I need to download files/read strings from a specified url in C++. I've done some research with this, cURL seems to be the most popular method. Also, I've used it before in PHP. The problem with cURL is that the lib is huge, and my file has to be small. I think you can do it with winsock, but I can't find any simple examples. If you have a simple winsock example, a light cURL/Something else, or anything that could get the job done. I would greatly appreciated. Also, I need this to work with native C++.
I can repeat me answer Is it possible to handle proxies at socket level? (see also comments) about two important interfaces Windows Internet (WinINet) API and Windows HTTP Services (WinHTTP). An important restriction of WinINet is that WinINet should be not used in a service (only in GUI app.) because of possible dialogs.
you should try WinInet: this library is part of Windows operating system, and allows to download a resource identified by an URL, using either HTTP or FTP.
if you are using HTTP, you might find the InternetOpenUrl() function useful.
Related
I am building a server-client application that involves heavy signal processing (e.g. FFT). I have a working application written in C++/Qt, where everything (signal processing and other calculations) is done in client and server just sends raw data. Now I feel it would be easier to implement these features on the server. So, that maintenance becomes easier.
As I am doing signal processing, I think I should stick to C++ for performance. But I am open to new ideas.
Constraints:
I need type checking so javascript is out of discussion.
Scaling includes adding more server and each server will have at the max
10-12 users. So, Hardware cost is important. I cannot use x number of
i7 processors.
No option of using cloud services.
So, right now my question is as follows:
How can I create web services using C++ for Linux server? (Although cross platform is not important, I would appreciate if I can achieve it.)
EDIT [02:09:2015]
Right now, I think the choice is between poco and C++ Rest SDK. I feel I should go for C++ Rest SDK. Mainly because it has only those features that I need. And Also it is supported by microsoft and uses boost internally. So, I feel in future, this might be well integreated with standard.
You could use cross-platform Poco library to implement HTTP server, it is really straightforward with this framework, and they have a lot of examples. You can also use JSON serialization (like rapidjson library) to implement REST service on top of HTTP - this way your Web service will be accesable by most of the modern Web frameworks.
You might want to take a look at the C++ Rest SDK, an open source, cross platform API from Microsoft.
Like #nogard suggested, I also recommend POCO for now. It's the most serious and feature-full solution. Given you mentioned Qt, I suggest you to take a look at Tufão.
EDIT:
I forgot to mention one comparison of mine on the C++ HTTP server frameworks.
If you directly handle HTTP requests, you might loose the functionality what Web Servers does well what it was build to do. I had a similar issue, what I did was wrap up my Qt c++ code inside a PHP extension. In your case you can do the same. Wrap your logic inside what ever technology you are about to use, doesn't matter it's PHP, net , Java or anything else.
What I want to do is read a webpage and then store it in a sting I know how to do this using libcurl but is there any other way to do this without using libcurl?(Using Cygwin to compile)
You can implement a simple HTTP request using raw sockets. But for other than learning exercises I would not recommend this and just go with libcurl.
For an example program which uses raw sockets look here: http://coding.debuntu.org/c-linux-socket-programming-tcp-simple-http-client (randomly found on google, quality not assured).
While you can easily create an HTTP client using raw sockets as the other posters have suggested, I recommend against it if you want to deploy your software anywhere outside of your own computer. In the real world your users are likely to be behind proxies and firewalls, and may require authentication. Libraries like libCurl deal with this complexity for you.
If you really can't use libCurl and don't care about cross-platform code, most operating systems have built in APIs for accessing web pages. WinINET is the Windows library.
You can always speak HTTP directly yourself over a socket.
I want to call a rest service written in WCF (which can support both XML and JSON Web Message Formats) from my C++ application.
What is the best solution to achieve this ? I have seen some utilities (gsoap) which create proxy classes for you to be used to call web services.
Can I achieve the same functionality without using any intermediate utility ? As its a rest service and it works using GET/PUT functions which are basic HTTP functions, is there any C++ library/Solution which could be used to invoke these function directly from a c++ application ?
On Linux, you probably could use curl library (and I guess it is ported to Windows). Curl is a library providing HTTP client functionality to a C or C++ program.
Use Casablanca. This should be helpful for people looking for this answer in 2013. CURL is perfectly appropriate but if you're doing C++ in Windows and using MS stuff, Casablanca seems fit.
Hope the following articles might be of help to you
1. Accessing an XML Web Service Using C++
2. SOAP client for C++
I tried gsoap myself but it became difficult to maintain cross platform versions of my app.
Instead i went the HTTP request route.
For cross platform and C++ i found this Call Rest Web Services from C++
If XML serialization with your REST approach is really not needed then curl is perfect to use. However, if you want type-safe XML serialization in C or C++ then it would become cumbersome to use curl, since you will have to use something that runs on top of curl to process XML such as with a DOM parser (slow and not type safe). If you have a WSDL, then I recommend gSOAP 2.8 which provides integrated REST and XML serialization capabilities (and JSON when you need it).
Is there a relatively easy way to display the output of a C++ program on a webpage? And I don't mean manually, in other words, you see it on a webpage as it runs not as in I make a code tag and write it in myself.
EDIT: Just so everybody can get this clear I am going to post this up here. I am NOT trying to make a webpage in C++. Please excuse me if this sounds spiteful or anything but I am getting a lot of answers relating to that.
Step one, get yourself a server-side language. Be that PHP, ASP, Python, Ruby, whatever. Get it set up so you can serve it.
Step two, find your language's exec equivalent. Practically all of them have them. It'll let you run a command as if it were from the command line, usually with arguments and capture the output. Here's PHP's:
http://php.net/manual/en/function.exec.php
Of course, if you're passing user-input as arguments, sanitise!
I've just seen that you accepted Scott's answer. I usually wouldn't chase up a SO thread so persistently but I fear you're about to make a mistake that you'll come to regret down the line. Giving direct access to your program and its own built-in server is a terrible idea for two reasons:
You waste a day implementing this built-in server and then getting it to persist and testing it
More importantly, you've just opened up another attack vector into your server. When it comes to security, keep it simple.
You're far better having your C++ app running behind another (mature) server side language as all the work is done for you and it can filter the input to keep things safe.
You could write a CGI app in C++, or you could use an existing web server language to execute the command and send the output to the client.
You want to use Witty.
Wt (pronounced 'witty') is a C++
library for developing interactive web
applications.
The API is widget-centric and similar
to desktop GUI APIs. To the developer,
it offers complete abstraction of any
web-specific implementation details,
including event handling, graphics
support, graceful degradation (or
progressive enhancement), and pretty
URLs.
Unlike many page-based frameworks, Wt
was designed for creating stateful
applications that are at the same time
highly interactive (leveraging
techinques such as AJAX to their
fullest) and accessible (supporting
plain HTML browsers), using automatic
graceful degradation or progressive
enhancement.
The library comes with an application
server that acts as a stand-alone web
server or integrates through FastCGI
with other web servers.
I am not sure this is what you are looking for but you may want CGI You may want to look at this SO question, C++ may not be the best language for what you want to do.
based off the questions you posted Writing a web app like what you want is no simple task. What I would recommend is use some other library (this is one i found with a quick google) to get a web console on your server and give the user it is running under execute deny permissions on every folder except the folder you have your app installed.
This is still is a risky method if you don't set up the security correctly but it is the easiest solution without digging around too much on existing libraries to just have the application interactive.
EDIT --
The "Best" solution is learn AJAX and have your program post its own pages with it but like I said, it will not be easy.
It sounds like you want something like a telnet session embedded in a webpage. A quick google turns up many Java telnet apps, though I'm not qualified to evaluate which would be most ideal to embed in html.
You would set up the login script on the host machine to run your c++ app and the user would interact with it through the shell window. Note though that this will only work for pure command line apps. If you want to use a GUI app in this way, then you should look into remote desktop software or VNC.
It may be worth looking into Adobe's "Alchemy" project on Adobe Labs
This may help you with what you're trying to achieve.
:)
Are you looking for something like what codepad.org does? I believe they explain how they did it here.
There is a library called C++ Server Pages - Poco. I used it for one of my college project, its pretty good. There is also good documentation to get started with, u can find it here http://pocoproject.org/docs/
I have recently been given a task to add the ability to interact with Web Map Services to an existing MFC application and I am in need of a client-side HTTP API.
Based on my research, the leading candidates seem to be CAtlHttpClient and WinHTTP. I was curious to see if anyone had experiences they could share or opinions on which would be the better way to go (or suggestions for something else entirely).
At first glance, CAtlHttpClient seems to be a bit higher level and easier to use. However, in my research it seemed that any time people had a problem with not being able to do something with it, the answer was "use WinHTTP".
Result
I wound up using WinHTTP because WinInet displays dialog boxes and our application is usable through a COM API. I avoided Ultimate TCP/IP because I work for a large company and getting third party software approved for use in a product is a complete nightmare.
The simplest one is the WinInet MFC wrappers: CInternetSession and friends.
WinHTTP, although a different API, is built on the same model as WinInet yet provides better HTTP support (no FTP though but you probably don't care). Whether you need the extra goodies provided by WinHTTP should be examined.
A down side of WinHTTP is that ATL/MFC don't provide wrappers for it, as opposed to WinInet.
And as Rob mentioned, UltimateTCP is a excellent alternative. One of its advantages is that it's a library: you link the code into your application, thereby eliminating DLL hell potential problems. Also, it comes with full source code which might be convenient if you run into a limitation of the implementation.
Make your pick!
Try Ultimate TCP/IP available for free from here:
http://www.codeproject.com/KB/MFC/UltimateTCPIP.aspx
It's a very good library and very easy to integrate with your apps.