Django : open application on client station - django

I would like to ask a relatively simple question in which I didn't put much thought in yet. But I'd just like to know if this is possible before starting painful implementations of my app!
Here it is : Is it possible (and easy..) to run an application and communicate with files on the client's computer from a web application developped in Django ?
I'd really just like to know if it's feasible. Of course if you have a few hints on how to do it, they would be appreciated :)

Yes, it's perfectly possible to do that. You just need to add a proper URL with its corresponding view, processing your HTTP request from client machines and interacting with local files as you need.
Key thing here is to use a proper HttpClient on the machine accessing your client's file.

Related

How to define URLs only once for server and client?

everyone! I am building a web application, i.e. a server-client application. For the interaction between the two, I have to define the URLs twice (hard-coded strings), both on the backend and the frontend, which makes future changes hard, because it would require changing the code in two places, rather than just one.
I am using Django and Angular and so I am looking for a way to specify the back end endpoints once, then ideally read them and use them for the Angular production build. Therefore changes to the endpoints will only require a new build, but no further changes.
Should these be defined in some .cfg file and be read by the back end on server startup and maybe somehow add them to the Angular's build process? Any suggestion would help because this redundancy comes in almost every webapp project and there has to be a more clever solution!
Thanks for the help in advance!
Here, it is the backend application that owns and defines url mappings to entities. It is possible that multiple clients can consume from the same API, like a web client, an Android client and an iOS client. In this setup, your backend is the point of truth for the url mappings, and client applications should be configured to use the url mappings defined in the backend application.
One possible way to do this is to serve defined urls in the backend on a path of the backend application, and have your client applications configure themselves using the data provided there. For example, if you use Django Rest Framework, by default, on the root path of the API ("/"), resources along with url mappings for the resources are served. You can use such a mechanism to configure your client applications on build time.
How many endpoints and how likely are you to alter them? Most likely you will always have to make more changes than just in 1 place as the reason behind changing an endpoint is normally you are trying to POST or GET new data structures. This would mean you will have to alter that request process anyway to handle the new data type or what was being posted.
Also, consider some of the publicly available api's out there - they don't give you an endpoint that serves a config file of available routes. When they make a change to their endpoints they usually create a versioned api so that consumers can upgrade in their own time.
In my opinion, unless you are planning a large scale web app, I wouldn't be too worried about trying to implement something like this.

How to make Django pass cookies when communicating with Node.js server using socket.io?

I am currently developing an instant messaging feature for my apps (ideally cross platform mobile app/web app), and I am out of ideas to fix my issue.
So far, I have been able to make everything work locally, using a Node.js server with socket.io, django, and redis, following what most tutorials online suggest.
The step I am now at consists in putting all that in the cloud using amazon AWS. My Django server is up and running, I created a new separate Node.js server, and I am using Elasticache to handle the Redis part. I launch the different parts, and no error shows up.
However, whenever I try using my messaging feature on the web, I keep getting an error 500:
handshake error
I then used the console to check the request header, and I observed that the cookies are not in there, contrary to when I am on localhost. I know it is necessary to authorize the handshake, so I guess that's where my error is coming from..
Furthermore, I have also checked that the cookies do exist, they are just not set in the request header.
My question is then: How can I make sure Django or socket client (not sure who's responsible here..) puts the cookies in the header??
One of my ideas was that maybe I am supposed to put everything on the same server, with different ports, instead of 2 separate servers? Documentation on that specific architecture problem is surprisingly scarce, compared to the number of tutorials describing how to make it work on local.
I hope I described the problem accurately enough! :)
Important note: I am using socket.io v0.9.1-1, only one compatible with a titanium mobile app.
Thank you for any help!
All right, so I've made some progress.
The cookie problem came from the fact I was making cross-domain request, adding a few lines enabled CORS, which didn't solve the cookie issue, but allowed me to communicate between servers (basically I set the headers of the response using express. I then passed necessary data in the query, even if not the most secure way to do it, I'm just building an MVP, and it's enough for now.
I haven't been able to make the chat work from my Titanium mobile app, but since I can use a webview to handle it, I will be fine.
Hopefully that will help someone.. If anyone needs me to post some code snippets I will gladly do so upon request!
Cheers

Creating a web app on django with phone calls functionality

So basically i'm developing a piece of software that will allow user to call any number he wants right from the website. So i need some help in choosing the correct platform or semi cheap service to use. I guess i need a solution with open API because i want to make a db entry (want to record duration and date) for every call made from website.
I've started research and stumbled upon couple of open source solutions: Asterisk and FreeSWITCH. Trying them out right now, but i still have poor understanding of how SIP works. If it will be a softphone will the user have need to install it on their pc or there are server solutions
One possible solution that works with any SIP server is to use PJSUA Python bindings and to implement in Python a basic softphone. Thus your web application will be seen by the SIP server just as a regular soft phone and the server configuration is much easier.

Two way communication using AJAX from an HTML page to a C++ application running in same server

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.

REST Server, Delphi and Web Services - Advice needed

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.