node.js 通过ajax上传图片
这个阶段,利用晚上剩余的时间用node.js+mongdb+express+jade去实现自己的一个博客网站,里面的发表博客中需要用到上传图片,嵌入到自己用textarea标签实现的markdown编辑器中。这部分实现是利用了html5的formData函数去实现html代码(jade):
<ol style="margin:0 1px 0 0px;padding-left:40px;" start="1" class="dp-css"><li>form#uploadfile</li><li>div.form-group</li><li>input#inputfile(type="file" name="inputfile")</li><li>p.help-block#upfiletip 只支持png和ipg格式的图片上传</li><li>button.btn.btn-success(type="button" onclick="upFile()") 上传</li></ol>
ajax代码(javascript):
<ol style="margin:0 1px 0 0px;padding-left:40px;" start="1" class="dp-css"><li>//判断图片的格式是否是png/ipg的格式<br /> </li><li>function judgePhotoExt(name){<br /></li><li>if(name.length === 0){<br /></li><li>$("#upfiletip").css("color","red");<br /></li><li>$("#upfiletip").text = "你没有选择任何图片!!!"<br /></li><li>return false;<br /></li><li>}<br /></li><li>var extName = name.substring(name.lastIndexOf('.'),name.length).toLowerCase();<br /></li><li>if(extName != '.png' && extName != '.ipg'){<br /></li><li>$("#upfiletip").css("color","red");<br /></li><li>$("#upfiletip").text = "只支持png和ipg格式的格式的文件!!!"<br /></li><li>return false;<br /></li><li>}<br /></li><li>return true;<br /></li><li>}<br /></li><li><br /></li><li>//上传图片文件<br /></li><li>function upFile(){<br /></li><li>var filename = $("#inputfile").val();<br /></li><li>if(judgePhotoExt(filename)){<br /></li><li>var data = new FormData(); </li><li> var files = $("#inputfile")[0].files;<br /></li><li>if(files){<br /></li><li> data.append("file", files[0]);<br /></li><li>}<br /></li><li>$.ajax({<br /></li><li>url: '/blog/photo/new',<br /></li><li>type: 'POST',<br /></li><li>data: data,<br /></li><li>async: false,<br /></li><li>cache: false,<br /></li><li>contentType: false,<br /></li><li>processData: false,<br /></li><li>success: function(data){<br /></li><li>var text = $("#content-textarea").val();<br /></li><li>text = text+"";<br /></li><li>$("#content-textarea").val(text);<br /></li><li>$('#imageModal').modal('hide');<br /></li><li>},<br /></li><li>error: function(err){<br /></li><li>console.log(err);<br /></li><li>}<br /></li><li>})<br /></li><li>}<br /></li><li>} </li></ol>注意:其中一定要注意的点:processData的属性要设置为false,这个是html5的属性,如果没有设置为false的话,这个地方会出问题。主要是文件的内容不希望转换成字符串。具体可查看jquery ajax的参数解释:http://www.w3school.com.cn/jquery/ajax_ajax.asp
对于FormData对象,你可以先创建一个空的FormData对象,然后使用append()方法向该对象里添加字段(引用别的网站的描述)
比如:
<ol style="margin:0 1px 0 0px;padding-left:40px;" start="1" class="dp-css"><li>var oMyForm = new FormData();<br /> </li><li><br /></li><li>oMyForm.append("username", "Groucho");<br /></li><li>oMyForm.append("accountnum", 123456); // 数字123456被立即转换成字符串"123456"<br /></li><li><br /></li><li>// fileInputElement中已经包含了用户所选择的文件<br /></li><li>oMyForm.append("userfile", fileInputElement.files[0]);<br /></li><li><br /></li><li>var oFileBody = "<a id="a"><b id="b">hey!"; // Blob对象包含的文件内容<br /></li><li>var oBlob = new Blob([oFileBody], { type: "text/xml"});<br /></li><li><br /></li><li>oMyForm.append("webmasterfile", oBlob);<br /></li><li><br /></li><li>var oReq = new XMLHttpRequest();<br /></li><li>oReq.open("POST", "http://foo.com/submitform.php");<br /></li><li>oReq.send(oMyForm); </li></ol>这部分内容需要查看FormData对象的具体内容,可查看该网址:http://www.cnblogs.com/lhb25/p/html5-formdata-tutorials.html
node.js后台代码如下:
<ol style="margin:0 1px 0 0px;padding-left:40px;" start="1" class="dp-css"><li>router.post('/photo/new',function(req,res,next){<br /> </li><li>let form = new formidable.IncomingForm(); //创建上传表单<br /></li><li>form.uploadDir = UPLOAD_PATH;<br /></li><li>form.keepExtensions = true; //保留后缀<br /></li><li>form.maxFieldsSize = 4*1024*1024; //文件大小<br /></li><li>form.parse(req,function(err,fields,files){<br /></li><li>if(err){<br /></li><li>res.send("插入标签失败");<br /></li><li>return;<br /></li><li>}<br /></li><li>let extName = '';<br /></li><li>let urls = [];<br /></li><li>for(var key in files){<br /></li><li>let file = files[key];<br /></li><li>switch(file.type){<br /></li><li>case 'image/pjpeg':<br /></li><li>extName = 'jpg';<br /></li><li>break;<br /></li><li>case 'image/jpeg':<br /></li><li>extName = 'jpg';<br /></li><li>break;<br /></li><li>case 'image/png':<br /></li><li>extName = 'png';<br /></li><li>case 'image/x-png':<br /></li><li>extName = 'png';<br /></li><li>break;<br /></li><li>}<br /></li><li>if(extName.length === 0){<br /></li><li>res.send("只支持png和jpg格式的图片文件");<br /></li><li>return;<br /></li><li>}<br /></li><li>let saveName = uuid.v1()+'.'+extName;<br /></li><li>let savePath = form.uploadDir+saveName;<br /></li><li>urls.push(PHOTO_URL+saveName);<br /></li><li>fs.renameSync(file.path,savePath);<br /></li><li>}<br /></li><li>res.send(urls[0]);<br /></li><li>})<br /></li><li>}) </li></ol>
使用formidable库辅助实现
其实里面最重要的还是FormData的使用,用html5实现这部分的异步上传还是比较方便的

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