Adding example on how to integrate a Waku node in NodeJs

.gitignore

@@ -53,3 +53,4 @@ nimbus-build-system.paths
 *.sqlite3-shm
 *.sqlite3-wal
 
+/examples/nodejs/build/

Makefile

@@ -311,6 +311,10 @@ cwaku_example: | build libwaku
 		vendor/nim-libbacktrace/libbacktrace_wrapper.o \
 		vendor/nim-libbacktrace/install/usr/lib/libbacktrace.a
 
+nodejswaku: | build deps
+		echo -e $(BUILD_MSG) "build/$@" && \
+		node-gyp build --directory=examples/nodejs/
+
 endif # "variables.mk" was not included
 
 ###################

examples/nodejs/binding.gyp

@@ -0,0 +1,9 @@
+{
+  "targets": [
+    {
+      "target_name": "waku",
+      "sources": [ "waku_addon.c", "../cbindings/base64.c" ],
+      "libraries": [ "-lwaku", "-L../../../build/" ]
+    }
+  ]
+}

examples/nodejs/waku.js

@@ -0,0 +1,74 @@
+
+var express = require('express');
+var app = express();
+
+function create_random_string(length) {
+  let result = '';
+  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+  const charactersLength = characters.length;
+  let counter = 0;
+  while (counter < length) {
+    result += characters.charAt(Math.floor(Math.random() * charactersLength));
+    counter += 1;
+  }
+  return result;
+}
+
+var wakuMod = require('bindings')('waku');
+
+var cfg = `{
+    "host": "0.0.0.0",
+    "port": 60001,
+    "key": "364d111d729a6eb6d3e6113e163f017b5ef03a6f94c9b5b7bb1bb36fa5cb07a9",
+    "relay": true
+}`
+
+function event_handler(event) {
+    console.log("evento NodeJs: " + event)
+}
+
+wakuMod.wakuVersion(function(msg){ console.log("Waku Version: " + msg) })
+
+// Example on how to retrieve a value from the waku library
+var defaultPubsubTopic = ""
+wakuMod.wakuDefaultPubsubTopic(function(msg){ defaultPubsubTopic = msg })
+
+console.log("Setting callback event callback function")
+wakuMod.wakuSetEventCallback(event_handler)
+wakuMod.wakuNew(cfg)
+
+wakuMod.wakuStart()
+
+wakuMod.wakuConnect("/ip4/127.0.0.1/tcp/60000/p2p/16Uiu2HAmVFXtAfSj4EiR7mL2KvL4EE2wztuQgUSBoj2Jx2KeXFLN",
+                    10000,
+                    function onErr(msg) {
+                      console.log("Error connecting node: " + msg)
+                    })
+
+wakuMod.wakuRelaySubscribe(defaultPubsubTopic,
+                           function onErr(msg) {
+                             console.log("Error subscribing: " + msg)
+                           })
+
+app.post('/publish', 
+  function (req, res) {
+    // First read existing users.
+    console.log("Publish event received")
+
+    wakuMod.wakuRelayPublish(defaultPubsubTopic,
+                            "content_topic_name",
+                            create_random_string(10),
+                            10000,
+                            function onError(msg) {
+                              console.log("Error: " + msg)
+                              process.exit(-1)
+                            });
+
+    res.end( JSON.stringify("OK publish"))
+  })
+
+var server = app.listen(8081, function () {
+  var host = server.address().address
+  var port = server.address().port
+  console.log("Example waku listening at http://%s:%s", host, port)
+})