Dynamsoft Barcode Reader provides C/C++ shared libraries for Windows, Linux, and Mac. The ultimate benefit is that any high-level programming languages, such as JavaScript, Python, Java, Ruby, PHP and so on, are capable of wrapping C/C++ APIs using an extension or an addon. No matter which programming language you are familiar with, the SDK will expedite the coding work of barcode reader app with a few lines of code.
This article has been posted on CodeProject.
Node.js Barcode Addon
Node.js Addons are dynamically-linked shared objects written in C/C++. If you have never touched this part before, you’d better follow the official tutorial to get started.
Create Addon
Create dbr.cc and add a method DecodeFile:
#include <node.h>
#include <string.h>
#include "If_DBR.h"
#include "BarcodeFormat.h"
#include "BarcodeStructs.h"
#include "ErrorCode.h"
using namespace v8;
void DecodeFile(const FunctionCallbackInfo<Value>& args) {
}
void Init(Handle<Object> exports) {
NODE_SET_METHOD(exports, "decodeFile", DecodeFile);
}
NODE_MODULE(dbr, Init)
Parse parameters that passed from JavaScript:
Isolate* isolate = Isolate::GetCurrent(); HandleScope scope(isolate); String::Utf8Value license(args[0]->ToString()); String::Utf8Value fileName(args[1]->ToString()); char *pFileName = *fileName; char *pszLicense = *license; __int64 llFormat = args[2]->IntegerValue(); Local<Function> cb = Local<Function>::Cast(args[3]);
Decode barcode image:
int iMaxCount = 0x7FFFFFFF;
ReaderOptions ro = {0};
pBarcodeResultArray pResults = NULL;
ro.llBarcodeFormat = llFormat;
ro.iMaxBarcodesNumPerPage = iMaxCount;
DBR_InitLicense(pszLicense);
// Decode barcode image
int ret = DBR_DecodeFile(pFileName, &ro, &pResults);
Convert barcode formats to String:
const char * GetFormatStr(__int64 format)
{
if (format == CODE_39)
return "CODE_39";
if (format == CODE_128)
return "CODE_128";
if (format == CODE_93)
return "CODE_93";
if (format == CODABAR)
return "CODABAR";
if (format == ITF)
return "ITF";
if (format == UPC_A)
return "UPC_A";
if (format == UPC_E)
return "UPC_E";
if (format == EAN_13)
return "EAN_13";
if (format == EAN_8)
return "EAN_8";
if (format == INDUSTRIAL_25)
return "INDUSTRIAL_25";
if (format == QR_CODE)
return "QR_CODE";
if (format == PDF417)
return "PDF417";
if (format == DATAMATRIX)
return "DATAMATRIX";
return "UNKNOWN";
}
Convert results to v8 object:
Local<Array> barcodeResults = Array::New(isolate);
for (int i = 0; i < count; i++)
{
tmp = ppBarcodes[i];
Local<Object> result = Object::New(isolate);
result->Set(String::NewFromUtf8(isolate, "format"), String::NewFromUtf8(isolate, GetFormatStr(tmp->llFormat)));
result->Set(String::NewFromUtf8(isolate, "value"), String::NewFromUtf8(isolate, tmp->pBarcodeData));
barcodeResults->Set(Number::New(isolate, i), result);
}
Build Addon
Prerequisites:
- Windows: Install DBR for Windows, Visual Studio, and Python v2.7.
- Linux: Install DBR for Linux.
- Mac: Install DBR for Mac and Xcode.
Install node-gyp:
npm install -g node-gyp
Create binding.gyp for multiplatform compilation:
{
"targets": [
{
'target_name': "dbr",
'sources': [ "dbr.cc" ],
'conditions': [
['OS=="linux"', {
'defines': [
'LINUX_DBR',
],
'include_dirs': [
"/home/xiao/Dynamsoft/BarcodeReader4.0/Include"
],
'libraries': [
"-lDynamsoftBarcodeReaderx64", "-L/home/xiao/Dynamsoft/BarcodeReader4.0/Redist"
],
'copies': [
{
'destination': 'build/Release/',
'files': [
'/home/xiao/Dynamsoft/BarcodeReader4.0/Redist/libDynamsoftBarcodeReaderx64.so'
]
}]
}],
['OS=="win"', {
'defines': [
'WINDOWS_DBR',
],
'include_dirs': [
"F:\Program Files (x86)\Dynamsoft\Barcode Reader 4.1\Components\C_C++\Include"
],
'libraries': [
"-lF:\Program Files (x86)\Dynamsoft\Barcode Reader 4.1\Components\C_C++\Lib\DBRx64.lib"
],
'copies': [
{
'destination': 'build/Release/',
'files': [
'F:\Program Files (x86)\Dynamsoft\Barcode Reader 4.1\Components\C_C++\Redist\DynamsoftBarcodeReaderx64.dll'
]
}]
}],
['OS=="mac"', {
'defines': [
'MAC_DBR',
],
'include_dirs' : [
"/Applications/Dynamsoft/Barcode\ Reader\ 4.1/Include"
],
'libraries': [
"-lDynamsoftBarcodeReader"
]
}]
]
}
]
}
Replace the DBR Installation Directory with yours.
Configure the building environment:
node-gyp configure
Probably you will see the following error when configuring the environment on Mac:
error: xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance
Here is the solution:
sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
Build the project:
node-gyp build
Online Barcode Reader
You have successfully built the Node barcode reader module. Now it is time to create a simple barcode reader app.
Install Express and Formidable:
npm install express npm install formidable
Create a simple Website using Express:
var formidable = require('formidable');
var util = require('util');
var express = require('express');
var fs = require('fs');
var app = express();
var path = require('path');
var dbr = require('./build/Release/dbr');
var http = require('http');
fs.readFile('./license.txt', 'utf8', function(err, data) {
app.use(express.static(__dirname));
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "PUT, POST, GET, DELETE, OPTIONS");
res.header("Access-Control-Allow-Headers", "X-Requested-With, content-type");
res.header("Access-Control-Allow-Credentials", true);
next();
});
var server = app.listen(2016, function() {
var host = server.address().address;
var port = server.address().port;
console.log('listening at http://%s:%s', host, port);
});
});
Use Formidable to extract the image data from Form.
app.post('/upload', function(req, res) {
var form = new formidable.IncomingForm();
form.parse(req, function(err, fields, files) {
var dir = 'uploads';
fs.mkdir(dir, function(err) {
var flag = fields.uploadFlag;
var barcodeType = parseInt(fields.barcodetype);
console.log('flag: ' + flag);
if (flag === '1') { // read barcode image file
fs.readFile(files.fileToUpload.path, function(err, data) {
// save file from temp dir to new dir
var fileName = path.join(__dirname, dir, files.fileToUpload.name);
console.log(fileName);
fs.writeFile(fileName, data, function(err) {
if (err) throw err;
});
});
} else { // read barcode image url
var tmpFileName = path.join(__dirname, dir, 'tmp.jpg');
var tmp = fs.createWriteStream(tmpFileName);
var url = fields.fileToDownload;
console.log('url: ' + url);
http.get(url, function(response) {
response.pipe(tmp);
tmp.on('finish', function() {
tmp.close(function() {
});
});
});
}
});
});
});
Import the barcode module to decode the image file.
decodeBarcode(res, license, tmpFileName, barcodeType);
Run the app:
node server.js
Visit http://localhost:2016/index.htm:
