From f75753286fa44f6fe90e978f5e2eed4f87663329 Mon Sep 17 00:00:00 2001
From: Martin Endler <pokusew@seznam.cz>
Date: Thu, 27 Feb 2020 21:16:44 +0100
Subject: [PATCH] Add example of the API addressing the issue #30

---
 README.md           |  3 +-
 examples/example.js | 12 ++++--
 examples/public.js  | 89 +++++++++++++++++++++++++++++++++++++++++++++
 lib/constants.js    | 15 ++++++++
 lib/pcsclite.js     | 11 ++++--
 5 files changed, 122 insertions(+), 8 deletions(-)
 create mode 100755 examples/public.js
 create mode 100644 lib/constants.js

diff --git a/README.md b/README.md
index 9cb897ad..300f33f9 100644
--- a/README.md
+++ b/README.md
@@ -136,8 +136,7 @@ pcsc.on('reader', (reader) => {
 
             });
 
-        }
-        else if ((changes & reader.SCARD_STATE_PRESENT) && (status.state & reader.SCARD_STATE_PRESENT)) {
+        } else if ((changes & reader.SCARD_STATE_PRESENT) && (status.state & reader.SCARD_STATE_PRESENT)) {
 
             console.log("card inserted");
 
diff --git a/examples/example.js b/examples/example.js
index 75f27847..51de5649 100755
--- a/examples/example.js
+++ b/examples/example.js
@@ -1,9 +1,16 @@
 "use strict";
 
 const pcsclite = require('../lib/pcsclite');
+const {
+	SCARD_SCOPE_USER,
+	SCARD_SCOPE_TERMINAL,
+	SCARD_SCOPE_SYSTEM,
+	SCARD_SCOPE_GLOBAL,
+} = require('../lib/constants');
 
 
-const pcsc = pcsclite();
+// const pcsc = pcsclite(); // without options (scope defaults to SCARD_SCOPE_SYSTEM)
+const pcsc = pcsclite({ scope: SCARD_SCOPE_USER }); // overwriting default scope
 
 pcsc.on('reader', (reader) => {
 
@@ -39,8 +46,7 @@ pcsc.on('reader', (reader) => {
 
 			});
 
-		}
-		else if ((changes & reader.SCARD_STATE_PRESENT) && (status.state & reader.SCARD_STATE_PRESENT)) {
+		} else if ((changes & reader.SCARD_STATE_PRESENT) && (status.state & reader.SCARD_STATE_PRESENT)) {
 
 			console.log("card inserted");
 
diff --git a/examples/public.js b/examples/public.js
new file mode 100755
index 00000000..a3bc706b
--- /dev/null
+++ b/examples/public.js
@@ -0,0 +1,89 @@
+"use strict";
+
+const pcsclite = require('@pokusew/pcsclite');
+const {
+	SCARD_SCOPE_USER,
+	SCARD_SCOPE_TERMINAL,
+	SCARD_SCOPE_SYSTEM,
+	SCARD_SCOPE_GLOBAL,
+} = require('@pokusew/pcsclite/lib/constants');
+
+
+// const pcsc = pcsclite(); // without options (scope defaults to SCARD_SCOPE_SYSTEM)
+const pcsc = pcsclite({ scope: SCARD_SCOPE_USER }); // overwriting default scope
+
+pcsc.on('reader', (reader) => {
+
+	console.log('New reader detected', reader.name);
+
+	reader.on('error', err => {
+		console.log('Error(', reader.name, '):', err.message);
+	});
+
+	reader.on('status', (status) => {
+
+		console.log('Status(', reader.name, '):', status);
+
+		// check what has changed
+		const changes = reader.state ^ status.state;
+
+		if (!changes) {
+			return;
+		}
+
+		if ((changes & reader.SCARD_STATE_EMPTY) && (status.state & reader.SCARD_STATE_EMPTY)) {
+
+			console.log("card removed");
+
+			reader.disconnect(reader.SCARD_LEAVE_CARD, err => {
+
+				if (err) {
+					console.log(err);
+					return;
+				}
+
+				console.log('Disconnected');
+
+			});
+
+		} else if ((changes & reader.SCARD_STATE_PRESENT) && (status.state & reader.SCARD_STATE_PRESENT)) {
+
+			console.log("card inserted");
+
+			reader.connect({ share_mode: reader.SCARD_SHARE_SHARED }, (err, protocol) => {
+
+				if (err) {
+					console.log(err);
+					return;
+				}
+
+				console.log('Protocol(', reader.name, '):', protocol);
+
+				reader.transmit(Buffer.from([0x00, 0xB0, 0x00, 0x00, 0x20]), 40, protocol, (err, data) => {
+
+					if (err) {
+						console.log(err);
+						return;
+					}
+
+					console.log('Data received', data);
+					reader.close();
+					pcsc.close();
+
+				});
+
+			});
+
+		}
+
+	});
+
+	reader.on('end', () => {
+		console.log('Reader', reader.name, 'removed');
+	});
+
+});
+
+pcsc.on('error', err => {
+	console.log('PCSC error', err.message);
+});
diff --git a/lib/constants.js b/lib/constants.js
new file mode 100644
index 00000000..fb1a87d0
--- /dev/null
+++ b/lib/constants.js
@@ -0,0 +1,15 @@
+"use strict";
+
+const {
+	SCARD_SCOPE_USER,
+	SCARD_SCOPE_TERMINAL,
+	SCARD_SCOPE_SYSTEM,
+	SCARD_SCOPE_GLOBAL,
+} = require('../build/Release/pcsclite.node');
+
+module.exports = {
+	SCARD_SCOPE_USER,
+	SCARD_SCOPE_TERMINAL,
+	SCARD_SCOPE_SYSTEM,
+	SCARD_SCOPE_GLOBAL,
+};
diff --git a/lib/pcsclite.js b/lib/pcsclite.js
index 363bd8e9..af797cc9 100644
--- a/lib/pcsclite.js
+++ b/lib/pcsclite.js
@@ -8,7 +8,7 @@ const EventEmitter = require('events');
 // see https://github.com/nodejs/node-gyp/issues/263, https://github.com/nodejs/node-gyp/issues/631
 const pcsclite = require('../build/Release/pcsclite.node');
 
-const { PCSCLite, CardReader } = pcsclite;
+const { PCSCLite, CardReader, SCARD_SCOPE_SYSTEM } = pcsclite;
 
 
 inherits(PCSCLite, EventEmitter);
@@ -45,11 +45,16 @@ function diff(a, b) {
 
 }
 
-module.exports = function () {
+module.exports = function (options = {}) {
 
 	const readers = {};
 
-	const p = new PCSCLite();
+	// const scope = options.scope ?? SCARD_SCOPE_SYSTEM;
+	// ^ this syntax above (null coalescing operator) would need transpiler as it is not available in the Node.js yet
+	const scope = options.scope !== undefined && options.scope !== null ? options.scope : SCARD_SCOPE_SYSTEM;
+
+	// TODO: consider alternative approach > allow call with undefined and the C++ side will supply the default value
+	const p = new PCSCLite(scope);
 
 	p.readers = readers;