Added NATS server and frontend code to connect to it

backend/nats/Containerfile

@@ -0,0 +1,3 @@
+FROM nats:2.7.4-scratch
+COPY ./nats-server.conf /nats-server.conf
+EXPOSE 4223

backend/nats/nats-server.conf

@@ -0,0 +1,137 @@
+# Client port of 4222 on all interfaces
+port: 4222
+
+# HTTP monitoring port
+monitor_port: 8222
+
+# This is for clustering multiple servers together.
+cluster {
+  # It is recommended to set a cluster name
+  name: "sakal_cluster"
+
+  # Route connections to be received on any interface on port 6222
+  port: 6222
+
+  # Routes are protected, so need to use them with --routes flag
+  # e.g. --routes=nats-route://ruser:T0pS3cr3t@otherdockerhost:6222
+  authorization {
+    user: ruser
+    password: T0pS3cr3t
+    timeout: 2
+  }
+
+  # Routes are actively solicited and connected to from this server.
+  # This Docker image has none by default, but you can pass a
+  # flag to the nats-server docker image to create one to an existing server.
+  routes = []
+}
+
+
+websocket {
+    # Specify a host and port to listen for websocket connections
+    #
+    # listen: "host:port"
+
+    # It can also be configured with individual parameters,
+    # namely host and port.
+    #
+    # host: "hostname"
+    port: 4223
+
+    # This will optionally specify what host:port for websocket
+    # connections to be advertised in the cluster.
+    #
+    # advertise: "host:port"
+
+    # TLS configuration is required by default
+    #
+    #tls {
+    #  cert_file: "/path/to/cert.pem"
+    #  key_file: "/path/to/key.pem"
+    #}
+
+    # For test environments, you can disable the need for TLS
+    # by explicitly setting this option to `true`
+    #
+    no_tls: true
+
+    # [Cross-origin resource sharing option](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS).
+    #
+    # IMPORTANT! This option is used only when the http request presents an Origin
+    # header, which is the case for web browsers. If no Origin header is present,
+    # this check will not be performed.
+    #
+    # When set to `true`, the HTTP origin header must match the request’s hostname.
+    # The default is `false`.
+    #
+    # same_origin: true
+
+    # [Cross-origin resource sharing option](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS).
+    #
+    # IMPORTANT! This option is used only when the http request presents an Origin
+    # header, which is the case for web browsers. If no Origin header is present,
+    # this check will not be performed.
+    #
+    # List of accepted origins. When empty, and `same_origin` is `false`, clients from any origin are allowed to connect.
+    # This list specifies the only accepted values for the client's request Origin header. The scheme,
+    # host and port must match. By convention, the absence of TCP port in the URL will be port 80
+    # for an "http://" scheme, and 443 for "https://".
+    #
+    # allowed_origins [
+    #    "http://www.example.com"
+    #    "https://www.other-example.com"
+    # ]
+
+    # This enables support for compressed websocket frames
+    # in the server. For compression to be used, both server
+    # and client have to support it.
+    #
+    # compression: true
+
+    # This is the total time allowed for the server to
+    # read the client request and write the response back
+    # to the client. This includes the time needed for the
+    # TLS handshake.
+    #
+    # handshake_timeout: "2s"
+
+    # Name for an HTTP cookie, that if present will be used as a client JWT.
+    # If the client specifies a JWT in the CONNECT protocol, this option is ignored.
+    # The cookie should be set by the HTTP server as described [here](https://developer.mozilla.org/en-US/docs/Web/HTTP/Cookies#restrict_access_to_cookies).
+    # This setting is useful when generating NATS `Bearer` client JWTs as the
+    # result of some authentication mechanism. The HTTP server after correct
+    # authentication can issue a JWT for the user, that is set securely preventing
+    # access by unintended scripts. Note these JWTs must be [NATS JWTs](https://docs.nats.io/nats-server/configuration/securing_nats/jwt).
+    #
+    # jwt_cookie: "my_jwt_cookie_name"
+
+    # If no user name is provided when a websocket client connects, will default
+    # this user name in the authentication phase. If specified, this will
+    # override, for websocket clients, any `no_auth_user` value defined in the
+    # main configuration file.
+    # Note that this is not compatible with running the server in operator mode.
+    #
+    # no_auth_user: "my_username_for_apps_not_providing_credentials"
+
+    # See below to know what is the normal way of limiting websocket clients
+    # to specific users.
+    # If there are no users specified in the configuration, this simple authorization
+    # block allows you to override the values that would be configured in the
+    # equivalent block in the main section.
+    #
+    # authorization {
+    #     # If this is specified, the client has to provide the same username
+    #     # and password to be able to connect.
+    #     # username: "my_user_name"
+    #     # password: "my_password"
+    #
+    #     # If this is specified, the password field in the CONNECT has to
+    #     # match this token.
+    #     # token: "my_token"
+    #
+    #     # This overrides the main's authorization timeout. For consistency
+    #     # with the main's authorization configuration block, this is expressed
+    #     # as a number of seconds.
+    #     # timeout: 2.0
+    #}
+}

backend/nats/run.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+cd "${0%/*}"  # set current directory of this script to where the script is located. necessary for podman "-v" bind mounts to be relative paths
+podman run -d --name sakal-nats -p 4222:4222 -p 4223:4223 localhost/sakal-nats-server:latest

frontend/.gitignore

@@ -75,6 +75,7 @@ typings/
 
 # parcel-bundler cache (https://parceljs.org/)
 .cache
+.parcel-cache
 
 # Next.js build output
 .next

frontend/package.json

@@ -16,7 +16,8 @@
   "dependencies": {
     "PubSubJS": "^0.0.3",
     "incremental-dom": "^0.7.0",
-    "nanoid": "^3.3.1"
+    "nanoid": "^3.3.1",
+    "nats.ws": "^1.7.2"
   },
   "devDependencies": {
     "parcel": "^2.3.2"

frontend/pnpm-lock.yaml

@@ -4,12 +4,14 @@ specifiers:
   PubSubJS: ^0.0.3
   incremental-dom: ^0.7.0
   nanoid: ^3.3.1
+  nats.ws: ^1.7.2
   parcel: ^2.3.2
 
 dependencies:
   PubSubJS: 0.0.3
   incremental-dom: 0.7.0
   nanoid: 3.3.1
+  nats.ws: 1.7.2
 
 devDependencies:
   parcel: 2.3.2
@@ -705,6 +707,11 @@ packages:
     engines: {node: '>=10.13.0'}
     dev: true
 
+  /@types/node/14.18.12:
+    resolution: {integrity: sha512-q4jlIR71hUpWTnGhXWcakgkZeHa3CCjcQcnuzU8M891BAWA2jHiziiWEPEkdS5pFsz7H9HJiy8BrK7tBRNrY7A==}
+    dev: false
+    optional: true
+
   /@types/parse-json/4.0.0:
     resolution: {integrity: sha512-//oorEZjL6sbPcKUaCdIGlIUeH26mgzimjBB77G6XRgnDl/L5wOnpyBGRe/Mmf5CVW3PwEBE1NjiMZ/ssFh4wA==}
     dev: true
@@ -1197,6 +1204,22 @@ packages:
     engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1}
     hasBin: true
 
+  /nats.ws/1.7.2:
+    resolution: {integrity: sha512-joNHe8DOXrzwPA7Kk7qZug39DmFRUifRVoB1Be0w/29Xj4PnqpF9HNihid/QxwHBs/JfFbwaJGhQDRgC7z3SpQ==}
+    optionalDependencies:
+      nkeys.js: 1.0.0-9
+    dev: false
+
+  /nkeys.js/1.0.0-9:
+    resolution: {integrity: sha512-m9O0NQT+3rUe1om6MWpxV77EuHql/LdorDH+FYQkoeARcM2V0sQ89kM36fArWaHWq/25EmNmQUW0MhLTcbqW1A==}
+    engines: {node: '>=10.0.0'}
+    requiresBuild: true
+    dependencies:
+      '@types/node': 14.18.12
+      tweetnacl: 1.0.3
+    dev: false
+    optional: true
+
   /node-addon-api/3.2.1:
     resolution: {integrity: sha512-mmcei9JghVNDYydghQmeDX8KoAm0FAiYyIcUt/N4nhyAipB17pllZQDOJD2fotxABnt4Mdz+dKTO7eftLg4d0A==}
     dev: true
@@ -1718,6 +1741,11 @@ packages:
     resolution: {integrity: sha1-QFQRqOfmM5/mTbmiNN4R3DHgK9Q=}
     dev: true
 
+  /tweetnacl/1.0.3:
+    resolution: {integrity: sha512-6rt+RN7aOi1nGMyC4Xa5DdYiukl2UWCbcJft7YhxReBGQD7OAM8Pbxw6YMo4r2diNEA8FEmu32YOn9rhaiE5yw==}
+    dev: false
+    optional: true
+
   /type-fest/0.20.2:
     resolution: {integrity: sha512-Ne+eE4r0/iWnpAxD852z3A+N0Bt5RN//NjJwRd2VFHEmrywxf5vsZlh4R6lixl6B+wz/8d+maTSAkN1FIkI3LQ==}
     engines: {node: '>=10'}

frontend/src/behaviors.js

@@ -0,0 +1,44 @@
+import {pub, sub} from './pubsub.js';
+import state from './state.js';
+import redraw from './redraw.js';
+
+// "raw" event listeners, which publish meaningful events, which are listened-to further-down:
+// ...
+
+  
+// "meaningful" event listeners:
+//sub('set-current-node', (node_vm)=>{
+//  state.current_node_vm = node_vm;
+//  redraw();
+//  });
+
+// connect to NATS thru WebSockets:
+import { connect, StringCodec } from "nats.ws";
+const strcodec = StringCodec();
+const init_nats = async function(){
+  const nc = await connect({servers: "ws://localhost:4223"});
+  console.log(nc);
+  
+  (async ()=>{
+    const sub =  nc.subscribe('price');
+    for await (const msg of sub){
+      console.log(`[${sub.getProcessed()}]: ${strcodec.decode(msg.data)}`);
+      }
+    })();
+  (async ()=>{
+    const sub = nc.subscribe('close');
+    for await (const msg of sub){
+      nc.close();
+      console.log('closed!');
+      break;
+      }
+    })();
+  
+  nc.publish('price', strcodec.encode('4.23'));
+  nc.publish('price', strcodec.encode('5.00'));
+  //nc.close();
+  };
+init_nats()
+
+
+export default null;

frontend/src/index.js

@@ -2,6 +2,7 @@ import redraw from './redraw.js';
 import state from './state.js';
 import x from './behaviors.js';
 
+
 // bootstrap initial state:
 
 

frontend/src/state.js

@@ -1,3 +1,4 @@
+const someFn = null;
 const state = {
   front_months: { // front months, i.e. calendar expiry, at which the user has an opinion on where the underlying price may be
     "2022-03-11": {

src/behaviors.js

@@ -1,16 +0,0 @@
-import {pub, sub} from './pubsub.js';
-import state from './state.js';
-import redraw from './redraw.js';
-
-// "raw" event listeners, which publish meaningful events, which are listened-to further-down:
-// ...
-
-  
-// "meaningful" event listeners:
-//sub('set-current-node', (node_vm)=>{
-//  state.current_node_vm = node_vm;
-//  redraw();
-//  });
-
-
-export default null;