How to initiate barcode scanner from html button - php

Question

I'm setting up web-based application using cakePHP, on one point i need to scan barcode then input the barcode result to text-input then run the calculation.
I want to open this web-based app on android tablet on its browser, then my idea is to provide button, on press it will open barcode scanner, then on scanning, it will insert the scanning result to the web-based app in the browser of the android tablet i have.
I tried to explore and find how to do it, but find none.
Is there any idea or insight if this possible? so I can only use 1 tablet device to run web-based system and run barcode scanner on that same tablet.

Answer 1

That is not quite possible in this case with PHP.
PHP is the script that runs on the server, doing things and/or dumping out data (HTML, files, JS, etc.) to the client's browser.
From what I understand, you want to run the barcode scanner on the client side, where it's not PHP that's running, but most likely Javascript.

Answer 2

You can do with JS inside HTML page.
For barcode scanning you need a barcodescanner.js file :
(function ($) {
$.fn.scannerDetection = function (options) {
// If string given, call onComplete callback
if (typeof options === "string") {
this.each(function () {
this.scannerDetectionTest(options);
});
return this;
}
// If false (boolean) given, deinitialize plugin
if (options === false) {
this.each(function () {
this.scannerDetectionOff();
});
return this;
}
var defaults = {
onComplete: false, // Callback after detection of a successfull scanning (scanned string in parameter)
onError: false, // Callback after detection of a unsuccessfull scanning (scanned string in parameter)
onReceive: false, // Callback after receiving and processing a char (scanned char in parameter)
onKeyDetect: false, // Callback after detecting a keyDown (key char in parameter) - in contrast to onReceive, this fires for non-character keys like tab, arrows, etc. too!
timeBeforeScanTest: 100, // Wait duration (ms) after keypress event to check if scanning is finished
avgTimeByChar: 30, // Average time (ms) between 2 chars. Used to do difference between keyboard typing and scanning
minLength: 6, // Minimum length for a scanning
endChar: [9, 13], // Chars to remove and means end of scanning
startChar: [], // Chars to remove and means start of scanning
ignoreIfFocusOn: false, // do not handle scans if the currently focused element matches this selector
scanButtonKeyCode: false, // Key code of the scanner hardware button (if the scanner button a acts as a key itself)
scanButtonLongPressThreshold: 3, // How many times the hardware button should issue a pressed event before a barcode is read to detect a longpress
onScanButtonLongPressed: false, // Callback after detection of a successfull scan while the scan button was pressed and held down
stopPropagation: false, // Stop immediate propagation on keypress event
preventDefault: false // Prevent default action on keypress event
};
if (typeof options === "function") {
options = { onComplete: options }
}
if (typeof options !== "object") {
options = $.extend({}, defaults);
} else {
options = $.extend({}, defaults, options);
}
this.each(function () {
var self = this, $self = $(self), firstCharTime = 0, lastCharTime = 0, stringWriting = '', callIsScanner = false, testTimer = false, scanButtonCounter = 0;
var initScannerDetection = function () {
firstCharTime = 0;
stringWriting = '';
scanButtonCounter = 0;
};
self.scannerDetectionOff = function () {
$self.unbind('keydown.scannerDetection');
$self.unbind('keypress.scannerDetection');
}
self.isFocusOnIgnoredElement = function () {
if (!options.ignoreIfFocusOn) return false;
if (typeof options.ignoreIfFocusOn === 'string') return $(':focus').is(options.ignoreIfFocusOn);
if (typeof options.ignoreIfFocusOn === 'object' && options.ignoreIfFocusOn.length) {
var focused = $(':focus');
for (var i = 0; i < options.ignoreIfFocusOn.length; i++) {
if (focused.is(options.ignoreIfFocusOn[i])) {
return true;
}
}
}
return false;
}
self.scannerDetectionTest = function (s) {
// If string is given, test it
if (s) {
firstCharTime = lastCharTime = 0;
stringWriting = s;
}
if (!scanButtonCounter) {
scanButtonCounter = 1;
}
// If all condition are good (length, time...), call the callback and re-initialize the plugin for next scanning
// Else, just re-initialize
if (stringWriting.length >= options.minLength && lastCharTime - firstCharTime < stringWriting.length * options.avgTimeByChar) {
if (options.onScanButtonLongPressed && scanButtonCounter > options.scanButtonLongPressThreshold) options.onScanButtonLongPressed.call(self, stringWriting, scanButtonCounter);
else if (options.onComplete) options.onComplete.call(self, stringWriting, scanButtonCounter);
$self.trigger('scannerDetectionComplete', { string: stringWriting });
initScannerDetection();
return true;
} else {
if (options.onError) options.onError.call(self, stringWriting);
$self.trigger('scannerDetectionError', { string: stringWriting });
initScannerDetection();
return false;
}
}
$self.data('scannerDetection', { options: options }).unbind('.scannerDetection').bind('keydown.scannerDetection', function (e) {
// If it's just the button of the scanner, ignore it and wait for the real input
if (options.scanButtonKeyCode !== false && e.which == options.scanButtonKeyCode) {
scanButtonCounter++;
// Cancel default
e.preventDefault();
e.stopImmediatePropagation();
}
// Add event on keydown because keypress is not triggered for non character keys (tab, up, down...)
// So need that to check endChar and startChar (that is often tab or enter) and call keypress if necessary
else if ((firstCharTime && options.endChar.indexOf(e.which) !== -1)
|| (!firstCharTime && options.startChar.indexOf(e.which) !== -1)) {
// Clone event, set type and trigger it
var e2 = jQuery.Event('keypress', e);
e2.type = 'keypress.scannerDetection';
$self.triggerHandler(e2);
// Cancel default
e.preventDefault();
e.stopImmediatePropagation();
}
// Fire keyDetect event in any case!
if (options.onKeyDetect) options.onKeyDetect.call(self, e);
$self.trigger('scannerDetectionKeyDetect', { evt: e });
}).bind('keypress.scannerDetection', function (e) {
if (this.isFocusOnIgnoredElement()) return;
if (options.stopPropagation) e.stopImmediatePropagation();
if (options.preventDefault) e.preventDefault();
if (firstCharTime && options.endChar.indexOf(e.which) !== -1) {
e.preventDefault();
e.stopImmediatePropagation();
callIsScanner = true;
} else if (!firstCharTime && options.startChar.indexOf(e.which) !== -1) {
e.preventDefault();
e.stopImmediatePropagation();
callIsScanner = false;
} else {
if (typeof (e.which) != 'undefined') {
stringWriting += String.fromCharCode(e.which);
}
callIsScanner = false;
}
if (!firstCharTime) {
firstCharTime = Date.now();
}
lastCharTime = Date.now();
if (testTimer) clearTimeout(testTimer);
if (callIsScanner) {
self.scannerDetectionTest();
testTimer = false;
} else {
testTimer = setTimeout(self.scannerDetectionTest, options.timeBeforeScanTest);
}
if (options.onReceive) options.onReceive.call(self, e);
$self.trigger('scannerDetectionReceive', { evt: e });
});
});
return this;
}
})(jQuery);
For usecase inside a HTML :
<script type="text/javascript">
$(document).scannerDetection({
timeBeforeScanTest: 200, // wait for the next character for upto 200ms
startChar: [120], // Prefix character for the cabled scanner (OPL6845R)
endChar: [13], // be sure the scan is complete if key 13 (enter) is detected
avgTimeByChar: 40, // it's not a barcode if a character takes longer than 40ms
onComplete: function(barcode, qty) {
console.log(barcode);
console.log(qty);
// barcode number code
// qty scanned by barcode scanner
},
onKeyDetect: function(event) {
return false;
}
});
</script>