# -*- test-case-name: twisted.web.test.test_web -*- # # Copyright (c) 2001-2004 Twisted Matrix Laboratories. # See LICENSE for details. """This module is DEPRECATED.""" import warnings warnings.warn("This module is deprecated, please use Woven instead.", DeprecationWarning) # System Imports import string, time, types, traceback, pprint, sys, os import linecache import re from cStringIO import StringIO # Twisted Imports from twisted.python import failure, log, rebuild, reflect, util from twisted.internet import defer from twisted.protocols import http # Sibling Imports import html, resource, error import util as webutil #backwards compatibility from util import formatFailure, htmlrepr, htmlUnknown, htmlDict, htmlList,\ htmlInst, htmlString, htmlReprTypes from server import NOT_DONE_YET True = (1==1) False = not True """A twisted web component framework. This code is mainly old stuff which is being kept around for historical reasons. It is being very gradually deprecated in favor of twisted.web.woven; however, woven is still maturing and does not yet have equivalent functionality in all areas. (Though in some ways, it's already much more featureful.) This module will be removed when woven has reached feature- and documentation-parity with it, and all Twisted functionality that uses it has been rewritten. """ # magic value that sez a widget needs to take over the whole page. FORGET_IT = 99 def listify(x): return [x] def _ellipsize(x): y = repr(x) if len(y) > 1024: return y[:1024]+"..." return y class Widget: """A component of a web page. """ title = None def getTitle(self, request): return self.title or reflect.qual(self.__class__) def display(self, request): """Implement me to represent your widget. I must return a list of strings and twisted.internet.defer.Deferred instances. """ raise NotImplementedError("%s.display" % reflect.qual(self.__class__)) class StreamWidget(Widget): """A 'streamable' component of a webpage. """ def stream(self, write, request): """Call 'write' multiple times with a string argument to represent this widget. """ raise NotImplementedError("%s.stream" % reflect.qual(self.__class__)) def display(self, request): """Produce a list containing a single string. """ l = [] try: result = self.stream(l.append, request) if result is not None: return result return l except: return [webutil.formatFailure(failure.Failure())] class WidgetMixin(Widget): """A mix-in wrapper for a Widget. This mixin can be used to wrap functionality in any other widget with a method of your choosing. It is designed to be used for mix-in classes that can be mixed in to Form, StreamWidget, Presentation, etc, to augment the data available to the 'display' methods of those classes, usually by adding it to a Session. """ def display(self): raise NotImplementedError("%s.display" % self.__class__) def displayMixedWidget(self, request): for base in reflect.allYourBase(self.__class__): if issubclass(base, Widget) and not issubclass(base, WidgetMixin): return base.display(self, request) class Presentation(Widget): """I am a widget which formats a template with interspersed python expressions. """ template = ''' Hello, %%%%world%%%%. ''' world = "you didn't assign to the 'template' attribute" def __init__(self, template=None, filename=None): if filename: self.template = open(filename).read() elif template: self.template = template self.variables = {} self.tmpl = string.split(self.template, "%%%%") def addClassVars(self, namespace, Class): for base in Class.__bases__: # Traverse only superclasses that know about Presentation. if issubclass(base, Presentation) and base is not Presentation: self.addClassVars(namespace, base) # 'lower' classes in the class heirarchy take precedence. for k in Class.__dict__.keys(): namespace[k] = getattr(self, k) def addVariables(self, namespace, request): self.addClassVars(namespace, self.__class__) def prePresent(self, request): """Perform any tasks which must be done before presenting the page. """ def formatTraceback(self, tb): return [html.PRE(tb)] def streamCall(self, call, *args, **kw): """Utility: Call a method like StreamWidget's 'stream'. """ io = StringIO() apply(call, (io.write,) + args, kw) return io.getvalue() def display(self, request): tm = [] flip = 0 namespace = {} self.prePresent(request) self.addVariables(namespace, request) # This variable may not be obscured... namespace['request'] = request namespace['self'] = self for elem in self.tmpl: flip = not flip if flip: if elem: tm.append(elem) else: try: x = eval(elem, namespace, namespace) except: log.deferr() tm.append(webutil.formatFailure(failure.Failure())) else: if isinstance(x, types.ListType): tm.extend(x) elif isinstance(x, Widget): val = x.display(request) if not isinstance(val, types.ListType): raise Exception("%s.display did not return a list, it returned %s!" % (x.__class__, repr(val))) tm.extend(val) else: # Only two allowed types here should be deferred and # string. tm.append(x) return tm def htmlFor_hidden(write, name, value): write('' % (name, value)) def htmlFor_file(write, name, value): write('' % name) def htmlFor_string(write, name, value): write('' % (name, value)) def htmlFor_password(write, name, value): write('' % name) def htmlFor_text(write, name, value): write('' % (name, value)) def htmlFor_menu(write, name, value, allowMultiple=False): "Value of the format [(optionName, displayName[, selected]), ...]" write(' \n") def htmlFor_multimenu(write, name, value): "Value of the format [(optionName, displayName[, selected]), ...]" return htmlFor_menu(write, name, value, True) def htmlFor_checkbox(write, name, value): "A checkbox." if value: value = 'checked = "1"' else: value = '' write('\n' % (name, value)) def htmlFor_checkgroup(write, name, value): "A check-group." for optionName, displayName, checked in value: checked = (checked and 'checked = "1"') or '' write('%s
\n' % (name, optionName, checked, displayName)) def htmlFor_radio(write, name, value): "A radio button group." for optionName, displayName, checked in value: checked = (checked and 'checked = "1"') or '' write('%s
\n' % (name, optionName, checked, displayName)) class FormInputError(Exception): pass class Form(Widget): """I am a web form. In order to use me, you probably want to set self.formFields (or override 'getFormFields') and override 'process'. In order to demonstrate how this is done, here is a small sample Form subclass:: | from twisted.web import widgets | class HelloForm(widgets.Form): | formFields = [ | ['string', 'Who to greet?', 'whoToGreet', 'World', | 'This is for choosing who to greet.'], | ['menu', 'How to greet?', 'how', [('cheerfully', 'with a smile'), | ('sullenly', 'without enthusiasm'), | ('spontaneously', 'on the spur of the moment')]] | 'This is for choosing how to greet them.'] | def process(self, write, request, submit, whoToGreet, how): | write('The web wakes up and %s says, \"Hello, %s!\"' % (how, whoToGreet)) If you load this widget, you will see that it displays a form with 2 inputs derived from data in formFields. Note the argument names to 'process': after 'write' and 'request', they are the same as the 3rd elements ('Input Name' parameters) of the formFields list. """ formGen = { 'hidden': htmlFor_hidden, 'file': htmlFor_file, 'string': htmlFor_string, 'int': htmlFor_string, 'float': htmlFor_string, 'text': htmlFor_text, 'menu': htmlFor_menu, 'multimenu': htmlFor_multimenu, 'password': htmlFor_password, 'checkbox': htmlFor_checkbox, 'checkgroup': htmlFor_checkgroup, 'radio': htmlFor_radio, } formParse = { 'int': int, 'float': float, } formFields = [ ] # do we raise an error when we get extra args or not? formAcceptExtraArgs = 0 def getFormFields(self, request, fieldSet = None): """I return a list of lists describing this form, or a Deferred. This information is used both to display the form and to process it. The list is in the following format:: | [['Input Type', 'Display Name', 'Input Name', 'Input Value', 'Description'], | ['Input Type 2', 'Display Name 2', 'Input Name 2', 'Input Value 2', 'Description 2'] | ...] Valid values for 'Input Type' are: - 'hidden': a hidden field that contains a string that the user won't change - 'string': a short string - 'int': an integer, e.g. 1, 0, 25 or -23 - 'float': a float, e.g. 1.0, 2, -3.45, or 28.4324231 - 'text': a longer text field, suitable for entering paragraphs - 'menu': an HTML SELECT input, a list of choices - 'multimenu': an HTML SELECT input allowing multiple choices - 'checkgroup': a group of checkboxes - 'radio': a group of radio buttons - 'password': a 'string' field where the contents are not visible as the user types - 'file': a file-upload form (EXPERIMENTAL) 'Display Name' is a descriptive string that will be used to identify the field to the user. The 'Input Name' must be a legal Python identifier that describes both the value's name on the HTML form and the name of an argument to 'self.process()'. The 'Input Value' is usually a string, but its value can depend on the 'Input Type'. 'int' it is an integer, 'menu' it is a list of pairs of strings, representing (value, name) pairs for the menu options. Input value for 'checkgroup' and 'radio' should be a list of ('inputName', 'Display Name', 'checked') triplets. The 'Description' field is an (optional) string which describes the form item to the user. If this result is statically determined for your Form subclass, you can assign it to FormSubclass.formFields; if you need to determine it dynamically, you can override this method. Note: In many cases it is desirable to use user input for defaults in the form rather than those supplied by your calculations, which is what this method will do to self.formFields. If this is the case for you, but you still need to dynamically calculate some fields, pass your results back through this method by doing:: | def getFormFields(self, request): | myFormFields = [self.myFieldCalculator()] | return widgets.Form.getFormFields(self, request, myFormFields) """ fields = [] if fieldSet is None: fieldSet = self.formFields if not self.shouldProcess(request): return fieldSet for field in fieldSet: if len(field)==5: inputType, displayName, inputName, inputValue, description = field else: inputType, displayName, inputName, inputValue = field description = "" if inputType == 'checkbox': if request.args.has_key('__checkboxes__'): if inputName in request.args['__checkboxes__']: inputValue = 1 else: inputValue = 0 else: inputValue = 0 elif inputType in ('checkgroup', 'radio'): if request.args.has_key(inputName): keys = request.args[inputName] else: keys = [] iv = inputValue inputValue = [] for optionName, optionDisplayName, checked in iv: checked = optionName in keys inputValue.append([optionName, optionDisplayName, checked]) elif request.args.has_key(inputName): iv = request.args[inputName][0] if inputType in ['menu', 'multimenu']: if iv in inputValue: inputValue.remove(iv) inputValue.insert(0, iv) else: inputValue = iv fields.append([inputType, displayName, inputName, inputValue, description]) return fields submitNames = ['Submit'] actionURI = '' def format(self, form, write, request): """I display an HTML FORM according to the result of self.getFormFields. """ write('
\n' '\n' % (self.actionURI or request.uri)) for field in form: if len(field) == 5: inputType, displayName, inputName, inputValue, description = field else: inputType, displayName, inputName, inputValue = field description = "" write('\n\n' '\n\n' % description) write('\n
%s\n' % (displayName, ((inputType == 'text') and 'top') or 'middle')) self.formGen[inputType](write, inputName, inputValue) write('\n
\n%s
\n') for submitName in self.submitNames: write('\n' % submitName) write('
\n' '\n' % (reflect.qual(self.__class__))) fid = self.getFormID() if fid: write('\n' % fid) write("
\n") def getFormID(self): """Override me: I disambiguate between multiple forms of the same type. In order to determine which form an HTTP POST request is for, you must have some unique identifier which distinguishes your form from other forms of the same class. An example of such a unique identifier would be: on a page with multiple FrobConf forms, each FrobConf form refers to a particular Frobnitz instance, which has a unique id(). The FrobConf form's getFormID would probably look like this:: | def getFormID(self): | return str(id(self.frobnitz)) By default, this method will return None, since distinct Form instances may be identical as far as the application is concerned. """ def process(self, write, request, submit, **kw): """Override me: I process a form. I will only be called when the correct form input data to process this form has been received. I take a variable number of arguments, beginning with 'write', 'request', and 'submit'. 'write' is a callable object that will append a string to the response, 'request' is a twisted.web.request.Request instance, and 'submit' is the name of the submit action taken. The remainder of my arguments must be correctly named. They will each be named after one of the """ write("
Submit: %s 
 %s
" % (submit, html.PRE(pprint.PrettyPrinter().pformat(kw)))) def _doProcess(self, form, write, request): """(internal) Prepare arguments for self.process. """ args = request.args.copy() kw = {} for field in form: inputType, displayName, inputName, inputValue = field[:4] if inputType == 'checkbox': if request.args.has_key('__checkboxes__'): if inputName in request.args['__checkboxes__']: formData = 1 else: formData = 0 else: formData = 0 elif inputType in ['checkgroup', 'radio', 'multimenu']: if args.has_key(inputName): formData = args[inputName] del args[inputName] else: formData = [] else: if not args.has_key(inputName): raise FormInputError("missing field %s." % repr(inputName)) formData = args[inputName] del args[inputName] if not len(formData) == 1: raise FormInputError("multiple values for field %s." %repr(inputName)) formData = formData[0] method = self.formParse.get(inputType) if method: try: formData = method(formData) except: raise FormInputError("%s: %s" % (displayName, "error")) kw[inputName] = formData submitAction = args.get('submit') if submitAction: submitAction = submitAction[0] for field in ['submit', '__formtype__', '__checkboxes__']: if args.has_key(field): del args[field] if args and not self.formAcceptExtraArgs: raise FormInputError("unknown fields: %s" % repr(args)) return apply(self.process, (write, request, submitAction), kw) def formatError(self,error): """Format an error message. By default, this will make the message appear in red, bold italics. """ return '%s
\n' % error def shouldProcess(self, request): args = request.args fid = self.getFormID() return (args and # there are arguments to the request args.has_key('__formtype__') and # this is a widgets.Form request args['__formtype__'][0] == reflect.qual(self.__class__) and # it is for a form of my type ((not fid) or # I am only allowed one form per page (args.has_key('__formid__') and # if I distinguish myself from others, the request must too args['__formid__'][0] == fid))) # I am in fact the same def tryAgain(self, err, req): """Utility method for re-drawing the form with an error message. This is handy in forms that process Deferred results. Normally you can just raise a FormInputError() and this will happen by default. """ l = [] w = l.append w(self.formatError(err)) self.format(self.getFormFields(req), w, req) return l def display(self, request): """Display the form.""" form = self.getFormFields(request) if isinstance(form, defer.Deferred): if self.shouldProcess(request): form.addCallback(lambda form, f=self._displayProcess, r=request: f(r, form)) else: form.addCallback(lambda form, f=self._displayFormat, r=request: f(r, form)) return [form] else: if self.shouldProcess(request): return self._displayProcess(request, form) else: return self._displayFormat(request, form) def _displayProcess(self, request, form): l = [] write = l.append try: val = self._doProcess(form, write, request) if val: l.extend(val) except FormInputError, fie: write(self.formatError(str(fie))) return l def _displayFormat(self, request, form): l = [] self.format(form, l.append, request) return l class DataWidget(Widget): def __init__(self, data): self.data = data def display(self, request): return [self.data] class Time(Widget): def display(self, request): return [time.ctime(time.time())] class Container(Widget): def __init__(self, *widgets): self.widgets = widgets def display(self, request): value = [] for widget in self.widgets: d = widget.display(request) value.extend(d) return value class _RequestDeferral: def __init__(self): self.deferred = defer.Deferred() self.io = StringIO() self.write = self.io.write def finish(self): self.deferred.callback([self.io.getvalue()]) def possiblyDeferWidget(widget, request): # web in my head get it out get it out try: disp = widget.display(request) # if this widget wants to defer anything -- well, I guess we've got to # defer it. for elem in disp: if isinstance(elem, defer.Deferred): req = _RequestDeferral() RenderSession(disp, req) return req.deferred return string.join(disp, '') except: io = StringIO() traceback.print_exc(file=io) return html.PRE(io.getvalue()) class RenderSession: """I handle rendering of a list of deferreds, outputting their results in correct order.""" class Sentinel: pass def __init__(self, lst, request): self.lst = lst self.request = request self.needsHeaders = 0 self.beforeBody = 1 self.forgotten = 0 self.pauseList = [] for i in range(len(self.lst)): item = self.lst[i] if isinstance(item, defer.Deferred): self._addDeferred(item, self.lst, i) self.keepRendering() def _addDeferred(self, deferred, lst, idx): sentinel = self.Sentinel() if hasattr(deferred, 'needsHeader'): # You might want to set a header from a deferred, in which # case you have to set an attribute -- needsHeader. self.needsHeaders = self.needsHeaders + 1 args = (sentinel, 1) else: args = (sentinel, 0) lst[idx] = sentinel, deferred deferred.pause() self.pauseList.append(deferred) deferred.addCallbacks(self.callback, self.callback, callbackArgs=args, errbackArgs=args) def callback(self, result, sentinel, decNeedsHeaders): if self.forgotten: return if result != FORGET_IT: self.needsHeaders = self.needsHeaders - decNeedsHeaders else: result = [FORGET_IT] # Make sure result is a sequence, if not type(result) in (types.ListType, types.TupleType): result = [result] # If the deferred does not wish to produce its result all at # once, it can give us a partial result as # (NOT_DONE_YET, partial_result) ## XXX: How would a deferred go about producing the result in multiple ## stages?? --glyph if result[0] is NOT_DONE_YET: done = 0 result = result[1] if not type(result) in (types.ListType, types.TupleType): result = [result] else: done = 1 for i in xrange(len(result)): item = result[i] if isinstance(item, defer.Deferred): self._addDeferred(item, result, i) for position in range(len(self.lst)): item = self.lst[position] if type(item) is types.TupleType and len(item) > 0: if item[0] is sentinel: break else: raise AssertionError('Sentinel for Deferred not found!') if done: self.lst[position:position+1] = result else: self.lst[position:position] = result self.keepRendering() def keepRendering(self): while self.pauseList: pl = self.pauseList self.pauseList = [] for deferred in pl: deferred.unpause() return if self.needsHeaders: # short circuit actual rendering process until we're sure no # more deferreds need to set headers... return assert self.lst is not None, "This shouldn't happen." while 1: item = self.lst[0] if self.beforeBody and FORGET_IT in self.lst: # If I haven't moved yet, and the widget wants to take # over the page, let it do so! self.forgotten = 1 return if isinstance(item, types.StringType): self.beforeBody = 0 self.request.write(item) elif type(item) is types.TupleType and len(item) > 0: if isinstance(item[0], self.Sentinel): return elif isinstance(item, failure.Failure): self.request.write(webutil.formatFailure(item)) else: self.beforeBody = 0 unknown = html.PRE(repr(item)) self.request.write("RENDERING UNKNOWN: %s" % unknown) del self.lst[0] if len(self.lst) == 0: self.lst = None self.request.finish() return ## XXX: is this needed? class WidgetResource(resource.Resource): def __init__(self, widget): self.widget = widget resource.Resource.__init__(self) def render(self, request): RenderSession(self.widget.display(request), request) return NOT_DONE_YET class Page(resource.Resource, Presentation): def __init__(self): resource.Resource.__init__(self) Presentation.__init__(self) def render(self, request): displayed = self.display(request) RenderSession(displayed, request) return NOT_DONE_YET class WidgetPage(Page): """ I am a Page that takes a Widget in its constructor, and displays that Widget wrapped up in a simple HTML template. """ stylesheet = ''' a { font-family: Lucida, Verdana, Helvetica, Arial, sans-serif; color: #369; text-decoration: none; } th { font-family: Lucida, Verdana, Helvetica, Arial, sans-serif; font-weight: bold; text-decoration: none; text-align: left; } pre, code { font-family: "Courier New", Courier, monospace; } p, body, td, ol, ul, menu, blockquote, div { font-family: Lucida, Verdana, Helvetica, Arial, sans-serif; color: #000; } ''' template = ''' %%%%self.title%%%%

%%%%self.title%%%%

%%%%self.widget%%%% ''' title = 'No Title' widget = 'No Widget' def __init__(self, widget): Page.__init__(self) self.widget = widget if hasattr(widget, 'stylesheet'): self.stylesheet = widget.stylesheet def prePresent(self, request): self.title = self.widget.getTitle(request) def render(self, request): displayed = self.display(request) RenderSession(displayed, request) return NOT_DONE_YET class Gadget(resource.Resource): """I am a collection of Widgets, to be rendered through a Page Factory. self.pageFactory should be a Resource that takes a Widget in its constructor. The default is twisted.web.widgets.WidgetPage. """ isLeaf = 0 def __init__(self): resource.Resource.__init__(self) self.widgets = {} self.files = [] self.modules = [] self.paths = {} def render(self, request): #Redirect to view this entity as a collection. request.setResponseCode(http.FOUND) # TODO who says it's not https? request.setHeader("location","http%s://%s%s/" % ( request.isSecure() and 's' or '', request.getHeader("host"), (string.split(request.uri,'?')[0]))) return "NO DICE!" def putWidget(self, path, widget): """ Gadget.putWidget(path, widget) Add a Widget to this Gadget. It will be rendered through the pageFactory associated with this Gadget, whenever 'path' is requested. """ self.widgets[path] = widget #this is an obsolete function def addFile(self, path): """ Gadget.addFile(path) Add a static path to this Gadget. This method is obsolete, use Gadget.putPath instead. """ log.msg("Gadget.addFile() is deprecated.") self.paths[path] = path def putPath(self, path, pathname): """ Gadget.putPath(path, pathname) Add a static path to this Gadget. Whenever 'path' is requested, twisted.web.static.File(pathname) is sent. """ self.paths[path] = pathname def getWidget(self, path, request): return self.widgets.get(path) def pageFactory(self, *args, **kwargs): """ Gadget.pageFactory(*args, **kwargs) -> Resource By default, this method returns self.page(*args, **kwargs). It is only for backwards-compatibility -- you should set the 'pageFactory' attribute on your Gadget inside of its __init__ method. """ #XXX: delete this after a while. if hasattr(self, "page"): log.msg("Gadget.page is deprecated, use Gadget.pageFactory instead") return apply(self.page, args, kwargs) else: return apply(WidgetPage, args, kwargs) def getChild(self, path, request): if path == '': # ZOOP! if isinstance(self, Widget): return self.pageFactory(self) widget = self.getWidget(path, request) if widget: if isinstance(widget, resource.Resource): return widget else: p = self.pageFactory(widget) p.isLeaf = getattr(widget,'isLeaf',0) return p elif self.paths.has_key(path): prefix = getattr(sys.modules[self.__module__], '__file__', '') if prefix: prefix = os.path.abspath(os.path.dirname(prefix)) return static.File(os.path.join(prefix, self.paths[path])) elif path == '__reload__': return self.pageFactory(Reloader(map(reflect.namedModule, [self.__module__] + self.modules))) else: return error.NoResource("No such child resource in gadget.") class TitleBox(Presentation): template = '''\ \
%%%%self.title%%%%
\ \ \
%%%%self.widget%%%%
\ ''' borderColor = '#000000' titleTextColor = '#ffffff' boxTextColor = '#000000' boxColor = '#ffffff' widthOption = 'width="100%"' title = 'No Title' widget = 'No Widget' def __init__(self, title, widget): """Wrap a widget with a given title. """ self.widget = widget self.title = title Presentation.__init__(self) class Reloader(Presentation): template = ''' Reloading... ... reloaded! ''' def __init__(self, modules): Presentation.__init__(self) self.modules = modules def reload(self, request): request.redirect("..") x = [] write = x.append for module in self.modules: rebuild.rebuild(module) write('
  • reloaded %s
    ' % module.__name__) return x class Sidebar(StreamWidget): bar = [ ['Twisted', ['mirror', 'http://coopweb.org/ssd/twisted/'], ['mailing list', 'cgi-bin/mailman/listinfo/twisted-python'] ] ] headingColor = 'ffffff' headingTextColor = '000000' activeHeadingColor = '000000' activeHeadingTextColor = 'ffffff' sectionColor = '000088' sectionTextColor = '008888' activeSectionColor = '0000ff' activeSectionTextColor = '00ffff' def __init__(self, highlightHeading, highlightSection): self.highlightHeading = highlightHeading self.highlightSection = highlightSection def getList(self): return self.bar def stream(self, write, request): write("") for each in self.getList(): if each[0] == self.highlightHeading: headingColor = self.activeHeadingColor headingTextColor = self.activeHeadingTextColor canHighlight = 1 else: headingColor = self.headingColor headingTextColor = self.headingTextColor canHighlight = 0 write('\n' % (headingColor, headingTextColor, each[0])) for name, link in each[1:]: if canHighlight and (name == self.highlightSection): sectionColor = self.activeSectionColor sectionTextColor = self.activeSectionTextColor else: sectionColor = self.sectionColor sectionTextColor = self.sectionTextColor write('' '' % (sectionColor, sectionColor, request.sibLink(link), sectionTextColor, name)) write("
    ' '%s' '
    -%s' '
    ") # moved from template.py from twisted.web.woven import template from twisted.python import components class WebWidgetNodeMutator(template.NodeMutator): """A WebWidgetNodeMutator replaces the node that is passed in to generate with the result of generating the twisted.web.widget instance it adapts. """ def generate(self, request, node): widget = self.data displayed = widget.display(request) try: html = string.join(displayed) except: pr = Presentation() pr.tmpl = displayed #strList = pr.display(request) html = string.join(displayed) stringMutator = template.StringNodeMutator(html) return stringMutator.generate(request, node) components.registerAdapter(WebWidgetNodeMutator, Widget, template.INodeMutator) import static