Python standard library to POST multipart/form-data encoded data

Question

I would like to POST multipart/form-data encoded data. I have found an external module that does it: http://atlee.ca/software/poster/index.html however I would rather avoid this dependency. Is there a way to do this using the standard libraries?

thanks

Answer 1

The standard library does not currently support that. There is cookbook recipe that includes a fairly short piece of code that you just may want to copy, though, along with long discussions of alternatives.

Answer 2

It's an old thread but still a popular one, so here is my contribution using only standard modules.

The idea is the same than here but support Python 2.x and Python 3.x. It also has a body generator to avoid unnecessarily memory usage.

import codecs import mimetypes import sys import uuid try:     import io except ImportError:     pass # io is requiered in python3 but not available in python2  class MultipartFormdataEncoder(object):     def __init__(self):         self.boundary = uuid.uuid4().hex         self.content_type = 'multipart/form-data; boundary={}'.format(self.boundary)      @classmethod     def u(cls, s):         if sys.hexversion < 0x03000000 and isinstance(s, str):             s = s.decode('utf-8')         if sys.hexversion >= 0x03000000 and isinstance(s, bytes):             s = s.decode('utf-8')         return s      def iter(self, fields, files):         """         fields is a sequence of (name, value) elements for regular form fields.         files is a sequence of (name, filename, file-type) elements for data to be uploaded as files         Yield body's chunk as bytes         """         encoder = codecs.getencoder('utf-8')         for (key, value) in fields:             key = self.u(key)             yield encoder('--{}\r\n'.format(self.boundary))             yield encoder(self.u('Content-Disposition: form-data; name="{}"\r\n').format(key))             yield encoder('\r\n')             if isinstance(value, int) or isinstance(value, float):                 value = str(value)             yield encoder(self.u(value))             yield encoder('\r\n')         for (key, filename, fd) in files:             key = self.u(key)             filename = self.u(filename)             yield encoder('--{}\r\n'.format(self.boundary))             yield encoder(self.u('Content-Disposition: form-data; name="{}"; filename="{}"\r\n').format(key, filename))             yield encoder('Content-Type: {}\r\n'.format(mimetypes.guess_type(filename)[0] or 'application/octet-stream'))             yield encoder('\r\n')             with fd:                 buff = fd.read()                 yield (buff, len(buff))             yield encoder('\r\n')         yield encoder('--{}--\r\n'.format(self.boundary))      def encode(self, fields, files):         body = io.BytesIO()         for chunk, chunk_len in self.iter(fields, files):             body.write(chunk)         return self.content_type, body.getvalue() 

Demo

# some utf8 key/value pairs fields = [('প্রায়', 42), ('bar', b'23'), ('foo', 'ން:')] files = [('myfile', 'image.jpg', open('image.jpg', 'rb'))]  # iterate and write chunk in a socket content_type, body = MultipartFormdataEncoder().encode(fields, files)