Add method to fetch individual prices specified by user (#61)

* add getAssetPricesFromAccounts method

* add check for price data format

* add getAssetPricesFromAccounts tests

* remove duplicate test

Author: cryptopapi997

src/PythHttpClient.ts

@@ -114,4 +114,33 @@ export class PythHttpClient {
 
     return result
   }
+
+  /**
+   * Get the price state for an array of specified price accounts.
+   * The result is the price state for the given assets if they exist, throws if at least one account does not exist.
+   */
+  public async getAssetPricesFromAccounts(priceAccounts: PublicKey[]): Promise<PriceData[]> {
+    const priceDatas: PriceData[] = []
+    const currentSlotPromise = this.connection.getSlot(this.commitment)
+    const accountInfos = await this.connection.getMultipleAccountsInfo(priceAccounts, this.commitment)
+
+    const currentSlot = await currentSlotPromise
+    for (let i = 0; i < priceAccounts.length; i++) {
+      // Declare local variable to silence typescript warning; otherwise it thinks accountInfos[i] can be undefined
+      const accInfo = accountInfos[i]
+      if (!accInfo) {
+        throw new Error('Could not get account info for account ' + priceAccounts[i].toBase58())
+      }
+      
+      const baseData = parseBaseData(accInfo.data)
+      if (baseData === undefined || baseData.type !== AccountType.Price) {
+        throw new Error('Account ' + priceAccounts[i].toBase58() + ' is not a price account')
+      }
+
+      const priceData = parsePriceData(accInfo.data, currentSlot)
+      priceDatas.push(priceData)
+    }
+
+    return priceDatas
+  }
 }

src/__tests__/PythNetworkRestClient-test.ts

@@ -1,7 +1,7 @@
-import { clusterApiUrl, Connection } from '@solana/web3.js'
-import { getPythProgramKeyForCluster, PythHttpClient } from '..'
+import { clusterApiUrl, Connection, PublicKey, SystemProgram } from '@solana/web3.js'
+import { getPythProgramKeyForCluster, parseProductData, PythHttpClient } from '..'
 
-test('PythHttpClientCall', (done) => {
+test('PythHttpClientCall: getData', (done) => {
   jest.setTimeout(20000)
   try {
     const programKey = getPythProgramKeyForCluster('testnet')
@@ -25,3 +25,99 @@ test('PythHttpClientCall', (done) => {
     done(err_catch)
   }
 })
+
+test('PythHttpClientCall: getAssetPricesFromAccounts for one account', (done) => {
+  const solUSDKey = new PublicKey('7VJsBtJzgTftYzEeooSDYyjKXvYRWJHdwvbwfBvTg9K')
+  try {
+    const programKey = getPythProgramKeyForCluster('testnet')
+    const currentConnection = new Connection(clusterApiUrl('testnet'))
+    const pyth_client = new PythHttpClient(currentConnection, programKey)
+    pyth_client
+      .getAssetPricesFromAccounts([solUSDKey])
+      .then((result) => {
+        try {
+          expect(result.length).toBe(1)
+          // Check the symbol through the product account
+          const productAcc = result[0].productAccountKey
+
+          return currentConnection.getAccountInfo(productAcc)
+        } catch (cerr) {
+          done(cerr)
+        }
+      })
+      .then((productAcc) => {
+        if (!productAcc) {
+          done(new Error('Product account not found'))
+        }
+        // We can assert it's defined here because we call done otherwise above
+        const productData = parseProductData(productAcc!.data)
+        expect(productData.product.symbol).toBe('Crypto.SOL/USD')
+        done()
+      })
+  } catch (err_catch) {
+    done(err_catch)
+  }
+}, 20000)
+
+test('PythHttpClientCall: getAssetPricesFromAccounts for multiple accounts', (done) => {
+  const solUSDKey = new PublicKey('7VJsBtJzgTftYzEeooSDYyjKXvYRWJHdwvbwfBvTg9K')
+  const bonkUSDKey = new PublicKey('FPPnzp74SGt72T463B62fQh3Di9fXrBe82YnQh8ycQp9')
+  const usdcUSDKey = new PublicKey('GBvYgUMCt4nvycUZMEBpHyLEXGbKjr6G9HjMjmLyf6mA')
+
+  try {
+    const programKey = getPythProgramKeyForCluster('testnet')
+    const currentConnection = new Connection(clusterApiUrl('testnet'))
+    const pyth_client = new PythHttpClient(currentConnection, programKey)
+    pyth_client
+      .getAssetPricesFromAccounts([solUSDKey, bonkUSDKey, usdcUSDKey])
+      .then((result) => {
+        try {
+          expect(result.length).toBe(3)
+          // Check the symbol through the product account
+          const productAccs = result.map((r) => r.productAccountKey)
+
+          return currentConnection.getMultipleAccountsInfo(productAccs)
+        } catch (cerr) {
+          done(cerr)
+        }
+      })
+      .then((productAccs) => {
+        // We can assert it's defined here because we call done otherwise above
+        const expectedSymbols = ['Crypto.SOL/USD', 'Crypto.BONK/USD', 'Crypto.USDC/USD']
+        productAccs!.forEach((acc, i) => {
+          if (!acc) {
+            done(new Error('Product account not found'))
+          }
+          const productData = parseProductData(acc!.data)
+          expect(productData.product.symbol).toBe(expectedSymbols[i])
+        })
+        done()
+      })
+  } catch (err_catch) {
+    done(err_catch)
+  }
+}, 20000)
+
+test('PythHttpClientCall: getAssetPricesFromAccounts should throw for invalid account inclusion', (done) => {
+  const solUSDKey = new PublicKey('7VJsBtJzgTftYzEeooSDYyjKXvYRWJHdwvbwfBvTg9K')
+  // Should never be a pricefeed
+  const systemProgram = SystemProgram.programId
+  const usdcUSDKey = new PublicKey('GBvYgUMCt4nvycUZMEBpHyLEXGbKjr6G9HjMjmLyf6mA')
+
+  try {
+    const programKey = getPythProgramKeyForCluster('testnet')
+    const currentConnection = new Connection(clusterApiUrl('testnet'))
+    const pyth_client = new PythHttpClient(currentConnection, programKey)
+    pyth_client
+      .getAssetPricesFromAccounts([solUSDKey, systemProgram, usdcUSDKey])
+      .then((result) => {
+        done(new Error('Should not have gotten here'))
+      })
+      .catch((err) => {
+        expect(err.message).toBe('Account ' + systemProgram.toBase58() + ' is not a price account')
+        done()
+      })
+  } catch (err_catch) {
+    done(err_catch)
+  }
+}, 20000)