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从 helloworld 到 hello 红包之一

今天，我们来看看如何在 EOS 智能合约内部发起转帐（发红包）。在下面第一部分的例子代码里，我们在官方 Helloworld 标准的打招呼 hi()接口的基础上,增加新的参数“金额”，实现在打招呼的同时，通过合约内部转帐给对方账户发红包。第二部分的测试中，合约账号 eosonetest1 通过新的打招呼接口，给 eosonetest2 发送转帐。 使用合约内转帐，和标准转帐相比，可以在合约里加上各种条件和控制逻辑，实现丰富多彩的合约玩法。

从零开始

创建 helloworld 智能合约

$ eosiocpp -n helloworld created helloworld from skeleton 

得到的 helloworld.cpp 源代码是这个样子的

#include <eosiolib/eosio.hpp> using namespace eosio; class hello : public eosio::contract { public: using contract::contract; /// @abi action void hi( account_name user ) { print( "Hello, ", name{user} ); } }; EOSIO_ABI( hello, (hi) ) 

现在我们开始把它改造成“红包合约” 添加必要的头文件

#include <eosiolib/asset.hpp> 

给 hi() 函数添加通证

void hi( account_name to, const asset& quantity ) { 

加上一些安全检查

 require_auth( _self ); eosio_assert( quantity.is_valid(), "invalid token" ); eosio_assert( quantity.amount > 0, "must be positive quantity" ); require_recipient( _self ); require_recipient( to ); 

添加合约里转账

 action( permission_level{ _self, N(active) }, N(eosio.token), N(transfer), std::make_tuple(_self, to, quantity, std::string("hello money")) ).send(); 

改造好的 hi()函数变成这个样子：

 /// @abi action hi void hi( account_name to, const asset& quantity ) { require_auth( _self ); eosio_assert( quantity.is_valid(), "invalid token" ); eosio_assert( quantity.amount > 0, "must be positive quantity" ); require_recipient( _self ); require_recipient( to ); action( permission_level{ _self, N(active) }, N(eosio.token), N(transfer), std::make_tuple(_self, to, quantity, std::string("hello money")) ).send(); print( "Hello, here is some money for ", name{to} ); } 

在 Jungle testnet 上实测

给合约账号购买适当的 RAM

cleos -u http://jungle.cryptolions.io:18888 system buyram -k eosonetest2 eosonetest2 1000 

把合约布署到合约账号

cleos -u http://jungle.cryptolions.io:18888 set contract eosonetest2 ../helloworld -p eosonetest2 

合约里转账需要添加的 eosio.code permission

cleos -u http://jungle.cryptolions.io:18888 set account permission eosonetest2 active '{"threshold": 1,"keys": [{"key": "EOS8xxxxxxxxxxxxxxx","weight": 1}],"accounts": [{"permission":{"actor":"eosonetest2","permission":"eosio.code"},"weight":1}]}' owner -p eosonetest2@owner 

测试网上的输出

测试前的余额

@joel-Lenovo-Y520:helloworld $ cleos -u https://jungle.eosio.cr:443 get currency balance eosio.token eosonetest1 EOS 7970.3411 EOS @joel-Lenovo-Y520:helloworld $ cleos -u https://jungle.eosio.cr:443 get currency balance eosio.token eosonetest2 EOS 6733.2414 EOS 

通过合约发红包

@joel-Lenovo-Y520:helloworld $ cleos -u http://jungle.cryptolions.io:18888 push action eosonetest2 hi '["eosonetest1", "103.0000 EOS"]' -p eosonetest2 executed transaction: 71fxxxxxxxxxab706fxx3ea1cxxxxx1f70f05cxxxxx 120 bytes 2483 us # eosonetest2 <= eosonetest2::hi {"to":"eosonetest1","quantity":"103.0000 EOS"} >> Hello, here is some money for eosonetest1 # eosonetest1 <= eosonetest2::hi {"to":"eosonetest1","quantity":"103.0000 EOS"} # eosio.token <= eosio.token::transfer {"from":"eosonetest2","to":"eosonetest1","quantity":"103.0000 EOS","memo":"hello money"} # eosonetest2 <= eosio.token::transfer {"from":"eosonetest2","to":"eosonetest1","quantity":"103.0000 EOS","memo":"hello money"} # eosonetest1 <= eosio.token::transfer {"from":"eosonetest2","to":"eosonetest1","quantity":"103.0000 EOS","memo":"hello money"} warning: transaction executed locally, but may not be confirmed by the network yet ] 

测试后的余额

@joel-Lenovo-Y520:helloworld $ cleos -u https://jungle.eosio.cr:443 get currency balance eosio.token eosonetest1 EOS 8073.3411 EOS @joel-Lenovo-Y520:helloworld $ cleos -u https://jungle.eosio.cr:443 get currency balance eosio.token eosonetest2 EOS 6630.2414 EOS 

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