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Sending blockchain actions

This functionality needs a host private key to be set in the W3bstream configuration​
An applet can send any blockchain action using the ws_send_tx function provided by W3nstream.

Send a transfer

The example below shows how to send a native token transfer from the W3bstream host account:
Rust
#[link(wasm_import_module = "env")]
extern "C" {
fn ws_send_tx(ptr: *const u8, size: i32) -> i32;
}
​
#[no_mangle]
pub extern "C" fn start(event_id: i32) -> i32 {
let tx = #r"{
to: "0x46fF054D4275A4aB9d42179C3bcA59f938e658C8",
value: "110",
data: "",
}"#,
match unsafe { ws_send_tx(tx.as_ptr(), tx.len() as _) } {
0 => Ok(()),
_ => bail!("Error while sending the transaction"),
}
}

Execute a contract function

It's also possible to use ws_send_tx to execute a smart contract function by encoding the call inside the transaction payload. The example below shows an example:
#[link(wasm_import_module = "env")]
extern "C" {
fn ws_send_tx(ptr: *const u8, size: i32) -> i32;
}
​
#[no_mangle]
pub extern "C" fn start(event_id: i32) -> i32 {
let tx =
r#"{
// The recipient is supposed to be a smart contract address
"to": "0xb73eE6EB5b1984c78CCcC49eA7Ad773E71d74F51",
"value": "0",
// The payload encodes a smart contract function call
"data": "40c10f190000000000000000000000000x4c123380CA640a146D803f844E0D9c90b52C5C970000000000000000000000000000000000000000000000000de0b6b3a7640000"
}"#;
unsafe { ws_send_tx(tx.as_ptr(), tx.len() as _) };
​
return 0;
}