When new pools are created in Uniswap V4, our hook automatically registers them for treasury management through the afterInitialize callback:<\/p>\n
function _afterInitialize(
address,
PoolKey calldata key,
uint160,
int24
) internal override returns (bytes4) {
PoolId poolId = key.toId();
isPoolManaged[poolId] = true;
return IHooks.afterInitialize.selector;
}<\/p>\n
Universal Coverage<\/strong>: The hook automatically registers all newly initialized pools, ensuring fee collection across the entire protocol.<\/p>\n Efficient Identification<\/strong>: Uses PoolKey.toId() to generate consistent, unique identifiers for each pool, leveraging Uniswap V4’s built-in hashing mechanism.<\/p>\n Single Storage Write<\/strong>: Each pool registration requires only one storage operation, minimizing gas costs during pool creation.<\/p>\n Proper Return Value<\/strong>: Returns the correct selector to confirm successful hook processing, maintaining compatibility with the hook\u00a0chain.<\/p>\n The beforeSwap hook implements a crucial optimization pattern that determines whether to process swaps for fee collection:<\/p>\n function _beforeSwap( if (!isPoolManaged[poolId]) { return (IHooks.beforeSwap.selector, BeforeSwapDelta.wrap(0), 0); Early Exit Strategy<\/strong>: For unmanaged pools, returning bytes4(0) signals the hook system to skip the afterSwap callback entirely, saving significant gas.<\/p>\n Managed Pool Processing<\/strong>: Managed pools return the proper selector, ensuring the fee collection logic in afterSwap will\u00a0execute.<\/p>\n Gas Efficiency<\/strong>: This pattern prevents unnecessary processing for pools that shouldn\u2019t participate in fee collection.<\/p>\n View Function Optimization<\/strong>: The function is marked as view, enabling the EVM to optimize storage reads during execution.<\/p>\n The afterSwap hook contains the primary fee collection logic:<\/p>\n function _afterSwap( if (treasuryFeeRate == 0) { (Currency tokenIn, uint256 amountIn) = _getSwapInputDetails(key, params, delta);<\/p>\n if (amountIn > 0) { if (feeAmount > 0) { emit TreasuryFeeCollected(poolId, tokenIn, feeAmount);<\/p>\n return (IHooks.afterSwap.selector, int128(int256(feeAmount))); return (IHooks.afterSwap.selector, 0); Validation Phase<\/strong>: Verifies that treasuryFeeRate is non-zero to avoid unnecessary processing<\/p>\n Input Extraction<\/strong>: Calls _getSwapInputDetails to determine which token and amount to charge fees\u00a0on<\/p>\n Fee Calculation<\/strong>: Applies the basis points calculation: (amountIn * treasuryFeeRate) \/ BASIS_POINTS<\/p>\n State Updates<\/strong>:<\/p>\n Accumulates fees in the token-specific mappingUses poolManager.take() to transfer tokens from the pool to the hook\u00a0contract<\/p>\n Event Emission<\/strong>: Logs the fee collection for transparency and off-chain monitoring<\/p>\n Return Value<\/strong>: Reports the collected fee amount back to the pool\u00a0manager<\/p>\n The _getSwapInputDetails function determines which token and amount to charge fees\u00a0on:<\/p>\n function _getSwapInputDetails( Direction Detection<\/strong>: params.zeroForOne indicates whether the swap is from currency0 to currency1 or vice\u00a0versa<\/p>\n Token Mapping<\/strong>: Maps the swap direction to the correct input currency from the pool\u00a0key<\/p>\n Amount Extraction<\/strong>: Negative delta values represent tokens being input to the pool (sold by the\u00a0trader)<\/p>\n Safe Type Conversion<\/strong>: Converts signed int128 delta values to unsigned uint256 amounts, handling the sign flip\u00a0properly<\/p>\n Zero Amount Handling<\/strong>: Returns 0 for cases where the delta is positive or zero (no\u00a0input)<\/p>\n The fee calculation system uses basis points for precise\u00a0control:<\/p>\n uint256 feeAmount = (amountIn * treasuryFeeRate) \/ BASIS_POINTS;<\/p>\n Precision Control<\/strong>: 10,000 basis points provide 0.01% precision, allowing fine-tuned fee adjustments<\/p>\n Range Coverage<\/strong>: Fee rates from 0 to 1000 basis points cover 0% to 10% in 0.01% increments<\/p>\n Overflow Protection<\/strong>: Uses 256-bit arithmetic to prevent overflow even with maximum possible\u00a0values<\/p>\n Trader-Favorable Rounding<\/strong>: Integer division rounds down, ensuring traders aren\u2019t overcharged due to\u00a0rounding<\/p>\n Assume amountIn<\/strong> is\u00a01000;<\/p>\n 1% fee<\/strong> (100 basis points): (1000 * 100) \/ 10000 = 10\u00a0tokens0.5% fee<\/strong> (50 basis points): (1000 * 50) \/ 10000 = 5\u00a0tokens0.25% fee<\/strong> (25 basis points): (1000 * 25) \/ 10000 = 2\u00a0tokens10% fee<\/strong> (1000 basis points): (1000 * 1000) \/ 10000 = 100\u00a0tokens<\/p>\n Fee collection leverages Uniswap V4\u2019s optimized transfer\u00a0system:<\/p>\n poolManager.take(tokenIn, address(this), feeAmount);<\/p>\n Automatic Deduction<\/strong>: Fees are automatically deducted from the swap proceeds before tokens reach the\u00a0trader<\/p>\n Gas Optimization<\/strong>: Leverages the pool manager\u2019s already-optimized transfer mechanisms rather than implementing custom\u00a0logic<\/p>\n Seamless Integration<\/strong>: Works with Uniswap V4\u2019s internal accounting system without requiring additional approvals<\/p>\n Multi-Token Support<\/strong>: Handles any ERC-20 token or ETH through the Currency abstraction<\/p>\n The contract emits comprehensive events for all treasury operations:<\/p>\n event TreasuryFeeCollected(PoolId indexed poolId, Currency indexed token, uint256 amount); Indexed Parameters<\/strong>: Enable efficient filtering and searching in event\u00a0logs<\/p>\n Complete Coverage<\/strong>: All significant treasury operations emit events for full transparency<\/p>\n Gas Optimization<\/strong>: Events include only essential data to minimize gas\u00a0costs<\/p>\n Frontend Integration<\/strong>: Support real-time monitoring dashboards and analytics tools<\/p>\n Audit Trail<\/strong>: Create permanent, immutable records of all treasury activities<\/p>\n The implementation employs several techniques to minimize gas consumption:<\/p>\n Single Reads<\/strong>: Frequently accessed variables like treasuryFeeRate are read once and cached in\u00a0memory<\/p>\n Conditional Processing<\/strong>: Early exits prevent expensive operations when they\u2019re unnecessary<\/p>\n Optimized Mappings<\/strong>: Separate mappings for different data types avoid complex struct operations<\/p>\n Integer Arithmetic<\/strong>: All calculations use integer math to avoid expensive floating-point operations<\/p>\n Minimal Type Conversions<\/strong>: Carefully designed to minimize casting between different numeric\u00a0types<\/p>\n Basis Points System<\/strong>: Avoids decimal calculations while maintaining precision<\/p>\n Selective Processing<\/strong>: The beforeSwap optimization prevents unnecessary afterSwap execution<\/p>\n View Function Usage<\/strong>: Marking functions as view where possible enables EVM optimizations<\/p>\n Minimal Return Data<\/strong>: Returns only necessary data to reduce transaction costs<\/p>\n The contract provides both automatic and manual pool management capabilities:<\/p>\n function getPoolManagedStatus(PoolKey calldata key) external view returns (bool) { function setPoolManaged(PoolKey calldata key, bool managed) external { Status Queries<\/strong>: External contracts and frontends can check which pools participate in fee collection<\/p>\n Manual Override<\/strong>: Allows disabling fee collection for specific pools when\u00a0needed<\/p>\n Testing Support<\/strong>: Enables controlled testing scenarios with custom pool configurations<\/p>\n Flexible Configuration<\/strong>: Supports different treasury strategies for different pool\u00a0types<\/p>\n The fee collection mechanics demonstrated here provide a foundation for automated treasury management. The system efficiently processes high-frequency swap operations while maintaining precise fee collection and monitoring capabilities. In Part 3, we\u2019ll explore the treasury operations and withdrawal mechanisms that complete the\u00a0system.<\/p>\n Building a Treasury Management Hook for Uniswap V4\u200a\u2014\u200aPart 2: Hook Lifecycle and Fee Collection\u2026<\/a> was originally published in Coinmonks<\/a> on Medium, where people are continuing the conversation by highlighting and responding to this story.<\/p>","protected":false},"excerpt":{"rendered":" Building a Treasury Management Hook for Uniswap V4\u200a\u2014\u200aPart 2: Hook Lifecycle and Fee Collection Mechanics Pool Initialization and Registration When new pools are created in Uniswap V4, our hook automatically registers them for treasury management through the afterInitialize callback: function _afterInitialize( address, PoolKey calldata key, uint160, int24) internal override returns (bytes4) { PoolId poolId = […]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-78771","post","type-post","status-publish","format-standard","hentry","category-interesting"],"_links":{"self":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/posts\/78771"}],"collection":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=78771"}],"version-history":[{"count":0,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/posts\/78771\/revisions"}],"wp:attachment":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=78771"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=78771"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=78771"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Pre-Swap Validation and Optimization<\/h3>\n
address,
PoolKey calldata key,
IPoolManager.SwapParams calldata,
bytes calldata
) internal view override returns (bytes4, BeforeSwapDelta, uint24) {
PoolId poolId = key.toId();<\/p>\n
return (bytes4(0), BeforeSwapDelta.wrap(0), 0);
}<\/p>\n
}<\/p>\nOptimization Logic<\/h3>\n
Core Fee Collection Implementation<\/h3>\n
address,
PoolKey calldata key,
IPoolManager.SwapParams calldata params,
BalanceDelta delta,
bytes calldata
) internal override returns (bytes4, int128) {
PoolId poolId = key.toId();<\/p>\n
return (IHooks.afterSwap.selector, 0);
}<\/p>\n
uint256 feeAmount = (amountIn * treasuryFeeRate) \/ BASIS_POINTS;<\/p>\n
accumulatedFees[tokenIn] += feeAmount;
poolManager.take(tokenIn, address(this), feeAmount);<\/p>\n
}
}<\/p>\n
}<\/p>\nFee Collection Flow\u00a0Analysis<\/h3>\n
Swap Input\u00a0Analysis<\/h3>\n
PoolKey calldata key,
IPoolManager.SwapParams calldata params,
BalanceDelta delta
) private pure returns (Currency tokenIn, uint256 amountIn) {
if (params.zeroForOne) {
tokenIn = key.currency0;
amountIn = delta.amount0() < 0 ? uint256(uint128(-delta.amount0())) : 0;
} else {
tokenIn = key.currency1;
amountIn = delta.amount1() < 0 ? uint256(uint128(-delta.amount1())) : 0;
}
}<\/p>\nSwap Direction Logic<\/h3>\n
Fee Calculation Mathematics<\/h3>\n
Mathematical Properties<\/h3>\n
Example Calculations<\/h3>\n
Token Transfer Integration<\/h3>\n
Transfer Mechanism Benefits<\/h3>\n
Event System for Transparency<\/h3>\n
event TreasuryAddressChanged(address indexed oldTreasury, address indexed newTreasury);
event TreasuryFeeRateChanged(uint24 oldRate, uint24 newRate);
event FeesWithdrawn(Currency indexed token, uint256 amount);<\/p>\nEvent Design\u00a0Benefits<\/h3>\n
Gas Optimization Strategies<\/h3>\n
Efficient Storage\u00a0Access<\/h3>\n
Computational Efficiency<\/h3>\n
Hook-Specific Optimizations<\/h3>\n
Pool Management Features<\/h3>\n
return isPoolManaged[key.toId()];
}<\/p>\n
isPoolManaged[key.toId()] = managed;
}<\/p>\nManagement Capabilities<\/h3>\n