本文所有实践都是基于EOS dawn-v4.1.0，请切到该分支然后实践
切换命令:git checkout dawn-v4.1.0
HelloWorld源码
#include <eosiolib/eosio.hpp>
#include <eosiolib/print.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) )
#define EOSIO_ABI( TYPE, MEMBERS ) \
extern "C" { \
void apply( uint64_t receiver, uint64_t code, uint64_t action ) { \
auto self = receiver; \
if( code == self ) { \
TYPE thiscontract( self ); \
switch( action ) { \
EOSIO_API( TYPE, MEMBERS ) \
} \
/* does not allow destructor of thiscontract to run: eosio_exit(0); */ \
} \
} \
} \
编译
生成wast文件
$ eosiocpp -o hello.wast hello.cpp
编译完成后，会生成两个新文件，hello.wast, hello.wasm
$ ls
hello.cpp hello.wasm hello.wast
.wast文件是wasm的代码文本格式，.wasm是汇编代码二级制格式
生成abi文件
$ eosiocpp -g hello.abi hello.cpp
764454ms thread-0 abi_generator.hpp:68 ricardian_contracts ] Warning, no ricardian clauses found for hello
764454ms thread-0 abi_generator.hpp:75 ricardian_contracts ] Warning, no ricardian contract found for hi
部署智能合约
创建新账号
我们知道智能合约是附着在账号上的，因而需要为合约准备一个账号
创建key并导入到钱包
$ cleos create key
Private key: 5JdchMrwMwD1PsZKCjpbaCQ4aJ3cFKzSWmCQfRzKCiGrDWds3PU
Public key: EOS7KBTMkUq4VPakqsZUnZfBbMbS2U7cn9qSa3q6G5ZzEeUeNSVgv
$ cleos wallet import 5JdchMrwMwD1PsZKCjpbaCQ4aJ3cFKzSWmCQfRzKCiGrDWds3PU
以上面的key创建账号
$ cleos create account eosio hello.code EOS7KBTMkUq4VPakqsZUnZfBbMbS2U7cn9qSa3q6G5ZzEeUeNSVgv EOS7KBTMkUq4VPakqsZUnZfBbMbS2U7cn9qSa3q6G5ZzEeUeNSVgv
executed transaction: 9cdfd59700f8fb13b9a3b330d75f9e1d6a014d54f5bec21cee9afe35c8c49b99 200 bytes 5304 us
# eosio <= eosio::newaccount {"creator":"eosio","name":"hello.code","owner":{"threshold":1,"keys":[{"key":"EOS7KBTMkUq4VPakqsZUnZ...
warning: transaction executed locally, but may not be confirmed by the network yet
将合约代码绑定到账号
这里需要注意的是，xxx.wasm文件的目录必须是xxx,这里的hello.cpp, hello.wasm的目录就必须是hello,因为该命令会搜索xx/xx.wasm文件，这里会搜索hello/hello.wasm文件
$ cleos set contract hello.code ./hello -p hello.code
Reading WAST/WASM from ./hello/hello.wasm...
Using already assembled WASM...
Publishing contract...
executed transaction: b26872e44b439ce289f7c449f959a7c9ad574045f69c53039ff365e79e1b8494 1800 bytes 5647 us
# eosio <= eosio::setcode {"account":"hello.code","vmtype":0,"vmversion":0,"code":"0061736d01000000013b0c60027f7e006000017e600...
# eosio <= eosio::setabi {"account":"hello.code","abi":"00010c6163636f756e745f6e616d650675696e74363401026869000104757365720c6...
warning: transaction executed locally, but may not be confirmed by the network yet
执行智能合约函数
$cleos push action hello.code hi '["args.user"]' -p args.user
“非法参数”错误
结果报如下错误
itleaks$cleos push action hello.code hi '["args.user"]' -p args.user
Error 3050002: Invalid Action Arguments
Ensure that your arguments follow the contract abi!
You can check the contract's abi by using 'cleos get code' command.
Error Details:
'["args.user"]' is invalid args for action 'hi' code 'hello.code'. expected '[{"name":"user","type":"account_name"}]'
Couldn't parse uint64_t
这是什么鬼？参数'["arg.user"]'可是官方的文档的描述。从这个错误log可以看出系统需要的是account_name,且尝试解释为uint64_t时出错的, 我们传了一个字母字符串"args.user"过去，如果尝试解释uint64_t确实会报错。于是改成数字再次尝试
$ cleos push action hello.code hi '["1234"]' -p args.user
executed transaction: 48060522d3bc73a34075256ba2f6657cce0473dd2a9ee1a3669f89d349b65973 104 bytes 6623 us
# hello.code <= hello.code::hi {"user":1234}
>> Hello, ..........2h2
warning: transaction executed locally, but may not be confirmed by the network yet
让我吃惊的是确实成功了。那问题是这个参数确实就应该要传数字吗？但是官网确实是传的字母类型的账号名啊。且expected的数据类型不是account_name吗？怎么就成了uint64_t了呢？
为了进一步解开这个疑惑，我们来看看nodeos程序段的错误log
疑点1：account_name怎么变成uint64_t类型了？
'["args.user"]' is invalid args for action 'hi' code 'hello.code'. expected '[{"name":"user","type":"account_name"}]'
{"args":["args.user"],"action":"hi","code":"hello.code","proto":[{"name":"user","type":"account_name"}]}
thread-0 chain_plugin.cpp:673 abi_json_to_bin
Couldn't parse uint64_t
{}
thread-0 string.cpp:113 to_uint64
{"i":"args.user"}
thread-0 string.cpp:116 to_uint64
{"*this":"args.user"}
thread-0 variant.cpp:403 as_uint64
{"type":"account_name","var":"args.user"}
thread-0 abi_serializer.cpp:328 variant_to_binary
{"type":"hi","var":["args.user"]}
thread-0 abi_serializer.cpp:328 variant_to_binary
{"type":"hi","var":["args.user"]}
thread-0 abi_serializer.cpp:340 variant_to_binary
{"params.code":"hello.code","params.action":"hi","params.args":["args.user"]}
thread-0 chain_plugin.cpp:676 abi_json_to_bin
从上面的Log可知这个错误跟abi相关，于是查看hello.abi
uint64终于出现了，原来abi将account_name重新定义为uint64，所以才会出现前面的错误。
疑点2：官方程序eosio.system为啥可以直接用字母账号名？
查看eosio.system.abi
看到区别没，eosio.system.abi里account_name被定义为name而不是uint64。
都是account_name,为啥生成的abi文件一个定义为name而另一个定义为uint64呢？这个
我会单独写一篇博文来解读
“非法参数”错误解决
通过上面分析，我们知道差异在account_name的类型定义，因而手动将hello.abi文件中的account_name的type改为name就可解决这个问题，更新code后再次执行，果然成功了
$ cleos push action hello.code hi '["args.user"]' -p args.user
executed transaction: f694bfbc0c4d26751aa35a57bc1695fb24ff1a7606934dea64edd1e15f79664d 104 bytes 2444 us
# hello.code <= hello.code::hi {"user":"args.user"}
>> Hello, args.user
warning: transaction executed locally, but may not be confirmed by the network yet
智能合约权限检测实践
前面的智能合约没有执行任何权限检测，因而在hi函数里新增一个权限检测
class hello : public eosio::contract {
public:
using contract::contract;
/// @abi action
void hi( account_name user) {
require_auth(user);
print( "Hello, ", name{user} );
}
};
红色字体的意思是执行"hi" action的权限必须是作为参数传进来的user
如果使用hello.code账号执行则会报错
$ cleos push action hello.code hi '["args.user"]' -p hello.code
Error 3090004: missing required authority
Ensure that you have the related authority inside your transaction!;
If you are currently using 'cleos push action' command, try to add the relevant authority using -p option.
Error Details:
missing authority of args.user
将参数换成hello.code执行成功
$ cleos push action hello.code hi '["
hello.code
"]' -p
hello.code
executed transaction: 49db2db96c3719992af6e31d378385ac99ff611453ef81fd03cbcb822d223bd5 104 bytes 1752 us
# hello.code <= hello.code::hi {"user":"hello.code"}
>> Hello, hello.code
warning: transaction executed locally, but may not be confirmed by the network yet
/********************************
* 本文来自CSDN博主"爱踢门"
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