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.
Related
I have a project which generates a puzzle and solves it in separate classes using the REPL. Is there any way to separate those classes into separate projects so that I can create a server that is on the same machine and can find puzzles already generated and return them to the calling client (puzzle solver) without the use of web servers?
Update: initially misunderstood what I was trying to do and reworded my question
Definitely you can. In broad strokes, you probably want:
A single project with clear client, server and shared namespaces (eg. logic about solving puzzles that might be shared between client and server). There's nothing intrinsically wrong about bundling all the code together at first (later you can ship client+shared and server+shared separately)
A library to make client/server communication simpler. A common use case is exposing the server with a web API because it's also simpler to test with web browsers, CLI clients (such as cURL), but it's OK if you want to use plain sockets and exchange messages in whatever format (EDN strings?) makes sense to you.
An example of a library for sockets would be https://github.com/atroche/clj-sockets , if you don't want to use Java interop and use classes from the java.net package directly.
Also note that web servers are actually socket servers too that listen for connections on fixed ports (eg. 80, 443 or 8080) for HTTP messages using certain conventions (eg. GET /api/puzzles/1)
Finally, you'll need at least two namespaces that export a -main method: one to launch the server and another to launch a client.
Background: I've got an C++/Qt-based application that communicates with servers on the user's LAN. It uses non-blocking TCP and UDP sockets, and the networking is implemented via calls to the BSD sockets API (i.e. socket()/send()/recv()/select()/etc). It all works well.
The other day, just for fun, I decided to recompile the application using emscripten, so that it could run as a WebAssembly app inside a web browser.
This worked surprisingly well -- within an hour or two, I had my app up and running inside Google Chrome. However, the app's usefulness in this configuration is severely limited by the fact that it isn't able to connect to any servers -- presumably this is because it is running in a restricted/sandboxed environment.
If I wanted to pursue this line of development beyond the clever-hack-demo stage and try to make it useful, I would need to find a way for my program to discover and connect to servers on the user's LAN.
My question is: is that functionality at all possible for a Emscripten/WebAssembly-based app to perform? If so, what steps would I need to take? (i.e. would it require upgrading the LAN's servers to handle WebSocket-based connections? Would it require adding some sort of proxy server to run on the web server that the web page was served from? Is UDP even a thing in a web-app context? Are there other hoops that would also have to be jumped through?)
I'm working on a project of which a large part is server side software. I started programming in C++ using the sockets library. But, one of my partners suggested that we use a standard server like IIS, Apache or nginx.
Which one is better to do, in the long run? When I program it in C++, I have direct access to the raw requests where as in the case of using standard servers I need to use a scripting language to handle the requests. In any case, which one is the better option and why?
Also, when it comes to security for things like DDOS attacks etc., do the standard servers already have protection? If I would want to implement it in my socket server, what is the best way?
"Server side software" could mean lots of different things, for example this could be a trivial app which "echoes" everything back on a specific port, to a telnet/ftp server to a webserver running lots of "services".
So where in this gamut of possibilities does your particular application lie? Without further information, it's difficult to make any suggestions, but let's see..
Web Services, i.e. your "server side" requirement is to handle individual requests and respond having done some set of business logic. Typically communication is via SOAP/XML, and this is ideal if you bave web based clients (though nothing prevents your from accessing these services via standalone clients). Typially you host these on web servers as you mentioned, and often they are easiest written in Java (I've yet to come across one that needed to be written in C++!)
Simple web site - slightly different to the above, respods to HTML get/post requests and serves up static or dymanic content (I'm guessing this is not what you're after!)
Standalone server which responds to something specific, here you'd have to implement your own "messaging"/protocols etc. and the server will carry out a specific function on incoming request and potentially send responses back. Key thing here is that the server does something specific, and is not a generic container (at which point 1 makes more sense!)
So where does your application lie? If 1/2 use Java or some scripting language (such as Perl/ASP/JSP etc.) If 3, you can certainly use C++, and if you do, use a suitable abstraction, such as boost::asio and Google Protocol buffers, save yourself a lot of headache...
With regards to security, ofcourse bugs and security holes are found all the time, however the good thing with some of these OS projects is that the community will tackle and fix them. Let's just say, you'll be safer using them than your own custom handrolled imlpementation, the likelyhood that you'll be able to address all the issues that they would have encountered in the years they've been around is very small (no disrespect to your abilities!)
EDIT: now that there's a little more info, here is one possible approach (this is what I've done in the past, and I've jused Java most of the way..)
The client facing server should be something reliable, esp. if it's over the internet, here I would use a proven product, something like Apache is good or IIS (depends on which technologies you have available). IMHO, I would go for jBoss AS - really powerful and easily customisable piece of kit, and integrates really nicely with lots of different things (all Java ofcourse!) You could then have a simple bit of Java which can then delegate to your actual Server processes that do the work..
For the Server procesess you can use C++ if that's what you are comfortable with
There is one key bit which I left out, and this is how 1 & 2 talk to each other. This is where you should look at an open source messaging product (even more higher level than asio or protocol buffers), and here I would look at something like Zero MQ, or Red Hat Messaging (both are MQ messaging protocols), the great advantage of this type of "messaging bus" is that there is no tight coupling between your servers, with your own handrolled implementation, you'll be doing lots of boilerplate to get the interaction to work just right, with something like MQ, you'll have multiplatform communication without having to get into the details... You wil save yourself a lot of time and bother if you elect to use something like that.. (btw. there are other messaging products out there, and some are easier to use - such as Tibco RV or EMS etc, however they are commercial products and licenses will cost a lot of money!)
With a messaging solution your servers become trivial as they simply handle incoming messagins and send messages back out again, and you can focus on the business logic...
my two pennies... :)
If you opt for 1st solution in Nim's list (web services) I would suggest you to have a look at WSO's web services framework for C++ , Axis CPP and Axis2/C web services framework (if you are not restricted to C++). Web Services might be the best solution for your requirement as you can quickly build them and use either as processing or proxy modules on the server side of your system.
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
I develop industrial client/server application (C++) with strong real time requirements.
I feel it is time to change the look of the client interface - which is developed in MFC - but I am wondering which would be the right choice.
If I go for a web client is there any way to exchange data between C++ and javascript other than AJAX <-> Web service <-> COM ?
Requirements for the web client are: Quick statuses refresh, user commands, tables
My team had to make that same decision a few months ago...
The cool thing about making it a web application would be that it would be very easy to modify later on. Even the user of the interface (with a little know-how) could modify it to suit his/her needs. Custom software becomes just that much easier.
We went with a web interface and ajax seems the way to go, it was quite responsive.
On the other hand, depending on how strong your real time requirements are, it might prove difficult. We had the challenge of plotting real time data through a browser, we ended up going with a firefox plugin to draw the plot. If you're simply trying to display real time text data, it shouldn't be as big an issue.
Run some tests for your specific application and see what it looks like.
Something else to consider, if you are having a web page be an interface to your server, keep in mind you will need to figure a way to update one client when another changes the state of the server if you plan on allowing multiple interfaces to your server.
I usually build my applications 2-folded :
Have the real heavy-duty application CLI-only. The protocol used is usually text-only based, composed of requests and answers.
Wrap a GUI around as another process that talks to the CLI back-end.
The web interface is then just another GUI to wrap around. It is also much easier to wrap a REST/JSON based API on the CLI interface (just automatically translate the messages).
The debugging is also quite easy to do, since you can just dump the requests between the 2 elements and reproduce the bugs much more easily.
Write an HTTP server in your server to handle the AJAX feedback. If you don't want to serve files, create your server on a non-standard port (eg. 8081) and use a regular web server for the actual web page delivery. Now have your AJAX engine communicate with the server on the Bizarro port instead of port 80.
But it's not that hard to write the file server part, also. If you do that, you also get to generate web pages on-the-fly with your data pre-filled, if you want.
Google Desktop Search does this now. When I search my desktop for 'foobar', the URL that opens is this:
http://127.0.0.1:4664/search?q=foobar&flags=68&num=10
In this case, the 4664 is the Bizarro port. (GoogleDesktop serves all the data here; it only uses the Bizarro port to avoid conflicts with any web server I might be running.)
You may want to consider where your data lives. If your application feeds a back-end database, you could write a web app leaving your c++ code in tact -- the web application would be independent and offer up pages to web users and talk directly to the database -- In this case you have as many options, and more, as you have indicated.