text: """Request body processing for CherryPy.
  
  .. versionadded:: 3.2
  
  Application authors have complete control over the parsing of HTTP request
  entities. In short,
  :attr:`cherrypy.request.body<cherrypy._cprequest.Request.body>`
  is now always set to an instance of
  :class:`RequestBody<cherrypy._cpreqbody.RequestBody>`,
  and *that* class is a subclass of :class:`Entity<cherrypy._cpreqbody.Entity>`.
  
  When an HTTP request includes an entity body, it is often desirable to
  provide that information to applications in a form other than the raw bytes.
  Different content types demand different approaches. Examples:
  
   * For a GIF file, we want the raw bytes in a stream.
   * An HTML form is better parsed into its component fields, and each text field
     decoded from bytes to unicode.
   * A JSON body should be deserialized into a Python dict or list.
  
  When the request contains a Content-Type header, the media type is used as a
  key to look up a value in the
  :attr:`request.body.processors<cherrypy._cpreqbody.Entity.processors>` dict.
  If the full media
  type is not found, then the major type is tried; for example, if no processor
  is found for the 'image/jpeg' type, then we look for a processor for the
  'image' types altogether. If neither the full type nor the major type has a
  matching processor, then a default processor is used
  (:func:`default_proc<cherrypy._cpreqbody.Entity.default_proc>`). For most
  types, this means no processing is done, and the body is left unread as a
  raw byte stream. Processors are configurable in an 'on_start_resource' hook.
  
  Some processors, especially those for the 'text' types, attempt to decode bytes
  to unicode. If the Content-Type request header includes a 'charset' parameter,
  this is used to decode the entity. Otherwise, one or more default charsets may
  be attempted, although this decision is up to each processor. If a processor
  successfully decodes an Entity or Part, it should set the
  :attr:`charset<cherrypy._cpreqbody.Entity.charset>` attribute
  on the Entity or Part to the name of the successful charset, so that
  applications can easily re-encode or transcode the value if they wish.
  
  If the Content-Type of the request entity is of major type 'multipart', then
  the above parsing process, and possibly a decoding process, is performed for
  each part.
  
  For both the full entity and multipart parts, a Content-Disposition header may
  be used to fill :attr:`name<cherrypy._cpreqbody.Entity.name>` and
  :attr:`filename<cherrypy._cpreqbody.Entity.filename>` attributes on the
  request.body or the Part.
  
  .. _custombodyprocessors:
  
  Custom Processors
  =================
  
  You can add your own processors for any specific or major MIME type. Simply add
  it to the :attr:`processors<cherrypy._cprequest.Entity.processors>` dict in a
  hook/tool that runs at ``on_start_resource`` or ``before_request_body``.
  Here's the built-in JSON tool for an example::
  
      def json_in(force=True, debug=False):
          request = cherrypy.serving.request
          def json_processor(entity):
              \"""Read application/json data into request.json.\"""
              if not entity.headers.get("Content-Length", ""):
                  raise cherrypy.HTTPError(411)
  
              body = entity.fp.read()
              try:
                  request.json = json_decode(body)
              except ValueError:
                  raise cherrypy.HTTPError(400, 'Invalid JSON document')
          if force:
              request.body.processors.clear()
              request.body.default_proc = cherrypy.HTTPError(
                  415, 'Expected an application/json content type')
          request.body.processors['application/json'] = json_processor
  
  We begin by defining a new ``json_processor`` function to stick in the
  ``processors`` dictionary. All processor functions take a single argument,
  the ``Entity`` instance they are to process. It will be called whenever a
  request is received (for those URI's where the tool is turned on) which
  has a ``Content-Type`` of "application/json".
  
  First, it checks for a valid ``Content-Length`` (raising 411 if not valid),
  then reads the remaining bytes on the socket. The ``fp`` object knows its
  own length, so it won't hang waiting for data that never arrives. It will
  return when all data has been read. Then, we decode those bytes using
  Python's built-in ``json`` module, and stick the decoded result onto
  ``request.json`` . If it cannot be decoded, we raise 400.
  
  If the "force" argument is True (the default), the ``Tool`` clears the
  ``processors`` dict so that request entities of other ``Content-Types``
  aren't parsed at all. Since there's no entry for those invalid MIME
  types, the ``default_proc`` method of ``cherrypy.request.body`` is
  called. But this does nothing by default (usually to provide the page
  handler an opportunity to handle it.)
  But in our case, we want to raise 415, so we replace
  ``request.body.default_proc``
  with the error (``HTTPError`` instances, when called, raise themselves).
  
  If we were defining a custom processor, we can do so without making a ``Tool``.
  Just add the config entry::
  
      request.body.processors = {'application/json': json_processor}
  
  Note that you can only replace the ``processors`` dict wholesale this way,
  not update the existing one.
  """
  
  try:
      from io import DEFAULT_BUFFER_SIZE
  except ImportError:
      DEFAULT_BUFFER_SIZE = 8192
  import re
  import sys
  import tempfile
  try:
      from urllib import unquote_plus
  except ImportError:
      def unquote_plus(bs):
          """Bytes version of urllib.parse.unquote_plus."""
          bs = bs.replace(ntob('+'), ntob(' '))
          atoms = bs.split(ntob('%'))
          for i in range(1, len(atoms)):
              item = atoms[i]
              try:
                  pct = int(item[:2], 16)
                  atoms[i] = bytes([pct]) + item[2:]
              except ValueError:
                  pass
          return ntob('').join(atoms)
  
  import cherrypy
  from cherrypy._cpcompat import basestring, ntob, ntou
  from cherrypy.lib import httputil
  
  
  # ------------------------------- Processors -------------------------------- #
  
  def process_urlencoded(entity):
      """Read application/x-www-form-urlencoded data into entity.params."""
      qs = entity.fp.read()
      for charset in entity.attempt_charsets:
          try:
              params = {}
              for aparam in qs.split(ntob('&')):
                  for pair in aparam.split(ntob(';')):
                      if not pair:
                          continue
  
                      atoms = pair.split(ntob('='), 1)
                      if len(atoms) == 1:
                          atoms.append(ntob(''))
  
                      key = unquote_plus(atoms[0]).decode(charset)
                      value = unquote_plus(atoms[1]).decode(charset)
  
                      if key in params:
                          if not isinstance(params[key], list):
                              params[key] = [params[key]]
                          params[key].append(value)
                      else:
                          params[key] = value
          except UnicodeDecodeError:
              pass
          else:
              entity.charset = charset
              break
      else:
          raise cherrypy.HTTPError(
              400, "The request entity could not be decoded. The following "
              "charsets were attempted: %s" % repr(entity.attempt_charsets))
  
      # Now that all values have been successfully parsed and decoded,
      # apply them to the entity.params dict.
      for key, value in params.items():
          if key in entity.params:
              if not isinstance(entity.params[key], list):
                  entity.params[key] = [entity.params[key]]
              entity.params[key].append(value)
          else:
              entity.params[key] = value
  
  
  def process_multipart(entity):
      """Read all multipart parts into entity.parts."""
      ib = ""
      if 'boundary' in entity.content_type.params:
          # http://tools.ietf.org/html/rfc2046#section-5.1.1
          # "The grammar for parameters on the Content-type field is such that it
          # is often necessary to enclose the boundary parameter values in quotes
          # on the Content-type line"
          ib = entity.content_type.params['boundary'].strip('"')
  
      if not re.match("^[ -~]{0,200}[!-~]$", ib):
          raise ValueError('Invalid boundary in multipart form: %r' % (ib,))
  
      ib = ('--' + ib).encode('ascii')
  
      # Find the first marker
      while True:
          b = entity.readline()
          if not b:
              return
  
          b = b.strip()
          if b == ib:
              break
  
      # Read all parts
      while True:
          part = entity.part_class.from_fp(entity.fp, ib)
          entity.parts.append(part)
          part.process()
          if part.fp.done:
              break
  
  
  def process_multipart_form_data(entity):
      """Read all multipart/form-data parts into entity.parts or entity.params.
      """
      process_multipart(entity)
  
      kept_parts = []
      for part in entity.parts:
          if part.name is None:
              kept_parts.append(part)
          else:
              if part.filename is None:
                  # It's a regular field
                  value = part.fullvalue()
              else:
                  # It's a file upload. Retain the whole part so consumer code
                  # has access to its .file and .filename attributes.
                  value = part
  
              if part.name in entity.params:
                  if not isinstance(entity.params[part.name], list):
                      entity.params[part.name] = [entity.params[part.name]]
                  entity.params[part.name].append(value)
              else:
                  entity.params[part.name] = value
  
      entity.parts = kept_parts
  
  
  def _old_process_multipart(entity):
      """The behavior of 3.2 and lower. Deprecated and will be changed in 3.3."""
      process_multipart(entity)
  
      params = entity.params
  
      for part in entity.parts:
          if part.name is None:
              key = ntou('parts')
          else:
              key = part.name
  
          if part.filename is None:
              # It's a regular field
              value = part.fullvalue()
          else:
              # It's a file upload. Retain the whole part so consumer code
              # has access to its .file and .filename attributes.
              value = part
  
          if key in params:
              if not isinstance(params[key], list):
                  params[key] = [params[key]]
              params[key].append(value)
          else:
              params[key] = value
  
  
  # -------------------------------- Entities --------------------------------- #
  class Entity(object):
  
      """An HTTP request body, or MIME multipart body.
  
      This class collects information about the HTTP request entity. When a
      given entity is of MIME type "multipart", each part is parsed into its own
      Entity instance, and the set of parts stored in
      :attr:`entity.parts<cherrypy._cpreqbody.Entity.parts>`.
  
      Between the ``before_request_body`` and ``before_handler`` tools, CherryPy
      tries to process the request body (if any) by calling
      :func:`request.body.process<cherrypy._cpreqbody.RequestBody.process>`.
      This uses the ``content_type`` of the Entity to look up a suitable
      processor in
      :attr:`Entity.processors<cherrypy._cpreqbody.Entity.processors>`,
      a dict.
      If a matching processor cannot be found for the complete Content-Type,
      it tries again using the major type. For example, if a request with an
      entity of type "image/jpeg" arrives, but no processor can be found for
      that complete type, then one is sought for the major type "image". If a
      processor is still not found, then the
      :func:`default_proc<cherrypy._cpreqbody.Entity.default_proc>` method
      of the Entity is called (which does nothing by default; you can
      override this too).
  
      CherryPy includes processors for the "application/x-www-form-urlencoded"
      type, the "multipart/form-data" type, and the "multipart" major type.
      CherryPy 3.2 processes these types almost exactly as older versions.
      Parts are passed as arguments to the page handler using their
      ``Content-Disposition.name`` if given, otherwise in a generic "parts"
      argument. Each such part is either a string, or the
      :class:`Part<cherrypy._cpreqbody.Part>` itself if it's a file. (In this
      case it will have ``file`` and ``filename`` attributes, or possibly a
      ``value`` attribute). Each Part is itself a subclass of
      Entity, and has its own ``process`` method and ``processors`` dict.
  
      There is a separate processor for the "multipart" major type which is more
      flexible, and simply stores all multipart parts in
      :attr:`request.body.parts<cherrypy._cpreqbody.Entity.parts>`. You can
      enable it with::
  
          cherrypy.request.body.processors['multipart'] = _cpreqbody.process_multipart
  
      in an ``on_start_resource`` tool.
      """
  
      # http://tools.ietf.org/html/rfc2046#section-4.1.2:
      # "The default character set, which must be assumed in the
      # absence of a charset parameter, is US-ASCII."
      # However, many browsers send data in utf-8 with no charset.
      attempt_charsets = ['utf-8']
      """A list of strings, each of which should be a known encoding.
  
      When the Content-Type of the request body warrants it, each of the given
      encodings will be tried in order. The first one to successfully decode the
      entity without raising an error is stored as
      :attr:`entity.charset<cherrypy._cpreqbody.Entity.charset>`. This defaults
      to ``['utf-8']`` (plus 'ISO-8859-1' for "text/\*" types, as required by
      `HTTP/1.1 <http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1>`_),
      but ``['us-ascii', 'utf-8']`` for multipart parts.
      """
  
      charset = None
      """The successful decoding; see "attempt_charsets" above."""
  
      content_type = None
      """The value of the Content-Type request header.
  
      If the Entity is part of a multipart payload, this will be the Content-Type
      given in the MIME headers for this part.
      """
  
      default_content_type = 'application/x-www-form-urlencoded'
      """This defines a default ``Content-Type`` to use if no Content-Type header
      is given. The empty string is used for RequestBody, which results in the
      request body not being read or parsed at all. This is by design; a missing
      ``Content-Type`` header in the HTTP request entity is an error at best,
      and a security hole at worst. For multipart parts, however, the MIME spec
      declares that a part with no Content-Type defaults to "text/plain"
      (see :class:`Part<cherrypy._cpreqbody.Part>`).
      """
  
      filename = None
      """The ``Content-Disposition.filename`` header, if available."""
  
      fp = None
      """The readable socket file object."""
  
      headers = None
      """A dict of request/multipart header names and values.
  
      This is a copy of the ``request.headers`` for the ``request.body``;
      for multipart parts, it is the set of headers for that part.
      """
  
      length = None
      """The value of the ``Content-Length`` header, if provided."""
  
      name = None
      """The "name" parameter of the ``Content-Disposition`` header, if any."""
  
      params = None
      """
      If the request Content-Type is 'application/x-www-form-urlencoded' or
      multipart, this will be a dict of the params pulled from the entity
      body; that is, it will be the portion of request.params that come
      from the message body (sometimes called "POST params", although they
      can be sent with various HTTP method verbs). This value is set between
      the 'before_request_body' and 'before_handler' hooks (assuming that
      process_request_body is True)."""
  
      processors = {'application/x-www-form-urlencoded': process_urlencoded,
                    'multipart/form-data': process_multipart_form_data,
                    'multipart': process_multipart,
                    }
      """A dict of Content-Type names to processor methods."""
  
      parts = None
      """A list of Part instances if ``Content-Type`` is of major type
      "multipart"."""
  
      part_class = None
      """The class used for multipart parts.
  
      You can replace this with custom subclasses to alter the processing of
      multipart parts.
      """
  
      def __init__(self, fp, headers, params=None, parts=None):
          # Make an instance-specific copy of the class processors
          # so Tools, etc. can replace them per-request.
          self.processors = self.processors.copy()
  
          self.fp = fp
          self.headers = headers
  
          if params is None:
              params = {}
          self.params = params
  
          if parts is None:
              parts = []
          self.parts = parts
  
          # Content-Type
          self.content_type = headers.elements('Content-Type')
          if self.content_type:
              self.content_type = self.content_type[0]
          else:
              self.content_type = httputil.HeaderElement.from_str(
                  self.default_content_type)
  
          # Copy the class 'attempt_charsets', prepending any Content-Type
          # charset
          dec = self.content_type.params.get("charset", None)
          if dec:
              self.attempt_charsets = [dec] + [c for c in self.attempt_charsets
                                               if c != dec]
          else:
              self.attempt_charsets = self.attempt_charsets[:]
  
          # Length
          self.length = None
          clen = headers.get('Content-Length', None)
          # If Transfer-Encoding is 'chunked', ignore any Content-Length.
          if (
              clen is not None and
              'chunked' not in headers.get('Transfer-Encoding', '')
          ):
              try:
                  self.length = int(clen)
              except ValueError:
                  pass
  
          # Content-Disposition
          self.name = None
          self.filename = None
          disp = headers.elements('Content-Disposition')
          if disp:
              disp = disp[0]
              if 'name' in disp.params:
                  self.name = disp.params['name']
                  if self.name.startswith('"') and self.name.endswith('"'):
                      self.name = self.name[1:-1]
              if 'filename' in disp.params:
                  self.filename = disp.params['filename']
                  if (
                      self.filename.startswith('"') and
                      self.filename.endswith('"')
                  ):
                      self.filename = self.filename[1:-1]
  
      # The 'type' attribute is deprecated in 3.2; remove it in 3.3.
      type = property(
          lambda self: self.content_type,
          doc="A deprecated alias for "
              ":attr:`content_type<cherrypy._cpreqbody.Entity.content_type>`."
      )
  
      def read(self, size=None, fp_out=None):
          return self.fp.read(size, fp_out)
  
      def readline(self, size=None):
          return self.fp.readline(size)
  
      def readlines(self, sizehint=None):
          return self.fp.readlines(sizehint)
  
      def __iter__(self):
          return self
  
      def __next__(self):
          line = self.readline()
          if not line:
              raise StopIteration
          return line
  
      def next(self):
          return self.__next__()
  
      def read_into_file(self, fp_out=None):
          """Read the request body into fp_out (or make_file() if None).
  
          Return fp_out.
          """
          if fp_out is None:
              fp_out = self.make_file()
          self.read(fp_out=fp_out)
          return fp_out
  
      def make_file(self):
          """Return a file-like object into which the request body will be read.
  
          By default, this will return a TemporaryFile. Override as needed.
          See also :attr:`cherrypy._cpreqbody.Part.maxrambytes`."""
          return tempfile.TemporaryFile()
  
      def fullvalue(self):
          """Return this entity as a string, whether stored in a file or not."""
          if self.file:
              # It was stored in a tempfile. Read it.
              self.file.seek(0)
              value = self.file.read()
              self.file.seek(0)
          else:
              value = self.value
          return value
  
      def process(self):
          """Execute the best-match processor for the given media type."""
          proc = None
          ct = self.content_type.value
          try:
              proc = self.processors[ct]
          except KeyError:
              toptype = ct.split('/', 1)[0]
              try:
                  proc = self.processors[toptype]
              except KeyError:
                  pass
          if proc is None:
              self.default_proc()
          else:
              proc(self)
  
      def default_proc(self):
          """Called if a more-specific processor is not found for the
          ``Content-Type``.
          """
          # Leave the fp alone for someone else to read. This works fine
          # for request.body, but the Part subclasses need to override this
          # so they can move on to the next part.
          pass
  
  
  class Part(Entity):
  
      """A MIME part entity, part of a multipart entity."""
  
      # "The default character set, which must be assumed in the absence of a
      # charset parameter, is US-ASCII."
      attempt_charsets = ['us-ascii', 'utf-8']
      """A list of strings, each of which should be a known encoding.
  
      When the Content-Type of the request body warrants it, each of the given
      encodings will be tried in order. The first one to successfully decode the
      entity without raising an error is stored as
      :attr:`entity.charset<cherrypy._cpreqbody.Entity.charset>`. This defaults
      to ``['utf-8']`` (plus 'ISO-8859-1' for "text/\*" types, as required by
      `HTTP/1.1 <http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1>`_),
      but ``['us-ascii', 'utf-8']`` for multipart parts.
      """
  
      boundary = None
      """The MIME multipart boundary."""
  
      default_content_type = 'text/plain'
      """This defines a default ``Content-Type`` to use if no Content-Type header
      is given. The empty string is used for RequestBody, which results in the
      request body not being read or parsed at all. This is by design; a missing
      ``Content-Type`` header in the HTTP request entity is an error at best,
      and a security hole at worst. For multipart parts, however (this class),
      the MIME spec declares that a part with no Content-Type defaults to
      "text/plain".
      """
  
      # This is the default in stdlib cgi. We may want to increase it.
      maxrambytes = 1000
      """The threshold of bytes after which point the ``Part`` will store
      its data in a file (generated by
      :func:`make_file<cherrypy._cprequest.Entity.make_file>`)
      instead of a string. Defaults to 1000, just like the :mod:`cgi`
      module in Python's standard library.
      """
  
      def __init__(self, fp, headers, boundary):
          Entity.__init__(self, fp, headers)
          self.boundary = boundary
          self.file = None
          self.value = None
  
      def from_fp(cls, fp, boundary):
          headers = cls.read_headers(fp)
          return cls(fp, headers, boundary)
      from_fp = classmethod(from_fp)
  
      def read_headers(cls, fp):
          headers = httputil.HeaderMap()
          while True:
              line = fp.readline()
              if not line:
                  # No more data--illegal end of headers
                  raise EOFError("Illegal end of headers.")
  
              if line == ntob('\r\n'):
                  # Normal end of headers
                  break
              if not line.endswith(ntob('\r\n')):
                  raise ValueError("MIME requires CRLF terminators: %r" % line)
  
              if line[0] in ntob(' \t'):
                  # It's a continuation line.
                  v = line.strip().decode('ISO-8859-1')
              else:
                  k, v = line.split(ntob(":"), 1)
                  k = k.strip().decode('ISO-8859-1')
                  v = v.strip().decode('ISO-8859-1')
  
              existing = headers.get(k)
              if existing:
                  v = ", ".join((existing, v))
              headers[k] = v
  
          return headers
      read_headers = classmethod(read_headers)
  
      def read_lines_to_boundary(self, fp_out=None):
          """Read bytes from self.fp and return or write them to a file.
  
          If the 'fp_out' argument is None (the default), all bytes read are
          returned in a single byte string.
  
          If the 'fp_out' argument is not None, it must be a file-like
          object that supports the 'write' method; all bytes read will be
          written to the fp, and that fp is returned.
          """
          endmarker = self.boundary + ntob("--")
          delim = ntob("")
          prev_lf = True
          lines = []
          seen = 0
          while True:
              line = self.fp.readline(1 << 16)
              if not line:
                  raise EOFError("Illegal end of multipart body.")
              if line.startswith(ntob("--")) and prev_lf:
                  strippedline = line.strip()
                  if strippedline == self.boundary:
                      break
                  if strippedline == endmarker:
                      self.fp.finish()
                      break
  
              line = delim + line
  
              if line.endswith(ntob("\r\n")):
                  delim = ntob("\r\n")
                  line = line[:-2]
                  prev_lf = True
              elif line.endswith(ntob("\n")):
                  delim = ntob("\n")
                  line = line[:-1]
                  prev_lf = True
              else:
                  delim = ntob("")
                  prev_lf = False
  
              if fp_out is None:
                  lines.append(line)
                  seen += len(line)
                  if seen > self.maxrambytes:
                      fp_out = self.make_file()
                      for line in lines:
                          fp_out.write(line)
              else:
                  fp_out.write(line)
  
          if fp_out is None:
              result = ntob('').join(lines)
              for charset in self.attempt_charsets:
                  try:
                      result = result.decode(charset)
                  except UnicodeDecodeError:
                      pass
                  else:
                      self.charset = charset
                      return result
              else:
                  raise cherrypy.HTTPError(
                      400,
                      "The request entity could not be decoded. The following "
                      "charsets were attempted: %s" % repr(self.attempt_charsets)
                  )
          else:
              fp_out.seek(0)
              return fp_out
  
      def default_proc(self):
          """Called if a more-specific processor is not found for the
          ``Content-Type``.
          """
          if self.filename:
              # Always read into a file if a .filename was given.
              self.file = self.read_into_file()
          else:
              result = self.read_lines_to_boundary()
              if isinstance(result, basestring):
                  self.value = result
              else:
                  self.file = result
  
      def read_into_file(self, fp_out=None):
          """Read the request body into fp_out (or make_file() if None).
  
          Return fp_out.
          """
          if fp_out is None:
              fp_out = self.make_file()
          self.read_lines_to_boundary(fp_out=fp_out)
          return fp_out
  
  Entity.part_class = Part
  
  try:
      inf = float('inf')
  except ValueError:
      # Python 2.4 and lower
      class Infinity(object):
  
          def __cmp__(self, other):
              return 1
  
          def __sub__(self, other):
              return self
      inf = Infinity()
  
  
  comma_separated_headers = [
      'Accept', 'Accept-Charset', 'Accept-Encoding',
      'Accept-Language', 'Accept-Ranges', 'Allow',
      'Cache-Control', 'Connection', 'Content-Encoding',
      'Content-Language', 'Expect', 'If-Match',
      'If-None-Match', 'Pragma', 'Proxy-Authenticate',
      'Te', 'Trailer', 'Transfer-Encoding', 'Upgrade',
      'Vary', 'Via', 'Warning', 'Www-Authenticate'
  ]
  
  
  class SizedReader:
  
      def __init__(self, fp, length, maxbytes, bufsize=DEFAULT_BUFFER_SIZE,
                   has_trailers=False):
          # Wrap our fp in a buffer so peek() works
          self.fp = fp
          self.length = length
          self.maxbytes = maxbytes
          self.buffer = ntob('')
          self.bufsize = bufsize
          self.bytes_read = 0
          self.done = False
          self.has_trailers = has_trailers
  
      def read(self, size=None, fp_out=None):
          """Read bytes from the request body and return or write them to a file.
  
          A number of bytes less than or equal to the 'size' argument are read
          off the socket. The actual number of bytes read are tracked in
          self.bytes_read. The number may be smaller than 'size' when 1) the
          client sends fewer bytes, 2) the 'Content-Length' request header
          specifies fewer bytes than requested, or 3) the number of bytes read
          exceeds self.maxbytes (in which case, 413 is raised).
  
          If the 'fp_out' argument is None (the default), all bytes read are
          returned in a single byte string.
  
          If the 'fp_out' argument is not None, it must be a file-like
          object that supports the 'write' method; all bytes read will be
          written to the fp, and None is returned.
          """
  
          if self.length is None:
              if size is None:
                  remaining = inf
              else:
                  remaining = size
          else:
              remaining = self.length - self.bytes_read
              if size and size < remaining:
                  remaining = size
          if remaining == 0:
              self.finish()
              if fp_out is None:
                  return ntob('')
              else:
                  return None
  
          chunks = []
  
          # Read bytes from the buffer.
          if self.buffer:
              if remaining is inf:
                  data = self.buffer
                  self.buffer = ntob('')
              else:
                  data = self.buffer[:remaining]
                  self.buffer = self.buffer[remaining:]
              datalen = len(data)
              remaining -= datalen
  
              # Check lengths.
              self.bytes_read += datalen
              if self.maxbytes and self.bytes_read > self.maxbytes:
                  raise cherrypy.HTTPError(413)
  
              # Store the data.
              if fp_out is None:
                  chunks.append(data)
              else:
                  fp_out.write(data)
  
          # Read bytes from the socket.
          while remaining > 0:
              chunksize = min(remaining, self.bufsize)
              try:
                  data = self.fp.read(chunksize)
              except Exception:
                  e = sys.exc_info()[1]
                  if e.__class__.__name__ == 'MaxSizeExceeded':
                      # Post data is too big
                      raise cherrypy.HTTPError(
                          413, "Maximum request length: %r" % e.args[1])
                  else:
                      raise
              if not data:
                  self.finish()
                  break
              datalen = len(data)
              remaining -= datalen
  
              # Check lengths.
              self.bytes_read += datalen
              if self.maxbytes and self.bytes_read > self.maxbytes:
                  raise cherrypy.HTTPError(413)
  
              # Store the data.
              if fp_out is None:
                  chunks.append(data)
              else:
                  fp_out.write(data)
  
          if fp_out is None:
              return ntob('').join(chunks)
  
      def readline(self, size=None):
          """Read a line from the request body and return it."""
          chunks = []
          while size is None or size > 0:
              chunksize = self.bufsize
              if size is not None and size < self.bufsize:
                  chunksize = size
              data = self.read(chunksize)
              if not data:
                  break
              pos = data.find(ntob('\n')) + 1
              if pos:
                  chunks.append(data[:pos])
                  remainder = data[pos:]
                  self.buffer += remainder
                  self.bytes_read -= len(remainder)
                  break
              else:
                  chunks.append(data)
          return ntob('').join(chunks)
  
      def readlines(self, sizehint=None):
          """Read lines from the request body and return them."""
          if self.length is not None:
              if sizehint is None:
                  sizehint = self.length - self.bytes_read
              else:
                  sizehint = min(sizehint, self.length - self.bytes_read)
  
          lines = []
          seen = 0
          while True:
              line = self.readline()
              if not line:
                  break
              lines.append(line)
              seen += len(line)
              if seen >= sizehint:
                  break
          return lines
  
      def finish(self):
          self.done = True
          if self.has_trailers and hasattr(self.fp, 'read_trailer_lines'):
              self.trailers = {}
  
              try:
                  for line in self.fp.read_trailer_lines():
                      if line[0] in ntob(' \t'):
                          # It's a continuation line.
                          v = line.strip()
                      else:
                          try:
                              k, v = line.split(ntob(":"), 1)
                          except ValueError:
                              raise ValueError("Illegal header line.")
                          k = k.strip().title()
                          v = v.strip()
  
                      if k in comma_separated_headers:
                          existing = self.trailers.get(envname)
                          if existing:
                              v = ntob(", ").join((existing, v))
                      self.trailers[k] = v
              except Exception:
                  e = sys.exc_info()[1]
                  if e.__class__.__name__ == 'MaxSizeExceeded':
                      # Post data is too big
                      raise cherrypy.HTTPError(
                          413, "Maximum request length: %r" % e.args[1])
                  else:
                      raise
  
  
  class RequestBody(Entity):
  
      """The entity of the HTTP request."""
  
      bufsize = 8 * 1024
      """The buffer size used when reading the socket."""
  
      # Don't parse the request body at all if the client didn't provide
      # a Content-Type header. See
      # https://bitbucket.org/cherrypy/cherrypy/issue/790
      default_content_type = ''
      """This defines a default ``Content-Type`` to use if no Content-Type header
      is given. The empty string is used for RequestBody, which results in the
      request body not being read or parsed at all. This is by design; a missing
      ``Content-Type`` header in the HTTP request entity is an error at best,
      and a security hole at worst. For multipart parts, however, the MIME spec
      declares that a part with no Content-Type defaults to "text/plain"
      (see :class:`Part<cherrypy._cpreqbody.Part>`).
      """
  
      maxbytes = None
      """Raise ``MaxSizeExceeded`` if more bytes than this are read from
      the socket.
      """
  
      def __init__(self, fp, headers, params=None, request_params=None):
          Entity.__init__(self, fp, headers, params)
  
          # http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1
          # When no explicit charset parameter is provided by the
          # sender, media subtypes of the "text" type are defined
          # to have a default charset value of "ISO-8859-1" when
          # received via HTTP.
          if self.content_type.value.startswith('text/'):
              for c in ('ISO-8859-1', 'iso-8859-1', 'Latin-1', 'latin-1'):
                  if c in self.attempt_charsets:
                      break
              else:
                  self.attempt_charsets.append('ISO-8859-1')
  
          # Temporary fix while deprecating passing .parts as .params.
          self.processors['multipart'] = _old_process_multipart
  
          if request_params is None:
              request_params = {}
          self.request_params = request_params
  
      def process(self):
          """Process the request entity based on its Content-Type."""
          # "The presence of a message-body in a request is signaled by the
          # inclusion of a Content-Length or Transfer-Encoding header field in
          # the request's message-headers."
          # It is possible to send a POST request with no body, for example;
          # however, app developers are responsible in that case to set
          # cherrypy.request.process_body to False so this method isn't called.
          h = cherrypy.serving.request.headers
          if 'Content-Length' not in h and 'Transfer-Encoding' not in h:
              raise cherrypy.HTTPError(411)
  
          self.fp = SizedReader(self.fp, self.length,
                                self.maxbytes, bufsize=self.bufsize,
                                has_trailers='Trailer' in h)
          super(RequestBody, self).process()
  
          # Body params should also be a part of the request_params
          # add them in here.
          request_params = self.request_params
          for key, value in self.params.items():
              # Python 2 only: keyword arguments must be byte strings (type
              # 'str').
              if sys.version_info < (3, 0):
                  if isinstance(key, unicode):
                      key = key.encode('ISO-8859-1')
  
              if key in request_params:
                  if not isinstance(request_params[key], list):
                      request_params[key] = [request_params[key]]
                  request_params[key].append(value)
              else:
                  request_params[key] = value
  