netsh added

lib/netsh.js

@@ -1,3 +1,90 @@
 /**
+ * Scanning WiFis on Windows
  * Created by kc on 04.04.16.
  */
+
+const systemRoot = process.env.SystemRoot || 'C:\\Windows';
+const tool       = systemRoot + '\\System32\\netsh.exe';
+const cmdLine    = tool + ' wlan show networks mode=Bssid';
+
+/**
+ * Parsing netnsh output. Unfortunately netsh supplies the network information
+ * in the language of the operating system. Translating the terms into every
+ * language supplied is not possible, therefore this implementation follows
+ * an approach of analyzing the structure of the output
+ */
+function parseOutput(str, callback) {
+  var blocks = str.split('\n\n');
+  var wifis  = [];
+  var err    = null;
+  try {
+    if (!blocks || blocks.length === 1) {
+      // No WiFis found
+      return [];
+    }
+
+    // Each block has the same structure, while some parts might be available and others
+    // not. A sample structure:
+    // SSID 1 : AP-Test1
+    //     Network type              : Infrastructure
+    //     Authentication            : WPA2-Personal
+    //     Encryption                : CCMP
+    //     BSSID 1                   : 00:aa:f2:77:a5:53
+    //          Signal               : 46%
+    //          Radio type           : 802.11n
+    //          Channel              : 6
+    //          Basic rates (MBit/s) : 1 2 5.5 11
+    //          Other rates (MBit/s) : 6 9 12 18 24 36 48 54
+    for (var i = 1, l = blocks.length; i < l; i++) {
+      var network      = {};
+      var lines        = blocks[i].split('\n');
+      var regexChannel = /[a-zA-Z0-9()\s]+:[\s]*[0-9]+$/g;
+      if (!lines || lines.length < 2) {
+        continue;
+      }
+
+      // First line is always the SSID (which can be empty)
+      var ssid = lines[0].substring(lines[0].indexOf(':') + 1).trim();
+
+      for (var t = 1, n = lines.length; t < n; t++) {
+        if (lines[t].split(':').length === 7) {
+          // This is the mac address, use this one as trigger for a new network
+          if (network.mac) {
+            wifis.push(network);
+          }
+          network = {
+            ssid: ssid,
+            mac : lines[t].substring(lines[t].indexOf(':') + 1).trim()
+          };
+        }
+        else if (lines[t].indexOf('%') > 0) {
+          // Network signal strength, identified by '%'
+          var level = parseInt(lines[t].split(':')[1].split('%')[0].trim(), 10);
+
+          network.signal_level = (level / 2) - 100;
+        }
+        else if (!network.channel) {
+          // A tricky one: the channel is the first one having just ONE number. Set only
+          // if the channel is not already set ("Basic Rates" can be a single number also)
+          if (regexChannel.exec(lines[t])) {
+            network.channel = parseInt(lines[t].split(':')[1].trim());
+          }
+        }
+      }
+      if (network) {
+        wifis.push(network);
+      }
+    }
+  }
+  catch (ex) {
+    err = ex;
+  }
+  callback(err, wifis);
+}
+
+
+module.exports = {
+  parseOutput: parseOutput,
+  cmdLine    : cmdLine,
+  tool       : tool
+};