I have a vocabulary described with RDFS, consider for example the "Friend of a Friend" (FOAF).
Now I want to populate my database, so I want to insert the classes (the Person classes) and their relations (the friendship). I want to do that with a web page with the appropriate form field connected to a back-end server.
My ontology is more complicated than the FOAF (but it is based on it), so I am searching for a tool that automatically creates the web forms.
Presently I am not linked to a particular technology, but I would like to stay with RDF since I am also using rdflib, in particular for querying. Django seems to be a solution, but I am not sure how it interacts with RDF.
Related
First off, I'm very much a newbie when it comes to Django.
The problem I'm struggling with is in trying to create templates for the built-in authentication forms in Django 1.7 but there is very little that I can find in the way of concrete examples anywhere in the documentation or elsewhere.
I can find plenty of questions and examples that describe how to manually create the templates (or copy them from the Django packages) but from what I understand about the Form class and the built-in authentication forms is that I don't need to manually create the actual form in the template. In fact, it seems more desirable to use the Form classes because that would add ensure that fields are named correctly, that the validation such as max length on text fields is applied, etc.
Can anyone point me to some concrete examples or documentation of what I'm talking about? I've read the following sections already,
https://docs.djangoproject.com/en/1.7/topics/forms/
https://docs.djangoproject.com/en/1.7/topics/auth/default/
https://docs.djangoproject.com/en/1.7/topics/auth/customizing/
In fact, I would say that this question extends to any Form class in general but I'm specifically looking at the authentication forms here because I obviously haven't written these Form classes.
I don't think it should make any difference from what I've read since the same process should apply, but I will say that I'm using the django-authtools package (http://django-authtools.readthedocs.org/en/latest/)
I have the actual authentication system working fine. It logs users in and out, I can enforce that certain urls require the user to be logged in first, etc. so its only the actual form display that is an issue.
I want to add a layout model to my website (a general settings file), and I want it to be available in the admin interface for configuration.
class Layout(...Model):
primary_header
logo_image
...
This structure shouldn't saved be in a table.
I am wondering if there is a built-in feature that can help me do this.
Thanks
My use case is a configurable layout of the website. Wordpress style. I would like to store that data in a concrete class, without having to implement the file /xml serialization myself.
What about an abstract model? It does not save in the database and is meant to be subclassed, but you are allowed to create instances of it and use its attributes. I assume you want some kind of temporary data structure to pass around that meets the requirements of a model instance.
class Layout(models.Model):
class Meta:
abstract = True
If you for some reason need actual concrete models, and are fine with it creating tables for them, you could technically also re-implement the save() method and make it no-op.
I don't really understand where and how you will be using this, but this is indeed a model that doesn't save.
Personally, I have actually used models that aren't intended to be saved, in a project that uses mongodb and the nonrel django fork. I create models that are purely meant to be embedded into other models as nested sub-documents and I never want them to be committed to a separate collection.
Update
Here is another suggestion that might make things a whole lot easier for your goal. Why not just use a normal django model, save it to the database like normal, and create a simple import/export function to save it out to XML or read into an instance from XML. That way you get 100% normal admin functionality, you can still query the database for the values, and the XML part is just a simple add-on. You can also use this to version up preferences and mark a certain one as active.
I am using django with mongodb through django-mongodb. I was able to set up the django admin site (through the fixes on the troubleshooting page), now when I use the admin site I am able to view all of the top-level fields, but (somewhat as expected) the embedded objects and lists are not able to be viewed, they just show up as a print would show them, "List Object" for example.
Is there any way to use the admin interface to view the sub-models etc...?
If there is no convenient third-party way, how would I go about supporting this behavior myself?
If there is no simple way to support this myself, is there a phpmyadmin type of thing for mongo that I can use in conjunction with django-mongodb (This could just be something that sits on top of mongodb not necessarily using python/django)?
*Note: I have been using the word 'view' in reference to my interaction with the model, my first preference is to be able to view and not edit, however if there is editing capability out there, that might be better, depending on how complex the modifications will be.
I have actually been doing the same project lately. The admin site doesnt really know how to represent the non-relational style elements that are present in a mongodb document, so you would have to define custom field/widgets. Refer to this part of the documentation which explains how to extend your ModelAdmin to specify overrides.
https://docs.djangoproject.com/en/1.3/ref/contrib/admin/#modeladmin-objects
For list types for instance, django has no way to know what type of values the list contains and how to represent them.
As for a visual mongodb manager, not sure what OS you are on, but Im on OSX and I love this one: http://mongohub.todayclose.com/
Otherwise, here is a list of other management options: http://www.mongodb.org/display/DOCS/Admin+UIs
Take your pick for either an OS native or web based.
I have created an article site, where articles are published in several languages. I am using transmeta (http://code.google.com/p/django-transmeta/) to support multiple languages in one model.
Also I am using generic comments framework, to make articles commentable. I wonder what will happen if the same article will be commented in one language and then in another. Looks like all comments will be displayed on both variants....
The question actually is:
Is there a possibility to display only comments submitted with current language of the article?
I tried the approach of transmeta for translation of dynamic texts and I had the following experience:
You want another language, you need to change the database model which is generally undesirable
You need every item in both languages, which is not flexible
You have problems linking with other objects (as you point out in your question)
If you take the way of transmeta you will need two solutions:
The transmeta solution for translating fields in a model
For objects connected to a model using transmeta you will need an additional field to determine the language, say CharField with "en", "de", "ru" etc.
These were major drawbacks that made me rethink the approach and switch to another solution: django.contrib.sites. Every model that needs internationalization inherits from a SiteModel:
class SiteModel(models.Model):
site = models.ForeignKey(Site)
Every object that would need transmeta translation is connected to a site. Every connected object can determine its language from the parent object's site attribute.
I basically ran the wikipedia approach and had a Site object for every language on a subdomain (en., de., ru.). For every site I started a server instance that had a custom settings file which would set the SITE_ID and the language of the site. I used django.contrib.sites.managers.CurrentSiteManagerto display only the items in the language of the current site. I also had a manager that would give you objects of every language. I constructed a model that connects objects of the same model from different languages denoting that they are semantically the same (think languages left column on wikipedia). The sites all use the same database and share the same untranslated User model, so users can switch between languages without any problem.
Advantages:
Your database schema doesn't need to change for additional languages
You are flexible: add languages easily, have objects in one language only etc.
Works with (generic) foreign keys, they connect to an object and know what language it is. You can display the comments of an object and they will be in one language. This solves your problem.
Disadvantages:
It's a greater deal to setup: you need a django server instance for every site and some more glue code
If you need e.g an article in different languages, you need another model to connect them
You may not need the django Site model and could implement something that does the same without the need of multiple django server instances.
I don't know what you are trying to build and what I described might not fit to your case, but it worked out perfectly for my project (internationalized community platform built upon pinax: http://www.bpmn-community.org/ ). So if you disclose some more about your project, I might be able to advise an approach.
To finally answer your question: No, the generic comments will not work out of the box with transmeta. As you realised you will have to display comments in both languages for the article that is displayed in one language. Or you will have to hack into the comments and change the model and do other dirty stuff (not recommended). The approach I described works with comments and any other pluggable app.
To answer your questions:
Two Django instances can share one database, no problem there.
If you don't want two Django instances, but one, you will have to do the following: A middleware checks the incoming request, extracts desired language from URL (en.example.com or example.com/en/ etc.) and saves the language preference in the request object. The view will have to take the request object with the language and take care of the filtering of objects accordingly. Since there is no dedicated server for the language (like in the sites approach where the language is stored in the settings.py file), you can only get the language from the request and you will have to pass attributes from the request object to Model managers to filter objects.
You could try to fake a global language state in the django application with an approach like threadlocals middleware, however I don't know if this plays out nicely with django I18N engine (which is also does some thread magic).
If you want to go big with your site in multiple languages, I recommend going for the sites-approach.
Hi everyone I have a few questions about the django admin.
First the relevant details. I currently have Client, Printer, Cartridge, and Order models.
The Printer model has a ManyToManyField to the Cartridge model, which would allow you to select all the cartridges that can be used with that printer.
The Cliente has a ManyToManyField to the printers which they own.
1) I want to create an Order through the Django admin which lets your specify the Client, a dicount, and multiple cartridges through a ManyToManyField. This is getting kinda tricky because I have to do it through another table that specifies whether it's a new Cartridge or a refill.
2) I want the admin to filters the Cartridges to only show the ones that belong to the printers that they own.
3) Also I would like to have a field that holds the total price of their order, but it should calculate it based on how many cartridges they have added to the order. I don't know if this should be done by adding more of the same cartridge to the order or by having another field in the related table that specifies the quantity.
Can this be done in the admin or do I need to use a form? And if so how would I go about adding this to the admin? It seems difficult and probably something I will have to do in multiple parts since in order to filter the list of cartridges I have to know the client beforehand.
As far as I can see, no, it's not really possible. The development version has some methods for limiting foreign keys, but it doesn't seem to me that limiting based on the customer is possible, since it depends on separate foreign keys.
The best suggestion, if you're really bent on doing it in the admin form, would be to use Javascript to do it. You would still have to make AJAX calls to get lists of what printers customers had and what cartridges to show based on that, but it could be done. You would just specify the JS files to load with the Media class.
But I think that's more work than it's worth. The easiest way I would see to do it would be with Form Wizards. That way, you'd have a step to select the customer so on the next step you know what cartridges to show.
Hope that helps!
I've worked similar problems, and have come to the conclusion that in many cases like this, it's really better to write your own administration interface using forms than it is to try and shoehorn functionality into the admin which is not intended to be there.
As far as 3) goes, it depends on what your product base looks like. If you're likely to have customers ordering 50 identical widgets, you probably do want a quantity field. If customers are more likely to be ordering 2 widgets, one in red, one in blue, add each item separately to the manytomany field and group them in your order interface.