Sascha Schulz
2024-07-26 8661e4358cd8a40e94c39f40b6147a5f37a7c7d3
Merge branch 'draft'
1 Dateien geändert
2 Dateien hinzugefügt
343 ■■■■■ Geänderte Dateien
assets/drawio/node-js.drawio 1 ●●●● Patch | Ansicht | Raw | Blame | Historie
assets/images/node-js.svg 3 ●●●●● Patch | Ansicht | Raw | Blame | Historie
index.html 339 ●●●●● Patch | Ansicht | Raw | Blame | Historie
assets/drawio/node-js.drawio
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assets/images/node-js.svg
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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
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index.html
@@ -36,9 +36,16 @@
                        <ul>
                            <li>JavaScript</li>
                            <li>Responsive Design</li>
                            <li>NodeJS</li>
                            <li>WebComponents / lit</li>
                            <li>NodeJS</li>
                            <li>Datenbank</li>
                        </ul>
                    </section>
                    <section>
                        <h3>Betrieb</h3>
                        <ul>
                            <li>Server einrichten</li>
                            <li>SSL- / TLS-Zertifikate</li>
                        </ul>
                    </section>
                    <section>
@@ -66,13 +73,6 @@
                            <li>Progressive Web Application</li>
                            <li>CEF / Electron</li>
                            <li>WebAssembly</li>
                        </ul>
                    </section>
                    <section>
                        <h3>Betrieb</h3>
                        <ul>
                            <li>Server einrichten</li>
                            <li>SSL- / TLS-Zertifikate</li>
                        </ul>
                    </section>
                    <section>
@@ -3916,7 +3916,328 @@
                    </section>
                    <section>
                        <h3>Aufgabe</h3>
                        <p>Entwickle eine Tab-Komponente (Vorlage "tab-componenmt.html"), welche beim Click auf einen Registerreite / Tab ein Event feurt, welches die Außenwelt über das gerade aktivierte Tab (tab-id) informiert</p>
                        <p>Entwickle eine Tab-Komponente (Vorlage "tab-componenmt.html"), welche beim Click auf einen Registerreite / Tab ein Event feuert, welches die Außenwelt über das gerade aktivierte Tab (tab-id) informiert</p>
                    </section>
                    <section>
                        <h3>Lösung</h3>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                this.root.innerHTML = `
                                    &lt;style>
                                        ::slotted(div) {
                                            display: none;
                                        }
                                        ::slotted(div.active) {
                                            display: block;
                                        }
                                    &lt;/style>
                                    &lt;div>&lt;slot name="tab">&lt;/slot>&lt;/div>
                                    &lt;div>&lt;slot name="content">&lt;/slot>&lt;/div>
                                `;
                            </code>
                        </pre>
                    </section>
                    <section>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                connectedCallback() {
                                    const firstContent = this.querySelector("div");
                                    firstContent.classList.add("active");
                                    this.addEventListener("click", (e) => {
                                        if (e.target.tagName === "SPAN" && e.target.hasAttribute("tab-id")) {
                                            const oldContent = this.querySelector("div.active");
                                            const newContent = this.querySelector(`[tab-id="${e.target.getAttribute("tab-id")}"]`);
                                            oldContent.classList.remove("active");
                                            newContent.classList.add("active");
                                            this.dispatchEvent(new CustomEvent("tabclick", {composed: true, bubbles: true, detail: e.target.getAttribute("tab-id"), cancelable: true}));
                                        }
                                    });
                                }
                            </code>
                        </pre>
                    </section>
                </section>
                <section>
                    <section>
                        <h2>NodeJS</h2>
                    </section>
                    <section>
                        <h3>Was ist NodeJS?</h3>
                        <ul>
                            <li class="fragment">"JavaScript auf dem Server"</li>
                            <li class="fragment">basiert auf der V8-Engine von Google</li>
                            <li class="fragment">Laufzeitumgebung für JavaScript mit eigener API</li>
                        </ul>
                    </section>
                    <section>
                        <img data-src="/assets/images/node-js.svg">
                    </section>
                    <section>
                        <h3>Überblick über die Node-API</h3>
                        <p>Die API ist in viele verschiedene Module aufgeteilt</p>
                        <table>
                            <tr><td>fs</td><td>Dateisystem</td></tr>
                            <tr><td>crypto</td><td>Kryptografie</td></tr>
                            <tr><td>zlib</td><td>Datenkompression</td></tr>
                            <tr><td>http</td><td>Webserver</td></tr>
                            <tr><td>net</td><td>Netzwerk (TCP)</td></tr>
                            <tr><td>tls</td><td>Verschlüsseltes Netzwerk (TCP)</td></tr>
                        </table>
                    </section>
                    <section>
                        <p>Aufruf eines Programmes in der Kommandozeile</p>
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                node [Node-Parameter] path/to/script.js [Anwendungsparameter]
                            </code>
                        </pre>
                        <p>z.B.</p>
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                node --inspect index.js --port 3000
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Einbinden von Modulen</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                const fs = require("fs");
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Aufbau eines Moduls</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                module.exports = {
                                    foo: 5,
                                    sayHello: function(name) {
                                        return "Hello " + name + "!";
                                    }
                                }
                            </code>
                        </pre>
                        <p>oder</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                exports.foo = 5;
                                exports.sayHello = function(name) {
                                    return "Hello " + name + "!";
                                };
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Aufgabe</p>
                        <p>Schreibe ein Modul, welches eine <code>Square</code>-Klasse zur Verfügung stellt, mit welchem man den Umfang und den Flächeninhalt eines Rechtecks berechnen kann:</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                const Square = require("./square");
                                const square = new Square(2, 3);
                                console.log(square.getArea()); // => 6
                                console.log(square.getPerimeter()); // => 10
                            </code>
                        </pre>
                    </section>
                    <section>
                        <h3>Module für die Kommandozeile</h3>
                        <p>package.json</p>
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                npm init -y
                            </code>
                        </pre>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                {
                                    ...
                                    "bin": {
                                        "my-command": "./index.js"
                                    }
                                }
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>index.js</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                #! /usr/bin/env node
                                console.log("Hello world from the command line!");
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Installation</p>
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                npm install -g path/to/project
                            </code>
                        </pre>
                        z.B.
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                npm install -g .
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Ausführung</p>
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                my-command
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Kommandozeilenparameter</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                console.log(process.argv);
                            </code>
                        </pre>
                        <p>angelehnt an die Parameter aus der Programmiersprache <code>c</code>:</p>
                        <pre>
                            <code class="c" data-trim data-line-numbers>
                                int main(int argc, char *argv[])
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Aufgabe</p>
                        <p>Mache das vorherige Programm für die Konsole aufrufbar, sodass die Länge und Breite für das Rechteck per Konsolenargumente übergeben werden können und der Flächeninhalt ausgegeben wird:</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                my-command 2 3
                            </code>
                        </pre>
                    </section>
                    <section>
                        <h3>Buffer</h3>
                        <p>Array-artige Struktur für rohe Bytes</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                const b1 = Buffer.from("abc"); // bevorzugt
                                const b2 = Buffer.alloc(100, 0); // Länge mit initialen Daten
                                const b3 = Buffer.allocUnsafe(100); // Länge ohne initiale Daten
                                const b4 = new Buffer("abc"); //  offiziell nicht empfohlen
                                console.log(b1); // => &lt;Buffer 61 62 63>
                                console.log(b1.toString("hex")); // => "616263"
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Mit Buffern arbeiten:</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                const a = Buffer.from("a") + Buffer.from("b");
                                const b = Buffer.concat([Buffer.from("a"), Buffer.from([98])]);
                                const c = b.toString()
                                console.log(a); // => ab
                                console.log(b); // => &lt;Buffer 61 62>
                                console.log(c); // => ab
                                for (const byte of a) {
                                    console.log(byte); // => 97 98
                                }
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Aufgabe</p>
                        <p>Implementiere eine XOR-Verschlüsselung (<code>^</code>-Operator), sodass jedes Byte einer Original-Nachricht der Reihe nach mit dem entsprechenden Byte eines Schlüsselwortes verschlüsselt wird und gebe die verschlüsselte Nachricht als Text aus.</p>
                    </section>
                    <section>
                        <p>Aufgabe</p>
                        <p>Implementiere zur vorherigen Verschlüsselung eine Entschlüsselung.</p>
                    </section>
                    <section>
                        <p>Lösung</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                const word = Buffer.from("abcdef");
                                const key = Buffer.from("xyz");
                                const encrypted = Buffer.alloc(word.length, 0);
                                // encrypt
                                for (let i = 0; i &lt; word.length; i++) {
                                    encrypted[i] = word[i] ^ key[i % key.length];
                                }
                                // decrypt
                                for (let i = 0; i &lt; word.length; i++) {
                                    word[i] = encrypted[i] ^ key[i % key.length];
                                }
                                console.log(word.toString()); // => "abcdef"
                            </code>
                        </pre>
                    </section>
                    <section>
                        <h3>Streams</h3>
                        <p>Konstanter Fluss von (meist) großen Datenmengen in kleinen Paketen</p>
                    </section>
                    <section>
                        <p>Gängige Typen von Streams</p>
                        <ul>
                            <li>Standard In / Out</li>
                            <li>HTTP-Requests / -Responses</li>
                            <li>TCP-Sockets</li>
                            <li>Lese- und Schreib-Streams auf Dateien</li>
                            <li>Große Datenbank-Ergebnisse mittels Cursor</li>
                        </ul>
                    </section>
                    <section>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                const readableStream = fs.createReadStream("./source.txt");
                                const writableStream = fs.createWriteStream("./target.txt");
                                readableStream.on("data", (data /* Buffer */) =&gt; {
                                    // process data here
                                    writableStream.write(data)
                                });
                                readableStream.on("end", (data) =&gt; {
                                    // stream has finished, e.g. EOF (end of file)
                                });
                                // alternatively pipe content
                                readableStream.pipe(writableStream);
                            </code>
                        </pre>
                    </section>
                    <section>
                        <p>Aufgabe</p>
                        <p>Lese eine beliebige Datei als Readable Stream, verschlüssele den Inhalt mit der XOR-Methode und schreibe die verschlüsselten Bytes in eine Zieldatei</p>
                    </section>
                    <section>
                        <p>Aufgabe</p>
                        <p>Ändere das Programm, sodass auf Konsolenebene ein Pipe (|) ermöglicht wird:</p>
                        <pre>
                            <code class="bash" data-trim data-line-numbers>
                                echo "Hello World!" | node index.js
                            </code>
                        </pre>
                        <p>Nutze dafür die implizit vorhandenen Streams von Standard In / Out:</p>
                        <pre>
                            <code class="js" data-trim data-line-numbers>
                                process.stdin; // Readable Stream
                                process.stdout; // Writable Stream
                            </code>
                        </pre>
                    </section>
                </section>
            </div>