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.
Related
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.
I have a very simple web page that uses the Facebook Javascript API and is installed as a tab on a Facebook page. When the page is loaded, the only thing it does after calling the usual Facebook init code is to listen to auth.authResponseChange and then show/hide various elements depending on whether the user is logged in or not.
If I load this page, via http or https in an ordinary browser session, everything is fine. The page loads reasonably fast.
But if I load the page tab in Facebook, it hangs for about two minutes. Chrome tells me that this wait is due to 'waiting' for my page. But if I watch the access log, I don't see an access request logged until just before the page displays. So it seems like Facebook is masking what is really going on behind the scenes.
I opened a ticket with Facebook, and they replied that this issue was due to my code and reproducible with any POST that contained a signed_response.
After much head scratching and experimentation, I found that adding the following two lines to the view that handles this page fixed it:
if 'signed_request' in request.POST:
pass
So clearly Django 1.3.1 is holding the HTTP session open until you actually read some POST values. Ouch.
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.
We're developing a tablet app, and my coworker had a rogue thought:
What if you put a manifest attribute on the html tag of a ColdFusion page? Would it
still work if the user couldn't get to the server?
I think it's lunacy, but I wanted to hear what you guys had to say.
The client side is not aware of how is generated the page. He didn't even know if the page is generated. So, the page is cached like another page.
If you are not connected, the could handle this case with some javascript and alert the user you can't communicate with the server.
You could simply disable the application or work with localStorage etc...
The start-up i currently work for is oriented around restaurant wait times. For our v1.25 specifications our clients -restaurants- that have Facebook pages want to be able to communicate to their app profile from their Facebook page.
The closest i have came to answering this question is the Graph API. However, the Graph API only allows us to read and write data to FB pages. So, is there a way for a restaurants FB page to write to its app profile? Secondly, Loso, whom we have modeled some of our designs from has this ability, does anyone have an idea as to how they have done it?
--Boris M.
Here is an option that you can consider...
When you are designing the app you can also develop a page tab to go with it...
You will find this option in the basic settings of the app.
You can make it to install for all first time users of your app, by getting a list of all his pages he created using that profile then install it on the one he selects.
This page tab when installed on a page will appears just where other tabs on the page appers(e.g. events, notes etc. occurs)
You can provide your required functionality on this tab as you like.
Thus the user can just select that tab on the page and use its functionality to post on the profile page of the app.
Hope this works for you... and also u can check out the jobcaster app it does something like that!