I have 5 models which needs to be populated using a key from 6th model:
I have two options, please suggest the most effective
Option1: I can fetch all the five one by one and send via context to template and then show the each via html tabs
Option2: Have separate page for each model and fetch when ever user goes to that page, like if user goes to page1 then i fetch data from model1 and so on
Which is good and effective? Like querying only needed or just query all and show up in a html tabs?
You can use django debug toolbar to analyze the cost of your queries.
Also, if the models has a lot of rows and you are rendering it by sending via context in a template then it might be quite slow . Instead you might want to populate asynchronously.
Related
I am trying to build a conversational form with Django.
It will be used in landing page. The form questions will be loaded one by one as user answers them. And there will be some greeting and "human-way" responses to user input (such as "wow! you did a good choice!" after user selects one of the choices from form). The experience and look of the app will be like a real-time chat but user can only select one of the choices from form or upload a file/image.
1. Which technology is better to use for it? I am planning to do it with Fetch.
2. Since I want it to work without page reloading, how do I need to load Django forms through Fetch? Do I need to pass elements of it with JSON and construct it in client-side or can I just pass it as an html with {{form.as_p}} and display it in HTML?
Does these options make difference in matter of security?
I do not know anything about Fetch, but anyway I think it must be constructed clientside, but at first I would simply display the form in a template to get the ids of its fields and then use it in clientside code.
What about security - you'll need to pass the csrf token via your form.
I have a similar situation as this post in which I encounter a slow page loading as I have thousands of entries in a foreignkey field.
At modelform, is there a way to improve the page loading while keeping the dropdown function? I have used select2 to efficiently find the chosen item in the dropdown, thus want to keep this function.
Django has to fetch all those foreignkey objects from database and then render them as HTML. This is why it takes a lot of time. Fetching from database can be pretty quick if you cache everything, but rendering to HTML will still be a problem.
Here's a solution that I think would work best:
Exclude that ForeignKey field from your form.
Instead, just create a blank input field. You'll have to capture user's input via JavaScript and send that value to your backed to fetch suggestions. In fact, select2 supports fetching data from backend via AJAX, So, half of your work is done.
Create a view which will take that AJAX request and search the database for suggestions and send them back to the client.
And you're done.
My view function takes a long time until returning a template. So, I'd like to show something to a user while running the function.
Is it possible to show loader until a start page is loaded?
What's important is the loader should be shown when loading the first page after first visit of a user?
Thank you for reading my question.
You would have to fetch the page using JS. You could use something like Intercooler or PJAX which provides HTML attributes that show a spinning animation while loading the content via AJAX.
A better solution would be to make your page faster. There are several things you should consider:
Check that all Model fields that you are using for filtering or sorting have set db_index=True unless the tables are small (few hundred entries) or the fields are already unique or foreign/primary keys. Also check that your DB does sorting and merging in RAM not on disk (== the DB has enough RAM resources and has also the correct configuration to use it).
Sometimes, if you show a list of model instances you end up making separate DB requests per row if you access related models in your template. Again, check which statements your DB executes and have a look at Django's select_related, prefetch_related, values and values_list methods that can dramatically increase lookup performance. Make sure your template context contains all necessary data and only the necessary data (e.g. pageing, how much, or maybe you should consider a search index like SOLR or Elastic which can be integrated nicely via Django Haystack).
Load everything except heavy data at once in your main view, which also includes JS. The JS then uses AJAX to load the rest from a second Django view which returns an HTML snippet that your JS simply adds to the DOM.
It really depends on how comfortable you are with JS and how much you want to stick to HTML to make as much use of Django as possible (thinking of Django Forms for example). But first, tune your DB setup (disclaimer: I have written that article).
it's better to make a request with javascript to your Django endpoint, until you get a response back from your server you should show your loader, and when you get the response back successfully you should make display: none for loader and mak display: block for your loaded content
Create a function in views.py and send JsonResponse. URL example: http://localhost:8000/somedata
Render any other HTMLlet's say it's index.html. URL example: http://localhost:8000/home
That index.html file need to have some JavaScript, let's say main.js
In main.js make a request to http://localhost:8000/somedata and fetch data. Use async javascript that way you can easily track fetched data or not
I've been playing around with python/django for the last couple of weeks and whilst the overall structure and makeup of the framework is making sense I'm rather confused on how to create advanced interfaces (in relation to tasks administrators would perform). One trivial example I'm playing around with at the moment is a bulk csv product import for different suppliers which will update various fields of a particular product (keeping track of any changes), creating items where they don't already exist and applying other business logic etc.
With the data successfully in the database and the models reflecting this I envisage a view whereby one could select a supplier from a drop down, which would load all the products silently in the background and display a datagrid on success. The user could then interact with each product individually, for example selecting would display a stacked line chart of pricing history above the datagrid and an optional fly-in panel to the right with options to update prices, add notes etc.
Are there any best practice approaches for achieving something along these lines, does one create custom views/templates or put some heavy lifting into overriding the default Django admin functionality?
Any help is appreciated, thanks in advance.
You can either:
Create a custom django admin action that will appear as an option in the changelist page dropdown menu (of the Supplier model for example.) You can then apply this action to the selected rows. You can also have intermediate pages when using admin actions
You can hook your own views into the django admin for particular models and and then overwrite the appropriate django admin templates to link the two together
I've got several forms in my django app that require support for attachments. Each form instance may have any number of attachments, including none. I want to present a jQuery based upload widget for managing these uploads, allowing the uploads to be processed asynchronously. The attachments are stored in their own model, so there is then a many-to-many from the attachments model to each model that requires attachments. When an attachment is sucessfully uploaded and processed, the view handling the upload will return the id in the attachments model, which will then be inserted into a hidden field on the form. I'm currently trying to decide how best to represent this in the form.
One method would be to simply have a single hidden input which takes a comma separated list of ids. This would then require quite a lot of manual processing and validation on submission, which I can't help feeling could be avoided.
Elsewhere, I've used a HiddenInput for a single value where I'm doing something similar and dynamically adding items to the related model in the form. I can't however see how I can extend this directly to a Many to Many from a simple Foreign Key.
Anyone able to suggest the best way to go about doing this?
Try to use formsets or model_formsets to create a form for creating/editing multiple objects, also you can use javascript to add forms dynamically in your browser.