create/SubmitMessage in pclib.

lib/pricecaster.js

@@ -188,7 +188,7 @@ class PricecasterLib {
       params.flatFee = true
 
       // create unsigned transaction
-      const txApp = algosdk.makeApplicationNoOpTxn(sender, params, this.appId, appArgs, appAccounts)
+      const txApp = algosdk.makeApplicationNoOpTxn(sender, params, this.appId, appArgs, appAccounts.length === 0 ? undefined : appAccounts)
       const txId = txApp.txID().toString()
 
       // Sign the transaction
@@ -296,6 +296,44 @@ class PricecasterLib {
       // display results
       return this.algodClient.pendingTransactionInformation(txId).do()
     }
+
+    /**
+     * Creates a message with price data for the PriceKeeper contract
+     * @param {BigInt} nonce Sequence number
+     * @param {String} symbol Symbol, must match appid support, 16-char UTF long
+     * @param {number} price Price, expected in 64-bit floating-point format.
+     * @param {number} confidence Confidence, expected in 64-bit floating-point format.
+     * @param {Uint8Array} sk Signing key.
+     * @returns A base64-encoded message.
+     */
+    this.createMessage = function (nonce, symbol, price, confidence, sk) {
+      const buf = Buffer.alloc(131)
+      buf.write('PRICEDATA', 0)
+      buf.writeInt8(1, 9)
+      buf.writeBigUInt64BE(BigInt(this.appId), 10)
+      buf.writeBigUInt64BE(nonce, 18)
+      buf.write(symbol, 26)
+      buf.writeDoubleBE(price, 42)
+      buf.writeDoubleBE(confidence, 50)
+      buf.writeBigUInt64BE(BigInt(Math.floor(Date.now() / 1000)), 58)
+
+      const signature = Buffer.from(algosdk.signBytes(buf, sk))
+      signature.copy(buf, 66)
+
+      // v-component (ignored in Algorand it seems)
+      buf.writeInt8(1, 130)
+      return buf.toString('base64')
+    }
+
+    /**
+     * Submits message to the PriceKeeper contract.
+     * @param {*} sender Sender account
+     * @param {*} msgb64 Base64-encoded message.
+     * @returns Transaction identifier (txid)
+     */
+    this.submitMessage = async function (sender, msgb64, signCallback) {
+      return await this.callApp(sender, [new Uint8Array(msgb64)], [], signCallback)
+    }
   }
 }