Inf*_*ty8 19 python file-upload twisted werkzeug flask
使用Flask处理超大文件上传(1 GB +)的最佳方法是什么？
我的应用程序本质上需要多个文件为它们分配一个唯一的文件号,然后根据用户选择的位置将其保存在服务器上.
我们如何将文件上传作为后台任务运行,这样用户就不会让浏览器旋转1小时,而是可以立即进入下一页？
Abd*_*man 13
我认为解决该问题的超级简单方法只是将文件分成许多小部分/大块发送。因此，要完成这项工作将需要两个部分，即前端（网站）和后端（服务器）。对于前端部分，您可以使用类似的东西Dropzone.js，它没有附加的依赖关系，并且包含不错的CSS。您所要做的就是将类添加dropzone到表单，它会自动将其变成其特殊的拖放字段之一（您也可以单击并选择）。
但是，默认情况下，dropzone不会对文件进行分块。幸运的是，它确实很容易启用。下面是一个示例文件上传形式DropzoneJS和chunking启用：
<html lang="en">
<head>
<meta charset="UTF-8">
<link rel="stylesheet"
href="https://cdnjs.cloudflare.com/ajax/libs/dropzone/5.4.0/min/dropzone.min.css"/>
<link rel="stylesheet"
href="https://cdnjs.cloudflare.com/ajax/libs/dropzone/5.4.0/min/basic.min.css"/>
<script type="application/javascript"
src="https://cdnjs.cloudflare.com/ajax/libs/dropzone/5.4.0/min/dropzone.min.js">
</script>
<title>File Dropper</title>
</head>
<body>
<form method="POST" action='/upload' class="dropzone dz-clickable"
id="dropper" enctype="multipart/form-data">
</form>
<script type="application/javascript">
Dropzone.options.dropper = {
paramName: 'file',
chunking: true,
forceChunking: true,
url: '/upload',
maxFilesize: 1025, // megabytes
chunkSize: 1000000 // bytes
}
</script>
</body>
</html>
这是使用flask的后端部分：
import logging
import os
from flask import render_template, Blueprint, request, make_response
from werkzeug.utils import secure_filename
from pydrop.config import config
blueprint = Blueprint('templated', __name__, template_folder='templates')
log = logging.getLogger('pydrop')
@blueprint.route('/')
@blueprint.route('/index')
def index():
# Route to serve the upload form
return render_template('index.html',
page_name='Main',
project_name="pydrop")
@blueprint.route('/upload', methods=['POST'])
def upload():
file = request.files['file']
save_path = os.path.join(config.data_dir, secure_filename(file.filename))
current_chunk = int(request.form['dzchunkindex'])
# If the file already exists it's ok if we are appending to it,
# but not if it's new file that would overwrite the existing one
if os.path.exists(save_path) and current_chunk == 0:
# 400 and 500s will tell dropzone that an error occurred and show an error
return make_response(('File already exists', 400))
try:
with open(save_path, 'ab') as f:
f.seek(int(request.form['dzchunkbyteoffset']))
f.write(file.stream.read())
except OSError:
# log.exception will include the traceback so we can see what's wrong
log.exception('Could not write to file')
return make_response(("Not sure why,"
" but we couldn't write the file to disk", 500))
total_chunks = int(request.form['dztotalchunkcount'])
if current_chunk + 1 == total_chunks:
# This was the last chunk, the file should be complete and the size we expect
if os.path.getsize(save_path) != int(request.form['dztotalfilesize']):
log.error(f"File {file.filename} was completed, "
f"but has a size mismatch."
f"Was {os.path.getsize(save_path)} but we"
f" expected {request.form['dztotalfilesize']} ")
return make_response(('Size mismatch', 500))
else:
log.info(f'File {file.filename} has been uploaded successfully')
else:
log.debug(f'Chunk {current_chunk + 1} of {total_chunks} '
f'for file {file.filename} complete')
return make_response(("Chunk upload successful", 200))
使用copy_current_request_context，它将复制上下文request。因此您可以使用线程或其他任何东西来使您的任务在后台运行。
也许一个例子会更清楚。我已经通过3.37G文件debian-9.5.0-amd64-DVD-1.iso对其进行了测试。
# coding:utf-8
from flask import Flask,render_template,request,redirect,url_for
from werkzeug.utils import secure_filename
import os
from time import sleep
from flask import copy_current_request_context
import threading
import datetime
app = Flask(__name__)
@app.route('/upload', methods=['POST','GET'])
def upload():
@copy_current_request_context
def save_file(closeAfterWrite):
print(datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S') + " i am doing")
f = request.files['file']
basepath = os.path.dirname(__file__)
upload_path = os.path.join(basepath, '',secure_filename(f.filename))
f.save(upload_path)
closeAfterWrite()
print(datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S') + " write done")
def passExit():
pass
if request.method == 'POST':
f= request.files['file']
normalExit = f.stream.close
f.stream.close = passExit
t = threading.Thread(target=save_file,args=(normalExit,))
t.start()
return redirect(url_for('upload'))
return render_template('upload.html')
if __name__ == '__main__':
app.run(debug=True)
这是模板，应该是 templates\upload.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h1>example</h1>
<form action="" enctype='multipart/form-data' method='POST'>
<input type="file" name="file">
<input type="submit" value="upload">
</form>
</body>
</html>
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