anchor.diff:  
   
   handle_explain_req(#httpd{method='POST'}=Req, Db) ->
  +    chttpd:validate_ctype(Req, "application/json"),
       {ok, Opts0} = mango_opts:validate_find(chttpd:json_body_obj(Req)),
       {value, {selector, Sel}, Opts} = lists:keytake(selector, 1, Opts0),
       Resp = mango_crud:explain(Db, Sel, Opts),
  
positive.code: 
  
  handle_find_req(#httpd{method='POST'}=Req, Db) ->
      {ok, Opts0} = mango_opts:validate_find(chttpd:json_body_obj(Req)),
      {value, {selector, Sel}, Opts} = lists:keytake(selector, 1, Opts0),
      {ok, Resp0} = start_find_resp(Req),
  
negative.code: 	chttpd:send_json(Req, {[{total_rows, TotalRows}, {indexes, JsonIdxs}]});
  
  handle_index_req(#httpd{method='POST', path_parts=[_, _]}=Req, Db) ->
      chttpd:validate_ctype(Req, "application/json"),
      {ok, Opts} = mango_opts:validate_idx_create(chttpd:json_body_obj(Req)),
      {ok, Idx0} = mango_idx:new(Db, Opts),
      {ok, Idx} = mango_idx:validate_new(Idx0),
  