Added nodejs code generator. (#1)

docker/code-templates/nodejs/starter/src/_projname_.js

@@ -0,0 +1,60 @@
+const fs = require('fs').promises;
+
+// This sample application writes and reads from a simple text file to serve user requests.
+// Real-world applications may use a proper local database like sqlite.
+const dataFile = 'datafile.txt'
+
+export class _projname_ {
+    sendOutput; // This function must be wired up by the caller.
+
+    async handleRequest(userPubKey, message, isReadOnly) {
+
+        // This sample application defines two simple messages. 'get' and 'set'.
+        // It's up to the application to decide the structure and contents of messages.
+
+        if (message.type == 'get') {
+
+            // Retrieved previously saved data and return to the user.
+            const data = await this.getData();
+            await this.sendOutput(userPubKey, {
+                type: 'data_result',
+                data: data
+            })
+        }
+        else if (message.type == 'set') {
+
+            if (!isReadOnly) {
+                // Save the provided data into storage.
+                await this.setData(message.data);
+            }
+            else {
+                await this.sendOutput(userPubKey, {
+                    type: 'error',
+                    error: 'Set data not supported in readonly mode'
+                })
+            }
+
+        }
+        else {
+            await this.sendOutput(userPubKey, {
+                type: 'error',
+                error: 'Unknown message type'
+            })
+        }
+    }
+
+    async setData(data) {
+        // Hot Pocket subjects data on-disk to consensus.
+        await fs.writeFile(dataFile, data);
+    }
+
+    async getData() {
+        try {
+            return (await fs.readFile(dataFile)).toString();
+        }
+        catch {
+            console.log('Data file not created yet. Returning empty data.');
+            return '';
+        }
+    }
+}

docker/code-templates/nodejs/starter/src/contract.js

@@ -0,0 +1,49 @@
+const HotPocket = require('hotpocket-nodejs-contract');
+const { _projname_ } = require('./_projname_');
+
+// Hot Pocket smart contract is defined as a function which takes the Hot Pocket ExecutionContext as an argument.
+// This function gets invoked every consensus round and whenever a user sends a out-of-concensus read-request.
+async function contract(ctx) {
+
+    // Create our application logic component.
+    // This pattern allows us to test the application logic independently of Hot Pocket.
+    const app = new _projname_();
+
+    // Wire-up output emissions from the application before we pass user inputs to it.
+    app.sendOutput = async (userPubKey, output) => {
+        // In Hot Pocket, each user is represented by their Ed25519 public key.
+        const user = ctx.users.find(userPubKey);
+        await user.send(output)
+    }
+    
+    // In 'readonly' mode, nothing our contract does will get persisted on the ledger. The benefit is
+    // readonly messages gets processed much faster due to not being subjected to consensus.
+    // We should only use readonly mode for returning/replying data for the requesting user.
+    //
+    // In consensus mode (NOT read-only), we can do anything like persisting to data storage and/or
+    // sending data to any connected user at the time. Everything will get subjected to consensus so
+    // there is a time-penalty.
+    const isReadOnly = ctx.readonly;
+
+    // Process user inputs.
+    // Loop through list of users who have sent us inputs.
+    for (const user of ctx.users.list()) {
+
+        // Loop through inputs sent by each user.
+        for (const input of user.inputs) {
+
+            // Read the data buffer sent by user (this can be any kind of data like string, json or binary data).
+            const buf = await ctx.users.read(input);
+
+            // Let's assume all data buffers for this contract are JSON.
+            // In real-world apps, we need to gracefully fitler out invalid data formats for our contract.
+            const message = JSON.parse(buf);
+
+            // Pass the JSON message to our application logic component.
+            await app.handleRequest(userPubKey, message, isReadOnly);
+        }
+    }
+}
+
+const hpc = new HotPocket.Contract();
+hpc.init(contract);