通过Dynamic Web TWAIN SDK和Node.js的组合，只需要几行代码就可以实现在浏览器中控制扫描仪，获取图像后上传到远程服务器。
原文：Document Imaging and Uploading With Dynamic Web TWAIN and Node.js
下载安装
通过Node.js创建server
创建工程目录，打开cmd.exe进入到工程目录，安装下面两个Node.js模块：
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npm install formidable@latestnpm install express |
创建server.js，初始化：
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var formidable = require('formidable');var util = require('util');var express = require('express');var fs = require('fs');var app = express(); |
把静态资源，比如图片，css等，都加载进来：
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app.use(express.static(__dirname, '/public')); |
要实现跨域访问，需要在header里添加权限，如果不添加，只能local访问：|
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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(); }); |
在POST请求中通过formidable解析数据：
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app.post('/upload', function(req, res) { var form = new formidable.IncomingForm(); form.parse(req, function(err, fields, files) { // console.log(util.inspect({ // fields: fields, // files: files // })); fs.readFile(files.RemoteFile.path, function(err, data) { // save file from temp dir to new dir var newPath = __dirname + "/uploads/" + files.RemoteFile.name; fs.writeFile(newPath, data, function(err) { if (err) throw err; console.log('file saved'); res.end(); }); }); });}) |
设置好IP和端口：|
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var server = app.listen(2014, function() { var host = server.address().address; var port = server.address().port; console.log('listening at http://%s:%s', host, port);}) |
通过Dynamic Web TWAIN创建client
创建一个网页，包含一个div和两个button：
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<html> <head> <title>Document Imaging & Uploading</title> <script src="/Resources/dynamsoft.webtwain.initiate.js"></script> <script src="/Resources/dynamsoft.webtwain.config.js"></script> </head> <body> <div id="dwtcontrolContainer"></div> <input type="button" value="Acquire" onclick="AcquireImage();" /> <input id="btnUpload" type="button" value="Upload Image" onclick="btnUpload_onclick()"> </body></html> |
这里需要把Web TWAIN SDK安装目录下的Resources目录拷贝过来。
加几行代码就可以扫描了：
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function AcquireImage(){ DWObject.IfShowUI = false; DWObject.SelectSource(); DWObject.OpenSource(); DWObject.AcquireImage();} |
到这里可以先测试下扫描能否正常工作。接下来实现远程上传：|
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function btnUpload_onclick() { DWObject.HTTPPort = 2014; var CurrentPathName = unescape(location.pathname); // get current PathName in plain ASCII var CurrentPath = CurrentPathName.substring(0, CurrentPathName.lastIndexOf("/") + 1); var strActionPage = CurrentPath + "upload"; var strHostIP = "localhost"; // modify the IP for cross-domain access var sFun = function(){ alert('successful'); }, fFun = function(){ alert('failed'); }; DWObject.HTTPUploadThroughPostEx( strHostIP, DWObject.CurrentImageIndexInBuffer, strActionPage, "test.jpg", 1,// JPEG sFun, fFun );} |
测试下。命令行启动server：|
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node server.js |
打开http://localhost:2014就可以玩了。
源码
https://github.com/DynamsoftRD/nodejs-dwt
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git clone https://github.com/DynamsoftRD/nodejs-dwt.git |