nodejs----上传显示图片

时间：2014-09-25 14:16:39 阅读：172 评论：0 收藏：0 [点我收藏+]

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Node.js实现图片的上传和显示，需要用到外部模块，formidable，这个模块是对解释上传的文件数据很好的抽象。文件上传，就是”处理“POST数据。

1,安装模块,打开nodejs安装目录,在命令行输入指令：

npm install formidable

2.引用formidable的模块，使用require指令。这个模块就是将通过http post请求提交的表单，在Node.js中可以被解释。

var formidable = require("formidable");

3.需要建立一个新的IncomingForm,对提交的表单的抽象表示，就可以用它解析request对象表单中需要的字。

var form = new formidable.IncomingForm();

4.实现图片的上传和显示这个引用因为要引用到formidable，必须把项目放在nodejs的安装目录下。

5.程序：

-----requestHandlers.js

-----server.js

-----router.js

-----index.js

requestHandlers.js

/*requestHandlers.js*/
var querystring = require("querystring"), fs = require("fs"), formidable = require ("formidable");

function start(response){
	console.log("Request handler ‘start‘ was called");
	
	var body = ‘<html>‘ + 
	‘<head>‘ +
	‘<meta http-equiv="Content-Type" content="text/html charset=UTF-8"/>‘ +
	‘</head>‘ + 
	‘<body>‘ +
	‘<form action="/upload" enctype="multipart/form-data" method="post">‘ +
	‘<input type="file" name="upload" multiple="multiple"/>‘+
	‘<input type="submit" value="Upload file"/>‘+
	‘</form>‘ +
	‘</body>‘ +
	‘</html>‘;
	response.writeHead(200,{"Content-Type":"text/html"});
	response.write(body);
	response.end();
	}
	
	function upload(response, request){
		console.log("Request handler ‘upload‘ was called");
		
		/*formidable外部模块，解析上传的文件数据做了很好的抽象*/
		var form = new formidable.IncomingForm();
		//在应用目录下创建文件夹tmp，设置为上传路径
		form.uploadDir = "tmp"		
		console.log("About to parse");
		form.parse(request,function(error,fields, files){
			console.log("parsing done");
			console.log(files.upload.path);
			//renameSync(oldpath,newpath)
			//同步操作，需要try catch
			try{
			fs.renameSync(files.upload.path,"./tmp/test.png");
			}catch(e){
				console.log(e);
			}
			response.writeHead(200,{"Content-Type":"text/html"});
			response.write("received image:<br/>");
			//返回/show处理程序显示图片
			response.write("<img src=‘/show‘/>");
			response.end();
		});
	}
	
	//显示图片
	function show(response){
		console.log("Request handler ‘show‘ was called.");
		fs.readFile("./tmp/test.png","binary",function(error, file){
			if(error){
				response.writeHead(500,{"Content-Type":"text/plain"});
				response.write(error + "/n");
				response.end();
			}else{
				response.writeHead(200,{"Content-Type":"image/png"});
				response.write(file,"binary");
				response.end();
			}
		});
	}
	
exports.start = start;
exports.upload = upload;
exports.show = show;

router.js

/*router.js*/
/*通过检查给定的路径对应的请求处理程序是否存在，如果存在的话直接调用相应的函数*/

function route(handle,pathname,response,request){
	console.log("About to route a request for " + pathname);
	if(typeof handle[pathname] === ‘function‘){
		handle[pathname](response,request);
	}else{
		console.log("No request handler found for " + pathname);
		response.writeHead(404,{"Content-Type":"text/html"});
		response.write("404 Not found");
		response.end();
	}
}
exports.route = route;

server.js

/*server.js  处理请求模块*/
var http = require("http");
var url = require("url");

function start(route,handle){
	function onRequest(request,response){
		var pathname = url.parse(request.url).pathname;
		console.log("Request for" +  pathname + "Received.");
		route(handle,pathname,response,request);
	}
	
	http.createServer(onRequest).listen(3000);
	console.log("Server has started");
}
	
exports.start = start;

index.js

/*index.js 主模块*/

var server = require("./server");
var router = require("./router");
var requestHandlers = require("./requestHandlers");

var handle = {};

handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;
handle["/show"] = requestHandlers.show;

server.start(router.route,handle);

6.启动应用：