用Python标准库发布多部分/表单数据编码的d

Question

我想发布多部分/表单数据编码数据。 我找到了一个执行此操作的外部模块：http://atlee.ca/software/poster/index.html 不过，我宁愿避免这种依赖。有没有办法使用标准库来实现这一点？

谢谢

Answer 1

这是一个老线程，但仍然是一个流行的线程，所以这里是我的贡献，只使用标准模块。

其思想与here相同，但支持Python 2.x和Python 3.x。 它还有一个主体生成器，以避免不必要的内存使用。

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()

演示

# 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)

Answer 2

标准库does not currently support that。有一个cookbook recipe包含了一段很短的代码，您可能只想复制它，但是，还有关于替代方案的长时间讨论。

Answer 3

你不能用stdlib这么快。但是，请参阅这个PyMOTW中的MultiPartForm类。您可以使用或修改它来完成所需的任何任务：

• PyMOTW: urllib2 - Library for opening URLs.