"""This package contains all WSGI specific code for cubicweb

NOTE: this package borrows a lot of code to Django

      (http://www.djangoproject.com) and to the wsgiref module

      of the python2.5's stdlib.

WSGI corresponding PEP: http://www.python.org/dev/peps/pep-0333/

:organization: Logilab

:copyright: 2008-2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

"""

__docformat__ = "restructuredtext en"

from email import message, message_from_string

from Cookie import SimpleCookie

from StringIO import StringIO

from cgi import parse_header, parse_qsl

from pprint import pformat as _pformat

def pformat(obj):

    """pretty prints `obj` if possible"""

    try:

        return _pformat(obj)

    except:

        return u'<could not parse>'

def qs2dict(qs):

    """transforms a query string into a regular python dict"""

    result = {}

    for key, value in parse_qsl(qs, True):

        result.setdefault(key, []).append(value)

    return result

def normalize_header(header):

    """returns a normalized header name

    >>> normalize_header('User_Agent')

    'User-agent'

    """

    return header.replace('_', '-').capitalize()

def safe_copyfileobj(fsrc, fdst, length=16*1024, size=0):

    """

    THIS COMES FROM DJANGO

    A version of shutil.copyfileobj that will not read more than 'size' bytes.

    This makes it safe from clients sending more than CONTENT_LENGTH bytes of

    data in the body.

    """

    if not size:

        return

    while size > 0:

        buf = fsrc.read(min(length, size))

        if not buf:

            break

        fdst.write(buf)

        size -= len(buf)

def parse_file_upload(header_dict, post_data):

    """This is adapted FROM DJANGO"""

    raw_message = '\r\n'.join('%s:%s' % pair for pair in header_dict.iteritems())

    raw_message += '\r\n\r\n' + post_data

    msg = message_from_string(raw_message)

    post, files = {}, {}

    for submessage in msg.get_payload():

        name_dict = parse_header(submessage['Content-Disposition'])[1]

        key = name_dict['name']

        # name_dict is something like {'name': 'file', 'filename': 'test.txt'} for file uploads

        # or {'name': 'blah'} for POST fields

        # We assume all uploaded files have a 'filename' set.

        if 'filename' in name_dict:

            assert type([]) != type(submessage.get_payload()), "Nested MIME messages are not supported"

            if not name_dict['filename'].strip():

                continue

            # IE submits the full path, so trim everything but the basename.

            # (We can't use os.path.basename because that uses the server's

            # directory separator, which may not be the same as the

            # client's one.)

            filename = name_dict['filename'][name_dict['filename'].rfind("\\")+1:]

            mimetype = 'Content-Type' in submessage and submessage['Content-Type'] or None

            content = StringIO(submessage.get_payload())

            files[key] = [filename, mimetype, content]

        else:

            post.setdefault(key, []).append(submessage.get_payload())

    return post, files