"""HTTP/1.1 client library

<intro stuff goes here>

<other stuff, too>

HTTPConnection goes through a number of "states", which define when a client

may legally make another request or fetch the response for a particular

request. This diagram details these state transitions:

    (null)

      |

      | HTTPConnection()

      v

    Idle

      |

      | putrequest()

      v

    Request-started

      |

      | ( putheader() )*  endheaders()

      v

    Request-sent

      |

      | response = getresponse()

      v

    Unread-response   [Response-headers-read]

      |\____________________

      |                     |

      | response.read()     | putrequest()

      v                     v

    Idle                  Req-started-unread-response

                     ______/|

                   /        |

   response.read() |        | ( putheader() )*  endheaders()

                   v        v

       Request-started    Req-sent-unread-response

                            |

                            | response.read()

                            v

                          Request-sent

This diagram presents the following rules:

  -- a second request may not be started until {response-headers-read}

  -- a response [object] cannot be retrieved until {request-sent}

  -- there is no differentiation between an unread response body and a

     partially read response body

Note: this enforcement is applied by the HTTPConnection class. The

      HTTPResponse class does not enforce this state machine, which

      implies sophisticated clients may accelerate the request/response

      pipeline. Caution should be taken, though: accelerating the states

      beyond the above pattern may imply knowledge of the server's

      connection-close behavior for certain requests. For example, it

      is impossible to tell whether the server will close the connection

      UNTIL the response headers have been read; this means that further

      requests cannot be placed into the pipeline until it is known that

      the server will NOT be closing the connection.

Logical State                  __state            __response

-------------                  -------            ----------

Idle                           _CS_IDLE           None

Request-started                _CS_REQ_STARTED    None

Request-sent                   _CS_REQ_SENT       None

Unread-response                _CS_IDLE           <response_class>

Req-started-unread-response    _CS_REQ_STARTED    <response_class>

Req-sent-unread-response       _CS_REQ_SENT       <response_class>

"""

import errno

import mimetools

import socket

from urlparse import urlsplit

try:

    from cStringIO import StringIO

except ImportError:

    from StringIO import StringIO

__all__ = ["HTTP", "HTTPResponse", "HTTPConnection", "HTTPSConnection",

           "HTTPException", "NotConnected", "UnknownProtocol",

           "UnknownTransferEncoding", "UnimplementedFileMode",

           "IncompleteRead", "InvalidURL", "ImproperConnectionState",

           "CannotSendRequest", "CannotSendHeader", "ResponseNotReady",

           "BadStatusLine", "error", "responses"]

HTTP_PORT = 80

HTTPS_PORT = 443

_UNKNOWN = 'UNKNOWN'

# connection states

_CS_IDLE = 'Idle'

_CS_REQ_STARTED = 'Request-started'

_CS_REQ_SENT = 'Request-sent'

# status codes

# informational

CONTINUE = 100

SWITCHING_PROTOCOLS = 101

PROCESSING = 102

# successful

OK = 200

CREATED = 201

ACCEPTED = 202

NON_AUTHORITATIVE_INFORMATION = 203

NO_CONTENT = 204

RESET_CONTENT = 205

PARTIAL_CONTENT = 206

MULTI_STATUS = 207

IM_USED = 226

# redirection

MULTIPLE_CHOICES = 300

MOVED_PERMANENTLY = 301

FOUND = 302

SEE_OTHER = 303

NOT_MODIFIED = 304

USE_PROXY = 305

TEMPORARY_REDIRECT = 307

# client error

BAD_REQUEST = 400

UNAUTHORIZED = 401

PAYMENT_REQUIRED = 402

FORBIDDEN = 403

NOT_FOUND = 404

METHOD_NOT_ALLOWED = 405

NOT_ACCEPTABLE = 406

PROXY_AUTHENTICATION_REQUIRED = 407

REQUEST_TIMEOUT = 408

CONFLICT = 409

GONE = 410

LENGTH_REQUIRED = 411

PRECONDITION_FAILED = 412

REQUEST_ENTITY_TOO_LARGE = 413

REQUEST_URI_TOO_LONG = 414

UNSUPPORTED_MEDIA_TYPE = 415

REQUESTED_RANGE_NOT_SATISFIABLE = 416

EXPECTATION_FAILED = 417

UNPROCESSABLE_ENTITY = 422

LOCKED = 423

FAILED_DEPENDENCY = 424

UPGRADE_REQUIRED = 426

# server error

INTERNAL_SERVER_ERROR = 500

NOT_IMPLEMENTED = 501

BAD_GATEWAY = 502

SERVICE_UNAVAILABLE = 503

GATEWAY_TIMEOUT = 504

HTTP_VERSION_NOT_SUPPORTED = 505

INSUFFICIENT_STORAGE = 507

NOT_EXTENDED = 510

# Mapping status codes to official W3C names

responses = {

    100: 'Continue',

    101: 'Switching Protocols',

    200: 'OK',

    201: 'Created',

    202: 'Accepted',

    203: 'Non-Authoritative Information',

    204: 'No Content',

    205: 'Reset Content',

    206: 'Partial Content',

    300: 'Multiple Choices',

    301: 'Moved Permanently',

    302: 'Found',

    303: 'See Other',

    304: 'Not Modified',

    305: 'Use Proxy',

    306: '(Unused)',

    307: 'Temporary Redirect',

    400: 'Bad Request',

    401: 'Unauthorized',

    402: 'Payment Required',

    403: 'Forbidden',

    404: 'Not Found',

    405: 'Method Not Allowed',

    406: 'Not Acceptable',

    407: 'Proxy Authentication Required',

    408: 'Request Timeout',

    409: 'Conflict',

    410: 'Gone',

    411: 'Length Required',

    412: 'Precondition Failed',

    413: 'Request Entity Too Large',

    414: 'Request-URI Too Long',

    415: 'Unsupported Media Type',

    416: 'Requested Range Not Satisfiable',

    417: 'Expectation Failed',

    500: 'Internal Server Error',

    501: 'Not Implemented',

    502: 'Bad Gateway',

    503: 'Service Unavailable',

    504: 'Gateway Timeout',

    505: 'HTTP Version Not Supported',

}

# maximal amount of data to read at one time in _safe_read

MAXAMOUNT = 1048576

class HTTPMessage(mimetools.Message):

    def addheader(self, key, value):

        """Add header for field key handling repeats."""

        prev = self.dict.get(key)

        if prev is None:

            self.dict[key] = value

        else:

            combined = ", ".join((prev, value))

            self.dict[key] = combined

    def addcontinue(self, key, more):

        """Add more field data from a continuation line."""

        prev = self.dict[key]

        self.dict[key] = prev + "\n " + more

    def readheaders(self):

        """Read header lines.

        Read header lines up to the entirely blank line that terminates them.

        The (normally blank) line that ends the headers is skipped, but not

        included in the returned list.  If a non-header line ends the headers,

        (which is an error), an attempt is made to backspace over it; it is

        never included in the returned list.

        The variable self.status is set to the empty string if all went well,

        otherwise it is an error message.  The variable self.headers is a

        completely uninterpreted list of lines contained in the header (so

        printing them will reproduce the header exactly as it appears in the

        file).

        If multiple header fields with the same name occur, they are combined

        according to the rules in RFC 2616 sec 4.2:

        Appending each subsequent field-value to the first, each separated

        by a comma. The order in which header fields with the same field-name

        are received is significant to the interpretation of the combined

        field value.

        """

        # XXX The implementation overrides the readheaders() method of

        # rfc822.Message.  The base class design isn't amenable to

        # customized behavior here so the method here is a copy of the

        # base class code with a few small changes.

        self.dict = {}

        self.unixfrom = ''

        self.headers = hlist = []

        self.status = ''

        headerseen = ""

        firstline = 1

        startofline = unread = tell = None

        if hasattr(self.fp, 'unread'):

            unread = self.fp.unread

        elif self.seekable:

            tell = self.fp.tell

        while True:

            if tell:

                try:

                    startofline = tell()

                except IOError:

                    startofline = tell = None

                    self.seekable = 0

            line = self.fp.readline()

            if not line:

                self.status = 'EOF in headers'

                break

            # Skip unix From name time lines

            if firstline and line.startswith('From '):

                self.unixfrom = self.unixfrom + line

                continue

            firstline = 0

            if headerseen and line[0] in ' \t':

                # XXX Not sure if continuation lines are handled properly

                # for http and/or for repeating headers

                # It's a continuation line.

                hlist.append(line)

                self.addcontinue(headerseen, line.strip())

                continue

            elif self.iscomment(line):

                # It's a comment.  Ignore it.

                continue

            elif self.islast(line):

                # Note! No pushback here!  The delimiter line gets eaten.

                break

            headerseen = self.isheader(line)

            if headerseen:

                # It's a legal header line, save it.

                hlist.append(line)

                self.addheader(headerseen, line[len(headerseen)+1:].strip())

                continue

            else:

                # It's not a header line; throw it back and stop here.

                if not self.dict:

                    self.status = 'No headers'

                else:

                    self.status = 'Non-header line where header expected'

                # Try to undo the read.

                if unread:

                    unread(line)

                elif tell:

                    self.fp.seek(startofline)

                else:

                    self.status = self.status + '; bad seek'

                break

class HTTPResponse:

    # strict: If true, raise BadStatusLine if the status line can't be

    # parsed as a valid HTTP/1.0 or 1.1 status line.  By default it is

    # false because it prevents clients from talking to HTTP/0.9

    # servers.  Note that a response with a sufficiently corrupted

    # status line will look like an HTTP/0.9 response.

    # See RFC 2616 sec 19.6 and RFC 1945 sec 6 for details.

    def __init__(self, sock, debuglevel=0, strict=0, method=None):

        self.fp = sock.makefile('rb', 0)

        self.debuglevel = debuglevel

        self.strict = strict

        self._method = method

        self.msg = None

        # from the Status-Line of the response

        self.version = _UNKNOWN # HTTP-Version

        self.status = _UNKNOWN  # Status-Code

        self.reason = _UNKNOWN  # Reason-Phrase

        self.chunked = _UNKNOWN         # is "chunked" being used?

        self.chunk_left = _UNKNOWN      # bytes left to read in current chunk

        self.length = _UNKNOWN          # number of bytes left in response

        self.will_close = _UNKNOWN      # conn will close at end of response

    def _read_status(self):

        # Initialize with Simple-Response defaults

        line = self.fp.readline()

        if self.debuglevel > 0:

            print "reply:", repr(line)

        if not line:

            # Presumably, the server closed the connection before

            # sending a valid response.

            raise BadStatusLine(line)

        try:

            [version, status, reason] = line.split(None, 2)

        except ValueError:

            try:

                [version, status] = line.split(None, 1)

                reason = ""

            except ValueError:

                # empty version will cause next test to fail and status

                # will be treated as 0.9 response.

                version = ""

        if not version.startswith('HTTP/'):

            if self.strict:

                self.close()

                raise BadStatusLine(line)

            else:

                # assume it's a Simple-Response from an 0.9 server

                self.fp = LineAndFileWrapper(line, self.fp)

                return "HTTP/0.9", 200, ""

        # The status code is a three-digit number

        try:

            status = int(status)

            if status < 100 or status > 999:

                raise BadStatusLine(line)

        except ValueError:

            raise BadStatusLine(line)

        return version, status, reason

    def begin(self):

        if self.msg is not None:

            # we've already started reading the response

            return

        # read until we get a non-100 response

        while True:

            version, status, reason = self._read_status()

            if status != CONTINUE:

                break

            # skip the header from the 100 response

            while True:

                skip = self.fp.readline().strip()

                if not skip:

                    break

                if self.debuglevel > 0:

                    print "header:", skip

        self.status = status

        self.reason = reason.strip()

        if version == 'HTTP/1.0':

            self.version = 10

        elif version.startswith('HTTP/1.'):

            self.version = 11   # use HTTP/1.1 code for HTTP/1.x where x>=1

        elif version == 'HTTP/0.9':

            self.version = 9

        else:

            raise UnknownProtocol(version)

        if self.version == 9:

            self.length = None

            self.chunked = 0

            self.will_close = 1

            self.msg = HTTPMessage(StringIO())

            return

        self.msg = HTTPMessage(self.fp, 0)

        if self.debuglevel > 0:

            for hdr in self.msg.headers:

                print "header:", hdr,

        # don't let the msg keep an fp

        self.msg.fp = None

        # are we using the chunked-style of transfer encoding?

        tr_enc = self.msg.getheader('transfer-encoding')

        if tr_enc and tr_enc.lower() == "chunked":

            self.chunked = 1

            self.chunk_left = None

        else:

            self.chunked = 0

        # will the connection close at the end of the response?

        self.will_close = self._check_close()

        # do we have a Content-Length?

        # NOTE: RFC 2616, S4.4, #3 says we ignore this if tr_enc is "chunked"

        length = self.msg.getheader('content-length')

        if length and not self.chunked:

            try:

                self.length = int(length)

            except ValueError:

                self.length = None

        else:

            self.length = None

        # does the body have a fixed length? (of zero)

        if (status == NO_CONTENT or status == NOT_MODIFIED or

            100 <= status < 200 or      # 1xx codes

            self._method == 'HEAD'):

            self.length = 0

        # if the connection remains open, and we aren't using chunked, and

        # a content-length was not provided, then assume that the connection

        # WILL close.

        if not self.will_close and \

           not self.chunked and \

           self.length is None:

            self.will_close = 1

    def _check_close(self):

        conn = self.msg.getheader('connection')

        if self.version == 11:

            # An HTTP/1.1 proxy is assumed to stay open unless

            # explicitly closed.

            conn = self.msg.getheader('connection')

            if conn and "close" in conn.lower():

                return True

            return False

        # Some HTTP/1.0 implementations have support for persistent

        # connections, using rules different than HTTP/1.1.

        # For older HTTP, Keep-Alive indiciates persistent connection.

        if self.msg.getheader('keep-alive'):

            return False

        # At least Akamai returns a "Connection: Keep-Alive" header,

        # which was supposed to be sent by the client.

        if conn and "keep-alive" in conn.lower():

            return False

        # Proxy-Connection is a netscape hack.

        pconn = self.msg.getheader('proxy-connection')

        if pconn and "keep-alive" in pconn.lower():

            return False

        # otherwise, assume it will close

        return True

    def close(self):

        if self.fp:

            self.fp.close()

            self.fp = None

    def isclosed(self):

        # NOTE: it is possible that we will not ever call self.close(). This

        #       case occurs when will_close is TRUE, length is None, and we

        #       read up to the last byte, but NOT past it.

        #

        # IMPLIES: if will_close is FALSE, then self.close() will ALWAYS be

        #          called, meaning self.isclosed() is meaningful.

        return self.fp is None

    # XXX It would be nice to have readline and __iter__ for this, too.

    def read(self, amt=None):

        if self.fp is None:

            return ''

        if self.chunked:

            return self._read_chunked(amt)

        if amt is None:

            # unbounded read

            if self.length is None:

                s = self.fp.read()

            else:

                s = self._safe_read(self.length)

                self.length = 0

            self.close()        # we read everything

            return s

        if self.length is not None:

            if amt > self.length:

                # clip the read to the "end of response"

                amt = self.length

        # we do not use _safe_read() here because this may be a .will_close

        # connection, and the user is reading more bytes than will be provided

        # (for example, reading in 1k chunks)