Browser file segmented breakpoint upload-JS Tutorial-php.cn

Browser file segmented breakpoint upload

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Release： 2018-03-10 15:52:26

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This time I will bring you the segmented breakpoint upload of browser files. What are the precautions for uploading browser files with segmented breakpoints? The following is a practical case, let's take a look.

The backend uses Python Flask

Front-end principle implementation:

1. Obtain the file feature code

2. Intercept file information and segment the file
3 .Verify whether there are unfinished uploaded files with the same feature code on the server
4. If there are files with the same feature code, get the upload progress
5. Otherwise, the progress starts from 0
6. Upload asynchronously and sequentially in a loop Segmented file
7. If the upload is completed, the prompt is successful

Back-end principle implementation:

Receive request (file hash) parameter

Judge whether the file is uploaded interrupted

If the hash folder exists, get the number of file segments under the folder and return it to the front end

If it does not exist, return 0 or empty
String 5. If the front end returns the uploaded file segment, save it File segment and identify the index for the file segment

If the upload is completed and the file is merged, delete the file segment

html code

The code takes a single

file upload as an example , use hashMe.js to obtain the feature code

<!DOCTYPE html><html><head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.1/jquery.min.js"></script>
    <script type="text/javascript" src="md5.js"></script>
    <script src="hashme.js"></script></head><body>
    <input type="file" onchange="hhh(this.files[0])" />
    <button onclick="uploadCk()">测试</button>
    <script>
        var up_f;//需要上传的信息
        var fileSplitSize = 1024 * 1024 * 2; //以2MB为一个分片
        function hhh(f) {　            if (true) { //假设这是判断文件大小
                var hash = new hashMe(f, function(msg) {
                    up_f = new Object();
                    up_f.hash = msg;
                    up_f.name = f.name;
                    up_f.size = f.size;
                    up_f.shardCount = Math.ceil(f.size / fileSplitSize); //总片数
                    up_f.shard = [];//文件段
                    for (var i = 0; i < up_f.shardCount; i++) {                        var start = i * fileSplitSize;                        var end = Math.min(f.size, start + fileSplitSize);
                        up_f.shard[up_f.shard.length] = f.slice(start, end);//保存分段
                    }
                });
            }
        }        function uploadCk() { //上传前检查 
            $.ajax({                url: "/upload_ck",                type: "get",                data: {                    hash: up_f.hash
                },                success: function(data) {                    if (data != "") {
                        upload(Number(data));//调用上传(索引为服务器存在的文件段索引)
                    } else { 
                        upload(0);//调用上传
                    }
                }
            });
        }        function upload(loadIndex) { //上传
            var form = new FormData();
            form.append("hash", up_f.hash);
            form.append("name", up_f.name);
            form.append("size", up_f.size);
            form.append("shardCount", up_f.shardCount);
            form.append("blob", up_f.shard[loadIndex]);
            form.append("sdIndex", loadIndex);            console.log("sdIndex:" + loadIndex + ",shardCount:" + up_f.shardCount)
            $.ajax({                url: "/upload",                type: "POST",                data: form,                async: true, 
                processData: false, //很重要，告诉jquery不要对form进行处理
                contentType: false, //很重要，指定为false才能形成正确的Content-Type
                success: function(data) {
                    data = Number(data) + 1;                    if (data <= up_f.shardCount) {                        console.log("data:" + data);
                        upload(data);
                    } else {                        console.log("上传完毕");
                    }
                }
            });
        }    </script></body></html>

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Python code

The Python code written for the example is somewhat irregular. Please try not to imitate my writing method (mime download)

from flask import Flask, url_for,request 
import codecs,re,osimport urllib.parse,mimeimport shutilfrom werkzeug.routing import BaseConverterclass RegexConverter(BaseConverter):
    def init(self, map, *args):
        self.map = map
        self.regex = args[0]
        
app = Flask(name)
mim=mime.types
app.config[&#39;UPLOAD_FOLDER&#39;] = &#39;uploads/&#39;#保存文件位置app.url_map.converters[&#39;regex&#39;] = RegexConverter@app.route(&#39;/<regex(".*"):url>&#39;)def index(url):
    ps=urllib.parse.unquote(url)   
    if ps=="upload":        return upload()    elif ps.split(&#39;?&#39;)[0]=="upload_ck":        if os.path.exists("./"+app.config[&#39;UPLOAD_FOLDER&#39;]+str(request.args.get(&#39;hash&#39;) ) ):            return str(len( os.listdir("./"+app.config[&#39;UPLOAD_FOLDER&#39;]+str(request.args.get(&#39;hash&#39;) )) )-1 )#返回文件段索引
        else:            return ""
    bt=codecs.open(ps,&#39;rb&#39;,"utf-8").read() 
    return  bt, 200, {&#39;Content-Type&#39;: mim[url.split(".")[-1]]}@app.route(&#39;/upload&#39;, methods=[&#39;POST&#39;])def upload():
    hashtxt=request.form[&#39;hash&#39;]
    sPs="./"+app.config[&#39;UPLOAD_FOLDER&#39;]+hashtxt+"/"
    if not os.path.exists(sPs):#文件夹不存在
        os.makedirs(sPs)#创建hash文件夹
    uploaded_files = request.files.getlist("blob")#获取文件流集
    filePs=hashtxt+"/"+request.form[&#39;name&#39;]+".part"+request.form[&#39;sdIndex&#39;] #文件段保存路径
    for file in uploaded_files:  
        file.save(os.path.join(app.config[&#39;UPLOAD_FOLDER&#39;],filePs ))#保存文件
    if (int(request.form[&#39;shardCount&#39;]))==(int(request.form[&#39;sdIndex&#39;])):#判断上传完最后一个文件
        mergeFile(app.config[&#39;UPLOAD_FOLDER&#39;],request.form[&#39;name&#39;],hashtxt);#合并文件
        shutil.rmtree("./"+app.config[&#39;UPLOAD_FOLDER&#39;]+hashtxt)#删除
    return request.form[&#39;sdIndex&#39;]#返回段索引
 
        def mergeFile(ps,nm,hs):#合并文件
    temp = open(ps+"/"+nm,&#39;wb&#39;)#创建新文件
    count=len(os.listdir(ps+"/"+hs))    for i in range(0,count):  
        fp = open(ps+"/"+hs+"/"+nm+".part"+str(i), &#39;rb&#39;)#以二进制读取分割文件
        temp.write(fp.read())#写入读取数据
        fp.close()  
    temp.close()with app.test_request_context():    #输出url
    passif name == &#39;main&#39;: 
    app.debug = True
    app.run()

Copy after login

There are so many examples, but the actual problem is not that simple. For example, before uploading and verifying, you can first obtain the file with the same signature and size that already exists in the server, and then directly copy the file to the uploaded directory or prompt whether to overwrite, etc. Of course, you can also optimize, such as uploading segments and then uploading them into segments and then uploading the segments at the same time.

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!