.
+    Max = chttpd:chunked_response_buffer_size(),
+    VAcc = #vacc{db=Db, req=Req, threshold=Max},
+    fabric:query_view(Db, DDoc, ViewName, fun couch_mrview_http:view_cb/2, VAcc, Args).
 
 handle_view_req(#httpd{method='GET',
         path_parts=[_, _, _, _, ViewName]}=Req, Db, DDoc) ->