Convert watch page to flask framework

1 files changed, 586 insertions, 0 deletions

diff --git a/python/werkzeug/formparser.py b/python/werkzeug/formparser.py
new file mode 100644
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+++ b/python/werkzeug/formparser.py
@@ -0,0 +1,586 @@
+# -*- coding: utf-8 -*-
+"""
+    werkzeug.formparser
+    ~~~~~~~~~~~~~~~~~~~
+
+    This module implements the form parsing.  It supports url-encoded forms
+    as well as non-nested multipart uploads.
+
+    :copyright: 2007 Pallets
+    :license: BSD-3-Clause
+"""
+import codecs
+import re
+from functools import update_wrapper
+from itertools import chain
+from itertools import repeat
+from itertools import tee
+
+from ._compat import BytesIO
+from ._compat import text_type
+from ._compat import to_native
+from .datastructures import FileStorage
+from .datastructures import Headers
+from .datastructures import MultiDict
+from .http import parse_options_header
+from .urls import url_decode_stream
+from .wsgi import get_content_length
+from .wsgi import get_input_stream
+from .wsgi import make_line_iter
+
+# there are some platforms where SpooledTemporaryFile is not available.
+# In that case we need to provide a fallback.
+try:
+    from tempfile import SpooledTemporaryFile
+except ImportError:
+    from tempfile import TemporaryFile
+
+    SpooledTemporaryFile = None
+
+
+#: an iterator that yields empty strings
+_empty_string_iter = repeat("")
+
+#: a regular expression for multipart boundaries
+_multipart_boundary_re = re.compile("^[ -~]{0,200}[!-~]$")
+
+#: supported http encodings that are also available in python we support
+#: for multipart messages.
+_supported_multipart_encodings = frozenset(["base64", "quoted-printable"])
+
+
+def default_stream_factory(
+    total_content_length, filename, content_type, content_length=None
+):
+    """The stream factory that is used per default."""
+    max_size = 1024 * 500
+    if SpooledTemporaryFile is not None:
+        return SpooledTemporaryFile(max_size=max_size, mode="wb+")
+    if total_content_length is None or total_content_length > max_size:
+        return TemporaryFile("wb+")
+    return BytesIO()
+
+
+def parse_form_data(
+    environ,
+    stream_factory=None,
+    charset="utf-8",
+    errors="replace",
+    max_form_memory_size=None,
+    max_content_length=None,
+    cls=None,
+    silent=True,
+):
+    """Parse the form data in the environ and return it as tuple in the form
+    ``(stream, form, files)``.  You should only call this method if the
+    transport method is `POST`, `PUT`, or `PATCH`.
+
+    If the mimetype of the data transmitted is `multipart/form-data` the
+    files multidict will be filled with `FileStorage` objects.  If the
+    mimetype is unknown the input stream is wrapped and returned as first
+    argument, else the stream is empty.
+
+    This is a shortcut for the common usage of :class:`FormDataParser`.
+
+    Have a look at :ref:`dealing-with-request-data` for more details.
+
+    .. versionadded:: 0.5
+       The `max_form_memory_size`, `max_content_length` and
+       `cls` parameters were added.
+
+    .. versionadded:: 0.5.1
+       The optional `silent` flag was added.
+
+    :param environ: the WSGI environment to be used for parsing.
+    :param stream_factory: An optional callable that returns a new read and
+                           writeable file descriptor.  This callable works
+                           the same as :meth:`~BaseResponse._get_file_stream`.
+    :param charset: The character set for URL and url encoded form data.
+    :param errors: The encoding error behavior.
+    :param max_form_memory_size: the maximum number of bytes to be accepted for
+                           in-memory stored form data.  If the data
+                           exceeds the value specified an
+                           :exc:`~exceptions.RequestEntityTooLarge`
+                           exception is raised.
+    :param max_content_length: If this is provided and the transmitted data
+                               is longer than this value an
+                               :exc:`~exceptions.RequestEntityTooLarge`
+                               exception is raised.
+    :param cls: an optional dict class to use.  If this is not specified
+                       or `None` the default :class:`MultiDict` is used.
+    :param silent: If set to False parsing errors will not be caught.
+    :return: A tuple in the form ``(stream, form, files)``.
+    """
+    return FormDataParser(
+        stream_factory,
+        charset,
+        errors,
+        max_form_memory_size,
+        max_content_length,
+        cls,
+        silent,
+    ).parse_from_environ(environ)
+
+
+def exhaust_stream(f):
+    """Helper decorator for methods that exhausts the stream on return."""
+
+    def wrapper(self, stream, *args, **kwargs):
+        try:
+            return f(self, stream, *args, **kwargs)
+        finally:
+            exhaust = getattr(stream, "exhaust", None)
+            if exhaust is not None:
+                exhaust()
+            else:
+                while 1:
+                    chunk = stream.read(1024 * 64)
+                    if not chunk:
+                        break
+
+    return update_wrapper(wrapper, f)
+
+
+class FormDataParser(object):
+    """This class implements parsing of form data for Werkzeug.  By itself
+    it can parse multipart and url encoded form data.  It can be subclassed
+    and extended but for most mimetypes it is a better idea to use the
+    untouched stream and expose it as separate attributes on a request
+    object.
+
+    .. versionadded:: 0.8
+
+    :param stream_factory: An optional callable that returns a new read and
+                           writeable file descriptor.  This callable works
+                           the same as :meth:`~BaseResponse._get_file_stream`.
+    :param charset: The character set for URL and url encoded form data.
+    :param errors: The encoding error behavior.
+    :param max_form_memory_size: the maximum number of bytes to be accepted for
+                           in-memory stored form data.  If the data
+                           exceeds the value specified an
+                           :exc:`~exceptions.RequestEntityTooLarge`
+                           exception is raised.
+    :param max_content_length: If this is provided and the transmitted data
+                               is longer than this value an
+                               :exc:`~exceptions.RequestEntityTooLarge`
+                               exception is raised.
+    :param cls: an optional dict class to use.  If this is not specified
+                       or `None` the default :class:`MultiDict` is used.
+    :param silent: If set to False parsing errors will not be caught.
+    """
+
+    def __init__(
+        self,
+        stream_factory=None,
+        charset="utf-8",
+        errors="replace",
+        max_form_memory_size=None,
+        max_content_length=None,
+        cls=None,
+        silent=True,
+    ):
+        if stream_factory is None:
+            stream_factory = default_stream_factory
+        self.stream_factory = stream_factory
+        self.charset = charset
+        self.errors = errors
+        self.max_form_memory_size = max_form_memory_size
+        self.max_content_length = max_content_length
+        if cls is None:
+            cls = MultiDict
+        self.cls = cls
+        self.silent = silent
+
+    def get_parse_func(self, mimetype, options):
+        return self.parse_functions.get(mimetype)
+
+    def parse_from_environ(self, environ):
+        """Parses the information from the environment as form data.
+
+        :param environ: the WSGI environment to be used for parsing.
+        :return: A tuple in the form ``(stream, form, files)``.
+        """
+        content_type = environ.get("CONTENT_TYPE", "")
+        content_length = get_content_length(environ)
+        mimetype, options = parse_options_header(content_type)
+        return self.parse(get_input_stream(environ), mimetype, content_length, options)
+
+    def parse(self, stream, mimetype, content_length, options=None):
+        """Parses the information from the given stream, mimetype,
+        content length and mimetype parameters.
+
+        :param stream: an input stream
+        :param mimetype: the mimetype of the data
+        :param content_length: the content length of the incoming data
+        :param options: optional mimetype parameters (used for
+                        the multipart boundary for instance)
+        :return: A tuple in the form ``(stream, form, files)``.
+        """
+        if (
+            self.max_content_length is not None
+            and content_length is not None
+            and content_length > self.max_content_length
+        ):
+            raise exceptions.RequestEntityTooLarge()
+        if options is None:
+            options = {}
+
+        parse_func = self.get_parse_func(mimetype, options)
+        if parse_func is not None:
+            try:
+                return parse_func(self, stream, mimetype, content_length, options)
+            except ValueError:
+                if not self.silent:
+                    raise
+
+        return stream, self.cls(), self.cls()
+
+    @exhaust_stream
+    def _parse_multipart(self, stream, mimetype, content_length, options):
+        parser = MultiPartParser(
+            self.stream_factory,
+            self.charset,
+            self.errors,
+            max_form_memory_size=self.max_form_memory_size,
+            cls=self.cls,
+        )
+        boundary = options.get("boundary")
+        if boundary is None:
+            raise ValueError("Missing boundary")
+        if isinstance(boundary, text_type):
+            boundary = boundary.encode("ascii")
+        form, files = parser.parse(stream, boundary, content_length)
+        return stream, form, files
+
+    @exhaust_stream
+    def _parse_urlencoded(self, stream, mimetype, content_length, options):
+        if (
+            self.max_form_memory_size is not None
+            and content_length is not None
+            and content_length > self.max_form_memory_size
+        ):
+            raise exceptions.RequestEntityTooLarge()
+        form = url_decode_stream(stream, self.charset, errors=self.errors, cls=self.cls)
+        return stream, form, self.cls()
+
+    #: mapping of mimetypes to parsing functions
+    parse_functions = {
+        "multipart/form-data": _parse_multipart,
+        "application/x-www-form-urlencoded": _parse_urlencoded,
+        "application/x-url-encoded": _parse_urlencoded,
+    }
+
+
+def is_valid_multipart_boundary(boundary):
+    """Checks if the string given is a valid multipart boundary."""
+    return _multipart_boundary_re.match(boundary) is not None
+
+
+def _line_parse(line):
+    """Removes line ending characters and returns a tuple (`stripped_line`,
+    `is_terminated`).
+    """
+    if line[-2:] in ["\r\n", b"\r\n"]:
+        return line[:-2], True
+    elif line[-1:] in ["\r", "\n", b"\r", b"\n"]:
+        return line[:-1], True
+    return line, False
+
+
+def parse_multipart_headers(iterable):
+    """Parses multipart headers from an iterable that yields lines (including
+    the trailing newline symbol).  The iterable has to be newline terminated.
+
+    The iterable will stop at the line where the headers ended so it can be
+    further consumed.
+
+    :param iterable: iterable of strings that are newline terminated
+    """
+    result = []
+    for line in iterable:
+        line = to_native(line)
+        line, line_terminated = _line_parse(line)
+        if not line_terminated:
+            raise ValueError("unexpected end of line in multipart header")
+        if not line:
+            break
+        elif line[0] in " \t" and result:
+            key, value = result[-1]
+            result[-1] = (key, value + "\n " + line[1:])
+        else:
+            parts = line.split(":", 1)
+            if len(parts) == 2:
+                result.append((parts[0].strip(), parts[1].strip()))
+
+    # we link the list to the headers, no need to create a copy, the
+    # list was not shared anyways.
+    return Headers(result)
+
+
+_begin_form = "begin_form"
+_begin_file = "begin_file"
+_cont = "cont"
+_end = "end"
+
+
+class MultiPartParser(object):
+    def __init__(
+        self,
+        stream_factory=None,
+        charset="utf-8",
+        errors="replace",
+        max_form_memory_size=None,
+        cls=None,
+        buffer_size=64 * 1024,
+    ):
+        self.charset = charset
+        self.errors = errors
+        self.max_form_memory_size = max_form_memory_size
+        self.stream_factory = (
+            default_stream_factory if stream_factory is None else stream_factory
+        )
+        self.cls = MultiDict if cls is None else cls
+
+        # make sure the buffer size is divisible by four so that we can base64
+        # decode chunk by chunk
+        assert buffer_size % 4 == 0, "buffer size has to be divisible by 4"
+        # also the buffer size has to be at least 1024 bytes long or long headers
+        # will freak out the system
+        assert buffer_size >= 1024, "buffer size has to be at least 1KB"
+
+        self.buffer_size = buffer_size
+
+    def _fix_ie_filename(self, filename):
+        """Internet Explorer 6 transmits the full file name if a file is
+        uploaded.  This function strips the full path if it thinks the
+        filename is Windows-like absolute.
+        """
+        if filename[1:3] == ":\\" or filename[:2] == "\\\\":
+            return filename.split("\\")[-1]
+        return filename
+
+    def _find_terminator(self, iterator):
+        """The terminator might have some additional newlines before it.
+        There is at least one application that sends additional newlines
+        before headers (the python setuptools package).
+        """
+        for line in iterator:
+            if not line:
+                break
+            line = line.strip()
+            if line:
+                return line
+        return b""
+
+    def fail(self, message):
+        raise ValueError(message)
+
+    def get_part_encoding(self, headers):
+        transfer_encoding = headers.get("content-transfer-encoding")
+        if (
+            transfer_encoding is not None
+            and transfer_encoding in _supported_multipart_encodings
+        ):
+            return transfer_encoding
+
+    def get_part_charset(self, headers):
+        # Figure out input charset for current part
+        content_type = headers.get("content-type")
+        if content_type:
+            mimetype, ct_params = parse_options_header(content_type)
+            return ct_params.get("charset", self.charset)
+        return self.charset
+
+    def start_file_streaming(self, filename, headers, total_content_length):
+        if isinstance(filename, bytes):
+            filename = filename.decode(self.charset, self.errors)
+        filename = self._fix_ie_filename(filename)
+        content_type = headers.get("content-type")
+        try:
+            content_length = int(headers["content-length"])
+        except (KeyError, ValueError):
+            content_length = 0
+        container = self.stream_factory(
+            total_content_length=total_content_length,
+            filename=filename,
+            content_type=content_type,
+            content_length=content_length,
+        )
+        return filename, container
+
+    def in_memory_threshold_reached(self, bytes):
+        raise exceptions.RequestEntityTooLarge()
+
+    def validate_boundary(self, boundary):
+        if not boundary:
+            self.fail("Missing boundary")
+        if not is_valid_multipart_boundary(boundary):
+            self.fail("Invalid boundary: %s" % boundary)
+        if len(boundary) > self.buffer_size:  # pragma: no cover
+            # this should never happen because we check for a minimum size
+            # of 1024 and boundaries may not be longer than 200.  The only
+            # situation when this happens is for non debug builds where
+            # the assert is skipped.
+            self.fail("Boundary longer than buffer size")
+
+    def parse_lines(self, file, boundary, content_length, cap_at_buffer=True):
+        """Generate parts of
+        ``('begin_form', (headers, name))``
+        ``('begin_file', (headers, name, filename))``
+        ``('cont', bytestring)``
+        ``('end', None)``
+
+        Always obeys the grammar
+        parts = ( begin_form cont* end |
+                  begin_file cont* end )*
+        """
+        next_part = b"--" + boundary
+        last_part = next_part + b"--"
+
+        iterator = chain(
+            make_line_iter(
+                file,
+                limit=content_length,
+                buffer_size=self.buffer_size,
+                cap_at_buffer=cap_at_buffer,
+            ),
+            _empty_string_iter,
+        )
+
+        terminator = self._find_terminator(iterator)
+
+        if terminator == last_part:
+            return
+        elif terminator != next_part:
+            self.fail("Expected boundary at start of multipart data")
+
+        while terminator != last_part:
+            headers = parse_multipart_headers(iterator)
+
+            disposition = headers.get("content-disposition")
+            if disposition is None:
+                self.fail("Missing Content-Disposition header")
+            disposition, extra = parse_options_header(disposition)
+            transfer_encoding = self.get_part_encoding(headers)
+            name = extra.get("name")
+            filename = extra.get("filename")
+
+            # if no content type is given we stream into memory.  A list is
+            # used as a temporary container.
+            if filename is None:
+                yield _begin_form, (headers, name)
+
+            # otherwise we parse the rest of the headers and ask the stream
+            # factory for something we can write in.
+            else:
+                yield _begin_file, (headers, name, filename)
+
+            buf = b""
+            for line in iterator:
+                if not line:
+                    self.fail("unexpected end of stream")
+
+                if line[:2] == b"--":
+                    terminator = line.rstrip()
+                    if terminator in (next_part, last_part):
+                        break
+
+                if transfer_encoding is not None:
+                    if transfer_encoding == "base64":
+                        transfer_encoding = "base64_codec"
+                    try:
+                        line = codecs.decode(line, transfer_encoding)
+                    except Exception:
+                        self.fail("could not decode transfer encoded chunk")
+
+                # we have something in the buffer from the last iteration.
+                # this is usually a newline delimiter.
+                if buf:
+                    yield _cont, buf
+                    buf = b""
+
+                # If the line ends with windows CRLF we write everything except
+                # the last two bytes.  In all other cases however we write
+                # everything except the last byte.  If it was a newline, that's
+                # fine, otherwise it does not matter because we will write it
+                # the next iteration.  this ensures we do not write the
+                # final newline into the stream.  That way we do not have to
+                # truncate the stream.  However we do have to make sure that
+                # if something else than a newline is in there we write it
+                # out.
+                if line[-2:] == b"\r\n":
+                    buf = b"\r\n"
+                    cutoff = -2
+                else:
+                    buf = line[-1:]
+                    cutoff = -1
+                yield _cont, line[:cutoff]
+
+            else:  # pragma: no cover
+                raise ValueError("unexpected end of part")
+
+            # if we have a leftover in the buffer that is not a newline
+            # character we have to flush it, otherwise we will chop of
+            # certain values.
+            if buf not in (b"", b"\r", b"\n", b"\r\n"):
+                yield _cont, buf
+
+            yield _end, None
+
+    def parse_parts(self, file, boundary, content_length):
+        """Generate ``('file', (name, val))`` and
+        ``('form', (name, val))`` parts.
+        """
+        in_memory = 0
+
+        for ellt, ell in self.parse_lines(file, boundary, content_length):
+            if ellt == _begin_file:
+                headers, name, filename = ell
+                is_file = True
+                guard_memory = False
+                filename, container = self.start_file_streaming(
+                    filename, headers, content_length
+                )
+                _write = container.write
+
+            elif ellt == _begin_form:
+                headers, name = ell
+                is_file = False
+                container = []
+                _write = container.append
+                guard_memory = self.max_form_memory_size is not None
+
+            elif ellt == _cont:
+                _write(ell)
+                # if we write into memory and there is a memory size limit we
+                # count the number of bytes in memory and raise an exception if
+                # there is too much data in memory.
+                if guard_memory:
+                    in_memory += len(ell)
+                    if in_memory > self.max_form_memory_size:
+                        self.in_memory_threshold_reached(in_memory)
+
+            elif ellt == _end:
+                if is_file:
+                    container.seek(0)
+                    yield (
+                        "file",
+                        (name, FileStorage(container, filename, name, headers=headers)),
+                    )
+                else:
+                    part_charset = self.get_part_charset(headers)
+                    yield (
+                        "form",
+                        (name, b"".join(container).decode(part_charset, self.errors)),
+                    )
+
+    def parse(self, file, boundary, content_length):
+        formstream, filestream = tee(
+            self.parse_parts(file, boundary, content_length), 2
+        )
+        form = (p[1] for p in formstream if p[0] == "form")
+        files = (p[1] for p in filestream if p[0] == "file")
+        return self.cls(form), self.cls(files)
+
+
+from . import exceptions