This builds on cw1-whitelist to provide the first non-trivial solution.
It still works like cw1-whitelist with a set of admins (typically 1)
which have full control of the account. However, you can then grant
a number of accounts allowances to send native tokens from this account.
This was proposed in Summer 2019 for the Cosmos Hub and resembles the functionality of ERC20 (allowances and transfer from).
Basically, any admin can add an allowance for a (spender, denom) pair
(similar to cw20 IncreaseAllowance / DecreaseAllowance). Any non-admin
account can try to execute a CosmosMsg::Bank(BankMsg::Send{}) from this
contract and if they have the required allowances, their allowance will be
reduced and the send message relayed. If they don't have sufficient authorization,
or if they try to proxy any other message type, then the attempt will be rejected.
This adds 2 messages beyond the cw1 spec:
rust
enum HandleMsg {
IncreaseAllowance {
spender: HumanAddr,
denom: String,
amount: Uint128,
expires: Option<Expiration>,
},
DecreaseAllowance {
spender: HumanAddr,
denom: String,
amount: Uint128,
expires: Option<Expiration>,
}
}
It also adds one more query type:
```rust enum QueryMsg { Allowance { spender: HumanAddr, } }
pub struct AllowanceResponse {
pub allowance: Vec
You will need Rust 1.44.1+ with wasm32-unknown-unknown target installed.
You can run unit tests on this via:
cargo test
Once you are happy with the content, you can compile it to wasm via:
RUSTFLAGS='-C link-arg=-s' cargo wasm
cp ../../target/wasm32-unknown-unknown/release/cw1_subkeys.wasm .
ls -l cw1_subkeys.wasm
sha256sum cw1_subkeys.wasm
Or for a production-ready (compressed) build, run the following from the repository root (not currently working with this monorepo...)
docker run --rm -v "$(pwd)":/code \
--mount type=volume,source="cosmwasm_plus_cache",target=/code/target \
--mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
cosmwasm/rust-optimizer:0.9.0 ./contracts/cw1-subkeys
mv contract.wasm cw1_subkeys.wasm