Coast Walker

README.txt

Coast Walker for use in Island Game
Ken Webb
Novemeber 13, 2021

cd ~/nodespace
mkdir expressCWalker
cd expressCWalker
npm init
  "main": "app.js",
npm install express --save
npm install cors
 - add JS content to app.js
node app.js

app.js

/**
Ken Webb
Learning Express.
November 13, 2021
Coast Walker or Coast Swimmer

see Xholon workbook: Express - web framework for node
3ede7991936fe5281657c494f8a92caf

(base) ken@ken-HP-ZBook-15-G2:~/nodespace/expressCWalker$ node app.js
Express+CoastWalker app listening at http://localhost:3000
NODE_ENV: undefined

see also: ~/gwtspace/Xholon/Xholon/module/ava2srvr/mCoastWalker.xml moduleAvatar2Server.xml etc.

Performance
-----------
see: https://expressjs.com/en/advanced/best-practice-performance.html
To set NODE_ENV to “production”, enter this command in the Linux/Ubuntu terminal window, before running node:
export NODE_ENV=production
This is temporary, and is only active for that terminal window.
 */

const express = require('express')
const cors = require('cors')
const {ftest, nesw, bchcmr, walk, swim} = require('./functions') // Procedural Memory
const {stest} = require('./storage') // Declarative Memory
const app = express()
const port = 3000

// enable CORS for all origins 
app.use(cors());

app.use(express.json()) // for parsing application/json

app.get('/', (req, res) => {
  res.send('Hello Coast Walker!')
})

// KSW test
app.get('/test1', (req, res) => {
  res.send('Testing CWalker 1.')
})

// KSW test
app.get('/test2', (req, res) => {
  res.send('Testing CWalker 2.')
})

app.get('/test2/:one', (req, res) => {
  res.send('Testing CWalker 3: ' + req.params.one)
})

app.get('/add/:one/:two', (req, res) => {
  res.send(`${req.params.one} + ${req.params.two} = ` + (0 + Number(req.params.one) + Number(req.params.two)))
})

/**
 * Walk.
 * @param {Request} req A Perception or similar Request.
 * @param {Response} res A Motor command or similar Response.
 */
app.post('/walk', (req, res) => {
  res.send("" + walk(req.body))
})

/**
 * Swim.
 * @param {Request} req A Perception or similar Request.
 * @param {Response} res A Motor command or similar Response.
 */
app.post('/swim', (req, res) => {
  res.send("" + swim(req.body))
})

/**
 * Test Walk
 * http://localhost:3000/testwalk
 */
app.get('/testwalk', (req, res) => {
  res.send("" + walk({ me: 'CoastCell', neighborhood: { n: 'CoastCell', e: 'LandCell', s: 'CoastCell', w: 'OceanCell' }, heading: 'n' }))
})

/**
 * Test Swim
 * http://localhost:3000/testswim
 */
app.get('/testswim', (req, res) => {
  res.send("" + swim({ me: 'CoastCell', neighborhood: { n: 'CoastCell', e: 'LandCell', s: 'CoastCell', w: 'OceanCell' }, heading: 'n' }))
})

app.listen(port, () => {
  console.log(`Express+CoastWalker app listening at http://localhost:${port}`)
  console.log("NODE_ENV: " + process.env.NODE_ENV)
})

functions.js

/**
Ken Webb
November 13, 2021
functions.js

Functions for use with app.js
Procedural Long-term Memory
 */

const ftest = () => "Hello Coasties from FTest!"

/**
 * Various functions that generate random integers within specified ranges.
 */
const random = max => () => Math.floor(Math.random() * max)
const random2 = random(2)

/**
 * Process a NESW JavaScript Object.
 * @param {Object} obj ex: { me: 'LandCell', n: 'CoastCell', e: 'LandCell', s: 'LandCell', w: 'LandCell' }
 * @return {Number} A direction to move to a random neighboring non-OceanCell gridCell.
 */
const nesw = obj => {
  const neswArr = Object.entries(obj).reduce((prev, curr) => {
    if ((curr[0] !== "me") && (curr[1] !== "OceanCell")) {
      prev.push(curr[0])
    }
    return prev
  }, [])
  const moveto = neswArr[random(neswArr.length)()]
  const movetoNum = moveto === "n" ? 0
    : moveto === "e" ? 1
    : moveto === "s" ? 2
    : 3
  //console.log(obj, neswArr, moveto, movetoNum)
  return movetoNum
}

/**
 * Process a Beach Comber JavaScript Object.
 * @param {Object} obj ex: { me: 'CoastCell', n: 'CoastCell', e: 'LandCell', s: 'CoastCell', w: 'OceanCell' }
 * @return {Number} A direction to move to a random neighboring CoastCell gridCell.
 */
const bchcmr = obj => {
  const arr = Object.entries(obj).reduce((prev, curr) => {
    if ((curr[0] !== "me") && (curr[1] === "CoastCell")) {
      prev.push(curr[0])
    }
    return prev
  }, [])
  const moveto = arr[random(arr.length)()]
  const movetoNum = moveto === "n" ? 0
    : moveto === "e" ? 1
    : moveto === "s" ? 2
    : 3
  //console.log(obj, arr, moveto, movetoNum)
  return movetoNum
}

/**
 * Return a left or right direction, chosen randomly if they both match.
 * @param {String} lcell Left Cell, with possible values: "CoastCell"|"LandCell"|"OceanCell"
 * @param {String} rcell Right Cell with possible values: "CoastCell"|"LandCell"|"OceanCell"
 * @param {String} ldir Left Direction
 * @param {String} rdir Right Direction
 * @param {String} searchstr Search String, either of "CoastCell"|"LandCell"
 * @return {String} ldir or rdir
 */
const leftright = (lcell, rcell, ldir, rdir, searchstr) => 
  lcell === searchstr && rcell !== searchstr ? ldir
  : rcell === searchstr && lcell !== searchstr ? rdir
  : [ldir, rdir][random2()]

/**
 * Process a Coast Walker JavaScript Object.
 * @param {Object} obj ex: { me: 'CoastCell', neighborhood: { n: 'CoastCell', e: 'LandCell', s: 'CoastCell', w: 'OceanCell' }, heading: 'n' }
 * @param {String} adjacentCell The adjacent type of cell that the Avatar might move into if it can't move to a CoastCell. "LandCell" | "OceanCell"
 * @return {Number} A direction to move to a random neighboring CoastCell gridCell.
 */
const travel = (obj, adjacentCell) => {
  //console.log("traveling");
  //console.log(obj);
  //console.log(adjacentCell);
  // heading direction
  const hdir = obj.heading
  // left direction
  const ldir = hdir === "n" ? "w"
    : hdir === "e" ? "n"
    : hdir === "s" ? "e"
    : "s"
  // rigt direction
  const rdir = hdir === "n" ? "e"
    : hdir === "e" ? "s"
    : hdir === "s" ? "w"
    : "n"
  // back direction
  const bdir = hdir === "n" ? "s"
    : hdir === "e" ? "w"
    : hdir === "s" ? "n"
    : "e"
  
  const hood = obj.neighborhood
  const hcell = hood[hdir]
  const lcell = hood[ldir]
  const rcell = hood[rdir]
  //console.log(hood + " " + hcell + " " + lcell + " " + rcell)
  
  const moveto = hcell === "CoastCell" ? hdir
    : lcell === "CoastCell" || rcell === "CoastCell" ? leftright(lcell, rcell, ldir, rdir, "CoastCell")
    : hcell === adjacentCell ? hdir
    : lcell === adjacentCell || rcell === adjacentCell ? leftright(lcell, rcell, ldir, rdir, adjacentCell)
    : bdir
  
  // TODO can I just return a String "n" "e" "s" "w" instead of a number 0 1 2 3 ?
  const movetoNum = moveto === "n" ? 0
    : moveto === "e" ? 1
    : moveto === "s" ? 2
    : 3
  return movetoNum
}

const walk = obj => travel(obj, "LandCell")

const swim = obj => travel(obj, "OceanCell")

module.exports = {ftest, nesw, bchcmr, walk, swim};

mCoastWalker.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
Xholon Avatar that walks or swims along the Coast within the Island Game world,
always moving in a consistent direction,
so that eventually it should return to its starting point.
Ken Webb
November 13, 2021
~/gwtspace/Xholon/Xholon/module/ava2srv/mCoastWalker.xml
based on mAva2SrvPostNesw.xml and mBeachComber.xml
See Xholon workbook: Express - web framework for node
Copy and paste, or drag, this entire text into a running Xholon app.
November 14, 2021
Added a check for network errors, and set a timer for recovery if there is a network error.
 - for example, if I stop and later restart the node server.
-->
<XholonModule>
  <XholonMap>
  
    <Attribute_String roleName="ih"><![CDATA[
<_-.XholonClass>
  <CoastWalker superClass="Avatar"/>
  <Talk2ServerCW superClass="Script"/>
</_-.XholonClass>
    ]]></Attribute_String>
    
    <Attribute_String roleName="cd"><![CDATA[
<xholonClassDetails>
  <CoastWalker><Color>magenta</Color></CoastWalker>
  
  <Talk2ServerCW><DefaultContent>
const REQ_REMOTE = true;
const SIGNAL_TIMEOUT = -1; // see xholon base/ISignal.java
var me, ava, request, headingArr, jstimeout, beh = {
postConfigure: function() {
  me = this.cnode;
  ava = me.parent().parent();
  if (!ava["subtrees"]) {
    ava.action("param subtrees true");
  }
  ava.action("param transcript false");
  const url = [`http://127.0.0.1:3000/${ava.travel}`, `http://192.168.0.39:3000/${ava.travel}`, `http://192.168.1.10:3000/${ava.travel}`];
  request = new Request(url[0]);
  headingArr = ["n", "e", "s", "w"];
  jstimeout = null;
  me.msg(101, "0");
  //console.log(ava.unveil);
  //console.log(ava.travel);
},
processReceivedMessage(msg) {
  this.doRequest(this.prepData(ava.parent(), msg.data));
},
prepData: function(pava, heading) {
  // { me: 'CoastCell', neighborhood: { n: 'CoastCell', e: 'LandCell', s: 'CoastCell', w: 'OceanCell' }, heading: 'n' }
  return {
    me: pava.xhc().name(),
    neighborhood: {
      n: pava.port(0).xhc().name(),
      e: pava.port(1).xhc().name(),
      s: pava.port(2).xhc().name(),
      w: pava.port(3).xhc().name()
    },
    //heading: heading // TODO this should be the current heading (=== direction of Avatar's last movement)
    heading: headingArr[heading]
  }
},
doRequest: function(jso) {
  if (REQ_REMOTE) {
    this.doRequestRemote(jso);
  }
  else {
    this.doRequestLocal(jso);
  }
},
doRequestRemote: function(jso) {
  fetch(request, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(jso)
  })
  .then((res) => {
    if (!res.ok) {
      throw new Error('Network response was not OK');
    }
    return res.text();
  })
  .then((responseText) => { // responseText is a Number without quotes, for example: 1
    this.moveto(responseText);
    me.msg(101, responseText);
    return null;
  })
  .catch(error => {
    console.error('There has been a problem with your fetch operation:', error);
    jstimeout = setTimeout(() => {
      console.log("timeout has expired");
      me.msg(SIGNAL_TIMEOUT, "0");
    }, 10*1000);
  })
},
doRequestLocal: function(obj) {
  // TODO this should be the same code used in the Server functions.js
},
moveto: function(direction) {
  ava.action("go " + direction); // go 0|1|2|3  OK
  if (ava.unveil === "true") {
    ava.parent().incognita = null;
  }
}
}
//# sourceURL=Talk2ServerCWbehavior.js
  </DefaultContent></Talk2ServerCW>
  
</xholonClassDetails>
    ]]></Attribute_String>
    
    <Attribute_String roleName="csh"><![CDATA[
<_-.csh>
  <!-- I can create additional instances of CoastWalker, by dragging in just the following subtree -->
  <CoastWalker unveil="true" travel="walk"> <!-- walk|swim -->
    <BehaviorsST>
      <Talk2ServerCW/>
    </BehaviorsST>
  </CoastWalker>
</_-.csh>
    ]]></Attribute_String>
    
  </XholonMap>
</XholonModule>

storage.js

/**
Ken Webb
November 13, 2021
storage.js

Storage for use with app.js
Declarative Long-term Memory

I'm not sure if this will be needed with Coast Walker.
 */

const stest = () => "Hello from Coast Walker STest!"

// storage, database
let sensorVal = 0

//const setVal = val => sensorVal = val

//const getVal = () => sensorVal

module.exports = {stest}; //, setVal, getVal};