szwork2013 / charity

An EOS smart contract that demo how to implement message processing of action， how to use auto increment primary key in table and how to send action to another contract.

charity

一个简单的EOS智能合约，演示合约收到捐款消息时，给捐款者回馈10倍于捐赠额的CHC慈善代币：

1. 转账时消息通知、处理机制
2. 持久化存储
3. 合约内调用另一个合约的接口

有3点值得参考：

1. 修改EOSIO_ABI，使其能够处理转发过来的通知消息。

#define EOSIO_ABI_EX( TYPE, MEMBERS ) \
extern "C" { \
   void apply( uint64_t receiver, uint64_t code, uint64_t action ) { \
      auto self = receiver; \
      if( action == N(onerror)) { \
         /* onerror is only valid if it is for the "eosio" code account and authorized by "eosio"'s "active permission */ \
         eosio_assert(code == N(eosio), "onerror action's are only valid from the \"eosio\" system account"); \
      } \
      if( code == self || code == N(eosio.token) || action == N(onerror) ) { \
         TYPE thiscontract( self ); \
         switch( action ) { \
            EOSIO_API( TYPE, MEMBERS ) \
         } \
         /* does not allow destructor of thiscontract to run: eosio_exit(0); */ \
      } \
   } \
}

2. 使用自增主键

    trans_table.emplace(_self, [&](auto &s) {
        s.id = trans_table.available_primary_key();
        s.from = from;
        s.to = to;
        s.quantity = quantity;
        s.memo = memo;
    });

3. 要使合约内部可以调用另一个合约的接口，对应的账号必须增加[email protected]的授权   本例需要charity对自己active权限增加[email protected]的授权

   cleos set account permission charity active '{"threshold": 1,"keys": [{"key": "EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4","weight": 1}],"accounts": [{"permission":{"actor":"charity","permission":"eosio.code"},"weight":1}]}' owner -p charity

  eosio.code权限更多内容请参考EOSIO/eos#3050