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.
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I want to create a small web server in c++ with http-parser from here nodejs/http-parser, I downloaded and I compiled what should I do next?
First of all, you need a way to communicate using TCP/IP in order to implement the HTTP server; depending on your case, you may also need to use other protocols, like UDP (for instance, if you need to resolve a domain name, you will typically use DNS) or ICMP.
If your application is running by an Operating System, take a look at its documentation about the networking facilities it can provide you. For instance, many operating systems provides a POSIX sockets API that will help you dealing with network devices and protocols.
If you prefer, you can use one of the networking libraries already written, provided they support your environment. They can help you with a useful abstraction of the network, so you can concentrate better on your application.
On the other hand, if your application will not be running by an Operating System, the first thing to do is to find some internet protocol suite that you will be able to use in your particular environment.
If you don't find one, you obviously need to implement everything by yourself.
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.
My application runs in Windows and is implemented using C++/Qt.
The application will invoke another application deployed in the Linux server which in turn will invoke some third party tools. The Linux server application will send some status updates based on the running of third party tools. Usually the third party application will run for hours and the updates will be sent at various stages. The Linux server may also has to send some files in addition to the status updates and the Windows client will also send some files required for the running of those third party tools.
I planned to implement this in libssh2 since file transfers can be done and applications can be executed as well using libssh2_channel_exec(). Updates can be sent and received through non-blocking socket transfers. Also the transfers must be secured and they are password authenticated, so I thought SSH will conform my requirements.
I also looked into Qpid of apache which implements the AMQP. The messaging seems to be a more appropriate one for my status updates since the updates are less frequent. But I am not so sure about the secured connection, password authentication and also the application invocation.
So, which one can I choose between these two? Or is there any other better option available? I am not quite used to network programming so any pointers, links regarding this are welcome..
Have you considered some web-based solutions like XML-RPC, REST, SOAP or other? Note that you can either have constant network connection and stream updates or just make your client ask for update as often as it needs.
Also, I think that building solution based on some of these protocols will give you easier coding - no need for some low-level solutions when you have great libraries. As for security part, I would consider SSL that is part of HTTPS protocol to be secure enough. Of course you can also do it hybrid style, for example SSH tunel to secure server and use SSH key authorization.
But if you are sure youwant SSH or AMQP then use first one - I think it has better security. Also, try not using username/passowrd. Instead use mentioned above keys.
Start with SSH, and then consider layering other protocols on top. You can use SSH port forwarding to create a VPN connection to a server, and maybe that will make it easier to use something like AMQP or 0MQ.
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 would like to create a connection between two applications. Should I be using Client-Server or is there another way of efficiently communicating between one another? Is there any premade C++ networking client server libraries which are easy to use/reuse and implement?
Application #1 <---> (Client) <---> (Server) <---> Application #2
Thanks!
Client / server is a generic architecture pattern (much like factory, delegation, inheritance, bridge are design patterns). What you probably want is a library to eliminate the tedium of packing and unpacking your data in a format that can be sent over the wire. I strongly recommend you take a look at the protocol buffers library, which is used extensively at Google and released as open source. It will automatically encode / decode data, and it makes it possible for programs written in different languages to send and receive messages of the same type with all the dirty work done for you automatically. Protobuf only deals with encoding, not actually sending and receiving. For that, you can use primitive sockets (strongly recommend against that) or the Boost.Asio asynchronous I/O library.
I should add that you seem to be confused about the meaning of client and server, since in your diagram you have the application talking to a client which talks to a server which talks to another application. This is wrong. Your application is the client (or the server). Client / server is simply a role that your application takes on during the communication. An application is considered to be a client when it initiates a connection or a request, while an application is considered to be a server when it waits for and processes incoming requests. Client / server are simply terms to describe application behavior.
If you know the applications will be running on the same machine, you can use sockets, message queues, pipes, or shared memory. Which option you choose depends on a lot of factors.
There is a ton of example code for any of these strategies as well as libraries that will abstract away a lot of the details.
If they are running on different machines, you will want to communicate through sockets.
There's a tutorial here, with decent code samples.