how to get tables rows count in plugin

Question

auto chain_plug = app().find_plugin<chain_plugin>();
eosio::chain_apis::read_only::get_table_by_scope_params param{N("eosio.token"), N("stat"), "EOS", "EOS", 1};
auto result = chain_plug->get_read_only_api().get_table_by_scope(param);
auto count = result.rows[0].count;

the nodeos just abort when runing above code,any way to get the table rows in plugin ?

Answer 1

The class get_table_by_scope_result is structured like this:

   struct get_table_by_scope_result {
      vector<get_table_by_scope_result_row> rows;
      string      more; ///< fill lower_bound with this value to fetch more rows
   };

So if you want to access the count for a particular scope, then you are doing it the correct way by saying result.rows[0].count, which will give you the number of rows in the first scope of the table.

I imagine the reason why you are getting an abort is because rows[0] doesn't exist, and then you are trying to deference a null pointer.

So trying wrapping your code like this:

uint32_t count(0);
if(!result.rows.empty())
{
  count = result.rows.at(0).count;
}

If you still get the error, then maybe post a bit more detail, and show or check that the stat table exists with the correct scope and rows as expected using something like cleos get table