如何在Ubuntu上创建Node.jsAddon

2019独角兽企业重金招聘Python工程师标准>>>

上次分享过Windows上的node.js扩展实现。今天分享下如何在Linux平台上&＃xff0c;通过封装Dynamsoft Barcode SDK for Linux (dbr)来创建node.js barcode addon。

参考原文&＃xff1a;How to Make Node Barcode Reader Addon on Linux

作者&＃xff1a;Xiao Ling

翻译&＃xff1a;yushulx

软件下载

在Ubuntu上一般习惯用apt-get来安装软件。如果是这样操作&＃xff0c;下载的node和npm版本都会比较旧。编译V8 C/C&＃43;&＃43;代码的时候会出现错误‘FunctionCallbackInfo’ does not name a type:

安装Node

从官网下载最新版本的Linux Node&＃xff1a;node-v5.3.0-linux-x64.tar.gz.

解压&＃xff1a;

tar -xzf node-v5.3.0-linux-x64.tar.gz

打开.bashrc&＃xff1a;

nano ~/.bashrc

导出node的路径并保存文件&＃xff1a;

export PATH&＃61;$(YOUR_HOME)/Downloads/node-v5.3.0-linux-x64/bin:$PATH

安装node-gyp&＃xff1a;

npm install -g node-gyp

安装DBR

下载v4.0.0-pre-alpha.tar.gz 。

解压&＃xff1a;

tar -xzf v4.0.0-pre-alpha.tar.gz

为了方便编译的时候找到SDK中提供的*.so动态链接库&＃xff0c;创建一个符号链接&＃xff1a;

sudo ln -s $(DynamsoftBarcodeReader)/Redist/libDynamsoftBarcodeReaderx64.so /usr/lib/libDynamsoftBarcodeReaderx64.so

创建Node Barcode Addon

创建文件 binding.gyp&＃xff0c;在里面添加目标名&＃xff0c;源码路径&＃xff0c;include路径&＃xff0c;以及依赖库的路径。

{"targets": [{"target_name": "dbr","sources": [ "dbr.cc" ],"include_dirs" : ["$(DynamsoftBarcodeReader)/Include"],"libraries": ["-lDynamsoftBarcodeReaderx64", "-L$(DynamsoftBarcodeReader)/Redist"]}] }

参考SDK中提供的sample&＃xff0c;创建dbr.cc&＃xff1a;

#include #include "If_DBR.h" #include "BarcodeFormat.h" #include "BarcodeStructs.h" #include "ErrorCode.h"using namespace v8;// Barcode format const char * GetFormatStr(__int64 format) {if (format &＃61;&＃61; CODE_39)return "CODE_39";if (format &＃61;&＃61; CODE_128)return "CODE_128";if (format &＃61;&＃61; CODE_93)return "CODE_93";if (format &＃61;&＃61; CODABAR)return "CODABAR";if (format &＃61;&＃61; ITF)return "ITF";if (format &＃61;&＃61; UPC_A)return "UPC_A";if (format &＃61;&＃61; UPC_E)return "UPC_E";if (format &＃61;&＃61; EAN_13)return "EAN_13";if (format &＃61;&＃61; EAN_8)return "EAN_8";if (format &＃61;&＃61; INDUSTRIAL_25)return "INDUSTRIAL_25";if (format &＃61;&＃61; QR_CODE)return "QR_CODE";if (format &＃61;&＃61; PDF417)return "PDF417";if (format &＃61;&＃61; DATAMATRIX)return "DATAMATRIX";return "UNKNOWN"; }void DecodeFile(const FunctionCallbackInfo& args) {Isolate* isolate &＃61; Isolate::GetCurrent();HandleScope scope(isolate);// convert v8 string to char *String::Utf8Value fileName(args[0]->ToString());String::Utf8Value license(args[1]->ToString());char *pFileName &＃61; *fileName;char *pszLicense &＃61; *license;// Dynamsoft Barcode Reader: init__int64 llFormat &＃61; (OneD | QR_CODE | PDF417 | DATAMATRIX);int iMaxCount &＃61; 0x7FFFFFFF;ReaderOptions ro &＃61; {0};pBarcodeResultArray pResults &＃61; NULL;// Initialize licenseif (pszLicense){printf("license: %s\n", pszLicense);DBR_InitLicense(pszLicense);}elseDBR_InitLicense("AC4561856D63EF392F46D7454052372D");ro.llBarcodeFormat &＃61; llFormat;ro.iMaxBarcodesNumPerPage &＃61; iMaxCount;// Decode barcode imageint ret &＃61; DBR_DecodeFile(pFileName, &ro, &pResults);printf("ret: %d\n", ret);if (ret &＃61;&＃61; DBR_OK){int count &＃61; pResults->iBarcodeCount;pBarcodeResult* ppBarcodes &＃61; pResults->ppBarcodes;pBarcodeResult tmp &＃61; NULL;// Javascript callback functionLocal cb &＃61; Local::Cast(args[2]);const unsigned argc &＃61; 1;// array for storing barcode resultsLocal barcodeResults &＃61; Array::New(isolate);for (int i &＃61; 0; i < count; i&＃43;&＃43;){tmp &＃61; ppBarcodes[i];Local result &＃61; Object::New(isolate);result->Set(String::NewFromUtf8(isolate, "format"), Number::New(isolate, tmp->llFormat));result->Set(String::NewFromUtf8(isolate, "value"), String::NewFromUtf8(isolate, tmp->pBarcodeData));barcodeResults->Set(Number::New(isolate, i), result);}// release memoryDBR_FreeBarcodeResults(&pResults);Local argv[argc] &＃61; { barcodeResults };cb->Call(isolate->GetCurrentContext()->Global(), argc, argv);} }void Init(Handle exports) {NODE_SET_METHOD(exports, "decodeFile", DecodeFile); }NODE_MODULE(dbr, Init)

通过命令自动创建工程构建的文件&＃xff1a;

node-gyp configure

创建之后makefile不需要再进行手动修改了。现在可以构建工程了&＃xff1a;

node-gyp build

写一个测试dbr.js&＃xff0c;包含读取license以及调用C/C&＃43;&＃43;接口&＃xff1a;

var dbr &＃61; require(&＃39;./build/Release/dbr&＃39;); var readline &＃61; require(&＃39;readline&＃39;); var fs &＃61; require(&＃39;fs&＃39;);fs.readFile(&＃39;./license.txt&＃39;, &＃39;utf8&＃39;, function (err, data) {if (err) throw err;var rl &＃61; readline.createInterface({input: process.stdin,output: process.stdout});var license &＃61; data.trim();rl.question("Please input a barcode image path: ", function(answer) {dbr.decodeFile(answer, license,function(msg){var result &＃61; null;for (index in msg) {result &＃61; msg[index]console.log(result[&＃39;format&＃39;]);console.log(result[&＃39;value&＃39;]);console.log("##################");}});rl.close();}); });

运行脚本&＃xff1a;

node dbr.js