Added streams examples

chapter03/src/process_request.js

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+/* @flow */
+"use strict";
+
+const url = require("url");
+const querystring = require("querystring");
+const http = require("http");
+
+function processRequest(req, res, body) {
+    /*
+        Get parameters, both from the URL and the request body
+    */
+    const urlObj = url.parse(req.url, true);
+    const urlParams = urlObj.query;
+    const bodyParams = querystring.parse(body);
+
+    console.log("URL OBJECT", urlObj);
+    console.log("URL PARAMETERS", urlParams);
+    console.log("BODY PARAMETERS", bodyParams);
+
+    /*
+        Here you would analyze the URL to decide what is required
+        Then you would do whatever is needed to fulfill the request
+        Finally, when everything was ready, results would be sent
+        In our case, we just send a FINISHED message
+    */
+
+    res.writeHead(200, "OK");
+    res.end(`FINISHED WITH THE ${req.method} REQUEST`);
+}
+
+/*
+    Minimal care for exceptions...
+*/
+process.on("uncaughtException", function(err) {
+    console.error("UNCAUGHT EXCEPTION...");
+    console.error(err);
+    console.error(err.stack);
+});
+
+http
+    .createServer((req, res) => {
+        //  For PUT/POST methods, wait until the
+        //  complete request body has been read.
+        if (req.method === "POST" || req.method === "PUT") {
+            let body = "";
+
+            req.on("data", data => {
+                body += data;
+            });
+
+            req.on("end", () => processRequest(req, res, body));
+        } else {
+            return processRequest(req, res, "");
+        }
+    })
+    .listen(8080, "localhost");

chapter03/src/zip_files.js

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+/* @flow */
+"use strict";
+
+const zlib = require("zlib");
+const fs = require("fs");
+
+const inputStream = fs.createReadStream(
+    "/home/fkereki/Documents/CHURCHES - Digital Taxonomy.pdf"
+);
+
+const gzipStream = zlib.createGzip();
+
+const outputStream = fs.createWriteStream(
+    "/home/fkereki/Documents/CHURCHES.gz"
+);
+
+inputStream.pipe(gzipStream).pipe(outputStream);

chapter03/src/zip_send.js

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+/* @flow */
+"use strict";
+
+const http = require("http");
+const zlib = require("zlib");
+const fs = require("fs");
+
+http
+    .createServer(function(request, response) {
+        // Tell the client, this is a zip file.
+        response.writeHead(200, {
+            "Content-Type": "application/zip",
+            "Content-disposition": "attachment; filename=churches.gz"
+        });
+
+        const inputStream = fs.createReadStream(
+            "/home/fkereki/Documents/CHURCHES - Digital Taxonomy.pdf"
+        );
+
+        const gzipStream = zlib.createGzip();
+
+        inputStream.pipe(gzipStream).pipe(response);
+    })
+    .listen(8080, "localhost");