Code Snippets - swap.coffee

Generic Information

All code examples are written in TypeScript using Blueprint. If you need more implementation details, refer to the DEX source code: it contains OOP implementations of all contracts, so this page is likely temporary until a full-fledged SDK is created based on that code. This document is for reference only and may contain errors. If you come across any, please consider contacting us via Telegram @swap.coffee DEV Chat.

(De)serialization of assets

import { Address, beginCell, Builder, Cell, Slice } from '@ton/core';

export abstract class CellSerializable {
    public abstract write(b: Builder): void;

    public toCell(): Cell {
        const b = beginCell();
        this.write(b);
        return b.endCell();
    }
}

export abstract class Asset extends CellSerializable {
    static fromSlice(slice: Slice): Asset {
        const type = slice.loadUint(2);
        if (type === 0) {
            return AssetNative.INSTANCE;
        } else if (type === 1) {
            return new AssetJetton(slice.loadUintBig(8), slice.loadUintBig(256));
        } else if (type === 2) {
            return new AssetExtra(slice.loadUintBig(32));
        } else {
            throw new Error('unexpected asset type');
        }
    }

    static fromAny(value: any): Asset {
        if (value == null) {
            return AssetNative.INSTANCE;
        } else if (value instanceof Address) {
            return AssetJetton.fromAddress(value);
        } else if (typeof value === 'bigint') {
            return new AssetExtra(value);
        } else {
            throw new Error('unexpected asset type');
        }
    }
}

export class AssetNative extends Asset {
    static INSTANCE = new AssetNative();

    private constructor() {
        super();
    }

    public write(b: Builder): void {
        b.storeUint(0, 2);
    }
}

export class AssetJetton extends Asset {
    constructor(
        public chain: bigint,
        public hash: bigint,
    ) {
        super();
    }

    static fromAddress(address: Address): AssetJetton {
        return new AssetJetton(
            BigInt(address.workChain),
            beginCell().storeBuffer(address.hash).endCell().beginParse().loadUintBig(256),
        );
    }

    public write(b: Builder): void {
        b.storeUint(1, 2).storeUint(this.chain, 8).storeUint(this.hash, 256);
    }

    public getAddress(): Address {
        return beginCell()
            .storeUint(4, 3)
            .storeUint(this.chain, 8)
            .storeUint(this.hash, 256)
            .endCell()
            .beginParse()
            .loadAddress()
    }
}

export class AssetExtra extends Asset {
    constructor(public id: bigint) {
        super();
    }

    public write(b: Builder): void {
        b.storeUint(2, 2).storeUint(this.id, 32);
    }
}

Vaults

Checking for existence and activity

To check whether asset’s Vault exists and is active, you firstly need to fetch its address from the factory, then invoke a get-method is_active.

import { NetworkProvider } from '@ton/blueprint';
import { Address } from '@ton/core';

export async function run(provider: NetworkProvider) {
    const asset: Asset = AssetNative.INSTANCE // or AssetJetton or AssetExtra
    const factoryAddress = Address.parse('EQAsf2sDPfoo-0IjnRA7l_gJBB9jyo4zqfCG_1IFCCI_Qbef')
    let resp = await provider.provider(factoryAddress).get('get_vault_address', [{ type: 'slice', cell: asset.toCell() }])
    const vaultAddress = resp.stack.readAddress()
    const vault = provider.provider(vaultAddress)
    const vaultState = await vault.getState()
    if (vaultState.state.type !== 'active') {
        throw new Error('Vault does not exist')
    }
    resp = await vault.get('is_active', [])
    const isActive = resp.stack.readBigNumber() !== 0n
    if (!isActive) {
        throw new Error('Vault exists, but is not active')
    }
}

Creating a new one

To create a new Vault, you need to send a create_vault internal message to the factory. If you are creating a Vault for jetton, make sure it goes through activation process as described here. If it was unable to automatically activate itself, please contact us via Telegram @swap.coffee DEV Chat.

import { NetworkProvider } from '@ton/blueprint';
import { beginCell, toNano, Address } from '@ton/core';

export async function run(provider: NetworkProvider) {
    const asset: Asset = AssetNative.INSTANCE // or AssetJetton or AssetExtra
    const factoryAddress = Address.parse('EQAsf2sDPfoo-0IjnRA7l_gJBB9jyo4zqfCG_1IFCCI_Qbef')
    const builder = beginCell()
        .storeUint(0xc0ffee06, 32)
        .storeUint(0, 64)
    asset.write(builder)
    await provider.sender().send({
        to: factoryAddress,
        value: toNano(.05),
        body: builder.endCell()
    })
}

Pools

Creating a new one

Check that Vaults for both assets exist and are active (or create them instead).
Send create_pool messages to both Vaults. Type of each message depends on the type of asset of associated Vault:
- For TON, use create_pool_native.
- For Jetton, use create_pool_jetton as a forward payload in jetton_transfer.
- For Extra Currency, use create_pool_extra.

import { NetworkProvider } from '@ton/blueprint';
import { beginCell, toNano, Address, Builder } from '@ton/core';

export async function run(provider: NetworkProvider) {
    const asset1: Asset = AssetNative.INSTANCE // or AssetJetton or AssetExtra
    const asset1Amount = 100n
    const asset2: Asset = new AssetExtra(1n) // or AssetNative or AssetJetton
    const asset2Amount = 100n
    const factoryAddress = Address.parse('EQAsf2sDPfoo-0IjnRA7l_gJBB9jyo4zqfCG_1IFCCI_Qbef')
    const factory = provider.provider(factoryAddress)
    let resp = await factory.get('get_vault_address', [{ type: 'slice', cell: asset1.toCell() }])
    const vault1Address = resp.stack.readAddress()
    resp = await factory.get('get_vault_address', [{ type: 'slice', cell: asset2.toCell() }])
    const vault2Address = resp.stack.readAddress()
    if (!provider.sender().address) {
        throw new Error('Sender address must be present')
    }
    const poolParams = beginCell()
    asset1.write(poolParams)
    asset2.write(poolParams)
    poolParams.storeUint(0, 3) // constant_product AMM
    poolParams.storeMaybeRef(null) // no AMM settings
    const poolCreationParams = beginCell()
        .storeAddress(provider.sender().address) // recipient of LP tokens
        .storeBit(false) // send funds to the address specified above instead of sender in case of failures
        .storeMaybeRef(null) // no notifications
        .storeUint(1, 1) // is_active = true
        .storeMaybeRef(null) // no extra settings
    await sendCreatePool(provider, poolParams, poolCreationParams, vault1Address, asset1, asset1Amount)
    await sendCreatePool(provider, poolParams, poolCreationParams, vault2Address, asset2, asset2Amount)
}

async function sendCreatePool(
    provider: NetworkProvider,
    poolParams: Builder,
    poolCreationParams: Builder,
    vaultAddress: Address,
    asset: Asset,
    amount: bigint
) {
    const sender = provider.sender()
    if (asset instanceof AssetNative) {
        await sender.send({
            to: vaultAddress,
            value: amount + toNano(.1),
            body: beginCell()
                .storeUint(0xc0ffee02, 32) // create_pool_native opcode
                .storeUint(0, 64)
                .storeCoins(amount)
                .storeBuilder(poolParams)
                .storeBuilder(poolCreationParams)
                .endCell()
        })
    } else if (asset instanceof AssetJetton) {
        const jettonMaster = provider.provider(asset.getAddress())
        let resp = await jettonMaster.get('get_wallet_address', [{
            type: 'slice',
            cell: beginCell().storeAddress(sender.address).endCell()
        }])
        const jettonWalletAddress = resp.stack.readAddress()
        await sender.send({
            to: jettonWalletAddress,
            value: toNano(.15),
            body: beginCell()
                .storeUint(0xf8a7ea5, 32) // jetton_transfer opcode
                .storeUint(0, 64)
                .storeAddress(vaultAddress)
                .storeAddress(sender.address)
                .storeMaybeRef(null) // no custom_payload
                .storeCoins(toNano(.1)) // fwd_gas
                .storeMaybeRef(
                    beginCell()
                        .storeUint(0xc0ffee11, 32) // create_pool_jetton opcode
                        .storeBuilder(poolParams)
                        .storeBuilder(poolCreationParams)
                        .endCell()
                ).endCell()
        })
    } else if (asset instanceof AssetExtra) {
        await sender.send({
            to: vaultAddress,
            value: toNano(.1),
            extracurrency: {
                [Number(asset.id)]: amount
            },
            body: beginCell()
                .storeUint(0xc0ffee03, 32) // create_pool_extra opcode
                .storeUint(0, 64)
                .storeBuilder(poolParams)
                .storeBuilder(poolCreationParams)
                .endCell()
        })
    }
}

Providing liquidity to existing one

All you need is to send deposit_liquidity messages to both Vaults. Type of each message depends on the type of asset of associated Vault:

For TON, use deposit_liquidity_native.
For Jetton, use deposit_liquidity_jetton as a forward payload in jetton_transfer.
For Extra Currency, use deposit_liquidity_extra.

The code itself is very similar to the one used in pools creation:

import { NetworkProvider } from '@ton/blueprint';
import { beginCell, toNano, Address, Cell } from '@ton/core';

export async function run(provider: NetworkProvider) {
    const asset1: Asset = AssetNative.INSTANCE // or AssetJetton or AssetExtra
    const asset1Amount = 100n
    const asset2: Asset = new AssetExtra(1n) // or AssetNative or AssetJetton
    const asset2Amount = 100n
    const factoryAddress = Address.parse('EQAsf2sDPfoo-0IjnRA7l_gJBB9jyo4zqfCG_1IFCCI_Qbef')
    const factory = provider.provider(factoryAddress)
    let resp = await factory.get('get_vault_address', [{ type: 'slice', cell: asset1.toCell() }])
    const vault1Address = resp.stack.readAddress()
    resp = await factory.get('get_vault_address', [{ type: 'slice', cell: asset2.toCell() }])
    const vault2Address = resp.stack.readAddress()
    if (!provider.sender().address) {
        throw new Error('Sender address must be present')
    }
    const poolParams = beginCell()
    asset1.write(poolParams)
    asset2.write(poolParams)
    poolParams.storeUint(0, 3) // constant_product AMM
    poolParams.storeMaybeRef(null) // no AMM settings
    const poolParamsCell = poolParams.endCell()
    const depositLiquidityParamsCell = beginCell()
        .storeAddress(provider.sender().address) // recipient of LP tokens
        .storeBit(false) // send funds to the address specified above instead of sender in case of failures
        .storeAddress(null) // no referral
        .storeUint(Math.floor(Date.now() / 1000) + 900, 32) // deadline
        .storeUint(0, 2) // using no condition
        .storeMaybeRef(null) // no extra settings
        .storeMaybeRef(null) // no notifications
        .endCell()
    await sendProvideLiquidity(provider, poolParamsCell, depositLiquidityParamsCell, vault1Address, asset1, asset1Amount)
    await sendProvideLiquidity(provider, poolParamsCell, depositLiquidityParamsCell, vault2Address, asset2, asset2Amount)
}

async function sendProvideLiquidity(
    provider: NetworkProvider,
    poolParams: Cell,
    depositLiquidityParams: Cell,
    vaultAddress: Address,
    asset: Asset,
    amount: bigint
) {
    const sender = provider.sender()
    if (asset instanceof AssetNative) {
        await sender.send({
            to: vaultAddress,
            value: amount + toNano(.1),
            body: beginCell()
                .storeUint(0xc0ffee04, 32) // deposit_liquidity_native opcode
                .storeUint(0, 64)
                .storeCoins(amount)
                .storeRef(depositLiquidityParams)
                .storeRef(poolParams)
                .endCell()
        })
    } else if (asset instanceof AssetJetton) {
        const jettonMaster = provider.provider(asset.getAddress())
        let resp = await jettonMaster.get('get_wallet_address', [{
            type: 'slice',
            cell: beginCell().storeAddress(sender.address).endCell()
        }])
        const jettonWalletAddress = resp.stack.readAddress()
        await sender.send({
            to: jettonWalletAddress,
            value: toNano(.15),
            body: beginCell()
                .storeUint(0xf8a7ea5, 32) // jetton_transfer opcode
                .storeUint(0, 64)
                .storeAddress(vaultAddress)
                .storeAddress(sender.address)
                .storeMaybeRef(null) // no custom_payload
                .storeCoins(toNano(.1)) // fwd_gas
                .storeMaybeRef(
                    beginCell()
                        .storeUint(0xc0ffee12, 32) // deposit_liquidity_jetton opcode
                        .storeRef(depositLiquidityParams)
                        .storeRef(poolParams)
                        .endCell()
                ).endCell()
        })
    } else if (asset instanceof AssetExtra) {
        await sender.send({
            to: vaultAddress,
            value: toNano(.1),
            extracurrency: {
                [Number(asset.id)]: amount
            },
            body: beginCell()
                .storeUint(0xc0ffee05, 32) // deposit_liquidity_extra opcode
                .storeUint(0, 64)
                .storeRef(depositLiquidityParams)
                .storeRef(poolParams)
                .endCell()
        })
    }
}

Rolling back liquidity provisioning

Both pool creation and liquidity provisioning operations require 2 transactions with corresponding assets to be sent. If only one of them appeared in the blockchain, you may want to rollback the whole process, therefore receiving sent funds back. In order to do so, please follow the given instructions:

Inspect the one transaction that appeared in the blockchain, and find out pool_creator or liquidity_depository contract address. It is the last contract in the transaction execution chain.
Send a withdraw_deposit message to that contract.

import { NetworkProvider } from '@ton/blueprint';
import { beginCell, toNano, Address } from '@ton/core';

export async function run(provider: NetworkProvider) {
    const contractAddress = Address.parse('INSERT ADDRESS HERE') // address of either pool_creator or liquidity_depository
    await provider.sender().send({
        to: contractAddress,
        value: toNano(.05),
        body: beginCell()
            .storeUint(0xc0ffee07, 32)
            .storeUint(0, 64)
            .endCell()
    })
}

Performing a swap

Fetch Vault’s address from factory for the input asset.
Fetch Pools addresses from factory (or another source of truth) for every pool throughout your way.
Send swap message to the Vault of input asset. Type of the message depends on the type of asset:

For TON, use swap_native.
For Jetton, use swap_jetton as a forward payload in jetton_transfer.
For Extra Currency, use swap_extra.

import { NetworkProvider } from '@ton/blueprint';
import { beginCell, toNano, Address, Builder } from '@ton/core';

export async function run(provider: NetworkProvider) {
    const inputAsset: Asset = AssetNative.INSTANCE // or AssetJetton or AssetExtra
    const poolTonUsdtAddress = Address.parse('EQDETPC2Trne37AQx7JKUIFA2G9uB3ifk4O7myFB6pwI6u8M')
    const poolUsdtTonnelAddress = Address.parse('EQBjj5LzN3L1PvFvH5mzbTc8zp3Sp_vSWmSI3nWKM-Fr3W_g')
    const inputAssetAmount = toNano(1)

    const factoryAddress = Address.parse('EQAsf2sDPfoo-0IjnRA7l_gJBB9jyo4zqfCG_1IFCCI_Qbef')
    const factory = provider.provider(factoryAddress)
    let resp = await factory.get('get_vault_address', [{ type: 'slice', cell: inputAsset.toCell() }])
    const vaultAddress = resp.stack.readAddress()

    const sender = provider.sender()
    const swapParamsCell = beginCell()
        .storeUint(Math.floor(Date.now() / 1000) + 900, 32) // deadline
        .storeAddress(sender.address) // recipient of output asset
        .storeAddress(null) // no referral
        .storeMaybeRef(null) // no notifications
        .endCell()
    let swapStepParams: Builder
    if (noMultihop) { // example for TON -> USDT
        swapStepParams = beginCell()
            .storeUint(getHashFromAddress(poolTonUsdtAddress), 256)
            .storeCoins(0n) // min USDT to receive after swap
            .storeMaybeRef(null) // no next step
    } else { // example for TON -> USDT -> TONNEL
        swapStepParams = beginCell()
            .storeUint(getHashFromAddress(poolTonUsdtAddress), 256)
            .storeCoins(0n) // min USDT to receive after 1st swap
            .storeMaybeRef(
                beginCell()
                    .storeUint(getHashFromAddress(poolUsdtTonnelAddress), 256)
                    .storeCoins(0n) // min TONNEL to receive after 2nd swap
                    .storeMaybeRef(null) // no next step
                    .endCell()
            )
    }
    if (inputAsset instanceof AssetNative) {
        await sender.send({
            to: vaultAddress,
            value: toNano(.05) + inputAssetAmount,
            body: beginCell()
                    .storeUint(0xc0ffee00, 32) // swap_native opcode
                    .storeUint(0, 64)
                    .storeCoins(inputAssetAmount)
                    .storeBuilder(swapStepParams)
                    .storeRef(swapParamsCell)
                    .endCell()
        })
    } else if (inputAsset instanceof AssetJetton) {
        const jettonMaster = provider.provider(inputAsset.getAddress())
        let resp = await jettonMaster.get('get_wallet_address', [{
            type: 'slice',
            cell: beginCell().storeAddress(sender.address).endCell()
        }])
        const jettonWalletAddress = resp.stack.readAddress()
        await sender.send({
            to: jettonWalletAddress,
            value: toNano(.1),
            body: beginCell()
                .storeUint(0xf8a7ea5, 32) // jetton_transfer opcode
                .storeUint(0, 64)
                .storeAddress(vaultAddress)
                .storeAddress(sender.address)
                .storeMaybeRef(null) // no custom_payload
                .storeCoins(toNano(.05)) // fwd_gas
                .storeMaybeRef(
                    beginCell()
                        .storeUint(0xc0ffee10, 32) // swap_jetton opcode
                        .storeBuilder(swapStepParams)
                        .storeRef(swapParamsCell)
                        .endCell()
                ).endCell()
        })
    } else if (inputAsset instanceof AssetExtra) {
        await sender.send({
            to: vaultAddress,
            value: toNano(.05),
            extracurrency: {
                [Number(inputAsset.id)]: inputAssetAmount
            },
            body: beginCell()
                    .storeUint(0xc0ffee01, 32) // swap_extra opcode
                    .storeUint(0, 64)
                    .storeBuilder(swapStepParams)
                    .storeRef(swapParamsCell)
                    .endCell()
        })
    }
}

function getHashFromAddress(address: Address): bigint {
    return beginCell().storeBuffer(address.hash).endCell().beginParse().loadUintBig(256)
}

Notifications

Notifications are a system that allows sending a custom_payload upon the successful or failed execution of operations on the DEX. They can be used during pool creation, liquidity provisioning or withdrawal, as well as performing swaps. In all these cases, the approach to using notifications is the same: they are optional, and you can specify a notification for only the success case, only the failure case, or define separate notifications for each outcome. Each notification can carry a unique custom_payload and have a distinct recipient. Notifications are passed as an additional parameter when constructing a transaction to be sent by the user. However, depending on the operation, there are some differences in how they are ultimately processed. More on that below. Keep in mind that depending on the situation, a notification may be sent either as an internal message with its own opcode, or as a forward_payload within a jetton_transfer. In both cases, the user-defined custom_payload is not sent directly: instead, it is encapsulated within a separate entity. In other words, the recipient must either be capable of handling notification’s opcode, or a proxy contract must be used to unwrap the encapsulated message and forward it further. The fwd_gas for notification must be explicitly specified in cases where the notification recipient differs from the funds recipient, or when the notification is sent as a forward_payload within a jetton_transfer.

On pool creation or liquidity provisioning

In case of failure, the notification will be sent twice - once from each Vault, along with the refund of the assets that were intended for liquidity provision.
In case of success, the notification will be sent once, but the delivery method may vary:
- If the notification recipient is the same as the LP tokens recipient, the notification will be delivered as a forward_payload inside the jetton_transfer that sends the LP tokens.
- If recipients differ, the notification will be sent as an internal message with its own opcode.

On liquidity withdrawal

For liquidity withdrawals only on-success notification may be provided. If operation succeeds, the notification will be sent twice - once from each Vault, along with the refund of the assets that were received as a result of a liquidity withdrawal.

On swap

In all cases the notification will be sent once throughout the Vault. The method of delivery may vary:

If the recipient of the funds is different from the notification recipient, the notification will be sent as an internal message with its own opcode.
If both the funds and the notification are to be sent to the same address, the behavior depends on the asset type:
- If the payout is in TON or Extra Currency, it will be an internal message with the notification opcode, and the corresponding TON or Extra Currency tokens will be attached to it.
- If the payout is in Jetton, the notification - still encapsulating the user’s custom_payload - will be sent a forward_payload within the jetton_transfer.

Technical Guides

​Generic Information

​(De)serialization of assets

​Vaults

​Checking for existence and activity

​Creating a new one

​Pools

​Creating a new one

​Providing liquidity to existing one

​Rolling back liquidity provisioning

​Performing a swap

​Notifications

​On pool creation or liquidity provisioning

​On liquidity withdrawal

​On swap

Generic Information

(De)serialization of assets

Vaults

Checking for existence and activity

Creating a new one

Pools

Creating a new one

Providing liquidity to existing one

Rolling back liquidity provisioning

Performing a swap

Notifications

On pool creation or liquidity provisioning

On liquidity withdrawal

On swap