closes #83

Author: sevenbitbyte

package.json

@@ -85,6 +85,7 @@
     "last-eventemitter": "^1.1.1",
     "lodash": "^4.17.21",
     "lokijs": "1.5.6",
+    "mdns": "^2.7.2",
     "mkdirp": "^0.5.1",
     "moment": "^2.29.4",
     "morgan": "^1.10.0",

src/service/service-host.js

@@ -1,12 +1,14 @@
 const CORS = require('cors')
 const {URL} = require('url')
+const mdns = require('mdns')
 const http = require('http')
 const https = require('https')
 const morgan = require('morgan')
 const express = require('express')
 const bodyParser = require('body-parser')
 const expressListRoutes = require('express-list-routes')
 const debug = require('debug')('dataparty.service.host')
+const objectHasher = require('node-object-hash').hasher()
 
 const reach = require('../utils/reach')
 
@@ -24,17 +26,18 @@ class ServiceHost {
    * @class module:Service.ServiceHost
    * @link module:Service
    * @param {Object}  options.cors            Cors to be passed to express via the `cors` package
-   * @param {boolean} options.trust_proxy     When true, the server will parse forwarding headers. This should be set when running behind a load-balancer for accurate error messages and logging
-   * @param {string}  options.listenUri       The uri of the host interface to tell express to listen on. Defaults to `http://0.0.0.0:4001
-   * @param {boolean} options.i2pEnabled      When true, this server will be available over i2p
-   * @param {string}  options.i2pSamHost      The hostname of the i2p SAM control API. Defaults to `127.0.0.1`
-   * @param {Integer} options.i2pSamPort      The port of the i2p SAM control API. Defaults to `7656`
-   * @param {string}  options.i2pForwardHost  Override i2p forward host. This defaults to `localhost` and typically doesn't need to be changed
+   * @param {boolean} [options.trust_proxy=false]     When true, the server will parse forwarding headers. This should be set when running behind a load-balancer for accurate error messages and logging
+   * @param {string}  [options.listenUri=http://0.0.0.0:4000]       The uri of the host interface to tell express to listen on. Defaults to `http://0.0.0.0:4001
+   * @param {boolean} [options.i2pEnabled=false]      When true, this server will be available over i2p
+   * @param {string}  [options.i2pSamHost=127.0.0.1]      The hostname of the i2p SAM control API. Defaults to `127.0.0.1`
+   * @param {Integer} [options.i2pSamPort=7656]      The port of the i2p SAM control API. Defaults to `7656`
+   * @param {string}  [options.i2pForwardHost=localhost]  Override i2p forward host. This defaults to `localhost` and typically doesn't need to be changed
    * @param {Integer} options.i2pForwardPort  Override i2p forward post. This defaults to the port supplied in `options.listenUri`.
    * @param {string}  options.i2pKey          When set this i2p key will be used to host the service. If not set a new i2p key will be generated. Defaults to `null`
-   * @param {boolean} options.wsEnabled       When true the server will host a dataparty websocket service. Defaults to `true`
+   * @param {boolean} [options.wsEnabled=true]       When true the server will host a dataparty websocket service. Defaults to `true`
    * @param {Integer} options.wsPort          Port for the websocket service to listen on. Defaults to `null`, using the same port as the http server.
-   * @param {string}  options.wsUpgradePath   The path within the http server to host an upgradeable websocket. Defaults to `/ws`
+   * @param {string}  [options.wsUpgradePath=/ws]   The path within the http server to host an upgradeable websocket. Defaults to `/ws`
+   * @param {boolean} [options.mdnsEnabled=true]     When true, the server will publish mDNS records advertising the service and party identity
    * @param {module:Service.ServiceRunner}  options.runner  A pre-configured runner
    */
 
@@ -51,6 +54,7 @@ class ServiceHost {
     wsEnabled = true,
     wsPort = null,
     wsUpgradePath = '/ws',
+    mdnsEnabled = true,
     runner
   }={}){
 
@@ -121,6 +125,8 @@ class ServiceHost {
       }
     }
 
+    this.mdnsEnabled = mdnsEnabled
+
     this.started = false
   }
 
@@ -221,6 +227,40 @@ class ServiceHost {
       debug('\t', 'address', this.i2pUri)
       debug('\t', 'key', this.i2p.getPublicKey())
     }
+
+    if(this.mdnsEnabled && this.apiServer && this.apiServerUri.protocol != 'file:'){
+
+      let servicePkg = null
+      let partyIdentity = null
+      const routerClass = this.runner.constructor.name
+
+      switch(routerClass){
+        case 'ServiceRunner':
+        case 'ServiceRunnerNode':
+          partyIdentity = this.runner.party.identity
+          servicePkg = this.runner.service.compiled.package
+          break
+        case 'RunnerRouter':
+          partyIdentity = this.runner.defaultRunner.party.identity
+          servicePkg = this.runner.defaultRunner.service.compiled.package
+          break
+      }
+
+
+      const idHash = objectHasher.hash(
+        partyIdentity.toJSON()
+      )
+
+      
+      const txt_record = {
+        partyhash: idHash,
+        pkgname: servicePkg.name
+      }
+      
+      console.log('mdns', servicePkg.name, idHash)
+      this.mdnsAd = mdns.createAdvertisement(mdns.tcp('party'), parseInt(listenPort), {txtRecord: txt_record})
+    }
+
   }
 
   /**