[couchdb] branch 3.x updated: Properly combine base and extra headers when making replicator requests

[va...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

vatamane pushed a commit to branch 3.x
in repository https://gitbox.apache.org/repos/asf/couchdb.git


The following commit(s) were added to refs/heads/3.x by this push:
     new ce15da0  Properly combine base and extra headers when making replicator requests
ce15da0 is described below

commit ce15da09a09407cefdf712eea4c2d20d3e83425f
Author: Nick Vatamaniuc <va...@apache.org>
AuthorDate: Fri Oct 9 18:10:44 2020 -0400

    Properly combine base and extra headers when making replicator requests
    
    Previously we subtly relied on one set of headers being sorted, then sorted the
    other set of headers, and ran `lists:ukeymerge/3`. That function, however,
    needs both arguments to be sorted in order for it to work as expected. If one
    argument wasn't sorted we could get duplicate headers easily, which is what was
    observed in testing.
    
    A better fix than just sorting both sets of keys, is to use an actual header
    processing library to combine them so we can account for case insensitivity as
    well.
---
 .../src/couch_replicator_httpc.erl                 | 28 ++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/couch_replicator/src/couch_replicator_httpc.erl b/src/couch_replicator/src/couch_replicator_httpc.erl
index 4dce319..466bc57 100644
--- a/src/couch_replicator/src/couch_replicator_httpc.erl
+++ b/src/couch_replicator/src/couch_replicator_httpc.erl
@@ -97,8 +97,8 @@ send_req(HttpDb, Params1, Callback) ->
 
 send_ibrowse_req(#httpdb{headers = BaseHeaders} = HttpDb0, Params) ->
     Method = get_value(method, Params, get),
-    UserHeaders = lists:keysort(1, get_value(headers, Params, [])),
-    Headers1 = lists:ukeymerge(1, UserHeaders, BaseHeaders),
+    UserHeaders = get_value(headers, Params, []),
+    Headers1 = merge_headers(BaseHeaders, UserHeaders),
     {Headers2, HttpDb} = couch_replicator_auth:update_headers(HttpDb0, Headers1),
     Url = full_url(HttpDb, Params),
     Body = get_value(body, Params, []),
@@ -493,3 +493,27 @@ backoff_before_request(Worker, HttpDb, Params) ->
         Sleep when Sleep == 0 ->
             ok
     end.
+
+
+merge_headers(Headers1, Headers2) when is_list(Headers1), is_list(Headers2) ->
+    Empty = mochiweb_headers:empty(),
+    Merged = mochiweb_headers:enter_from_list(Headers1 ++ Headers2, Empty),
+    mochiweb_headers:to_list(Merged).
+
+
+-ifdef(TEST).
+
+-include_lib("couch/include/couch_eunit.hrl").
+
+
+merge_headers_test() ->
+    ?assertEqual([], merge_headers([], [])),
+    ?assertEqual([{"a", "x"}], merge_headers([], [{"a", "x"}])),
+    ?assertEqual([{"a", "x"}], merge_headers([{"a", "x"}], [])),
+    ?assertEqual([{"a", "y"}], merge_headers([{"A", "x"}], [{"a", "y"}])),
+    ?assertEqual([{"a", "y"}, {"B", "x"}], merge_headers([{"B", "x"}],
+        [{"a", "y"}])),
+    ?assertEqual([{"a", "y"}], merge_headers([{"A", "z"}, {"a", "y"}], [])),
+    ?assertEqual([{"a", "y"}], merge_headers([], [{"A", "z"}, {"a", "y"}])).
+
+-endif.