#!/usr/bin/env python # """StickyForm -- state maintaining HTML forms Intended to work with HTMLgen. What is StickyForm? It is a class which works with HTMLgen to provide state maintaining forms. Forms can load and save their state to and from files. This persistent state is what makes them 'sticky'. Why would I want to use it? The same reason you'd want to use CGI.pm ;) Actually there are many CGI tasks which benefit from forms which can remember their settings. For example, in a hypothetical CGI program, a user could set their preferences with a form, and later return to the form to modify or review them. How do I use it? Simply create forms the same way you normally would with HTMLgen, only use the StickyForm class instead of the Form class. StickyForm works like a Form with the addition of a state attribute, a save method and a restore method. state -- is a FormState instance which holds the default values for all form elements. save -- tells the FormState instance to save itself to a file. restore -- tells the FormState instance to restore itself from a file. So how do I set a form's state? You can set a form's state when you create it, and you can always change the state later by assigning something else to the form's state attribute. There are three ways to indicate a StickyForm's state upon initialization: filename -- this loads the state of the form from a file FieldStorage -- this sets the state of the form from the information in the FieldStorage FormState -- this sets the state to the FormState instance For each method here are some examples: form=StickyForm(state="/tmp/form.txt") cgi_results=cgi.FieldStorage() form=StickyForm(state=cgi_results) fs=FormState() form=StickyForm(state=fs) What is the FormState class? This is a simple dictionary which StickyForm uses to store its state information. A FormState instance can be intitalized with a FieldStorage instance, to create a form state which reflects the form data in the FieldStorage instance. This just means turning a slightly complex FieldStorage into a simple dictionary. How is the form's state saved? It is pickled to a file. Does StickyForm work with Bobo or DocumentTemplate? Yes, see the [StickyForm page]. .. [StickyForm page] http://www.aracnet.com/~amos/stickyform/ """ # copyright 1998 by amos latteier, amos@aracnet.com from HTMLgen import * from types import ListType, StringType import UserDict #'$Id: StickyForm.py,v 1.3 1999/02/04 04:57:34 friedric Exp $' __version__ = '1.0.1' __author__ = 'Amos Latteier, amos@aracnet.com' # RKF - Trying out cPickle as a faster mechanism for the persistant # storage. try: import cPickle def dump(data, filename): file = open(filename,'wb') cPickle.dump(data, file, 1) file.close() def load(filename): file = open(filename, 'rb') unpickled_object = cPickle.load(file) file.close() return unpickled_object except ImportError: import pickle def dump(data, filename): file = open(filename,'w') pickle.dump(data, file) file.close() def load(filename): file = open(filename, 'r') unpickled_object = pickle.load(file) file.close() return unpickled_object class FormState(UserDict.UserDict): """This is a Dictionary which holds the state of a form. It is like a simplified FieldStorage class. Each key is the name of a form element. Each value is either a string or a list of strings which define that value. You can create a FormState from a FieldStorage. You can save and restore FormStates from text files""" def __init__(self, field_storage=None): self.data={} if not field_storage: field_storage={} for key in field_storage.keys(): item=field_storage[key] if type(item) == ListType: value=[] for sub_item in item: value.append(sub_item.value) else: value=item.value self.data[key]=value def save(self,filename): dump(self.data, filename) def restore(self,filename): self.data = load(filename) class StickyForm(Form): """Works like a Form with the addition of a state attribute, a save method and a restore method. A form's state is a FormState instance which holds the default values for all form elements. save tells the FormState instance to save itself to a file. restore tells the FormState instance to restore itself from a file. You can initalize the state 3 ways, with a: filename -- this loads the state of the form from a file FieldStorage -- this sets the state of the form from the information in the FieldStorage FormState -- this sets the state to the FormState instance For example: form=StickyForm(state="/tmp/form.txt") fs=cgi.FieldStorage() form=StickyForm(state=fs) fs=FormState() form=StickyForm(state=fs) """ def __init__(self, cgi = None, state=None,**kw): apply(Form.__init__, (self,cgi), kw) if type(state) == StringType: self.state=FormState() self.state.restore(state) elif state is None: self.state=FormState() elif state.__class__.__name__ == "FieldStorage": self.state=FormState(state) else: self.state=state def __str__(self): if not self.submit: self.contents.append(Input(type='submit', name='SubmitButton',value='Send')) else: self.contents.append(self.submit) if self.reset: self.contents.append(self.reset) s = ['\n
\n') for item in self.contents: if self.state is not None: s.append(self.with_state(item)) else: s.append(str(item)) s.append('\n
\n') return string.join(s, '') def with_state(self,input): """Here's where the actual work gets done. Each Input, Select and Textarea object in the form is modified to reflect it's value as defined in the form's state. """ try: input_class=input.__class__.__name__ if input_class not in ("Input","Select","Textarea"): return str(input) except: return str(input) if self.state.has_key(input.name): input_state=self.state[input.name] else: return str(input) if type(input_state) == ListType: input_state_list=input_state else: input_state_list=[input_state] if input_class == "Input": if input.type in ('checkbox','radio'): if input.value in input_state_list: input.checked=1 else: input.value=input_state elif input_class == "Select": input.selected=input_state_list elif input_class == "Textarea": input.text=input_state return str(input) def save(self,filename): self.state.save(filename) def restore(self,filename): self.state.restore(filename)