Merge branch '2059-feature-uri-len-negotiation'

3 files changed, 49 insertions, 11 deletions

diff --git a/etc/couchdb/default.ini.tpl.in b/etc/couchdb/default.ini.tpl.in
index 3267001ae..fd953c2fc 100644
--- a/etc/couchdb/default.ini.tpl.in
+++ b/etc/couchdb/default.ini.tpl.in
@@ -52,6 +52,8 @@ allow_jsonp = false
 ;socket_options = [{recbuf, 262144}, {sndbuf, 262144}, {nodelay, true}]
 log_max_chunk_size = 1000000
 enable_cors = false
+; CouchDB can optionally enforce a maximum uri length;
+; max_uri_length = 8000
 
 [ssl]
 port = 6984
diff --git a/src/couch_replicator/src/couch_replicator_api_wrap.erl b/src/couch_replicator/src/couch_replicator_api_wrap.erl
index 5a42bb31b..3cf942d69 100644
--- a/src/couch_replicator/src/couch_replicator_api_wrap.erl
+++ b/src/couch_replicator/src/couch_replicator_api_wrap.erl
@@ -50,6 +50,9 @@
 
 -define(MAX_WAIT, 5 * 60 * 1000).
 
+-define(MAX_URL_LEN, 7000).
+-define(MIN_URL_LEN, 200).
+
 db_uri(#httpdb{url = Url}) ->
     couch_util:url_strip_password(Url);
 
@@ -171,13 +174,16 @@ open_doc_revs(#httpdb{} = HttpDb, Id, Revs, Options, Fun, Acc) ->
     QS = options_to_query_args(HttpDb, Path, [revs, {open_revs, Revs} | Options]),
     {Pid, Ref} = spawn_monitor(fun() ->
         Self = self(),
-        Callback = fun(200, Headers, StreamDataFun) ->
+        Callback = fun
+          (200, Headers, StreamDataFun) ->
             remote_open_doc_revs_streamer_start(Self),
             {<<"--">>, _, _} = couch_httpd:parse_multipart_request(
                 get_value("Content-Type", Headers),
                 StreamDataFun,
                 fun mp_parse_mixed/1
-            )
+            );
+          (414, _, _) ->
+            exit(request_uri_too_long)
         end,
         Streamer = spawn_link(fun() ->
             Params = [
@@ -217,6 +223,17 @@ open_doc_revs(#httpdb{} = HttpDb, Id, Revs, Options, Fun, Acc) ->
             Ret;
         {'DOWN', Ref, process, Pid, {{nocatch, {missing_stub,_} = Stub}, _}} ->
             throw(Stub);
+        {'DOWN', Ref, process, Pid, request_uri_too_long} ->
+            NewMaxLen = get_value(max_url_len, Options, ?MAX_URL_LEN) div 2,
+            case NewMaxLen < ?MIN_URL_LEN of
+                true ->
+                    throw(request_uri_too_long);
+                false ->
+                    ?LOG_INFO("Reducing url length to ~B because of 414 response", [NewMaxLen]),
+                    Options1 = lists:keystore(max_url_len, 1, Options,
+                                              {max_url_len, NewMaxLen}),
+                    open_doc_revs(HttpDb, Id, Revs, Options1, Fun, Acc)
+            end;
         {'DOWN', Ref, process, Pid, Else} ->
             Url = couch_util:url_strip_password(
                 couch_replicator_httpc:full_url(HttpDb, [{path,Path}, {qs,QS}])
@@ -501,7 +518,11 @@ changes_json_req(Db, FilterName, {QueryParams}, _Options) ->
     ]}.
 
 
-options_to_query_args(HttpDb, Path, Options) ->
+options_to_query_args(HttpDb, Path, Options0) ->
+    case lists:keytake(max_url_len, 1, Options0) of
+        false -> MaxLen = ?MAX_URL_LEN, Options = Options0;
+        {value, {max_url_len, MaxLen}, Options} -> ok
+    end,
     case lists:keytake(atts_since, 1, Options) of
     false ->
         options_to_query_args(Options, []);
@@ -514,7 +535,7 @@ options_to_query_args(HttpDb, Path, Options) ->
         RevList = atts_since_arg(
             length("GET " ++ FullUrl ++ " HTTP/1.1\r\n") +
             length("&atts_since=") + 6,  % +6 = % encoded [ and ]
-            PAs, []),
+            PAs, MaxLen, []),
         [{"atts_since", ?JSON_ENCODE(RevList)} | QueryArgs1]
     end.
 
@@ -535,12 +556,9 @@ options_to_query_args([{open_revs, Revs} | Rest], Acc) ->
     JsonRevs = ?b2l(?JSON_ENCODE(couch_doc:revs_to_strs(Revs))),
     options_to_query_args(Rest, [{"open_revs", JsonRevs} | Acc]).
 
-
-atts_since_arg(_UrlLen, [], Acc) ->
+atts_since_arg(_UrlLen, [], _MaxLen, Acc) ->
     lists:reverse(Acc);
-atts_since_arg(UrlLen, [PA | Rest], Acc) ->
-    MaxUrlLen = list_to_integer(
-        couch_config:get("replicator", "max_url_len", "7000")),
+atts_since_arg(UrlLen, [PA | Rest], MaxLen, Acc) ->
     RevStr = couch_doc:rev_to_str(PA),
     NewUrlLen = case Rest of
     [] ->
@@ -550,11 +568,11 @@ atts_since_arg(UrlLen, [PA | Rest], Acc) ->
         % plus 2 double quotes and a comma (% encoded)
         UrlLen + size(RevStr) + 9
     end,
-    case NewUrlLen >= MaxUrlLen of
+    case NewUrlLen >= MaxLen of
     true ->
         lists:reverse(Acc);
     false ->
-        atts_since_arg(NewUrlLen, Rest, [RevStr | Acc])
+        atts_since_arg(NewUrlLen, Rest, MaxLen, [RevStr | Acc])
     end.
 
 
diff --git a/src/couchdb/couch_httpd.erl b/src/couchdb/couch_httpd.erl
index f00fdd068..7ee3e3acc 100644
--- a/src/couchdb/couch_httpd.erl
+++ b/src/couchdb/couch_httpd.erl
@@ -310,6 +310,7 @@ handle_request_int(MochiReq, DefaultFun,
 
     {ok, Resp} =
     try
+        check_request_uri_length(RawUri),
         case couch_httpd_cors:is_preflight_request(HttpReq) of
         #httpd{} ->
             case authenticate_request(HttpReq, AuthHandlers) of
@@ -343,6 +344,8 @@ handle_request_int(MochiReq, DefaultFun,
             send_error(HttpReq, {bad_otp_release, ErrorReason});
         exit:{body_too_large, _} ->
             send_error(HttpReq, request_entity_too_large);
+        exit:{uri_too_long, _} ->
+            send_error(HttpReq, request_uri_too_long);
         throw:Error ->
             Stack = erlang:get_stacktrace(),
             ?LOG_DEBUG("Minor error in HTTP request: ~p",[Error]),
@@ -369,6 +372,19 @@ handle_request_int(MochiReq, DefaultFun,
     couch_stats_collector:increment({httpd, requests}),
     {ok, Resp}.
 
+check_request_uri_length(Uri) ->
+    check_request_uri_length(Uri, couch_config:get("httpd", "max_uri_length")).
+
+check_request_uri_length(_Uri, undefined) ->
+    ok;
+check_request_uri_length(Uri, MaxUriLen) when is_list(MaxUriLen) ->
+    case length(Uri) > list_to_integer(MaxUriLen) of
+        true ->
+            throw(request_uri_too_long);
+        false ->
+            ok
+    end.
+
 % Try authentication handlers in order until one sets a user_ctx
 % the auth funs also have the option of returning a response
 % move this to couch_httpd_auth?
@@ -826,6 +842,8 @@ error_info(file_exists) ->
         "created, the file already exists.">>};
 error_info(request_entity_too_large) ->
     {413, <<"too_large">>, <<"the request entity is too large">>};
+error_info(request_uri_too_long) ->
+    {414, <<"too_long">>, <<"the request entity is too long">>};
 error_info({bad_ctype, Reason}) ->
     {415, <<"bad_content_type">>, Reason};
 error_info(requested_range_not_satisfiable) ->