Substrate 区块链应用开发之存证模块的功能开发
存证是一种在线服务，可用于在某一时间点验证计算机文件的存在性，最早是通过比特币网络带有时间戳的交易实现的。 存证的应用场景有：
数字版权
司法存证
供应链溯源
电子发票
...
存证的作用是：
证明文件在某一时间点确实存在
证明文件在某一时间点确实没有被篡改
证明文件在某一时间点确实由某个人创建
实操
Open a terminal shell on your computer.
Clone the node template repository by running the following command:
git clone https://github.com/substrate-developer-hub/substrate-node-template
Change to the root of the node template directory by running the following command:
cd substrate-node-template
Create a new branch to contain your work:
git switch -c my-learning-branch-2024-04-05
Compile the node template by running the following command:
cargo build --release
In the same terminal where you compiled your node, you can now start the node in development mode by running the following command:
./target/release/node-template --dev --tmp
polkadot.js.org/apps 查看
交易前查询状态 None
交易
提交交易
交易后查询状态
问题
编译报错后使用的命令
cargo clean
cargo update
cargo update -p wasm-bindgen
cargo update -p librocksdb-sys
cargo update -p schnorrkel@0.11.4
cargo update -p anstream@0.6.13 -Z sparse-registry
编译报错：error[E0220]: associated type BlockNumber not found for T
解决： 替换T::BlockNumber为BlockNumberFor<T>
https://substrate.stackexchange.com/questions/9848/associated-type-blocknumber-not-found-for-t
参考
https://docs.substrate.io/tutorials/build-a-blockchain/build-local-blockchain/
https://substrate.stackexchange.com/questions/9848/associated-type-blocknumber-not-found-for-t
https://polkadot.js.org/apps
更多详情
https://github.com/qiaopengjun5162/substrate-pallets-poe
