Error when subscribing to "$local" topic

[BorisPetelj]

Using emq_web_hook with emqttd 2.3.3.
When client subscribes to topic "$local/$share/group/#" it gets disconnected with error in emqttd log:

2018-01-17 15:04:23.697 [error] <0.4767.0> gen_server <0.4767.0> terminated with reason: no function clause matchin
767.0> terminated with reason: no function clause matchin
g mochijson2:'-json_encode_proplist/2-fun-0-'(local, [44,[34,<<"all">>,34],58,[34,<<"share">>,34],44,"0",58,[34,<<"
qos">>,34],123]) line 206
2018-01-17 15:04:23.697 [error] <0.4767.0> CRASH REPORT Process <0.4767.0> with 0 neighbours exited with reason: no
 function clause matching mochijson2:'-json_encode_proplist/2-fun-0-'(local, [44,[34,<<"all">>,34],58,[34,<<"share"
>>,34],44,"0",58,[34,<<"qos">>,34],123]) line 206 in gen_server2:terminate/3 line 1157
2018-01-17 15:04:23.697 [error] <0.4564.0> Supervisor 'esockd_connection_sup - <0.4564.0>' had child connection sta
rted with emqttd_client:start_link([{max_publish_rate,0},{client_idle_timeout,30000},{client_enable_stats,false},{max_clientid_len,...},...]) at <0.4767.0> exit with reason no function clause matching mochijson2:'-json_encode_proplist/2-fun-0-'(local, [44,[34,<<"all">>,34],58,[34,<<"share">>,34],44,"0",58,[34,<<"qos">>,34],123]) line 206 in context connection_crashed

If the topic is "$share/group/#" client subscribes normally.
$local prefix is needed for load-balancing in a cluster mode.
@emqplus

[BorisPetelj]

Any updates on this issue @emqplus ?

[BorisPetelj]

I found out that a problem is in the parsing of payload before issuing http request. Specifically, mochijson2:encode(Params) in send_http_request function.

The params object for basic topic looks like:
The params are: [{action,client_subscribe}, {client_id,<<"clientId">>}, {username,<<"user">>}, {topic,<<"topic">>}, {opts,[{qos,0}]}].

While params object for topic with prefix '$local/$share' looks like:
The params are: [{action,client_subscribe}, {client_id,<<"clientId">>}, {username,<<"username">>}, {topic,<<"topic">>}, {opts,[{qos,0},{share,<<"udm">>},local]}].

Even tough i'm not familiar to Erlang, it seems that opts object in the latter case is not valid. The property 'local' is not wrapped correctly.