urllib-multipart.py

import random
import string
import io
import os
import sys
import mimetypes
import urllib.request

def force_string(anything):
    if isinstance(anything,str):
        return anything
    elif isinstance(anything,bytes):
        return anything.decode()
    else:
        return str(anything)

def items(dct):
    its=[]
    for k in dct:
        v=dct[k]
        if isinstance(v,list) or isinstance(v,tuple):
            for i in v:
                its.append([k,i])
        else:

            its.append([k,v])
    return its
    
class File(io.IOBase):
    def __init__(self,buffer,filename,content_type=None):
        if content_type is None:
            content_type=force_string(mimetypes.guess_type(os.path.split(filename)[1])[0])
        content_type=force_string(content_type)

        self.size=len(buffer)
        self.buffer=io.BytesIO(buffer)

        self.name=force_string(os.path.split(filename)[1])
        self.mode='rb'
        self.content_type=content_type
    def read(self,size=-1):
        return self.buffer.read(size)
   
    def write(self,anything):
        raise(io.UnsupportedOperation('not writable'))
    @classmethod
    def open(self,file):
        reader=open(file,'rb')
        return File(reader.read(),file)
def _boundary():
    return ''.join(random.choices(string.ascii_letters+string.digits,k=10))
class Maker:
    def __init__(self,fields,boundary=None):
        if boundary is None:
            boundary=_boundary()
        self.boundary=boundary
        self.fields=fields
        self.headers={"Content-Type":"multipart/form-data; boundary="+self.boundary}
    def make(self):
        built=''
        bdr='--'+self.boundary+'\n'
        for field in items(self.fields):
            built+=bdr
            disp='Content-Disposition: form-data; name="'+field[0]+'"'
            val=field[1]
            if isinstance(val,File):
                disp+='; filename="'+val.name+'"\nContent-Type: '+val.content_type
                val=val.read().decode()
            disp+='\n\n'
            disp+=val+'\n'
            built+=disp
        built+=bdr.strip()+'--'
        return built.encode()
def urllib_send_files(data):
    maker=Maker(data)
    headers,built=maker.headers,maker.make()
    origh={"Content-Type":"multipart/form-data"}
    origh.update(headers)
    req=urllib.request.Request(url,
     data,
     headers=origh
     ) 
    urlopen=urllib.request.urlopen(req)
    return urlopen.read()