I want to create a server on one device and the changes I make on a certain website should be visible on other devices in real time, I don't want to cast the entire screen just the website.
Can anyone help me with that?
If you want really to use WebRTC to send something that appears in a web browser to another web client, you should see Canvas to peer connection.
Anyway, if various clients should be informed about an event via web, I suggest that you see Your first Web Progressive Application
Related
I've designed a desktop app using PyQt GUI toolkit and now I need to embed this app on my Django website. Do I need to clone it using django's own logic or is there a way to get it up on website using some interface. Coz I need this to work on my website same way it works as desktop. Do I need to find out packages in django to remake it over the web or is there way to simplify the task?
Please help.
I'm not aware of any libraries to port a PyQT desktop app to a django webapp. Django certainly does nothing to enable this one way or another. I think, you'll find that you have to rewrite it for the web. Django is a great framework and depending on the complexity of your app, it might not be too difficult. If you haven't done much with web development, there is a lot to learn!
If it seemed like common sense to you that you should be able to run a desktop app as a webapp, consider this:
Almost all web communication that you likely encounter is done via HTTP. HTTP is a protocol for passing data between servers and clients (often, browsers). What this means is that any communication that takes place must be resolved into discrete chunks. Consider an example flow:
You go to google in your browser.
Your browser then hits a DNS server (or cache) that resolves the name google.com to some IP address.
Cool, now your browser makes a request to that IP address and says "get me some stuff".
Google decides to send you back a minimal amount of HTML and lots of minified JavaScript in the page.
Your browser realizes that there are some image links in the HTML and so it makes additional requests to google to get each of the images so that it can display them.
Now all the content is loaded on your browser so it starts to execute the JavaScript code, and that code needs some more data from google so it starts sending requests to google too.
This is just a small example of how fundamentally different a web application operates than how a desktop application does. On a desktop app you have the added convenience that any operation doesn't need to be "packaged up" and sent, then have an action taken, etc (unless you're using a messaging architecture, but that's relatively uncommon outside of enterprise apps).
Is it possible to communicate from a web browser(Loaded an HTM page from server) to an application running in the same server using AJAX. Need to send the request from browser using a button click and update the page with responses received from one another application running in the same server machine?
I am using HTML pages to create website and not using any PHP or ASP like server side scripting. In server machine data are manipulated using a C++ application.
I think you can use any sort of Javascript functions to do that. But you might need to use jQuery or similar frameworks to make your live easier. You might need to search for "Comet Programming" to know exactly how to do 2-way communication between client and server
Updated:
Well, this kind of stuff requires you to read a lot (if you have not already known). Basically, what you need is a server that can do long-polling (or eventsource, websockets). There are many open-source ones that might help you to get started. I can list a several good ones here. There are a lot more
http://www.ape-project.org/
http://cometd.org/
http://socket.io/
http://code.google.com/p/erlycomet/
http://faye.jcoglan.com/
So after you have the comet server up and running you will need to setup the client side (probably Javascript). For those listed projects, most of them come with the client side code to interact with the server (Except for erlycomet). Therefore, you can just use the examples provided and run a quick prototype. If you want to use your raspberry pi, you can use nodejs which provide a lot of ease for dealing with real-time communication (socket.io, faye). And lately, http://www.meteor.com/
I would think of the problem this way: you want to provide a web front end to an existing c++ application. To achieve this you need to think about how your web server communicates with your c++ application. Communication between the browser and web server can be thought of as a separate problem - as you say AJAX calls can be used, or maybe have a look at websockets.
Once you have your request in the web server you need to communicate it to the C++ application (and/or visa versa). This can be done a number of ways, e.g. sockets or RPC. I found this question here which has some good advice.
I am working a real-time lighting control system.
User can turn on/off lights through web interface, but when another person turn on/off light switch manually the web interface should be updated immediately. That's the real-time goal I want.
The structure of the system is like this.
I have my own server at home, which control/monitor light status real-time. Django project is on my cloud server communicating with my home server real-time.
I have searched some similar posts and found many tools that confuse me a lot. All I want is to do long polling. User's browser will send http request to django server periodically(say 30s). If nothing comes up, server will hold the response until next one come. If there is an event, server will just reply immediately so real-time change at the browser side.
I know websocket is a better way, but I just want to make it work, the simpler the better. As long as it's reliable, compatible with existing browsers, performance is not a primary concern for me now. I can change it later if there is performance issue when scaling up. If it's possible, I still want to use Apache server to do this.
Does anyone knows a good tutorial or example that shows me how to implement it?
Thanks so much
I use Django 1.4, wsgi, Apache.
I am looking on advice on how best to approach a new project I need to develop. From the outset I must add, I have 0 experience with Web development on any level.
What I need to do is provide a web interface through the browser which will communicate with a server back end. The data retrieved will be sourced from either a DB or from another source - external device which the server itself will communicate with via IP. The data retrieved from the external device will always be a string format of n length (non unicode) and the DB data will mostly be strings and numbers with the odd blob thrown in (storing a picture). The communication will always go from the Client (web browser) to the Server. I don't believe that the server would need to instigate the comms.
I have Delphi XE, so started looking at using a REST server for communication and I think that seems to be OK. However, from what I can see, I need to create HTML web pages to "render" the data on the web browser. Is that true? Can I use the IW components with a REST server? If so, I'm not sure how to get the data to/from the browser UI. Am I better of investigating Ruby on Rails perhaps? From what I read on a different thread in here, it's based on MVC and some other areas which I feel, design wise, would fit how I would create the application (I was planning on creating the app based on the MVP or similar design pattern).
I think REST makes the most sense, so if the IW components can't be used, are there any 3rd party products I can use which would let me design "pretty" UI html. Given I don't know java script, would that be a stumbling block with REST too.
Thanks and hopefully I have provided enough information.
Thanks
Jason
Will a human being be responsible for typing the data retrieved from your external device into a web page?
If so, and you have no web development experience, Intraweb is definitely the way to go for Delphi programmers wanting to build a web application without learning new skills. For additional components to create a prettier UI I suggest using TMS Software's Intraweb Component Pack Pro.
If you don't need a human being to manually type in this data then you don't need Intraweb at all. Instead you would write a client application which presumably interrogated your external device for the data and then transmitted it to the REST server. Look at the documentation you've used to build your REST server and it should have a section on how to build a REST client.
You can build an ISAPI module with delphi that does the job, or include a HTTP server right into you executable with Indy, ICS or Synapse.
ISAPI will give you the freedom to choose Apache or IIS and give you all their power this way. Embeded HTTP server will give you a nice small application in which you control all ascpects of how it works.
Yes go with REST as it is simple and clean. All you need is to think and design the API (functions that your server will support). You can bind the APIs to the URL schema thus using the REST principle. I would do it simply like this.
A client makes a request. You show some form of GUI (load or render a HTML page with possible javascript)
User makes an action, you call appropriate API (or the user does it directly).
Show the user some result
Just guide the user process through a series of API calls until the result is made
You can use plain HTML and then add javascript if needed (jquery) or you can use ExtJS from Sencha which makes building a nice GUI a lot easier and is very well structured.
I would not use any "WYSIWYG" web tools. Plain old HTML written by your favorite editor is still the king in my opinion.
I have a little (maybe the answer could require a book) question about web services and server side programming.
But first, a little preamble.
Recently we have seen new kind of applications & games using some kind of real-time interaction with a database, or more generally, with other users. I'm talking about shared drawing canvas, games like this , or simple chats, or the Android app "a World of Photo", where in real time you see who is online, to share your photos, etc.
Now my question:
Are all these apps based on classic TCP client/server architectures or is there a way to make them in a simpler way, like a web platform like LAMP?
What I'm asking, in other words is:
Can PHP+MySQL (or JSP, or RoR, or any other server language) provide a way to make online users communicate in real time and share data? Is there a way to do that without the ugly and heavy mechanism of temporary tables?
Thank you! I hope I've been clear.
There is this crazy black magiccy thing called P2P (peer-to-peer) that makes all of this possible.
I don't know, but I don't think it will catch on.
8-D
EDIT: CRAP....I didn't see the date the question was posted.
I can't believe it. This is my third consecutive question that involves XHR Long Polling aka Comet programming. Daliz, what you want is possible, easy and been done by various websites using XHR Long Polling.
The concept: Normally, web browsers send a request to the server, server sends a response back and closes the connection to the browser. Instead of closing the connection at the end, Comet programming keeps the connection open. So, the connection between the browser and the server is still open. So, in simple terms, when we want to connect to Alice, we find the thread connecting to her browser and send the message to Alice.
Facebook chant uses the same concept. Please read This.
If your client is not a web browser but some web service, then it is more easy. Web services unlike web browsers have an address. So, client service calls the main service with a callback URL and registers to a particular event. When that event happens, like someone drawing something, main service will use the callback url of the client service to notify about that action.
On sharing data like Photos or another binary data: it is also possible as the input stream from one user is send to all other related users. So a simple String or a photo can be shared. But it also means the user on the receiving end of the photo will not have a message like "xxx has sent you a photo. Click here to download it". They will simply get a "Do you want to open or save this file" option.