I am fairly new in web development and I decided to handle a user's availability to send a POST request to server. However, I do not know even whether it is possible or not but when a user close my Django site without using logout button (For example close the browser or tab), in order to understand the user is offline or online, I want to send a request to server. As a result, when the server does not get an answer from the user for a while, it automatically logout the user.
Can you tell me is it a good way to handle a user's availability and first of all is it a realistic solution? If it is, can you suggest me a document or example that helps me please.
I agree to to the answer of #Mounir. That's not related to django, if you want to know when a user is "disconnected"(close the tab or window) you need to use javascript, in concrete you need to use Sockets.
I recommend you this ones:
http://socket.io/
https://github.com/centrifugal/centrifugo
I'm using centrifugo for one project right now. In concrete, for chat and inbox messaging. It's very simple to make it run with Django.
Greetings
For logging out user you can use the Session expiration, but for all other staff you want to achieve I don't see any thin really related to Django itself, everything depend on your requirements and is more Browser/javascript related than Django.
Related
I am creating an ecommerce webapp and I want to update my admin page when user place order. After research i found out about Django signals, but it seems pretty confusing. The idea behind this is that, when a user places an order I want the admin page to be refreshed and show the latest updates. I tried ajax but javascript can only work with the current open page. Can anyone help me with usibg django signals this way?
I think you misunderstand a little, if your idea is that the admin page viewed by the user in a browser is to be refreshed. The page viewed by a site visitor is retrieved on demand of the browser. The user could refresh a page, or a page script may auto-refresh on a timer (this is not a very good solution, but it is easy).
Django can't make the browser update the page.
Signals can cause django to do something in the backend, but they can't solve the problem that the browser is in charge.
There is one technology designed to allow the server to push content to the browser: websockets.
If you use websockets (Django's fairly recent built-in support is called Channels (https://channels.readthedocs.io/en/stable/)), then you can push content to the browser, where a receiving script on the page will do something with it. This is a very powerful technique, but there is a learning curve of some hours if you are starting from scratch.
Recently I came across this front-end library which tries to make this easy as
far as the browser goes: https://htmx.org/docs/
But you still have to deal with running a websocket server and learning how to send messages to a websocket. You will however feel like a superhero at the end of it, so there's that.
Basically what I'm doing is building a desktop application that needs to connect to a web server, perform some calculations, and then have the resulting values sent back to it. The calculations change over time, and also need to stay somewhat secure, which is why I'm not just coding them into the desktop application.
The issue is that only authenticated users should be allowed to access the server. So what I'm looking for is a way to log-in to Django from my desktop application (i.e. the desktop application will pop up a window asking for a username and password, which will then be sent to the Django site, used to authenticate the user, and if valid, will return the results of the computation. It also needs to work as a session (the user enters their password at the beginning and then doesn't need to log-in again until they close the desktop application, even if multiple computations are performed).
I think I need to use session keys for this, and perhaps the RemoteUserMiddleware described here but I really have no idea where to start as far as coding this. Any suggestions or pointers in the right direction would be hugely appreciated.
Thanks,
-Morag
P.S. If this is important, the desktop application is written in VB.NET.
Interesting. I've never done anything like this, but here is, what I assume, is the basic idea:
1) Get a good view of Django sessions; the basic idea is:
One logs in using the django auth framework login service
Django will create a session for you and handle all the difficult stuff
Django returns a HttpResponse with a sessionid cookie. You will need to send this back with any request following to identify yourself and 'operate within the session'.
One logs out using the django auth logout service and the session is destroyed by Django.
2) Now, the rest is relatively easy.
Setup django urls.py with the appropriate urls for login/logout + computation service
Execute a post request to the login service with the appropriate parameters set
Catch the response, extract the 'sessionid' cookie and save it somewhere
On each subsequent request, include the sessionid
This should get you started. Good luck!
As the title implies,
I need to fetch data from certain website which need logins to use.
The login procedure might need cookies, or sessions.
Do I need QtWebkit, or can I get away with just QNetworkAccessManager?
I have no experience at both, and will start learning as I go.
So please save me a bit of time of comparing both ^^
Thank you in advance,
Evan
Edit: Having read some related answers,
I'll add some clarifications:
The website in concern does not have an API. So I will need to scrape web elements for the data myself.
Can I do that with just QNetworkAccessManager?
No, in most cases you don't need a full simulated web browser. In most cases, just performing the same web requests like a web browser would do is enough.
Try to record the web requests in your browser, using a plugin like "HTTP Live Headers" or "Firebug" in Firefox. I think Chrome provides a similar tool out of the box. These tools record the GET and POST requests done by the website when you send a form in the webpage.
Another option is to inspect the HTML code of the login page. Find the <form> tag and its fields. Put them together in a GET / POST request in your application to simulate the same form.
Remember that some pages use randomized "tokens" in their forms, some set the tokens as cookies. In such cases, you need to request the login page itself in your application first (before sending the filled in form). Both QWebView and QNetworkAccessManager have cookie support.
To sum things up, I think QWebView provides a far more elegant way to simulate user interaction with a web page. The manual way is, however, more "lightweight", as you don't need Webkit and your application might be faster (because only the HTML page is loaded, without any linked resources like images, CSS, javascript files).
QWebView as class name states is a view, so it views something (in this case web pages). If you don't need to display loaded page, then you don't need a view. QNetworkAccessManager may do the work, but you need some knowledge about HTTP protocol, and also anything about target site: how does it hande logins, what type of request you have to send to login etc.
Intro
I am working on an e-commerce website. And we want to add a feature where a user can refer others via a custom link e.g.:
http://example.com/a1t2312 or http://example.com/?ref=a1t2312 (a1t231 being the referral code).
A user following such a link, will navigate a few pages on the site. And if he reached the 'buy' page and purchases something - the original referrer will get a discount.
The question is:
What is the best method to track the referral code? Put it in the user's cookies? Stick it somehow into the session? Other method?
I would definitely use cookies, as it is the easiest (but not foolproof, though). Sessions are by site, so that won't work, unless the receiving site has some code to handle the user.
All methods mentioned by you are OK. If I were you I would consider using sessions because it is more natural to me.
disclaimer: session has some limitations when you want to build application ready for heavy-load. For complicated demployment scenarios avoiding sessions might be a good choice.
I'm trying to write a simple GUI application using Qt framework.
The purpose of this app is to retrieve data from my isp and parse them for presentation.
How do i authenticate my user/password with the webserver and retrieve the html page in question?
Are there any utility libs that make this task trivial?
I figure i need to interact with the server php script and simulate a form input somehow.
Am i on the right track?
You're on the right track, I suggest taking a look at curl.
That should make it alot easier.
edit: Hm, thought it did more than just file-transfer.
Otherwise here's a load more of interesting lib's
The way to authenticate depends completely on the authentication method used by the server. If it's some form to log in you need to retrieve that and send the correct data to the forms action target (usually as POST request). You could do this by constructing your request using QHttpRequestHeader and then simply sending it to the server. If you even know about the form you might even not need to retrieve the login page. If the website uses HTTP authentication you should be able using QAuthenticator.