Crate we_cdk

we-cdk

we-cdk cargo-we

Toolkit for development WASM smart-contracts on Waves Enterprise ecosystem.

Usage

A prerequisite for compiling smart contracts is to have Rust and Cargo installed. Here’s an installation guide.

To work with the contract it is necessary to install cargo-we. It’s a CLI tool which helps set up and manage WASM smart contracts.

cargo install cargo-we --force

Use the --force to ensure you are updated to the most recent cargo-we version.

And there is also an option to install the CLI tool from this project folder.

cargo install --path ./crates/cargo-we/ --force

In order to initialize a new project you can use:

cargo we new flipper

This will create a folder flipper in your work directory. The folder contains a scaffold Cargo.toml and a lib.rs, which both contain the necessary building blocks for using WASM smart-contract.

The lib.rs contains our hello world contract ‒ the Flipper, which we explain in the next section.

In order to build the contract just execute this command in the flipper folder:

cargo we build

As a result you’ll get a target/we/flipper.wasm file and a flipper.json file in the target/we folder of your contract.

Create & Update contract

With cargo-we can also send CreateContract and UpdateContract transactions directly to a network node.

To do this, create a file with a description of access to the node and the transaction to be sent.

To send a transaction, all you need to do is execute the command:

cargo we tx --send --path_json=<path_json>

Example JSON file:

{
    "nodeUrl": "http://localhost:6862",
    "apiKey": "we",
    "transaction": {
        "contractId": "FofPw6DRQVhYVsYQzsFEWDBrJpS1GVFLS7vGHajuQUtD",
        "fee" : 100000000,
        "payments" : [ ],
        "groupOwners" : [ ],
        "type" : 107,
        "version" : 6,
        "groupParticipants" : [ ],
        "sender" : "3NgoqC9HdDfTYJtKjcW2v3LeTdd2uyhimVo",
        "feeAssetId" : null,
        "contractName" : "name",
        "validationPolicy" : {
            "type": "any"
        }
    }
}

Hello, World! ‒ The Flipper

The Flipper contract is a simple contract containing only a single bool value.

It provides method flip its value from true to false (and vice versa).

Below you can see the code using CDK.

#![no_std]
#![no_main]
use we_cdk::*;

// Declaring a function available for calling.
// `#[action]` keyword is used for this purpose.
// _constructor mandatory method that is called during CreateContract Transaction.
#[action]
fn _constructor(init_value: Boolean) {
    // Write the obtained value as an argument of the function into contract state.
    set_storage!(boolean :: "value" => init_value);
}

#[action]
fn flip() {
    // Read the value from the contract state.
    let value: Boolean = get_storage!(boolean :: "value");
    // Write the inverted value to the contract state.
    set_storage!(boolean :: "value" => !value);
}

Re-exports

• pub use wevm;

Modules

• macros

Macros

• base58
  Base58 string to bytes conversion
• block
  Get block fields
• burn
  Burn the asset
• call_contract
  Call contract
• caller
  Get the ContractId of the calling contract
• cancel_lease
  Cancel the lease
• contains
  Checks if the string/binary is contained in a string/binary
• contains_key
  Checks if a record with this key exists
• drop
  Returns a string/binary without the first N characters/bytes
• drop_right
  Returns a string/binary without the last N characters/bytes
• equals
  Comparison data of Binary and String types
• fast_hash
  Fast hash
• get_balance
  Get the balance of tokens
• get_storage
  Get storage
• get_tx_payment
  Get the asset_id or amount of the attached payment in the transaction
• get_tx_payments
  Get the number of attached payments in the transaction
• index_of
  Returns the index of the first occurrence of the substring (if no occurrence is found, returns -1)
• issue
  Issue the asset
• join
  Joining data of Binary and String types
• last_index_of
  Returns the index of the last occurrence of the substring (if no occurrence is found, returns -1)
• lease
  Leasing of funds
• parse_bool
  Converts a string representation of a boolean to an equivalent logical value
• parse_int
  Converts a string representation of a number to an equivalent integer number
• reissue
  Reissue the asset
• require
  Verify inputs and conditions
• secure_hash
  Secure hash
• set_storage
  Set storage
• sig_verify
  Signature verify
• take
  Returns the first N characters/bytes of the string/binary
• take_right
  Returns a string/binary without the last N characters/bytes
• to_base58_string
  Bytes to Base58 string conversion
• to_bytes
  Converts an integer to a byte array
• to_int
  Converts a byte array to an integer number
• to_string_binary
  Converts an binary to a string
• to_string_bool
  Converts a logical value to a string
• to_string_int
  Converts an integer to a string
• transfer
  Tokens transfer
• tx
  Get tx fields

Type Aliases

• Binary
  Binary is a data type for byte array.
• Boolean
  Boolean is a boolean data type.
• Integer
  Integer is an integer data type.
• Payment
  Payment is a payment that can be attached when calling the function of another contract.
• String
  String is a string data type. Strings are UTF-8 encoded.

Attribute Macros

• action
  Marks function as a called function.
• interface
  Marks trait as an interface to another contract.