(Sorry for my english)
First: I have an application created using C++ (this is for performance needs), this application uses an image to make some processing and returns a simple answer (1 or 0 ).
Now I need to expose this application from a webservice.
I think to create a webservice using Rails, but I don't know if it's possible using rails to call the C++ process..
The idea is to use the webservice to get an image sent by a client, pass this image to the C++ application and return (using the webservice) a message to the client, based on the result of C++ application.
Is this possible?
Any example or guideline?
Thanks in advance
EDIT: Solved using Thrift thrift.apache.org
I read something about Thrift .. but i think maybe i can't use to solve this problem (maybe) ..
The idea is use a mobile application (iOS and/or Android) where the user can upload an image to the service. The service take the image and make some image processing, this part (the processing) was written with C++ as standalone application that receive an image and return a message, so when the processing is done, the service receive the result (a message) from the processing app and return this to the mobile application.
So.. is this possible with Thrift (if so, i need to read more)? o i need to use something else?
Thanks in advance
I have never done that before, but I think you should take a look at Thrift which was initially developed by Facebook and allows you to make multiple languages work together via RPC calls.
Thrift allows you to define data types
and service interfaces in a simple
definition file. Taking that file as
input, the compiler generates code to
be used to easily build RPC clients
and servers that communicate
seamlessly across programming
languages.
I encourage you to search on Google with the following keywords : thrift C++ rails webservice etc.
Related
I have some framework doing specific task in C++ and a django-based web app. The idea is to launch this framework, receive some data from it, send some data or request and check it's status in some period.
I'm looking for the best way of communication. Both apps run on the same server. I was wondering if a json server in C++ is a good idea. Django would send a request to this server, and server would parse it, and delegate a worker thread to complete the task. Almost all data that need to be send is string-like. Other data will be stored in database so there is no problem with that.
Is JSON a good idea? Maybe you know some better mechanism for local communication between C++ and django?
If your requirement is guaranteed to always have the C++ application on the same machine as the Django web application, include the C++ code by converting it into a shared library and wrapping python around it. Just like this Calling C/C++ from python?
JSON and other serializations make sense if you are going to do remote calls and the code needs to communicate across machines.
JSON seems like a fair enough choice for data serialization - it's good at handling strings and there's existing libraries for encoding/decoding JSON in both python & C++.
However, I think your bigger problem is likely to be the transport protocol that you use for transferring JSON between your client and server. Here's some options:
You could build an HTTP server into your C++ application (which I think might be what you mean by "JSON server" in your question), which would work fine, though might be a bit of a pain to implement unless you get a hold of a library to handle the hard work for you.
Another option might be to use the 0MQ library to send JSON (or otherwise) messages between your client and server. I think this would probably be a lot easier than implementing a full HTTP server, and 0MQ has some interprocess communication code that would likely be a lot faster than sending things over the network.
A third option would just be to run your C++ as a standalone application and pass the data in to it via stdin or command line parameters. This is probably the simplest way to do things, though may not be the most flexble. If you were to go this way, you might be better off just building a Python/C++ binding as suggested by ablm.
Alternatively you could attempt to build some sort of job queue based on redis or something other database system. The idea being that your django application puts some JSON describing the job into the job queue, and then the C++ application could periodically poll the queue, and use a seperate redis entry to pass the results back to the client. This could have the advantage that you could reasonably easily have several "workers" reading from the job queue with minimal effort.
There's almost definitely some other ways to go about it, but those are the ones that immediately spring to mind.
Is it possible to write C++ code to interface with a server, but to be executed on client side, but on the browser instead of native?
Like, for example, imagine using open source classes so that you produce a file.
But because you don't want all this work to be done on the server, you run it on the browser.
So that the client gives a file or two or more as inputs, then the code runs on his machine, the final result is produced, then this file is uploaded to database on the server.
please see google native client project. http://code.google.com/p/nativeclient/
This is strange question.
You can prepare binaries that do task that you want done on client side and make server send proper binary to client when asked for it. Client then runs this binary and returns results to server.
It is possible if you know configurations of client machines (binaries must work on them). Also it have to be some security layer implemented - you don't want to allow every binary run on client (imagine man-in-the-middle attack when some malicious code is run on client).
I think your request contradicts with the idea behind server-side programming. The main purpose in using server-side programs is to make use of infrastructural components like database, network, etc. in a controlled manner. (The most typical usage of server-side applications are web sites with server side coding like JSP and ASP.)
Since servers are machines that are to be kept secure, a remote application should not be permitted to make changes or access filesystem freely. If you want to do changes on a server like doing database operations or reading/writing files, you should use applications that run on the server or provide interfaces like web services or web sites to remote client applications.
So there are a couple solutions when if you want to do work on the browser, then have the results posted in a server database.
First of all, you must set up your server ready for database work. I have done this using the MEAN stack, set up a MongoDB and interfaced it with the Mongoose API.
Now, for the meat of the question, there are many examples of browsers doing intensive work. The majority of these applications thought is not C++, but it is Javascript.
If you really want to focus on C++ (like i did in the past, in the time i asked this question, wanting to make something big for college), then you could do one of the following:
*Use Google Native Client (NaCl). This is a sandbox for running compiled C and C++ code in the browser efficiently and securely, independent of the user’s operating system.
*Maybe you should want to check out Emscripten, which is a framwork for translating C and C++ code to jaascript. This way, you can have your C or C++ binaries that worked, and have them translated to Javascript, in order to have them work in the browser too.
I have existing video streaming application which is based client server technlogy.
Existing system is as follows There is data center, client application and gateway. camera is connected with gateway and gateway is connected with data center.client request video to data center and datacenter get it from gateway.
Now we want to use p2p technology here and want to have direct communication between gateway and client.we want to use RTMFP .for client we can use flex, but the existing gtateway code and business logic is written on c++.
Is there any way around to call c++ code from flex.
Thanks
Hey,
Yes this is pretty much possible with flex 4,(ie. only if you are using a desktop application).From a web based swf, running in a browser you cannot start running a C++ code.
I am assuming that you are developing a desktop app.To call a c++ code , you would need to do the things mentioned in the following example link.It is pretty straightforward.
http://www.adobe.com/devnet/air/flex/quickstart/articles/interacting_with_native_process.html
Or, incase you have access to the C++ code, then you can use a few already built classes which allow C++/Flex interaction.
http://anirudhs.chaosnet.org/blog/2008.03.13.html
i am writing an program in c++ and i need an web interface to control the program and which will be efficient and best programming language ...
Your application will just have to listen to messages from the network that your web application would send to it.
Any web application (whatever the language) implementation could use sockets so don't worry about the details, just make sure your application manage messages that you made a protocol for.
Now, if you want to keep it all C++, you could use CPPCMS for your web application.
If it were Windows, I could advice you to register some COM component for your program. At least from ASP.NET it is easily accessible.
You could try some in-memory exchange techniques like reading/writing over a localhost socket connection. It however requires you to design some exchange protocol first.
Or data exchange via a database. You program writes/reads data from the database, the web front-end reads/writes data to the database.
You could use a framework like Thrift to communicate between a PHP/Python/Ruby/whatever webapp and a C++ daemon, or you could even go the extra mile (probably harder than just using something like Thrift) and write language bindings for the scripting language of your choice.
Either of the two options gives you the ability to write web-facing code in a language more suitable for the task while keeping the "heavy lifting" in C++.
Did you take a look at Wt? It's a widget-centric C++ framework for web applications, has a solid MVC system, an ORM, ...
The Win32 API method.
MSDN - Getting Started with Winsock:
http://msdn.microsoft.com/en-us/library/ms738545%28v=VS.85%29.aspx
(Since you didn't specify an OS, we're assuming Windows)
This is not as simple as it seems!
There is a mis-match between your C++ program (which presumibly is long running otherwise why would it need controlling) and a typical web program which starts up when it receives the http request and dies once the reply is sent.
You could possibly use one of the Java based web servers where it is possible to have a long running task.
Alternatively you could use a database or other storage as the communication medium:-
You program periodically writes it current status to a well know table, when a user invokes the control application it reads the current status and gives an appropriate set of options to the user which can then be stored in the DB, and actioned by your program the next time it polls for a request.
This works better if you have a queuing mechanism avaiable, as it can then be event driven rather than polled.
Go PHP :) Look at this Program execution Functions
In a normal client/server design, the client can execute functions implemented on the server-side. Is it possible to test a gSOAP server by connecting an extra client to it?
I have not used gSOAP, but from reading the documentation it allows you to write both clients and servers so you can write an test client to test the service.
However if you are planning to offer the service to clients written in .net or java I would recommend that you write the test client in one of these. This way you will know for certain that it is possible to use the service from one of these clients. You might also find that .net or java clients are easier to write if you server is designed in a specific way, your test client will help you find this out.
Sure it is, use SoapUI to generate client connections and data. Its free.
To add to the other comments: testing a gSOAP server can be easily done offline using IO redirect. When you invoke soap_serve() without any sockets set up prior to this call, the server engine will simply accept data from standard input and write data to standard output. This is a great way to hit an offline server implementation hard with XML data patterns for testing before deploying the server online. The gSOAP tool even generates example XML messages that you can use for this purpose.