Add working sniffer.js (#8)

* port sniffer completed

* implemented suggested improvements adn added function import

* linter installed

* Port-sniffer task completed

* new suggestions implemented

* Review changes

* Block deletion

* airbnb linter applied

* some more linting problems resolved

* eslint fix

* Revert "eslint fix"

This reverts commit 76e891a.

* resolved conflicts

* data structures task completed

* comment explaining api added to main.js

* moved responses to separate functions

* make get request react only on list

* Add working sniffer.js

* moved parsing json request to separate function

* bug in linked list isert corrected

* Review change

* some corrections

* some more corrections

* review sniffer v 2.0

* remove ionide folder

* Monorepo chores (#19)

* chores: Add subprojects CI build checks support

* chores: Add a note on yarn for consistency

* chores: Add .editorconfig to enforce UNIX style LF and end-of-file newline

* chores: Add pull request template

* submissions/Zakkarat/port-sniffer: Fix code style

* Add eslint disable rule
* Fix newline

* submissions/eneoff/data_structures: Fix CRLF (#23)

* Update README.md (#25)

* restructured instructions so that student makes any file operations when in a feature branch context to avoid commits to `master` before student reads instructions on pull request initialization
* added instructions on PR updates

* Port sniffer (#11)

* Add port-sniffer homework

* Add code after prettier and eslint check

* Fix eslint errors

* Add dependencies: commander, async

* Fixes respectively to PR 'Port sniffer' #11,

#11

* Delete dependencies from package.json

* Add all package-lock.jsons into .gitignore

* Add .gitignore in port-sniffer subdirectory

* Remove global package-lock.json

* Resolve integration with CI manager

* kissik/port-sniffer: integrate project into root package

* chores: make eslint ignoring nested node_modules

* change eslint+airbnb to semistandard (#24)

* change eslint+airbnb to semistandard

* fix linting errors

* submissions/kissik/port-sniffer: Fix linting errors

* Add working sniffer.js

* Review change

* review sniffer v 2.0

* change eslint and fix bug

Author: Siusarna

submissions/Siusarna/port-sniffer/sniffer.js

@@ -0,0 +1,134 @@
+const net = require('net');
+const dns = require('dns').promises;
+
+const args = process.argv;
+const help = `
+  Simple port sniffer
+This script takes 2 parameters:
+
+    --host     obligatory parameter which defines the host address for a port scan.
+               Address must be specified after the parameter.
+               It can be specified as IP address or URL.
+
+    --ports     Parameter which specifies port range.
+               After the parameter two numbers from 0 to 65535 must be specified with a delimiter '-' between them.
+
+               Example: node sniffer.js --host google.com --port 100-2345
+
+    --help     Parameter will show this instructions.
+`;
+
+const validHost = async host => {
+  if (!host) {
+    process.stdout.write(
+      'Invalid host parameter. Try node sniffer.js --help \n'
+    );
+  }
+  try {
+    return await dns
+      .lookup(host)
+      .then(({ address }) => address)
+      .catch(error => {
+        process.stdout.write(
+          `Invalit host name. ${error}. Try node sniffer.js --help \n`
+        );
+        return 0;
+      });
+  } catch (e) {
+    process.stdout.write(e);
+    return 0;
+  }
+};
+
+const checkRangePort = port => {
+  if (port[0] < 0 || port[1] > 65535 || port[2] || port[0] > port[1]) {
+    return false;
+  }
+  return true;
+};
+
+const validatorForPort = portRange => {
+  let validPort = [1, 65535];
+  if (portRange) {
+    if (checkRangePort(portRange)) {
+      validPort = portRange;
+    } else {
+      process.stdout.write('Invalid port range. See help \n');
+    }
+  } else {
+    process.stdout.write(
+      'No port range specified. Setting to default. For more information try --help \n'
+    );
+  }
+  return validPort;
+};
+
+const checkConnection = async (port, host) => {
+  return new Promise(resolve => {
+    const socket = new net.Socket();
+    socket.setTimeout(300);
+    socket.on('connect', () => {
+      process.stdout.write('.');
+      resolve(port);
+      socket.destroy();
+    });
+    socket.on('timeout', () => {
+      resolve(false);
+      socket.destroy();
+    });
+    socket.on('error', () => {
+      resolve(false);
+      socket.destroy();
+    });
+    socket.connect(port, host);
+  });
+};
+
+const findOpenPorts = async (ports, host) => {
+  const openPorts = [];
+  for (let i = ports[0]; i <= ports[1]; i += 1) {
+    openPorts.push(checkConnection(i, host));
+  }
+  return Promise.all(openPorts).then(values => values.filter(Number.isFinite));
+};
+
+const sniffer = async ({ helpFlag, port, host }) => {
+  if (helpFlag) {
+    process.stdout.write(help);
+  }
+  if (!host && !port) {
+    process.stdout.write('No arguments. Try node sniffer.js --help. \n');
+    return 0;
+  }
+  const checkPort = validatorForPort(port);
+  const checkHost = await validHost(host);
+  const result = await findOpenPorts(checkPort, checkHost);
+  process.stdout.write('\n');
+  for (let i = 0; i < result.length; i += 1) {
+    if (i !== result.length - 1) {
+      process.stdout.write(`${result[i].toString()},`);
+    } else {
+      process.stdout.write(result[i].toString());
+    }
+  }
+  process.stdout.write(' ports are opened \n');
+  return 0;
+};
+
+const parseArgs = () => {
+  const objWithInputData = {
+    helpFlag: false
+  };
+  if (args.indexOf('--help') !== -1) {
+    objWithInputData.helpFlag = true;
+  }
+  const indexPort = args.indexOf('--ports');
+  if (indexPort !== -1) {
+    objWithInputData.port = args[indexPort + 1].split('-').map(Number);
+  }
+  const indexHost = args.indexOf('--host');
+  if (indexHost !== -1) objWithInputData.host = args[indexHost + 1];
+  return objWithInputData;
+};
+
+sniffer(parseArgs());