#!/usr/bin/env python3
#
# run server with:
#
#     python3 -m http.server --cgi 8000
#
# upload file with:
#
#    echo foobar | curl -F 'arg=@-;filename=bla.txt' http://127.0.0.1:8000/cgi-bin/upload.cgi
#
# or:
#
#    curl -F 'arg=@blub/bla.txt' http://127.0.0.1:8000/cgi-bin/upload.cgi

import cgi
from os.path import basename

print("Content-Type: text/plain")
print()

form = cgi.FieldStorage()

if "arg" not in form:
    print("no arg field")
    exit()

fileitem = form["arg"]

if not hasattr(fileitem, "file") or not fileitem.file:
    print("not a file")
    exit()

if not fileitem.filename or fileitem.filename == "-":
    print("no filename")
    exit()

filename = basename(fileitem.filename)
if not filename:
    print("invalid filename")
    exit()

try:
    with open(filename, 'wb') as f:
        while True:
            data = fileitem.file.read(4096)
            if not data:
                break
            f.write(data)
except PermissionError:
    print("cannot open file for writing")
except IsADirectoryError:
    print("is a directory")
except FileNotFoundError:
    print("path doesn't exist")
else:
    print("uploaded as %s" % filename)