> For the complete documentation index, see [llms.txt](https://doc.defipie.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.defipie.com/uniswappriceoracle.md).

# UniswapPriceOracle

## Introduction

DeFiPIE protocol uses UniswapPriceOracle to get time-weighted average prices from Uniswap v2 or other DEX (clones Uniswap v2).

Every time the user interacts with a pool, the protocol gets the current price from Uniswap and averages it with the previously stored price, thereby achieving the Time-weighted average price effect, which in turn protects the protocol from price manipulation through flash loans.

## **Update price by pToken**

Updating the price of an asset by the pToken address.

#### UniswapPriceOracle

```
function updateUnderlyingPrice(address pToken) public override returns (uint)
```

* `pToken`: pToken address.
* `RETURN`: 0 on success, otherwise an Error code.

#### **Solidity**

```
UniswapPriceOracle oracle = UniswapPriceOracle(0xABCD...);
PErc20 pToken = PErc20(0x3FDB...);
oracle.updateUnderlyingPrice(address(pToken));
```

#### **Web3 1.0**

```
const oracle = UniswapPriceOracle.at(0xABCD...);
const pToken = PErc20.at(0x3FDB...);
oracle.methods.updateUnderlyingPrice(pToken).send({from: ...});
```

## Update price by an asset.

Updating the price of an asset by the asset address.

#### UniswapPriceOracle

```
function update(address asset) public returns (uint)
```

* `asset`: asset address.
* `RETURN`: 0 on success, otherwise an Error code.

#### **Solidity**

```
UniswapPriceOracle oracle = UniswapPriceOracle(0xABCD...);
Erc20 token = Erc20(0x3FDB...);
oracle.update(address(token));
```

#### **Web3 1.0**

```
const oracle = UniswapPriceOracle.at(0xABCD...);
const token = Erc20.at(0x3FDB...);
oracle.methods.update(token ).send({from: ...});
```

## Get asset price in ETH

Get an average asset price in ETH with 18 decimals of precision.

#### UniswapPriceOracle

```
function getCourseInETH(address asset) public view returns (uint)
```

* `asset`: asset address.
* `RETURN`: asset price.

#### **Solidity**

```
UniswapPriceOracle oracle = UniswapPriceOracle(0xABCD...);
Erc20 token = Erc20(0x3FDB...);
uint price = oracle.getCourseInETH(address(token));
```

#### **Web3 1.0**

```
const oracle = UniswapPriceOracle.at(0xABCD...);
const token = Erc20.at(0x3FDB...);
const price = oracle.methods.getCourseInETH(token).call();
```

## Get asset price in USD

Get an average asset price in USD with 18 decimals of precision.

#### UniswapPriceOracle

```
function getPriceInUSD(address asset) public view virtual returns (uint)
```

* `asset`: asset address.
* `RETURN`: asset price.

#### **Solidity**

```
UniswapPriceOracle oracle = UniswapPriceOracle(0xABCD...);
Erc20 token = Erc20(0x3FDB...);
uint price = oracle.getPriceInUSD(address(token));
```

#### **Web3 1.0**

```
const oracle = UniswapPriceOracle.at(0xABCD...);
const token = Erc20.at(0x3FDB...);
const price = oracle.methods.getPriceInUSD(token).call();
```