Source code for zope.publisher.browser

##############################################################################
#
# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Browser-specific Publisher classes

Here we define the specific 'BrowserRequest' and 'BrowserResponse' class. The
big improvement of the 'BrowserRequest' to 'HTTPRequest' is that is can handle
HTML form data and convert them into a Python-native format. Even file data is
packaged into a nice, Python-friendly 'FileUpload' object.
"""
from email.message import Message
import re

import multipart
import six
from six.moves.urllib.parse import parse_qsl
import zope.component
import zope.interface
from zope.interface import implementer, directlyProvides
from zope.i18n.interfaces import IUserPreferredLanguages
from zope.i18n.interfaces import IUserPreferredCharsets
from zope.i18n.interfaces import IModifiableUserPreferredLanguages
from zope.location import Location

from zope.publisher.interfaces import IHeld, NotFound
from zope.publisher.interfaces.browser import IBrowserRequest
from zope.publisher.interfaces.browser import IDefaultBrowserLayer
from zope.publisher.interfaces.browser import IBrowserApplicationRequest
from zope.publisher.interfaces.browser import IBrowserView
from zope.publisher.interfaces.browser import IBrowserPage
from zope.publisher.interfaces.http import IHTTPRequest
from zope.publisher.http import HTTPRequest
from zope.publisher.http import HTTPResponse
from zope.publisher.http import getCharsetUsingRequest

# BBB imports, these components got moved from this module
from zope.publisher.interfaces import ISkinType  # noqa: F401 import unused
from zope.publisher.interfaces import ISkinChangedEvent  # noqa: F401
from zope.publisher.skinnable import getDefaultSkin  # noqa: F401
from zope.publisher.skinnable import setDefaultSkin  # noqa: F401
from zope.publisher.skinnable import applySkin  # noqa: F401
from zope.publisher.skinnable import SkinChangedEvent  # noqa: F401

from zope.publisher._compat import PYTHON2


__ArrayTypes = (list, tuple)

start_of_header_search = re.compile(b'(<head[^>]*>)', re.I).search
base_re_search = re.compile(b'(<base.*?>)', re.I).search
isRelative = re.compile("[-_.!~*a-zA-z0-9'()@&=+$,]+(/|$)").match
newlines = re.compile('\r\n|\n\r|\r')


def is_text_html(content_type):
    return content_type.startswith('text/html')


# Flag Constants
SEQUENCE = 1
DEFAULT = 2
RECORD = 4
RECORDS = 8
REC = RECORD | RECORDS
CONVERTED = 32
DEFAULTABLE_METHODS = 'GET', 'POST', 'HEAD'


def field2string(v):
    if hasattr(v, 'read'):
        return v.read()
    return str(v)


def field2text(v, nl=newlines):
    return nl.sub("\n", field2string(v))


def field2required(v):
    v = field2string(v)
    if not v.strip():
        raise ValueError('No input for required field<p>')
    return v


def field2int(v):
    if isinstance(v, __ArrayTypes):
        return list(map(field2int, v))
    v = field2string(v)
    if not v:
        raise ValueError('Empty entry when <strong>integer</strong> expected')
    try:
        return int(v)
    except ValueError:
        raise ValueError("An integer was expected in the value '%s'" % v)


def field2float(v):
    if isinstance(v, __ArrayTypes):
        return list(map(field2float, v))
    v = field2string(v)
    if not v:
        raise ValueError(
            'Empty entry when <strong>floating-point number</strong> expected')
    try:
        return float(v)
    except ValueError:
        raise ValueError(
            "A floating-point number was expected in the value '%s'" % v)


def field2long(v):
    if isinstance(v, __ArrayTypes):
        return list(map(field2long, v))
    v = field2string(v)

    # handle trailing 'L' if present.
    if v and v[-1].upper() == 'L':
        v = v[:-1]
    if not v:
        raise ValueError('Empty entry when <strong>integer</strong> expected')
    try:
        return int(v)
    except ValueError:
        raise ValueError("A long integer was expected in the value '%s'" % v)


def field2tokens(v):
    return field2string(v).split()


def field2lines(v):
    if isinstance(v, __ArrayTypes):
        return [str(item) for item in v]
    return field2text(v).splitlines()


def field2boolean(v):
    return bool(v)


type_converters = {
    'float':    field2float,
    'int':      field2int,
    'long':     field2long,
    'string':   field2string,
    'required': field2required,
    'tokens':   field2tokens,
    'lines':    field2lines,
    'text':     field2text,
    'boolean':  field2boolean,
}

get_converter = type_converters.get


[docs]def registerTypeConverter(field_type, converter, replace=False): """Add a custom type converter to the registry. o If 'replace' is not true, raise a KeyError if a converter is already registered for 'field_type'. """ existing = type_converters.get(field_type) if existing is not None and not replace: raise KeyError('Existing converter for field_type: %s' % field_type) type_converters[field_type] = converter
def isCGI_NAME(key): return key in { # These fields are placed in request.environ instead of request.form. 'SERVER_SOFTWARE', 'SERVER_NAME', 'GATEWAY_INTERFACE', 'SERVER_PROTOCOL', 'SERVER_PORT', 'REQUEST_METHOD', 'PATH_INFO', 'PATH_TRANSLATED', 'SCRIPT_NAME', 'QUERY_STRING', 'REMOTE_HOST', 'REMOTE_ADDR', 'AUTH_TYPE', 'REMOTE_USER', 'REMOTE_IDENT', 'CONTENT_TYPE', 'CONTENT_LENGTH', 'SERVER_URL', } def hide_key(key): return key in { 'HTTP_AUTHORIZATION', 'HTTP_CGI_AUTHORIZATION', } class Record(object): _attrs = frozenset(('get', 'keys', 'items', 'values', 'copy', 'has_key', '__contains__')) def __getattr__(self, key, default=None): if key in self._attrs: return getattr(self.__dict__, key) raise AttributeError(key) def __getitem__(self, key): return self.__dict__[key] def __str__(self): items = list(self.__dict__.items()) items.sort() return "{" + ", ".join(["%s: %s" % item for item in items]) + "}" def __repr__(self): items = list(self.__dict__.items()) items.sort() return ("{" + ", ".join(["%s: %s" % (key, repr(value)) for key, value in items]) + "}") _get_or_head = 'GET', 'HEAD'
[docs]@implementer(IBrowserRequest, IBrowserApplicationRequest) class BrowserRequest(HTTPRequest): __slots__ = ( '__provides__', # Allow request to directly provide interfaces 'form', # Form data 'charsets', # helper attribute '__meth', '__tuple_items', '__defaults', '__annotations__', ) # Set this to True in a subclass to redirect GET requests when the # effective and actual URLs differ. use_redirect = False default_form_charset = 'UTF-8' def __init__(self, body_instream, environ, response=None): self.form = {} self.charsets = None super(BrowserRequest, self).__init__(body_instream, environ, response) def _createResponse(self): return BrowserResponse() def _decode(self, text): """Try to decode the text using one of the available charsets.""" if self.charsets is None: envadapter = IUserPreferredCharsets(self) self.charsets = envadapter.getPreferredCharsets() or ['utf-8'] self.charsets = [c for c in self.charsets if c != '*'] # All text comes from parse_qsl or multipart.parse_form_data, and # has normally already been decoded into Unicode according to a # request-specified encoding. However, in the case of query strings # for GET/HEAD requests we may not be sure of the encoding and must # guess. if isinstance(text, bytes): for charset in self.charsets: try: text = text.decode(charset) break except UnicodeError: pass # XXX so when none of the provided charsets works we just return bytes # and let the application crash??? return text
[docs] def processInputs(self): 'See IPublisherRequest' items = [] # We could simply not parse QUERY_STRING if it's absent, but this # provides slightly better doctest-compatibility with the old code # based on cgi.FieldStorage. self._environ.setdefault('QUERY_STRING', '') if self.method in _get_or_head: kwargs = {} if not PYTHON2: # For now, use an encoding that can decode any byte # sequence. We'll do some guesswork later. kwargs['encoding'] = 'ISO-8859-1' kwargs['errors'] = 'replace' query_items = parse_qsl( self._environ['QUERY_STRING'], keep_blank_values=True, **kwargs) for key, value in query_items: if not PYTHON2: # Encode back to bytes for later guessing. value = value.encode('ISO-8859-1') items.append((key, value)) elif self.method not in _get_or_head: env = self._environ.copy() env['wsgi.input'] = self._body_instream # cgi.FieldStorage used to set the default Content-Type for POST # requests to a "traditional" value. Do that here for # compatibility. if env.get('REQUEST_METHOD') == 'POST': env.setdefault( 'CONTENT_TYPE', 'application/x-www-form-urlencoded') ctype = env.get('CONTENT_TYPE') # Of course this isn't email, but email.message.Message has # a handy Content-Type parser. msg = Message() msg['Content-Type'] = ctype # cgi.FieldStorage treated any multipart/* Content-Type as # multipart/form-data. This seems a bit dodgy, but for # compatibility we emulate it for now. if ctype is not None and msg.get_content_maintype() == 'multipart': msg.set_type('multipart/form-data') env['CONTENT_TYPE'] = msg['Content-Type'] # cgi.FieldStorage allowed any HTTP method, while # multipart.parse_form_data only allows POST or PUT. However, # it's helpful to support methods such as PATCH too, and # multipart doesn't actually care beyond an initial check, so # just pretend everything is POST from here on. env['REQUEST_METHOD'] = 'POST' # According to PEP 333 CONTENT_LENGTH may be empty or absent. # An empty string here breaks multipart, because it's an invalid # value according to RFC 2616 (HTTP/1.1). if env.get('CONTENT_LENGTH') == '': env.pop('CONTENT_LENGTH') forms, files = multipart.parse_form_data( env, charset=self.default_form_charset, memfile_limit=0) items.extend(forms.iterallitems()) for key, item in files.iterallitems(): # multipart puts fields in 'files' even if no upload was # made. We only consider fields to be file uploads if a # filename was passed in and data was uploaded. if item.file: if item.filename: # RFC 7578 section 4.2 says: # Some commonly deployed systems use # multipart/form-data with file names directly # encoded including octets outside the US-ASCII # range. The encoding used for the file names is # typically UTF-8, although HTML forms will use # the charset associated with the form. # So we must decode the filename according to our # usual rules. item.filename = self._decode(item.filename) item = FileUpload(item) else: value = item.value item.file.close() item = value else: item = item.value self.hold(item) items.append((key, item)) if items: self.__meth = None self.__tuple_items = {} self.__defaults = {} # process all entries in the field storage (form) for key, item in items: self.__processItem(key, item) if self.__defaults: self.__insertDefaults() if self.__tuple_items: self.__convertToTuples() if self.__meth: self.setPathSuffix((self.__meth,))
_typeFormat = re.compile('([a-zA-Z][a-zA-Z0-9_]+|\\.[xy])$') def __processItem(self, key, item): """Process item in the field storage.""" flags = 0 converter = None # Loop through the different types and set # the appropriate flags # Syntax: var_name:type_name # We'll search from the back to the front. # We'll do the search in two steps. First, we'll # do a string search, and then we'll check it with # a re search. while key: pos = key.rfind(":") if pos < 0: break match = self._typeFormat.match(key, pos + 1) if match is None: break key, type_name = key[:pos], key[pos + 1:] # find the right type converter c = get_converter(type_name, None) if c is not None: converter = c flags |= CONVERTED elif type_name == 'list': flags |= SEQUENCE elif type_name == 'tuple': self.__tuple_items[key] = 1 flags |= SEQUENCE elif (type_name == 'method' or type_name == 'action'): if key: self.__meth = key else: self.__meth = item elif (type_name == 'default_method' or type_name == 'default_action') and not self.__meth: if key: self.__meth = key else: self.__meth = item elif type_name == 'default': flags |= DEFAULT elif type_name == 'record': flags |= RECORD elif type_name == 'records': flags |= RECORDS elif type_name == 'ignore_empty' and not item: # skip over empty fields return if key is not None: key = self._decode(key) if isinstance(item, (six.text_type, bytes)): item = self._decode(item) if flags: self.__setItemWithType(key, item, flags, converter) else: self.__setItemWithoutType(key, item) def __setItemWithoutType(self, key, item): """Set item value without explicit type.""" form = self.form if key not in form: form[key] = item else: found = form[key] if isinstance(found, list): found.append(item) else: form[key] = [found, item] def __setItemWithType(self, key, item, flags, converter): """Set item value with explicit type.""" # Split the key and its attribute if flags & REC: key, attr = self.__splitKey(key) # defer conversion if flags & CONVERTED: try: item = converter(item) except: # noqa: E722 do not use bare 'except' if item or flags & DEFAULT or key not in self.__defaults: raise item = self.__defaults[key] if flags & RECORD: item = getattr(item, attr) elif flags & RECORDS: item = getattr(item[-1], attr) # Determine which dictionary to use if flags & DEFAULT: form = self.__defaults else: form = self.form # Insert in dictionary if key not in form: if flags & SEQUENCE: item = [item] if flags & RECORD: r = form[key] = Record() setattr(r, attr, item) elif flags & RECORDS: r = Record() setattr(r, attr, item) form[key] = [r] else: form[key] = item else: r = form[key] if flags & RECORD: if not flags & SEQUENCE: setattr(r, attr, item) else: if not hasattr(r, attr): setattr(r, attr, [item]) else: getattr(r, attr).append(item) elif flags & RECORDS: last = r[-1] if not hasattr(last, attr): if flags & SEQUENCE: item = [item] setattr(last, attr, item) else: if flags & SEQUENCE: getattr(last, attr).append(item) else: new = Record() setattr(new, attr, item) r.append(new) else: if isinstance(r, list): r.append(item) else: form[key] = [r, item] def __splitKey(self, key): """Split the key and its attribute.""" i = key.rfind(".") if i >= 0: return key[:i], key[i + 1:] return key, "" def __convertToTuples(self): """Convert form values to tuples.""" form = self.form for key in self.__tuple_items: if key in form: form[key] = tuple(form[key]) else: k, attr = self.__splitKey(key) # remove any type_names in the attr i = attr.find(":") if i >= 0: attr = attr[:i] if k in form: item = form[k] if isinstance(item, Record): if hasattr(item, attr): setattr(item, attr, tuple(getattr(item, attr))) else: for v in item: if hasattr(v, attr): setattr(v, attr, tuple(getattr(v, attr))) def __insertDefaults(self): """Insert defaults into form dictionary.""" form = self.form for keys, values in self.__defaults.items(): if keys not in form: form[keys] = values else: item = form[keys] if isinstance(values, Record): for k, v in values.items(): if not hasattr(item, k): setattr(item, k, v) elif isinstance(values, list): for val in values: if isinstance(val, Record): for k, v in val.items(): for r in item: if not hasattr(r, k): setattr(r, k, v) elif val not in item: item.append(val)
[docs] def traverse(self, obj): """See IPublisherRequest.""" ob = super(BrowserRequest, self).traverse(obj) method = self.method base_needed = 0 if self._path_suffix: # We had a :method variable, so we need to set the base, # but we don't look for default documents any more. base_needed = 1 redirect = 0 elif method in DEFAULTABLE_METHODS: # We need to check for default documents publication = self.publication nsteps = 0 ob, add_steps = publication.getDefaultTraversal(self, ob) while add_steps: nsteps += len(add_steps) add_steps = list(add_steps) add_steps.reverse() self.setTraversalStack(add_steps) ob = super(BrowserRequest, self).traverse(ob) ob, add_steps = publication.getDefaultTraversal(self, ob) if nsteps != self._endswithslash: base_needed = 1 redirect = self.use_redirect and method == 'GET' if base_needed: url = self.getURL() response = self.response if redirect: response.redirect(url) return '' elif not response.getBase(): response.setBase(url) return ob
[docs] def keys(self): 'See Interface.Common.Mapping.IEnumerableMapping' d = {} d.update(self._environ) d.update(self._cookies) d.update(self.form) return list(d.keys())
[docs] def get(self, key, default=None): 'See Interface.Common.Mapping.IReadMapping' marker = object() result = self.form.get(key, marker) if result is not marker: return result return super(BrowserRequest, self).get(key, default)
[docs]@implementer(IHeld) class FileUpload(object): '''File upload objects File upload objects are used to represent file-uploaded data. File upload objects can be used just like files. In addition, they have a 'headers' attribute that is a dictionary containing the file-upload headers, and a 'filename' attribute containing the name of the uploaded file. ''' def __init__(self, aFieldStorage): file = aFieldStorage.file if hasattr(file, '__methods__'): methods = file.__methods__ else: methods = ['close', 'fileno', 'flush', 'isatty', 'read', 'readline', 'readlines', 'seek', 'tell', 'truncate', 'write', 'writelines', 'seekable'] d = self.__dict__ for m in methods: if hasattr(file, m): d[m] = getattr(file, m) self.headers = aFieldStorage.headers filename = aFieldStorage.filename if filename is not None: if isinstance(filename, bytes): filename = filename.decode('UTF-8') # fix for IE full paths filename = filename[filename.rfind('\\')+1:].strip() self.filename = filename def release(self): self.close()
[docs]class RedirectingBrowserRequest(BrowserRequest): """Browser requests that redirect when the actual and effective URLs differ """ use_redirect = True
[docs]class TestRequest(BrowserRequest): """Browser request with a constructor convenient for testing """ def __init__(self, body_instream=None, environ=None, form=None, skin=None, **kw): _testEnv = { 'SERVER_URL': 'http://127.0.0.1', 'HTTP_HOST': '127.0.0.1', 'CONTENT_LENGTH': '0', 'GATEWAY_INTERFACE': 'TestFooInterface/1.0', } if environ is not None: _testEnv.update(environ) if kw: _testEnv.update(kw) if body_instream is None: from io import BytesIO body_instream = BytesIO() super(TestRequest, self).__init__(body_instream, _testEnv) if form: self.form.update(form) # Setup locale object langs = BrowserLanguages(self).getPreferredLanguages() from zope.i18n.locales import locales if not langs or langs[0] == '': self._locale = locales.getLocale(None, None, None) else: parts = (langs[0].split('-') + [None, None])[:3] self._locale = locales.getLocale(*parts) if skin is not None: directlyProvides(self, skin) else: directlyProvides(self, IDefaultBrowserLayer)
[docs]class BrowserResponse(HTTPResponse): """Browser response """ __slots__ = ( '_base', # The base href ) def _implicitResult(self, body): content_type = self.getHeader('content-type') if content_type is None and self._status != 304: if isHTML(body): content_type = 'text/html' else: content_type = 'text/plain' self.setHeader('x-content-type-warning', 'guessed from content') self.setHeader('content-type', content_type) body, headers = super(BrowserResponse, self)._implicitResult(body) body = self.__insertBase(body) # Update the Content-Length header to account for the inserted # <base> tag. headers = [ (name, value) for name, value in headers if name != 'content-length' ] headers.append(('content-length', str(len(body)))) return body, headers def __insertBase(self, body): # Only insert a base tag if content appears to be html. content_type = self.getHeader('content-type', '') if content_type and not is_text_html(content_type): return body if self.getBase(): if body: match = start_of_header_search(body) if match is not None: index = match.start(0) + len(match.group(0)) ibase = base_re_search(body) if ibase is None: # Make sure the base URL is not a unicode string. base = self.getBase() if not isinstance(base, bytes): encoding = getCharsetUsingRequest( self._request) or 'utf-8' base = self.getBase().encode(encoding) body = b''.join([body[:index], b'\n<base href="', base, b'" />\n', body[index:]]) return body def getBase(self): return getattr(self, '_base', '') def setBase(self, base): self._base = base
[docs] def redirect(self, location, status=None, trusted=False): base = getattr(self, '_base', '') if base and isRelative(str(location)): pos = base.rfind('/') if pos >= 0: base = base[:pos + 1] else: base += '/' location = base + location # TODO: HTTP redirects must provide an absolute location, see # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.30 # So, what if location is relative and base is unknown? # Uncomment the following and you'll see that it actually # happens. # # if isRelative(str(location)): # raise AssertionError('Cannot determine absolute location') return super(BrowserResponse, self).redirect(location, status, trusted)
[docs] def reset(self): super(BrowserResponse, self).reset() self._base = ''
[docs]def isHTML(str): """Try to determine whether str is HTML or not.""" if isinstance(str, six.binary_type): try: str = str.decode() except UnicodeDecodeError: return False s = str.lstrip().lower() if s.startswith('<!doctype html'): return True if s.startswith('<html') and (s[5:6] in ' >'): return True if s.startswith('<!--'): idx = s.find('<html') return idx > 0 and (s[idx+5:idx+6] in ' >') else: return False
def normalize_lang(lang): lang = lang.strip().lower() lang = lang.replace('_', '-') lang = lang.replace(' ', '') return lang @zope.component.adapter(IHTTPRequest) @implementer(IUserPreferredLanguages) class BrowserLanguages(object): def __init__(self, request): self.request = request def getPreferredLanguages(self): '''See interface IUserPreferredLanguages''' accept_langs = self.request.get('HTTP_ACCEPT_LANGUAGE', '').split(',') # Normalize lang strings accept_langs = [normalize_lang(lang) for lang in accept_langs] # Then filter out empty ones accept_langs = [lang for lang in accept_langs if lang] accepts = [] for index, lang in enumerate(accept_langs): lang = lang.split(';', 2) # If not supplied, quality defaults to 1... quality = 1.0 if len(lang) == 2: q = lang[1] if q.startswith('q='): q = q.split('=', 2)[1] try: quality = float(q) except ValueError: # malformed quality value, skip it. continue if quality == 1.0: # ... but we use 1.9 - 0.001 * position to # keep the ordering between all items with # 1.0 quality, which may include items with no quality # defined, and items with quality defined as 1. quality = 1.9 - (0.001 * index) accepts.append((quality, lang[0])) # Filter langs with q=0, which means # unwanted lang according to the spec # See: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4 accepts = [acc for acc in accepts if acc[0]] accepts.sort() accepts.reverse() return [lang for quality, lang in accepts]
[docs]class NotCompatibleAdapterError(Exception): """Adapter not compatible with zope.i18n.interfaces.IModifiableBrowserLanguages has been used. """
BROWSER_LANGUAGES_KEY = "zope.publisher.browser.IUserPreferredLanguages" class CacheableBrowserLanguages(BrowserLanguages): def getPreferredLanguages(self): languages_data = self._getLanguagesData() if "overridden" in languages_data: return languages_data["overridden"] elif "cached" not in languages_data: languages_data["cached"] = super( CacheableBrowserLanguages, self).getPreferredLanguages() return languages_data["cached"] def _getLanguagesData(self): annotations = self.request.annotations languages_data = annotations.get(BROWSER_LANGUAGES_KEY) if languages_data is None: annotations[BROWSER_LANGUAGES_KEY] = languages_data = {} return languages_data @implementer(IModifiableUserPreferredLanguages) class ModifiableBrowserLanguages(CacheableBrowserLanguages): def setPreferredLanguages(self, languages): languages_data = self.request.annotations.get(BROWSER_LANGUAGES_KEY) if languages_data is None: # Better way to create a compatible with # IModifiableUserPreferredLanguages adapter is to use # CacheableBrowserLanguages as base class or as example. raise NotCompatibleAdapterError( "Adapter not compatible with" " zope.i18n.interfaces.IModifiableBrowserLanguages" " has been used.") languages_data["overridden"] = languages self.request.setupLocale()
[docs]@implementer(IBrowserView) class BrowserView(Location): """Browser View. >>> view = BrowserView("context", "request") >>> view.context 'context' >>> view.request 'request' >>> view.__parent__ 'context' >>> view.__parent__ = "parent" >>> view.__parent__ 'parent' """ def __init__(self, context, request): self.context = context self.request = request def __getParent(self): return getattr(self, '_parent', self.context) def __setParent(self, parent): self._parent = parent __parent__ = property(__getParent, __setParent)
[docs]@implementer(IBrowserPage) class BrowserPage(BrowserView): """Browser page To create a page, which is an object that is published as a page, you need to provide an object that: - has a __call__ method and that - provides IBrowserPublisher, and - if ZPT is going to be used, then your object should also provide request and context attributes. The BrowserPage base class provides a standard constructor and a simple implementation of IBrowserPublisher: >>> class MyPage(BrowserPage): ... pass >>> request = TestRequest() >>> context = object() >>> page = MyPage(context, request) >>> from zope.publisher.interfaces.browser import IBrowserPublisher >>> IBrowserPublisher.providedBy(page) True >>> page.browserDefault(request) == (page, ()) True >>> page.publishTraverse(request, 'bob') # doctest: +ELLIPSIS Traceback (most recent call last): ... NotFound: Object: <zope.publisher.browser.MyPage object at ...>, name: 'bob' >>> page.request is request True >>> page.context is context True But it doesn't supply a __call__ method: >>> page() Traceback (most recent call last): ... NotImplementedError: Subclasses should override __call__ to provide a response body It is the subclass' responsibility to do that. """ # noqa: E501 line too long def browserDefault(self, request): return self, () def publishTraverse(self, request, name): raise NotFound(self, name, request) def __call__(self, *args, **kw): raise NotImplementedError("Subclasses should override __call__ to " "provide a response body")