summaryrefslogtreecommitdiff
path: root/django/core/handlers/wsgi.py
blob: a2d5b124af04bc7e58ffe32bda9bb86d34a9b36f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
import cgi
import codecs
import re
from io import BytesIO

from django.conf import settings
from django.core import signals
from django.core.handlers import base
from django.http import HttpRequest, QueryDict, parse_cookie
from django.urls import set_script_prefix
from django.utils.encoding import repercent_broken_unicode
from django.utils.functional import cached_property

_slashes_re = re.compile(br'/+')


class LimitedStream:
    """Wrap another stream to disallow reading it past a number of bytes."""
    def __init__(self, stream, limit, buf_size=64 * 1024 * 1024):
        self.stream = stream
        self.remaining = limit
        self.buffer = b''
        self.buf_size = buf_size

    def _read_limited(self, size=None):
        if size is None or size > self.remaining:
            size = self.remaining
        if size == 0:
            return b''
        result = self.stream.read(size)
        self.remaining -= len(result)
        return result

    def read(self, size=None):
        if size is None:
            result = self.buffer + self._read_limited()
            self.buffer = b''
        elif size < len(self.buffer):
            result = self.buffer[:size]
            self.buffer = self.buffer[size:]
        else:  # size >= len(self.buffer)
            result = self.buffer + self._read_limited(size - len(self.buffer))
            self.buffer = b''
        return result

    def readline(self, size=None):
        while b'\n' not in self.buffer and \
              (size is None or len(self.buffer) < size):
            if size:
                # since size is not None here, len(self.buffer) < size
                chunk = self._read_limited(size - len(self.buffer))
            else:
                chunk = self._read_limited()
            if not chunk:
                break
            self.buffer += chunk
        sio = BytesIO(self.buffer)
        if size:
            line = sio.readline(size)
        else:
            line = sio.readline()
        self.buffer = sio.read()
        return line


class WSGIRequest(HttpRequest):
    def __init__(self, environ):
        script_name = get_script_name(environ)
        # If PATH_INFO is empty (e.g. accessing the SCRIPT_NAME URL without a
        # trailing slash), operate as if '/' was requested.
        path_info = get_path_info(environ) or '/'
        self.environ = environ
        self.path_info = path_info
        # be careful to only replace the first slash in the path because of
        # http://test/something and http://test//something being different as
        # stated in http://www.ietf.org/rfc/rfc2396.txt
        self.path = '%s/%s' % (script_name.rstrip('/'),
                               path_info.replace('/', '', 1))
        self.META = environ
        self.META['PATH_INFO'] = path_info
        self.META['SCRIPT_NAME'] = script_name
        self.method = environ['REQUEST_METHOD'].upper()
        self.content_type, self.content_params = cgi.parse_header(environ.get('CONTENT_TYPE', ''))
        if 'charset' in self.content_params:
            try:
                codecs.lookup(self.content_params['charset'])
            except LookupError:
                pass
            else:
                self.encoding = self.content_params['charset']
        self._post_parse_error = False
        try:
            content_length = int(environ.get('CONTENT_LENGTH'))
        except (ValueError, TypeError):
            content_length = 0
        self._stream = LimitedStream(self.environ['wsgi.input'], content_length)
        self._read_started = False
        self.resolver_match = None

    def _get_scheme(self):
        return self.environ.get('wsgi.url_scheme')

    @cached_property
    def GET(self):
        # The WSGI spec says 'QUERY_STRING' may be absent.
        raw_query_string = get_bytes_from_wsgi(self.environ, 'QUERY_STRING', '')
        return QueryDict(raw_query_string, encoding=self._encoding)

    def _get_post(self):
        if not hasattr(self, '_post'):
            self._load_post_and_files()
        return self._post

    def _set_post(self, post):
        self._post = post

    @cached_property
    def COOKIES(self):
        raw_cookie = get_str_from_wsgi(self.environ, 'HTTP_COOKIE', '')
        return parse_cookie(raw_cookie)

    @property
    def FILES(self):
        if not hasattr(self, '_files'):
            self._load_post_and_files()
        return self._files

    POST = property(_get_post, _set_post)


class WSGIHandler(base.BaseHandler):
    request_class = WSGIRequest

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.load_middleware()

    def __call__(self, environ, start_response):
        set_script_prefix(get_script_name(environ))
        signals.request_started.send(sender=self.__class__, environ=environ)
        request = self.request_class(environ)
        response = self.get_response(request)

        response._handler_class = self.__class__

        status = '%d %s' % (response.status_code, response.reason_phrase)
        response_headers = list(response.items())
        for c in response.cookies.values():
            response_headers.append(('Set-Cookie', c.output(header='')))
        start_response(status, response_headers)
        if getattr(response, 'file_to_stream', None) is not None and environ.get('wsgi.file_wrapper'):
            response = environ['wsgi.file_wrapper'](response.file_to_stream)
        return response


def get_path_info(environ):
    """Return the HTTP request's PATH_INFO as a string."""
    path_info = get_bytes_from_wsgi(environ, 'PATH_INFO', '/')

    return repercent_broken_unicode(path_info).decode()


def get_script_name(environ):
    """
    Return the equivalent of the HTTP request's SCRIPT_NAME environment
    variable. If Apache mod_rewrite is used, return what would have been
    the script name prior to any rewriting (so it's the script name as seen
    from the client's perspective), unless the FORCE_SCRIPT_NAME setting is
    set (to anything).
    """
    if settings.FORCE_SCRIPT_NAME is not None:
        return settings.FORCE_SCRIPT_NAME

    # If Apache's mod_rewrite had a whack at the URL, Apache set either
    # SCRIPT_URL or REDIRECT_URL to the full resource URL before applying any
    # rewrites. Unfortunately not every Web server (lighttpd!) passes this
    # information through all the time, so FORCE_SCRIPT_NAME, above, is still
    # needed.
    script_url = get_bytes_from_wsgi(environ, 'SCRIPT_URL', '') or get_bytes_from_wsgi(environ, 'REDIRECT_URL', '')

    if script_url:
        if b'//' in script_url:
            # mod_wsgi squashes multiple successive slashes in PATH_INFO,
            # do the same with script_url before manipulating paths (#17133).
            script_url = _slashes_re.sub(b'/', script_url)
        path_info = get_bytes_from_wsgi(environ, 'PATH_INFO', '')
        script_name = script_url[:-len(path_info)] if path_info else script_url
    else:
        script_name = get_bytes_from_wsgi(environ, 'SCRIPT_NAME', '')

    return script_name.decode()


def get_bytes_from_wsgi(environ, key, default):
    """
    Get a value from the WSGI environ dictionary as bytes.

    key and default should be strings.
    """
    value = environ.get(key, default)
    # Non-ASCII values in the WSGI environ are arbitrarily decoded with
    # ISO-8859-1. This is wrong for Django websites where UTF-8 is the default.
    # Re-encode to recover the original bytestring.
    return value.encode('iso-8859-1')


def get_str_from_wsgi(environ, key, default):
    """
    Get a value from the WSGI environ dictionary as str.

    key and default should be str objects.
    """
    value = get_bytes_from_wsgi(environ, key, default)
    return value.decode(errors='replace')