I have a WTForms custom validation function that returns a variable containing a hash:
def dupe_check(self, field):
"""
Check for duplicate images.
"""
def get_hash():
"""
Get hash of image.
"""
f = field.data
img = Image.open(f)
imghash = imagehash.dhash(img)
f.seek(0)
return imghash
imghash = str(get_hash())
hashcheck = str(Sights.query.filter(Sights.image_hash == imghash).first())
if hashcheck == imghash:
raise ValidationError('Duplicate image detected!')
class AddImageForm(FlaskForm):
sights_image = FileField('image', validators=[FileRequired(), FileAllowed(images, 'Images only!'), dupe_check])
What is the best way to expose the imghash variable which lives in forms.py to a Flask view which lives in views.py?
Should imghash go into a WTForms HiddenField? Should I create a session variable? Should I turn the dupe_check function into a Class?
My goal is to write the hash into DB during Flask view, but not have to regenerate the hash since it is already created during validation.
In your dupe_check(self, field) self is the form instance so you can store your calculated hash value in the form and use it later on in your processing.
Here's a self-contained example, note I've created a class validator rather then using a simple method.
from flask import Flask, request, flash, render_template_string, redirect
from flask_wtf import FlaskForm
from wtforms import ValidationError, StringField
app = Flask(__name__)
app.config['SECRET_KEY'] = '0123456789'
def get_hash(data):
# Use data to compute hash
image_hash = 1000000
return image_hash
class HashValidator(object):
def __init__(self, message=None):
if not message:
message = u'Duplicate image detected!'
self.message = message
def __call__(self, form, field):
# Pass field data to hash function
_img_hash = get_hash(field.data)
# Store the hash in the form
form.imghash = _img_hash
# calculate if existing hash exists
# hashcheck = str(Sights.query.filter(Sights.image_hash == _img_hash).first())
hashcheck = 1000000
if hashcheck == _img_hash:
raise ValidationError(self.message)
class AddImageForm(FlaskForm):
# sights_image = FileField('image', validators=[HashValidator()])
# Use an Stringfield to make the sample easier
sights_image = StringField('image', validators=[HashValidator()])
_template = '''
{% with messages = get_flashed_messages() %}
{% if messages %}
<ul class=flashes>
{% for message in messages %}
<li>{{ message }}</li>
{% endfor %}
</ul>
{% endif %}
{% endwith %}
<form action="/" method="POST">
{{form.csrf_token}}
{{form.sights_image}}
{% if form.sights_image.errors %}
<ul>{% for error in form.sights_image.errors %}<li>{{ error }}</li>{% endfor %}</ul>
{% endif %}
<button type='submit'>Submit</button>
</form>
'''
#app.route('/', methods=['GET', 'POST'])
def index():
if request.method == 'POST':
_image_form = AddImageForm()
if _image_form.validate_on_submit():
flash("Validated: get_hash returned {}".format(_image_form.imghash))
return redirect('/')
else:
# didn't validate template will show error
flash("Error. get_hash returned {}".format(_image_form.imghash))
return render_template_string(_template, form=_image_form)
else:
_image_form = AddImageForm()
return render_template_string(_template, form=_image_form)
if __name__ == '__main__':
app.run(port=9876, debug=True)
In this case, you can turn the function get_hash() into a method of the form class:
class AddImageForm(FlaskForm):
sights_image = FileField('image', validators=[...])
def get_hash(self):
f = self.sights_image.data
img = Image.open(f)
imghash = imagehash.dhash(img)
f.seek(0)
return imghash
Then in view function, you can simply call it with the form, such as:
from flask import request
#app.route('/', methods=['GET', 'POST'])
def test():
form = AddImageForm()
if request.method == 'POST':
hash = form.get_hash()
Related
I am using Flask, Pandas, WTForms.
I want to populate a selectfield with data from a csv file.
I have
routes.py
forms.py
tabular.html
I create form in forms.py then via routes.py display it into tabular.html.
Forms.py
class QueryTableForm(FlaskForm):
state_select = []
district_select = []
country = SelectField(u'Country', choices=state_select)
state = SelectField(u'State', choices=district_select)
submit = SubmitField(u'Search')
Routes.py
#csv imports
country_wise_data = list(pd.read_csv('country_data.csv').values)
state_wise_data = list(pd.read_csv('state_data.csv').values)
district_wise_data = list(pd.read_csv('district_data.csv').values)
#app.route("/tabular", methods=['GET', 'POST'])
#login_required
def tabular():
form = QueryTableForm()
if form.validate_on_submit():
post = Post(title=form.country.data, content=form.state.data)
flash('Your Selection is Registered!', 'success')
return render_template('tabular.html', state_wise_data = state_wise_data,
country_wise_data=country_wise_data, district_wise_data=district_wise_data,
title='Tabular Data', form=form, legend='Tabular',
max=17000, date=date)
tabular.html
<form method="POST" action="">
...
{{ form.country.label }} {{ form.country }}
{{ form.state.label }} {{ form.state}}
...
</form>
csv file format
State,Confirmed,Recovered,Deaths,Active,Last_Updated_Time,,,,,,
USA,3458996,2834473,58245,564746,12-04-2021 22.57,,,,,,
India,1180398,1123133,4815,52128,13-04-2021 19.02,,,,,,
Now I want to pull only the values "USA","India" etc and populate in the selectfield "form.country". I have tried to do a for loop on routes.py. But how do I pass it on to the HTML file ? I also tried to do a for loop via Jinja on the HTML file.
How do I dynamically populate the "choices" attribute of the WTF selectfield from the html file ?
#app.route("/tabular", methods=['GET', 'POST'])
#login_required
def tabular():
form = QueryTableForm()
form.country.choices = country_wise_data
if form.validate_on_submit():
post = Post(title=form.country.data, content=form.state.data)
flash('Your Selection is Registered!', 'success')
return render_template('tabular.html', state_wise_data = state_wise_data,
country_wise_data=country_wise_data, district_wise_data=district_wise_data,
title='Tabular Data', form=form, legend='Tabular',
max=17000, date=date)
I want to use django-import-export's forms to implement the import feature for regular users, so it needs to be outside the admin section.
So far, all the implementations I have found are about
a) extending the feature inside the admin or
b) reimplementing the default views outside the admin.
But since the default forms work perfectly (specially the ConfirmImportForm that shows a diff between old records and new records attempting to be imported) I would like to subclass them as part of my project (outside admin) without reimplementing the whole view's logic, if such thing is even possible.
So far I tried (foolishly, I'm afraid) to subclass the import_export.admin.ImportMixin as two separated class views to import a model Period with resource PeriodResource. The methods import_action and process_import were reimplemented (basically copy and paste the same code and eliminating any code using self.site_admin) as View.get() and View.post():
# staging/views.py
from django.http import HttpResponseRedirect, HttpResponse
from django.urls import reverse
from django.views import generic
from django.template.response import TemplateResponse
from django.utils.translation import gettext_lazy as _
from django.utils.encoding import force_text
from import_export.forms import ConfirmImportForm
from import_export.signals import post_import
import import_export.admin
from .models import Period
from .resources import PeriodResource
class PeriodImportView(import_export.admin.ImportMixin, generic.View):
"""
Subclassing of ImportMixin as a generic View implementing ImportForm
"""
#: template for import view
import_template_name = 'period/import.html'
#: resource class
resource_class = PeriodResource
#: model to be imported
model = Period
def get_confirm_import_form(self):
'''
Get the form type used to display the results and confirm the upload.
'''
return ConfirmImportForm
def get(self, request, *args, **kwargs):
"""
Overriding the GET part of ImportMixin.import_action method to be used without site_admin
"""
resource = self.get_import_resource_class()(**self.get_import_resource_kwargs(request, *args, **kwargs))
context = self.get_import_context_data()
import_formats = self.get_import_formats()
form_type = self.get_import_form()
form = form_type(import_formats,
request.POST or None,
request.FILES or None)
# context.update(self.admin_site.each_context(request))
context['title'] = _("Import")
context['form'] = form
context['opts'] = self.model._meta
context['fields'] = [f.column_name for f in resource.get_user_visible_fields()]
# request.current_app = self.admin_site.name
return TemplateResponse(request, [self.import_template_name],
context)
def post(self, request, *args, **kwargs):
"""
Overriding the POST part of ImportMixin.import_action method to be used without site_admin
"""
resource = self.get_import_resource_class()(**self.get_import_resource_kwargs(request, *args, **kwargs))
context = self.get_import_context_data()
import_formats = self.get_import_formats()
form_type = self.get_import_form()
form = form_type(import_formats,
request.POST or None,
request.FILES or None)
if request.POST and form.is_valid():
input_format = import_formats[
int(form.cleaned_data['input_format'])
]()
import_file = form.cleaned_data['import_file']
# first always write the uploaded file to disk as it may be a
# memory file or else based on settings upload handlers
tmp_storage = self.write_to_tmp_storage(import_file, input_format)
# then read the file, using the proper format-specific mode
# warning, big files may exceed memory
try:
data = tmp_storage.read(input_format.get_read_mode())
if not input_format.is_binary() and self.from_encoding:
data = force_text(data, self.from_encoding)
dataset = input_format.create_dataset(data)
except UnicodeDecodeError as ex1:
return HttpResponse(_(u"<h1>Imported file has a wrong encoding: %s</h1>" % ex1))
except Exception as ex2:
return HttpResponse(_(u"<h1>%s encountered while trying to read file: %s</h1>" % (type(ex2).__name__, import_file.name)))
result = resource.import_data(dataset, dry_run=True,
raise_errors=False,
file_name=import_file.name,
user=request.user)
context['result'] = result
if not result.has_errors() and not result.has_validation_errors():
context['confirm_form'] = self.get_confirm_import_form()(initial={
'import_file_name': tmp_storage.name,
'original_file_name': import_file.name,
'input_format': form.cleaned_data['input_format'],
})
# context.update(self.admin_site.each_context(request))
context['title'] = _("Import")
context['form'] = form
context['opts'] = self.model._meta
context['fields'] = [f.column_name for f in resource.get_user_visible_fields()]
# request.current_app = self.admin_site.name
return TemplateResponse(request, [self.import_template_name],
context)
class PeriodConfirmImportView(import_export.admin.ImportMixin, generic.View):
"""
Subclassing of ImportMixin as a generic View implementing ConfirmImportForm
"""
#: template for import view
import_template_name = 'period/import.html'
#: resource class
resource_class = PeriodResource
#: model to be imported
model = Period
def post(self, request, *args, **kwargs):
"""
Perform the actual import action (after the user has confirmed the import)
"""
# if not self.has_import_permission(request):
# raise PermissionDenied
confirm_form = ConfirmImportForm(request.POST)
if confirm_form.is_valid():
import_formats = self.get_import_formats()
input_format = import_formats[
int(confirm_form.cleaned_data['input_format'])
]()
tmp_storage = self.get_tmp_storage_class()(name=confirm_form.cleaned_data['import_file_name'])
data = tmp_storage.read(input_format.get_read_mode())
if not input_format.is_binary() and self.from_encoding:
data = force_text(data, self.from_encoding)
dataset = input_format.create_dataset(data)
result = self.process_dataset(dataset, confirm_form, request, *args, **kwargs)
tmp_storage.remove()
self.generate_log_entries(result, request)
self.add_success_message(result, request)
post_import.send(sender=None, model=self.model)
url = reverse('staging:index')
return HttpResponseRedirect(url)
and then just show the forms in the template:
# staging/templates/period/import.html
{% if confirm_form %}
<form action="{% url 'staging:confirm_import_period' %}" method="POST">
{% csrf_token %}
{{ confirm_form.as_p }}
<p>
{% trans "Below is a preview of data to be imported. If you are satisfied with the results, click 'Confirm import'" %}
</p>
<div class="submit-row">
<input type="submit" class="default" name="confirm" value="{% trans "Confirm import" %}">
</div>
</form>
{% else %}
<form action="" method="post" enctype="multipart/form-data">
{% csrf_token %}
<p>
{% trans "This importer will import the following fields: " %}
<code>{{ fields|join:", " }}</code>
</p>
<fieldset class="module aligned">
{% for field in form %}
<div class="form-row">
{{ field.errors }}
{{ field.label_tag }}
{{ field }}
{% if field.field.help_text %}
<p class="help">{{ field.field.help_text|safe }}</p>
{% endif %}
</div>
{% endfor %}
</fieldset>
<div class="submit-row">
<input type="submit" class="default" value="{% trans "Submit" %}">
</div>
</form>
{% endif %}
and my urls.py looks like this:
# staging/urls.py
from django.urls import path
from .views import PeriodIndexView, PeriodImportView, PeriodConfirmImportView
app_name = 'staging'
urlpatterns = [
path('period/', PeriodIndexView.as_view(), name='index'),
path('period/import/', PeriodImportView.as_view(), name='import_period'),
path('period/confirm_import/', PeriodConfirmImportView.as_view(), name='confirm_import_period'),
]
So far it works as intended, but this approach is so tightly coupled to the internal implementation of ImportMixin that I am afraid it will not survive any version upgrade of django-import-export.
Is there any way to achieve that without reimplementing the whole import_action and process_import methods?
After a lot of try and error I gave up on avoiding the re-implementation of methods import_action and process_import from import_export.admin.ImportMixin. Instead, I created my own mixins subclassing import_export.admin.ImportMixin and django.views.generic.View and removing all references to self.site_admin from methods import_action and process_import into equivalent methods get() and post().
# staging/views.py
from django.http import HttpResponseRedirect, HttpResponse
from django.urls import reverse
from django.views import generic
from django.template.response import TemplateResponse
from django.utils.translation import gettext_lazy as _
from django.utils.encoding import force_text
from import_export.forms import ConfirmImportForm
from import_export.signals import post_import
import import_export.admin
from .models import Period
from .resources import PeriodResource
class ImportView(import_export.admin.ImportMixin, generic.View):
"""
Subclassing of ImportMixin as a generic View implementing ImportForm
"""
#: template for import view
import_template_name = 'import.html'
#: resource class
resource_class = None
#: model to be imported
model = None
def get_confirm_import_form(self):
'''
Get the form type used to display the results and confirm the upload.
'''
return ConfirmImportForm
def get(self, request, *args, **kwargs):
"""
Overriding the GET part of ImportMixin.import_action method to be used without site_admin
"""
return self.post(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
"""
Overriding the POST part of ImportMixin.import_action method to be used without site_admin
"""
resource = self.get_import_resource_class()(**self.get_import_resource_kwargs(request,
*args,
**kwargs))
context = self.get_import_context_data()
import_formats = self.get_import_formats()
form = self.get_import_form()(import_formats, request.POST or None, request.FILES or None)
if request.POST and form.is_valid():
input_format = import_formats[
int(form.cleaned_data['input_format'])
]()
import_file = form.cleaned_data['import_file']
# first always write the uploaded file to disk as it may be a
# memory file or else based on settings upload handlers
tmp_storage = self.write_to_tmp_storage(import_file, input_format)
# then read the file, using the proper format-specific mode
# warning, big files may exceed memory
try:
data = tmp_storage.read(input_format.get_read_mode())
if not input_format.is_binary() and self.from_encoding:
data = force_text(data, self.from_encoding)
dataset = input_format.create_dataset(data)
except UnicodeDecodeError as ex1:
return HttpResponse(_(u"<h1>Imported file has a wrong encoding: %s</h1>" % ex1))
except Exception as ex2:
return HttpResponse(_(u"<h1>%s encountered while trying to read file: %s</h1>" % (type(ex2).__name__, import_file.name)))
result = resource.import_data(dataset, dry_run=True,
raise_errors=False,
file_name=import_file.name,
user=request.user)
context['result'] = result
if not result.has_errors() and not result.has_validation_errors():
context['confirm_form'] = self.get_confirm_import_form()(initial={
'import_file_name': tmp_storage.name,
'original_file_name': import_file.name,
'input_format': form.cleaned_data['input_format'],
})
# context.update(self.admin_site.each_context(request))
context['title'] = _("Import " + self.get_model_info()[1])
context['form'] = form
context['opts'] = self.model._meta
context['fields'] = [f.column_name for f in resource.get_user_visible_fields()]
# request.current_app = self.admin_site.name
return TemplateResponse(request, [self.import_template_name],
context)
class ConfirmImportView(import_export.admin.ImportMixin, generic.View):
"""
Subclassing of ImportMixin as a generic View implementing ConfirmImportForm
"""
#: template for import view
import_template_name = 'import.html'
#: resource class
resource_class = None
#: model to be imported
model = None
def get_confirm_import_form(self):
'''
Get the form type used to display the results and confirm the upload.
'''
return ConfirmImportForm
def post(self, request, *args, **kwargs):
"""
Perform the actual import action (after the user has confirmed the import)
"""
confirm_form = self.get_confirm_import_form()(request.POST)
if confirm_form.is_valid():
import_formats = self.get_import_formats()
input_format = import_formats[
int(confirm_form.cleaned_data['input_format'])
]()
tmp_storage = self.get_tmp_storage_class()(name=confirm_form.cleaned_data['import_file_name'])
data = tmp_storage.read(input_format.get_read_mode())
if not input_format.is_binary() and self.from_encoding:
data = force_text(data, self.from_encoding)
dataset = input_format.create_dataset(data)
result = self.process_dataset(dataset, confirm_form, request, *args, **kwargs)
tmp_storage.remove()
self.generate_log_entries(result, request)
self.add_success_message(result, request)
post_import.send(sender=None, model=self.model)
url = reverse('{}:{}_index'.format(self.get_model_info()[0], self.get_model_info()[1]))
return HttpResponseRedirect(url)
So now from my custom mixins ImportView and ConfirmImportView y can subclass the specific classes to import my specific models just setting the model and resource_class attributes, which was sort of what I was looking for.
class PeriodImportView(ImportView):
"""
ImportView specific for model Period and resource PeriodResource
"""
#: resource class
resource_class = PeriodResource
#: model to be imported
model = Period
class PeriodConfirmImportView(ConfirmImportView):
"""
ConfirmImportView specific for model Period and resource PeriodResource
"""
#: resource class
resource_class = PeriodResource
#: model to be imported
model = Period
I have multiple forms with one submit button for each of them, all in one template. render_template returns only empty StringFields. How can I render without touching my other StringFields?
#app.route('/', methods=['GET','POST'])
def index():
msform = msForm(request.form)
synform = synForm(request.form)
if request.method == 'POST' and msform.validate() and msform.ms_submit.data:
processed_text = model.most_similar(positive=[msform.ms_3.data, msform.ms_2.data], negative=[msform.ms_1.data])
msform.ms_submit.label.text = processed_text[0][0]
return render_template('my-form.html', msform=msform, synform=synform)
elif request.method == 'POST' and synform.validate() and synform.syn_submit:
processed_text = model.most_similar([synform.syn_1.data])
return render_template('my-form.html', msform=msform, synform=synform)
return render_template('my-form.html', msform=msform, synform=synform)
class msForm(Form):
ms_1 = StringField(label='Eingabe_1', default = 'king', validators=[validators.DataRequired(message='This Field is required')])
ms_2 = StringField(label='Eingabe_2', default = 'man', validators=[validators.DataRequired(message='This Field is required')])
ms_3 = StringField(label='Eingabe_3', default = 'queen', validators=[validators.DataRequired(message='This Field is required')])
ms_submit = InlineSubmitField(label = '?')
class synForm(Form):
syn_1 = StringField(label='Eingabe', default = 'king', validators=[validators.DataRequired()])
syn_submit = InlineSubmitField('?')
I am assuming you have two separate <form>s on your HTML page, like this for brevity:
<form>{{ msform }}</form>
<form>{{ synform }}</form>
I believe you are saying this: upon completing and submitting one form, the values are lost from the other. Is that correct?
If so, that's the expected behavior, not from Flask, but from your browser. When you submit an HTML <form>, only the data from that form tag is sent to the server. Therefor, any data in other <form> tags is lost.
To submit all forms, render all the forms in the same <form> tag. Give each form a prefix to ensure the input names don't collide.
msform = msForm(request.form, prefix='ms')
<form method="post">
{{ msform }}
{{ synform }}
</form>
Here is my html:
{% block my_dashboard_main %}
<form action="status/" method="post">{% csrf_token %}
{{ form.as_p }}
<input type="submit" value="Submit" />
</form>
{% endblock %}
My urls.py:
urlpatterns = patterns('',
url(r'^$', views.IndexView.as_view(), name='index'),
url(r'status/$', views.status),
url(r'thanks/$', views.thanks),
)
Here is my views.py:
STATUS_CHOICES = (
("GOOD", "Good"),
("BAD", "Bad"),
("COMPROMISED", "Compromised")
)
def thanks(request):
return render(request, "my_dashboard/ssa_panel/sent.html')
class SsaForm(forms.Form):
status = forms.ChoiceField(choices = STATUS_CHOICES, label="Status:")
def status(request):
print("STATUS CALLED method=",request.method)
if request.method == 'POST': # If the form has been submitted...
form = SsaForm(request.POST) # A form bound to the POST data
if form.is_valid(): # All validation rules pass
# Process the data in form.cleaned_data
# ...
print("redirect to THANKS!")
return HttpResponseRedirect('thanks/') # Redirect after POST
else:
print("Requesting form\n")
form = SsaForm(initial = {"status", "Good"}) # An unbound form
return render(request, 'my_dashboard/ssa_panel/index.html', {
'form': form,
})
class IndexView(views.APIView):
# A very simple class-based view...
template_name = 'my_dashboard/ssa_panel/index.html'
def get_data(self, request, context, *args, **kwargs):
print("GET_DATA Called", context)
# Add data to the context here...
return context
The first time my page renders the I want the status to show up. It doesn't. Just the Submit button. After I submit once the "Status: [Good] <- combo box" is there. I want to go get the data for the for status in get_data and set it but I don't know how. do I set context['status']="Good" or something like that?
I'm obviously new to DJango and REST stuff.
You are trying to construct your initial value dictionary incorrectly using a comma (,) instead of a colon and also using the wrong choice key. Instead of
form = SsaForm(initial = {"status", "Good"})
try
form = SsaForm(initial = {"status": "GOOD"})
I'm trying to understand how to edit or update a model. I have tried several scenarios which sometimes give an error message: 405 Method Not Allowed - The method POST is not allowed for this resource. Below is my code:
The Python Models:
import os
import webapp2
import wsgiref.handlers
from google.appengine.ext import db
from google.appengine.ext.webapp import template
class MessageModel(db.Model):
content = db.StringProperty(multiline=True)
date = db.DateTimeProperty(auto_now_add=True)
class Message(webapp2.RequestHandler):
def get(self):
doRender(self,'message.htm')
def post(self):
m = MessageModel()
m.content = self.request.get('content')
m.put()
self.redirect('/view')
class View(webapp2.RequestHandler):
def get(self):
que = db.Query(MessageModel)
messageview_list = que.fetch(999)
doRender(self,
'view.htm',
{'messageview_list': messageview_list })
class Edit(webapp2.RequestHandler):
def get(self):
doRender(self,'edit.htm')
def post(self):
updated_content = self.request.get('content')
content_query = db.GqlQuery("SELECT * "
"FROM MessageModel "
"ORDER BY date DESC LIMIT 1")
messageview_list = content_query.fetch(1)
m = MessageModel()
m.content = self.request.get(updated_content)
m.put()
doRender(self,
'edit.htm',
{'messageview_list': messageview_list })
class Main(webapp2.RequestHandler):
def get(self):
doRender(self,'index.htm')
def doRender(handler, tname = 'index.htm', values = { }):
temp = os.path.join(
os.path.dirname(__file__),
'templates/' + tname)
if not os.path.isfile(temp):
return False
newval = dict(values)
newval['path'] = handler.request.path
outstr = template.render(temp, newval)
handler.response.out.write(outstr)
return True
app = webapp2.WSGIApplication([('/', Main),
('/message', Message),
('/view', View),
('/edit', Edit)],
debug=True)
The HTML Form:
{% for messageview in messageview_list %}
<form method="post" action="/edit">
<p>
<textarea name="message" rows="3" cols="60" MAXLENGTH=60>
{{ messageview.content }}</textarea>
<br>
<input type="submit" value="Update"/>
</p>
</form>
{% ifnotequal error None %}
<p>
{{ error }}
</p>
{% endifnotequal %}
{% endfor %}
I am assuming the indentation is due to copy/paste, but make sure that the post() and get() functions are actually indented inside of your class.
In your form, you have <textarea name="message" rows="3" cols="60" MAXLENGTH=60>, but in your def post() you use updated_content = self.request.get('content'), which is looking for the content keyword in the request. Also, your edit doesn't look like it is doing what you want it to do. In order to edit an entity, the basic outline of the process is 1.) Retrieve the entity (so do as you do, query using some parameter); 2.) Modify the properties of the entity however you want; and 3.) put() the entity back in the datastore.
From your code, it looks like you are retrieving the last entity entered into the datastore, but then creating a new model instead of editing that one (assuming that is what you want to do - not quite sure if that is accurate :) ). If you are looking to modify the entity that is returned, this should work:
def post(self):
updated_content = self.request.get('message')
content_query = db.GqlQuery("SELECT * "
"FROM MessageModel "
"ORDER BY date DESC LIMIT 1")
# Your query will always return just one entity (due to the LIMIT),
# but you can use get() here instead of fetch(1)
latest_model = content_query.get()
# Update the model's content property
latest_model.content = updated_content
latest_model.put()
# Assuming you want to output that model, you'd output it now
doRender(self,
'edit.htm',
{'messageview_list': latest_model })