【问链-EOS公开课】第十一课 EOS 智能合约相互调用

EOS中合约之间是可以相互调用的,主要通过inline action完成合约之间的调用。

譬如在掷骰子游戏中，存在两个玩家先下注资金，然后比较骰子大小后决定胜负，赢的那一方将获得所有的下注资金。在eosio源代码eos/build/contract/dice 智能合约示例中，Alice和Bob是两个玩家，他们各自将资金账户里的3个EOS作为赌注，先抵押给Dice账户，然后在游戏决出胜负后，Dice账户就自动把赌注归还给胜方。这其中就涉及到代币的转账操作，因此很自然的可以想到，在deposit(下注抵押资金)和最后的withdraw(胜方赢取资金)这两个操作中，就可以通过调用eosio.token的transfer动作来完成。

dice合约说明
此合约实现了一个简单的骰子游戏，两位玩家各有 50% 几率获胜

玩家 1 下注 3 EOS，并提交一个 SHA256 加密的密钥1
玩家 2 下注 3 EOS，并提交一个 SHA256 加密的密钥2
因为两玩家下注数量相同，所以匹配，游戏开始

一位玩家公布密钥
五分钟倒计时后，如果第二位玩家没有公布密钥，则第一位玩家直接获胜
另一位玩家公布密钥，基于两个密钥决出获胜者，并支付赌注
游戏结束后，胜者可以取回奖励

下面是deposit 和 withdraw 的函数实现。其中均对eosio.token的action—— transfer进行了调用。

//@abi action  void deposit( const account_name from, const asset& quantity ) {//下注抵押资金eosio_assert( quantity.is_valid(), "invalid quantity" );eosio_assert( quantity.amount > 0, "must deposit positive quantity" );auto itr = accounts.find(from);//在账户列表中查找要转出代币的账号是否存在if( itr == accounts.end() ) {//不存在的话就插入账号列表itr = accounts.emplace(_self, [&](auto& acnt){acnt.owner = from;});}//对eosio.token的transfer进行合约调用，玩家开始下注资金//账户(from)对账户( _self)进行转账，对应于游戏中，抵押代币到action(permission_level{ from, N(active) },N(eosio.token), N(transfer),std::make_tuple(from, _self, quantity, std::string(""))).send();accounts.modify( itr, 0, [&]( auto& acnt ) {//修改转出账号的代币余额acnt.eos_balance += quantity;});}

//@abi actionvoid withdraw( const account_name to, const asset& quantity ) {//胜方赢取资金require_auth( to );eosio_assert( quantity.is_valid(), "invalid quantity" );eosio_assert( quantity.amount > 0, "must withdraw positive quantity" );auto itr = accounts.find( to );//在账户列表中查找要转入代币的账号是否存在eosio_assert(itr != accounts.end(), "unknown account");accounts.modify( itr, 0, [&]( auto& acnt ) {//转出代币eosio_assert( acnt.eos_balance >= quantity, "insufficient balance" );acnt.eos_balance -= quantity;});//对eosio.token的transfer进行合约调用，Dice主账号对胜利一方发送资金//代表在资金撤回操作中，通过调用eosio.token的transfer，账户(_self)对账户(to)进行转账，对应于游戏中，Dice主账户为胜利的一方发放所赢的赌注action(permission_level{ _self, N(active) },N(eosio.token), N(transfer),std::make_tuple(_self, to, quantity, std::string(""))).send();if( itr->is_empty() ) {accounts.erase(itr);}}

1.启动nodeos

nodeos -e -p eosio --plugin eosio::wallet_api_plugin --plugin eosio::chain_api_plugin

2.设置 Bios 合约

cleos set contract eosio build/contracts/eosio.bios -p eosio

3. 部署eosio.token合约

cleos create account eosio eosio.token EOS8YMWk6vxawJEDML7mYXA3mGUap7L68L3GroGUpDhpbuadwHXom
返回结果：
executed transaction: 968f488926441009ecfaf899379a2c304a7e771b46a5536330a3bd5c747550a3  200 bytes  135 useosio <= eosio::newaccount            {"creator":"eosio","name":"eosio.token","owner":{"threshold":1,"keys":[{"key":"EOS8YMWk6vxawJEDML7mY...
warning: transaction executed locally, but may not be confirmed by the network yet    ]

4.给 eosio.token 设置 eosio.token 合约用于发币

cleos set contract eosio.token build/contracts/eosio.token -p eosio.token

5.创建 dice 账号

cleos create account eosio dice EOS7EjVuYKxPRFECDkzsMtD57ootfQUMGQKrtmdmS3GPvTJTcwfSi
执行结果：
executed transaction: c9d7de164bf4749d958502ff9202087ca7d45a7463f72f8ab96054c589a694fb  200 bytes  169 useosio <= eosio::newaccount            {"creator":"eosio","name":"dice","owner":{"threshold":1,"keys":[{"key":"EOS7EjVuYKxPRFECDkzsMtD57oot...
warning: transaction executed locally, but may not be confirmed by the network yet    ]

6.给 dice 设置 dice 合约

cleos set contract dice build/contracts/dice -p dice

7.创建EOS代币

cleos push action eosio.token create '["eosio","100000000.0000 EOS"]' -p eosio.token
执行结果：
executed transaction: ff0a266a3125331d13d796a26c78d388ff6242e78e23ba404f86df6a2f28fbb0  120 bytes  437 useosio.token <= eosio.token::create          {"issuer":"eosio","maximum_supply":"100000000.0000 EOS"}
warning: transaction executed locally, but may not be confirmed by the network yet    ]

8.创建alice和bob账户

cleos create account eosio alice EOS5JUBZXokmgHR7yHFgxoZdQZyfvu2oCHiPBeGUE3fQyZ9MHdmi8
执行结果：
executed transaction: aac0663610d3763bb9f282c507a0923e1a1b973741525257f6e012fdac143535  200 bytes  183 useosio <= eosio::newaccount            {"creator":"eosio","name":"alice","owner":{"threshold":1,"keys":[{"key":"EOS5JUBZXokmgHR7yHFgxoZdQZy...cleos create account eosio bob EOS6FMtV7gnbBLQ2CbD7J3YAKA8hY6u6jZ2KGtcy628z8QQ8MvXBz
执行结果：
executed transaction: d53956cc2fea6e85d67dee1a17b1f3e85b9838f9acd02ad6d87a9672443774e3  200 bytes  138 useosio <= eosio::newaccount            {"creator":"eosio","name":"bob","owner":{"threshold":1,"keys":[{"key":"EOS6FMtV7gnbBLQ2CbD7J3YAKA8hY...

9.空投 1000 个 EOS 给 alice

cleos push action eosio.token issue '[ "alice", "1000.0000 EOS", "" ]' -p eosio

10.空投 1000 个 EOS 给 bob

cleos push action eosio.token issue '[ "bob", "1000.0000 EOS", "" ]' -p eosio

11.alice 给 dice 设置转账权限

cleos set account permission alice active '{"threshold": 1,"keys": [{"key": "EOS7EjVuYKxPRFECDkzsMtD57ootfQUMGQKrtmdmS3GPvTJTcwfSi","weight": 1}],"accounts": [{"permission":{"actor":"dice","permission":"eosio.code"},"weight":1}]}' owner -p alice
执行结果：
executed transaction: 86fde62595343963366db70d9f9f70edab12928437d622d0f9246e00a62687b1  184 bytes  327 useosio <= eosio::updateauth            {"account":"alice","permission":"active","parent":"owner","auth":{"threshold":1,"keys":[{"key":"EOS7...
warning: transaction executed locally, but may not be confirmed by the network yet    ]

12.给bob赋予转账权限

cleos set account permission bob active '{"threshold": 1,"keys": [{"key": "EOS7EjVuYKxPRFECDkzsMtD57ootfQUMGQKrtmdmS3GPvTJTcwfSi","weight": 1}],"accounts": [{"permission":{"actor":"dice","permission":"eosio.code"},"weight":1}]}' owner -p bob
执行结果：
executed transaction: dc21bcf296a9e749b4488d4188dbe42cb4f85ea7ed639dabcccaa682bdeab2df  184 bytes  183 useosio <= eosio::updateauth            {"account":"bob","permission":"active","parent":"owner","auth":{"threshold":1,"keys":[{"key":"EOS7Ej...
warning: transaction executed locally, but may not be confirmed by the network yet    ]

13.alice 存入 100 EOS 到合约

cleos push action dice deposit '[ "alice", "100.0000 SYS" ]' -p alice

14.bob 存入 100 EOS 到合约

cleos push action dice deposit '[ "bob", "100.0000 SYS" ]' -p bob

15.alice 生成一个密匙

openssl rand  -hex 32
执行结果：
28349b1d4bcdc9905e4ef9719019e55743c84efa0c5e9a0b077f0b54fcd84905

16.alice SHA256 加密密匙

echo -n '28349b1d4bcdc9905e4ef9719019e55743c84efa0c5e9a0b077f0b54fcd84905' | xxd -r -p | sha256sum -b | awk '{print $1}'
d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883

17.alice 下注 3 EOS

cleos push action dice offerbet '[ "3.0000 EOS", "alice", "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883" ]' -p alice

18.bob 生成一个密匙

openssl rand  -hex 32
15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12

19.bob SHA256 加密密匙

echo -n '15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12' | xxd -r -p | sha256sum -b | awk '{print $1}'
50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129

20.bob 下注 3 SYS，随后游戏开始

cleos push action dice offerbet '[ "3.0000 EOS", "bob", "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129" ]' -p bob

21. 游戏开始后，查看 Dice 合约的表数据

cleos get table dice dice account
{"rows": [{"owner": "alice","eos_balance": "97.0000 EOS","open_offers": 0,"open_games": 1},{"owner": "bob","eos_balance": "97.0000 EOS","open_offers": 0,"open_games": 1}],"more": false
}

22.cleos get table dice dice game

{"rows": [{"id": 1,"bet": "3.0000 EOS","deadline": "1970-01-01T00:00:00","player1": {"commitment": "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883","reveal": "0000000000000000000000000000000000000000000000000000000000000000"},"player2": {"commitment": "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129","reveal": "0000000000000000000000000000000000000000000000000000000000000000"}}],"more": false
}

23.bob 公布密匙

cleos push action dice reveal '[ "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129", "15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12" ]' -p bob

24.现在的表数据，game 表有个截止时间（5分钟后）

cleos get table dice dice game
{"rows": [{"id": 1,"bet": "3.0000 EOS","deadline": "2018-10-31T06:03:56","player1": {"commitment": "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883","reveal": "0000000000000000000000000000000000000000000000000000000000000000"},"player2": {"commitment": "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129","reveal": "15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12"}}],"more": false
}

25.alice 公布密匙，决出胜者，游戏结束，game 表中移除数据

cleos push action dice reveal '[ "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883", "28349b1d4bcdc9905e4ef9719019e55743c84efa0c5e9a0b077f0b54fcd84905" ]' -p alice

26.游戏结束后，查看 account 表数据，账户余额

cleos get table dice dice account
{"rows": [{"owner": "alice","eos_balance": "103.0000 EOS","open_offers": 0,"open_games": 0},{"owner": "bob","eos_balance": "97.0000 EOS","open_offers": 0,"open_games": 0}],"more": false
}

27.alice 取出金额

此处需先 dice 合约对 eosio.token 授权，才能进行转账

   cleos set account permission dice active '{"threshold": 1,"keys": [{"key": "EOS7EjVuYKxPRFECDkzsMtD57ootfQUMGQKrtmdmS3GPvTJTcwfSi","weight": 1}],"accounts": [{"permission":{"actor":"dice","permission":"eosio.code"},"weight":1}]}' owner -p dicecleos push action dice withdraw '[ "alice", "103.0000 EOS" ]' -p alice

28.查看 alice 账户余额

cleos get currency balance eosio.token alice eos
1003.0000 EOS