WavesChat script example

ride4dapps/waveschat/README.md

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+# WavesChat
+WavesChat is a decentralized messenger with an end-to-end encryption
+Basically works like a chat-roulette with an
+1. Optional channel
+2. Optional payment, which forces to pay the same amount to talk with you 
+
+Try now at https://chat.waves.today (Requires Waves Keeper **with InvokeScript support in TESTNET mode**)
+
+# How it works
+1. First user (Bob) invokes script function `init(bobPublicKey)`
+2. Second user (Alice) invokes `init(alicePublicKey)`
+3. Script matches Bob's and Alice's public keys, so that they can get the recipients public key from data entry `Base58(Blake2b256(publicKey))`
+4. Bob gets Alice's public key, encrypts message with it, and then invokes `sendMessage(bobPublicKey, cipherText)`
+5. Bob to Alice conversation id is `Base58(Blake2b256(bobPublicKey + alicePublicKey))`, so Alice can get message count from `conversationId + "_n"` and messages from `conversationId + "_" + 0...msgCount` data entries accordingly, and decrypt it with her private key

ride4dapps/waveschat/waveschat.ride

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+{-# STDLIB_VERSION 3 #-}
+{-# CONTENT_TYPE DAPP #-}
+{-# SCRIPT_TYPE ACCOUNT #-}
+
+let defaultAmount = 0
+let maxAmount = 5_0000_0000
+
+@Callable(invoke)
+func init(publicKey: ByteVector, channel: String) = {
+    let publicKeyHash = toBase58String(blake2b256(publicKey))
+    let channelId = toBase58String(blake2b256(toBytes(channel)))
+    let currentKey = "current_" + channelId
+    let currentAmountKey = "current_amount_" + channelId
+    let isPublicChannel = size(channel) < 6
+
+    let pmtAmount = match invoke.payment {
+        case pmt:AttachedPayment =>
+            if (isDefined(pmt.assetId)) then 0
+            else pmt.amount
+        case _ =>
+            0
+    }
+
+    let requiredAmount = match getInteger(this, currentAmountKey) {
+        case currentAmount: Int => currentAmount
+        case _ => 0
+    }
+
+    let newRequiredAmount = if (isPublicChannel && pmtAmount >= maxAmount) then maxAmount else pmtAmount
+
+    if (pmtAmount < requiredAmount)
+        then throw("Init requires " + toString(requiredAmount / 100000000) + " waves")
+    else {
+        match getBinary(this, publicKeyHash + "_owner") {
+            case b: ByteVector =>
+                if (b != invoke.caller.bytes) then throw("Public key is not yours")
+                else {
+                    match getBinary(this, currentKey) {
+                        case left:ByteVector =>
+                            let leftHash = toBase58String(blake2b256(left))
+                            WriteSet([DataEntry(publicKeyHash + "_owner", invoke.caller.bytes), DataEntry(leftHash, publicKey), DataEntry(publicKeyHash, left), DataEntry(currentKey, 0), DataEntry(currentAmountKey, defaultAmount)])
+
+                        case _ =>
+                            WriteSet([DataEntry(publicKeyHash + "_owner", invoke.caller.bytes), DataEntry(currentKey, publicKey), DataEntry(currentAmountKey, newRequiredAmount)])
+                    }
+                }
+
+            case _ =>
+                match getBinary(this, currentKey) {
+                    case left:ByteVector =>
+                        let leftHash = toBase58String(blake2b256(left))
+                        WriteSet([DataEntry(publicKeyHash + "_owner", invoke.caller.bytes), DataEntry(leftHash, publicKey), DataEntry(publicKeyHash, left), DataEntry(currentKey, 0), DataEntry(currentAmountKey, defaultAmount)])
+
+                    case _ =>
+                        WriteSet([DataEntry(publicKeyHash + "_owner", invoke.caller.bytes), DataEntry(currentKey, publicKey), DataEntry(currentAmountKey, newRequiredAmount)])
+                }
+        }
+    }
+}
+
+@Callable(invoke)
+func sendMessage(publicKey: ByteVector, message: ByteVector) = {
+    let publicKeyHash = toBase58String(blake2b256(publicKey))
+
+    match getBinary(this, publicKeyHash + "_owner") {
+        case assignedCaller: ByteVector =>
+            if (assignedCaller != invoke.caller.bytes) then throw("Public keys not match")
+            else match getBinary(this, publicKeyHash) {
+                case right: ByteVector =>
+                    let conversationId = toBase58String(blake2b256(publicKey + right))
+                    let nonceKey = conversationId + "_n"
+                    let nonce = match getInteger(this, nonceKey) {
+                        case i: Int => i + 1
+                        case _ => 1
+                    }
+                    WriteSet([DataEntry(conversationId + "_" + toString(nonce), message), DataEntry(nonceKey, nonce)])
+
+                case _ => throw("Not initialized")
+            }
+
+        case _ => throw("Owner not defined")
+    }
+}

ride4dapps/waveschat/waveschat_test.js

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+describe('Messenger test', () => {
+    const dappAddress = "3N3st6Cp9ZLz8kmT33EY41AVjwKqBVebvyq"
+
+    const firstPK = "FxKjemCJ9s9yrG5RuDXAtGXZNsTsAr1FMhzNmUKG4GyE"
+    const secondPK = "5nRF8WDnjWrGhZeYEV8zh7MG1kgpYbnJaEt5G3vsR4e2"
+
+    const firstPKHash = "4CfQDi9nwsps25XA9yrMAw4XWFaG5NwLf6gFVjrTSGL7"
+
+    it('Register for a chat', async function(){
+        const tx = invokeScript({ fee: 900000, dApp: dappAddress, call:{function:"init",args:[{"type": "binary", "value": firstPK}, {"type": "string", "value": "test"}]},
+            payment: [{amount: 1000000, assetId: null}]})
+        const tx1 = invokeScript({ fee: 900000, dApp: dappAddress, call:{function:"init",args:[{"type": "binary", "value": secondPK}, {"type": "string", "value": "test"}]},
+            payment: [{amount: 1000000, assetId: null}]})
+
+        await broadcast(tx)
+        await broadcast(tx1)
+        await waitForTx(tx1.id)
+    })
+
+    it('Send message', async function(){
+        const tx = invokeScript({ fee: 900000, dApp: dappAddress, call:{function:"sendMessage",args:[{"type": "binary", "value": firstPK}, {"type": "binary", "value": "4CfQDi9nwsps25XA9yrMAw4XWFaG5NwLf6gFVjrTSGL7"}]},
+            payment: [{amount: 1000000, assetId: null}]})
+
+        await broadcast(tx)
+        await waitForTx(tx.id)
+    })
+})