On Tue, Jan 12, 2010 at 8:51 AM, Paul Davis <[email protected]> wrote:
> Matteo,
>
> While you could technically do this, it's quite a violation of the
> properties required for map functions. Identical inputs must lead to
> identical outputs. Otherwise you get all sorts of wonky when the
> queried view changes and there's no way to figure out when
> invalidation should happen.
I think Matteo's not crazy.
This code used to be in couch_httpd_auth before I nuked it:
- case (catch couch_view:get_map_view(Db, DesignId, ViewName, nil)) of
- {ok, View, _Group} ->
- FoldFun = fun({_, Value}, _, {_}) -> {stop, Value} end,
- {ok, _, {Result}} = couch_view:fold(View, FoldFun, {nil},
- [{start_key, {UserName, ?MIN_STR}},{end_key,
{UserName, ?MAX_STR}}]),
- Result;
- {not_found, _Reason} ->
- nil
- % case (catch couch_view:get_reduce_view(Db, DesignId,
ViewName, nil)) of
- % {ok, _ReduceView, _Group} ->
- % not_implemented;
- % {not_found, _Reason} ->
- % nil
- % end
- end
>
> HTH,
> Paul Davis
>
> On Tue, Jan 12, 2010 at 8:18 AM, Matteo Caprari
> <[email protected]> wrote:
>> Hi.
>>
>> In an authorization handler I need to query a view (map only) with a single
>> key.
>> The map function emits (openid, username) and there is no reduce.
>>
>> I thounk I have to complete the snippet below with couch_view:fold but
>> can't figure out how to generate
>> a valid fold function, let alone one that filters on a given key.
>>
>> find_user_with_openid(Db, OpenId) ->
>> DesignId = <<"_design/_openid">>,
>> ViewName = <<"users_by_openids">>
>> Stale = nil,
>> {ok, View, Group} = couch_view:get_map_view(Db, DesignId, ViewName,
>> nil),
>>
>> Thanks.
>>
>> --
>> :Matteo Caprari
>> [email protected]
>>
>
--
Chris Anderson
http://jchrisa.net
http://couch.io
