IcpKit

A comprehensive iOS package for writing mobile applications that interact with the Internet Computer Protocol (ICP), written in Swift. IcpKit aims at facilitating the interaction between iOS apps and the ICP blockchain.

For more information about ICP Development, we recommend starting from https://internetcomputer.org/docs/current/references/

Contributors

This Package has been built by Bity SA with the help of the DFinity Foundation Developer Grant Program.

License

MIT License is applicable for all Swift Code (see LICENSE).

The BLS12381 Rust Library is licensed by Levi Feldman (see LICENSE).

Installation

Swift Package Manager

The Swift Package Manager is a tool for automating the distribution of Swift code and is integrated into the swift compiler. It is in early development, but HdWalletKit does support its use on supported platforms.

Once you have your Swift package set up, adding IcpKit as a dependency is as easy as adding it to the dependencies value of your Package.swift.

dependencies: [
    .package(url: "https://github.com/kosta-bity/IcpKit.git", .upToNextMajor(from: "0.1.0"))
]

What does it do?

IcpKit will take care of all the encoding and serialisation required to communicate with ICP allowing to developers to focus on the real functionality of their app and bootstrapping their development cycle.

The ICPRequestClient class is the main interaction point allowing to create and process requests to any canister.

The Ledger Canister is provided as a sample implementation which also allows for easy creation of ICP Wallet apps.

Main Functionalities

• Handles serialisation and encoding
• Candid implementation and serialisation/desirialisation for Swift
• CBOR serialisation
• Cryptographic methods applicable to ICP
• Basic ICP Models for transactions, accounts, self-authenticating principals etc.
• Ledger and Archive Canister implementation

Examples

How can I interact with a canister?

There are several ways to perform a request. Depending if it is a simple query or if the request actually changes the state of the blockchain.

Define the method you wish to call :

let method = ICPMethod(
    canister: ICPSystemCanisters.ledger,
    methodName: "account_balance",
    args: .record([
        "account": .blob(account.accountId)
    ])
)

Make the a simple query request:

let response = try await client.query(method, effectiveCanister: ICPSystemCanisters.ledger)

equivalently we can also do

let reponse = try await client.query(.uncertified, method, effectiveCanister: ICPSystemCanisters.ledger)

Make a call request and then poll for the response

let requestId = try await client.call(method, effectiveCanister: ICPSystemCanisters.ledger)
let reponse = try await client.pollRequestStatus(requestId: requestId, effectiveCanister: ICPSystemCanisters.ledger)

equivalently we can also do

let reponse = try await client.callAndPoll(requestId: requestId, effectiveCanister: ICPSystemCanisters.ledger)

or even

let reponse = try await client.query(.certified, method, effectiveCanister: ICPSystemCanisters.ledger)

All these have the exact same result.

How can I create an ICP Principal?

Starting from a seed

We recommend using the HdWalletKit.Swift from HorizontalSystems in order to derive the public/private Key Pair from the seed. The ICP derivation path is m/44'/223'/0'/0/0

Starting from a public/private Key Pair

1. Create a ICPPrincipal instance using ICPCryptography.selfAuthenticatingPrincipal(uncompressedPublicKey:).
2. If you need to sign requests (eg. to send transactions) you also need to create a ICPSigningPrincipal.
3. The main account of this principal can be created using ICPAccount.mainAccount(of:).