On 8/7/10 at 7:37 AM, [email protected] (Sivan Greenberg) wrote:
As I am also using a JS filter and fear the performance and load
consequences, how does one go about writing an erlang filter?
-SIvan
I can't claim it to be idiomatic Erlang, but this is the one I
am working on that accepts query argument from the client
opening the change feed.
fun({Doc}, {Req}) ->
{Query} = couch_util:get_value(<<"query">>, Req),
ExcludedServer = couch_util:get_value(<<"excludeServer">>, Query),
case {couch_util:get_value(<<"docType">>, Doc),
couch_util:get_value(<<"updatedOnServer">>, Doc)} of
{<<"CS_MANIFEST">>, null} ->
CreatedOnServer =
couch_util:get_value(<<"createdOnServer">>, Doc),
CreatedOnServer =/= ExcludedServer;
{<<"CS_MANIFEST">>, undefined} ->
false;
{<<CS_MANIFEST">>, UpdatedOnServer} ->
UpdatedOnServer =/= ExcludedServer;
_ ->
false
end
end.
BTW, since strings are represented as Binaries (<<>> syntax),
string manipulation in Erlang map-reduce and filter functions is
easy with Erlang's BIFs that manipulate binaries, like split_binary().
Matt
