[EOS源码分析]7.EOS智能合约开发实践之合约调用合约(inline action)

首先，目前dawn-4.1, dawn-4.2使用inline action是会报如下错误

transaction declares authority '{"actor":"hello.code","permission":"active"}', but does not have signatures for it under a provided delay of 0 ms

这个问题是4.0以后inline action的权限发生变化导致的。这个改动在eos官网的#3013这个issue讨论BM有提到过

核心是为智能合约账号添加eosio.code permission,比如hello.code调用hello.target智能合约，需要添加如下permission

cleos set account permission args.user active '{"threshold": 1,"keys": [{"key":"EOS6MRyAjQq8ud7hVNYcfnVPJqcVpscN5So8BhtHuGYqET5GDW5CV", "weight":1}],"accounts": [{"permission":{"actor":"hello.code","permission":"eosio.code"},"weight":1}]}' owner -p args.user@owner

代码

新建两个contract: hello.code和hello.target

hello.target代码如下

hello.code的代码：

class hello : public eosio::contract {

public:

using contract::contract;

/// @abi action

void hi( account_name from, account_name to) {

require_auth(from);

print( "Hello, from:", name{from}, ", to:", name{to});

action(

//这里{to, active}必须授权给{_self, eosio.code}

permission_level{to, N(active)},

//调用 hello.target合约 的'callme' action

N(hello.target), N(callme),

std::make_tuple(to)

).send();

}

};

核心就是上面的红色字体的内容action(xx).send()，具体参数的含义是：

Action(permssion_level, other_contract_account_name, method, args)

所以:

action(permission_level{to, N(active)},

N(hello.target), N(callme),

std::make_tuple(to)

).send();

这个等价于如下命令

$cleos push action hello.targetcallme '["to"]' -p to

编译

请参考我的博文【EOS编写HelloWorld智能合约】

测试

//cleos create account只适合本地私有链，其他网络需要使用cleos system newaccount命令

$cleos create account eosio hello.code $KEY_PUB_1 $KEY_PUB_1

$cleos set contract hello.code ./hello -p hello.code

$cleos create account eosio args.user $KEY_PUB_2 $KEY_PUB_2

$cleos create account eosio hello.target $KEY_PUB_3 $KEY_PUB_3

$cleos create account eosio args.user1 $KEY_PUB_4 $KEY_PUB_4

$cleos set contract hello.target ./hello.target -p hello.target

$cleos set account permission args.user1 active '{"threshold": 1,"keys": [],"accounts": [{"permission":{"actor":"hello.code","permission":"eosio.code"},"weight":1}]}' owner -p args.user1@owner

$cleos push action hello.code hi '["args.user", "args.user1"]' -p args.user

源码一键实践

从以下github网页下载源码，即可一键实践执行该智能合约

/itleaks/eos-contract/tree/master/callcontract-exp/

/********************************

* 本文来自CSDN博主"爱踢门"

* 转载请标明出处:/itleaks

******************************************/

如果你对EOS，ETH技术及开发感兴趣，请入QQ群讨论:829789117

如需实时查看最新文章，请关注公众号"区块链斜杠青年"，一起探索区块链未来