#!/usr/bin/env python3

# SPDX-License-Identifier: MIT

# Author: Anggit Arfanto

# Description: Upload, stream multipart/form-data and save.

import os

from urllib.parse import quote

from tremolo import Application

app = Application()

@app.route('/')

async def index():

return (

'<form action="/upload" method="post" enctype="multipart/form-data">'

'<p><input type="file" name="file1" /></p>'

'<p><input type="file" name="file2" /></p>'

'<p><input type="submit" value="Upload (Max. 100MiB)" /></p>'

'</form>'

)

@app.route('/upload')

async def upload(request, response):

# no worries, if the file is larger than `max_file_size`

# it can still be read continuously bit by bit according to this size

files = request.files(max_file_size=16384) # 16KiB

# keep track of incomplete writings

incomplete = set()

try:

# read while writing the file(s).

# `part` represents a field/file received in a multipart request

async for part in files:

filename = quote(part.get('filename', ''))

if not filename:

continue

with open('Uploaded_' + filename, 'wb') as fp:

incomplete.add(fp)

# stream a (possibly) large part in chunks

async for data in part.stream():

print('Writing %s (len=%d, eof=%s)' % (filename,

len(data),

part['eof']))

fp.write(data)

incomplete.discard(fp) # completed :)

filename = filename.encode()

content_type = quote(part['type']).encode()

yield (

b'File <a href="/download?type=%s&filename=%s">%s</a> '

b'was uploaded.<br />' % (content_type, filename, filename)

)

finally:

while incomplete:

path = incomplete.pop().name

print('Upload canceled, removing incomplete file: %s' % path)

os.unlink(path)

yield b''

@app.route('/download')

async def download(request, response):

# prepend / append a hardcoded string.

# do not let the user freely determine the path

path = 'Uploaded_' + quote(request.query['filename'][0])

content_type = request.query['type'][0]

await response.sendfile(path, content_type=content_type)

if __name__ == '__main__':

# 100MiB is a nice limit due to the default `app_handler_timeout=120`

# (120 seconds). however, it's perfectly fine to increase those limits

app.run('0.0.0.0', 8000, client_max_body_size=100 * 1048576)