WebFund 2024F: Tutorial 5

From Soma-notes

In this tutorial you'll be playing with domdemo, a version of Assignment 2's dbdemo2 modified to use some client-side JavaScript.

Once you have the application up and running you should do the following tasks.

Tasks

  1. A "GET /list" works differently in domdemo versus dbdemo2. How do they differ? What is the equivalent of domdemo's list.html in dbdemo2?
  2. What is the .then at the end of list.js? What happens if you remove this line?
  3. Is there similar code to insertTableData() in dbdemo2? How and why do they differ?
  4. Change the analyze page so that it is a static HTML document that loads the data to be displayed from the server as a JSON object.
  5. *Change the add page to not reload the page when the form is submitted. Instead, it should
    • submit the form contents via fetch(),
    • hide the form fields on submit,
    • display the response, which should be a JSON object that reflects what was inserted into the database.
  6. *Add a button to the list page that, when clicked, changes the sort order of the list from alphabetical by name to reverse alphabetical by name. This button should cause the list to be sorted on the client, not the server.

Code

All code: domdemo.zip

To install, unpack, and run domdemo in the class VM: 

 wget https://homeostasis.scs.carleton.ca/~soma/webfund-2024f/code/domdemo.zip
 unzip domdemo.zip
 cd domdemo
 deno run --allow-net --allow-read --allow-write domdemo.js

domdemo.js

// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright (C) 2024 Anil Somayaji
//
// dbdemo.js
// for COMP 2406 (Fall 2024), Carleton University
// 
// Initial version: October 9, 2024
//
// run with the following command:
//    deno run --allow-net --allow-read --allow-write domdemo.js
//

import { DB } from "https://deno.land/x/sqlite/mod.ts";

const status_NOT_FOUND = 404;
const status_OK = 200;
const status_NOT_IMPLEMENTED = 501;
const appTitle = "COMP 2406 DOM Demo";
const dbFile = "people.db";
const table = "people";

const db = new DB(dbFile);

db.execute(`
  CREATE TABLE IF NOT EXISTS ${table} (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT,
    city TEXT,
    country TEXT,
    birthday TEXT,
    email TEXT
  )
`);


function addRecordDB(db, table, r) {
    return db.query(`INSERT INTO ${table} ` +
                    "(name, city, country, birthday, email) " +
                    "VALUES (?, ?, ?, ?, ?)",
                    [r.name, r.city, r.country, r.birthday, r.email]);
}


function getAllRecordsDB(db, table) {
    var state = [];
    const query =
          db.prepareQuery(
              "SELECT id, name, city, country, birthday, email FROM " +
                  table + " ORDER BY name ASC LIMIT 50");

    for (const [id, name, city, country, birthday, email] of query.iter()) {
        state.push({id, name, city, country, birthday, email});
    }

    query.finalize();
    
    return state;
}


function analyzeRecordsDB(db, table) {
    var analysis = {};

    analysis.count = db.query("SELECT COUNT(*) FROM " + table);
    analysis.cityList = db.query("SELECT DISTINCT CITY FROM " + table);
    
    return analysis;
}


function MIMEtype(filename) {

    const MIME_TYPES = {
        'css': 'text/css',
        'gif': 'image/gif',
        'htm': 'text/html',
        'html': 'text/html',
        'ico': 'image/x-icon',
        'jpeg': 'image/jpeg',
        'jpg': 'image/jpeg',
        'js': 'text/javascript',
        'json': 'application/json',
        'pdf': 'application/pdf',
        'png': 'image/png',
        'txt': 'text/text'
    };

    var extension = "";
    
    if (filename) {
        extension = filename.slice(filename.lastIndexOf('.')+1).toLowerCase();
    }

    return MIME_TYPES[extension] || "application/octet-stream";
};


function template_header(title) {
    const fullTitle = appTitle + ": " + title;
    
    return `<!DOCTYPE html>
<html>
  <head>
    <title>${fullTitle}</title>
    <link rel="stylesheet" href="/style.css">
  </head>
`
}

function template_notFound(path) {
    return template_header("Page not found") +
        `<body>
<h1>Page not found</h1>

<p>Sorry, the requested page was not found.</p>
</body>
</html>
`
}


function template_addRecord(obj) {
    return template_header("Record just added") +
        `<body>
  <body>
    <h1>Person just added</h1>
    <p>Name: ${obj.name}</p>
    <p>City: ${obj.city}</p>
    <p>Country: ${obj.country}</p>
    <p>Birthday: ${obj.birthday}</p>
    <p>Email: ${obj.email}</p>
    <form method="get" action="/">
      <button type="submit">Home</button>
    </form>
  </body>
</html>
`
}


function listRecords() {
    var state = getAllRecordsDB(db, table);
    
    var response = { contentType: "application/JSON",
                     status: status_OK,
                     contents: JSON.stringify(state),
                   };

    return response;
}


async function routeGet(req) {
    const path = new URL(req.url).pathname;
    if (path === "/list") {
        return listRecords();
    } else if (path === "/analyze") {
        return await showAnalysis();
    }  else {
        return null;
    }
}


async function addRecord(req) {
    var body = await req.formData();
    var obj = { name: body.get("name"),
                city: body.get("city"),
                country: body.get("country"),
                birthday: body.get("birthday"),
                email: body.get("email") };

    addRecordDB(db, table, obj);

    var response = { contentType: "text/html",
                     status: status_OK,
                     contents: template_addRecord(obj),
                   };

    return response;
}


async function showAnalysis() {
    var analysis = analyzeRecordsDB(db, table);
    var cityList = '<li>' + analysis.cityList.join('</li> <li>') + '</li>';
    
    var analysisBody = `  <body>
  <body>
    <h1>Database analysis</h1>
    <p># Records: ${analysis.count}</p>
    <p>Cities:
      <ol>
       ${cityList}
      </ol>
    </p>

    <form method="get" action="/">
      <button type="submit">Home</button>
    </form>
  </body>
</html>`

    var contents = template_header("Analysis") + analysisBody;

    var response = { contentType: "text/html",
                     status: status_OK,
                     contents: contents,
                   };
    
    return response;
}


async function routePost(req) {
    const path = new URL(req.url).pathname;    

    if (path === "/add") {
        return await addRecord(req);
    } else {
        return null;
    }
}


async function route(req) {

    if (req.method === "GET") {
        return await routeGet(req);
    } else if (req.method === "POST") {
        return await routePost(req);
    } else {
        return {
            contents: "Method not implemented.",
            status: status_NOT_IMPLEMENTED,
            contentType: "text/plain"
        };
    }
}


async function fileData(path) {
    var contents, status, contentType;
    
    try {
        contents = await Deno.readFile("./static" + path);
        status = status_OK;
        contentType = MIMEtype(path);
    } catch (e) {
        contents = template_notFound(path);
        status = status_NOT_FOUND;
        contentType = "text/html";
    }
    
    return { contents, status, contentType };
}


async function handler(req) {

    var origpath = new URL(req.url).pathname;
    var path = origpath;
    var r =  await route(req);
    
    if (!r) {
        if (path === "/") {
            path = "/index.html";
        }
        r = await fileData(path);
    }

    console.log(`${r.status} ${req.method} ${r.contentType} ${origpath}`); 

    return new Response(r.contents,
                        {status: r.status,
                         headers: {
                             "content-type": r.contentType,
                         }});
}


const ac = new AbortController();

const server = Deno.serve(
    {
        signal: ac.signal,
        port: 8000,
        hostname: "0.0.0.0"
    },
    handler);

Deno.addSignalListener("SIGINT", () => {
    console.log("SIGINT received, terminating...");
    ac.abort();
});

server.finished.then(() => {
    console.log("Server terminating, closing database.")
    db.close();
});

static/index.html

<!DOCTYPE html>
<html>
  <head>
    <title>COMP 2406 DOM Demo</title>
    <link rel="stylesheet" href="/style.css">
  </head>
  <body>
    <h1>COMP 2406 DOM Demo</h1>

    <p>Please select what you would like to do:
      <ol>
        <li><a href="/add.html">Add a record.</a></li>
        <li><a href="/list.html">List records.</a></li>
        <li><a href="/analyze">Analyze records.</a></li>        
      </ol>
      </p>
  </body>
</html>

static/add.html

<!DOCTYPE html>
<html>
  <head>
    <title>COMP 2406 DOM Demo: Add Record</title>
    <link rel="stylesheet" href="/style.css">
  </head>
  <body>
    <h1>Add Record</h1>
    <div>
      <p>Fill out the info for the person to be added:</p>
      <form method="post" action="/add">
        <div>
          <input id="name" type="text" name="name">
          <label>Name</label>
        </div>
        <div>
          <input id="city" type="text" name="city">
          <label>City</label>
        </div>
        <div>
          <input id="country" type="text" name="country">
          <label>Country</label>
        </div>
        <div>
          <input id="birthday" type="text" name="birthday">
          <label>Birthday</label>
        </div>
        <div>
          <input id="email" type="text" name="email">
          <label>Email</label>
        </div>
        <button type="submit">Submit</button>
      </form>
    </div>
  </body>
</html>

static/list.html

<!DOCTYPE html>
<html>
  <head>
    <title>COMP 2406 DOM Demo: List of Records</title>
    <link rel="stylesheet" href="/style.css">
    <script src="/list.js" defer></script>
  </head>
  <body>
    <h1>People Listing</h1>
    <div>
      <div></div>
      <table>
        <thead>
          <th>Name</th>
          <th>City</th>
          <th>Country</th>
          <th>Birthday</th>
          <th>Email</th>
        </thead>
        <tbody id="table"/>
      </table>
    </div>
    <form method="get" action="/">
      <button type="submit">Home</button>
    </form>
  </body>
</html>

static/list.js

// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright (C) 2024 Anil Somayaji
//
// list.js, part of domdemo
// for COMP 2406 (Fall 2024), Carleton University
// 
// Initial version: October 9, 2024
//

function insertTableData(tableData) {
    var t = document.querySelector("#table");
    var row = [];
   
    function rowMarkup(s) {
        return "<td>" + s + "</td>";
    }

    for (let r of tableData) {
        row.push("<tr>")
        row.push(rowMarkup(r.name));
        row.push(rowMarkup(r.city));
        row.push(rowMarkup(r.country));
        row.push(rowMarkup(r.birthday));
        row.push(rowMarkup(r.email));
        row.push("</tr>")
    }

    t.innerHTML = row.join("\n");
}


async function updateTable() {
    console.log("Updating Table...");
    
    try {
        const response = await fetch("/list");
        if (response.ok) {
            const tableData = await response.json();
            insertTableData(tableData);
        } else {
            console.error("Table loading error response: " + response.status);
        }
    } catch (error) {
        console.error("Table loading fetch error: " + error.message);
    }
}

updateTable().then(() => {console.log("Table updated!");});

static/style.css

body {
  padding: 50px;
  font: 14px "Lucida Grande", Helvetica, Arial, sans-serif;
}

a {
  color: #00B7FF;
}
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