curlcpp

An object oriented C++ wrapper for CURL (libcurl)

Programming language: C++

License: MIT License

Tags: Networking    

Latest version: v1.4

README

curlcpp

An object-oriented C++ wrapper for cURL tool

If you want to know a bit more about cURL and libcurl, you should go on the official website http://curl.haxx.se/

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Compile and link

Standalone

cd build
cmake ..
make # -j2

Note: cURL >= 7.34 is required.

Then add <curlcpp root>/build/src/ to your library path and <curlcpp root>/include/ to your include path.

When linking, link against curlcpp (e.g.: g++ -std=c++11 example.cpp -o example -lcurlcpp -lcurl). Or if you want run from terminal,

g++ -std=c++11 example.cpp -L/home/username/path/to/build/src/ -I/home/username/path/to/include/ -lcurlcpp -lcurl

Submodule

When using a git submodule and CMake-buildsystem, add the following lines to your CMakeLists.txt:

ADD_SUBDIRECTORY(ext/curlcpp) # Change `ext/curlcpp` to a directory according to your setup
INCLUDE_DIRECTORIES(${CURLCPP_SOURCE_DIR}/include)

Simple usage example

Here are some usage examples. You will find more examples in the test folder!

Here's an example of a simple HTTP request to get google web page, using the curl_easy interface:

#include "curl_easy.h"

using curl::curl_easy;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;

/**
 * This example shows how to make a simple request with curl.
 */
int main() {
    // Easy object to handle the connection.
    curl_easy easy;

    // Add some options.
    easy.add<CURLOPT_URL>("http://<your_url_here>");
    easy.add<CURLOPT_FOLLOWLOCATION>(1L);

    try {
        easy.perform();
    } catch (curl_easy_exception &error) {
        // If you want to print the last error.
        std::cerr<<error.what()<<std::endl;
    }
    return 0;
}

If you want to get information about the current curl session, you could do:

#include "curl_easy.h"
#include "curl_ios.h"
#include "curl_exception.h"

using std::ostringstream;

using curl::curl_easy;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;
using curl::curl_ios;

/**
 * This example shows how to use the easy interface and obtain
 * informations about the current session.
 */
int main(int argc, const char **argv) {
    // Let's declare a stream
    ostringstream stream;

    // We are going to put the request's output in the previously declared stream
    curl_ios<ostringstream> ios(stream);

    // Declaration of an easy object
    curl_easy easy(ios);

    // Add some option to the curl_easy object.
    easy.add<CURLOPT_URL>("http://<your_url_here>");
    easy.add<CURLOPT_FOLLOWLOCATION>(1L);

    try {
        easy.perform();

        // Retrieve information about curl current session.
        auto x = easy.get_info<CURLINFO_CONTENT_TYPE>();

        /**
         * get_info returns a curl_easy_info object. With the get method we retrieve
         * the std::pair object associated with it: the first item is the return code of the
         * request. The second is the element requested by the specified libcurl macro.
         */
        std::cout<<x.get()<<std::endl;

    } catch (curl_easy_exception &error) {
        // If you want to print the last error.
        std::cerr<<error.what()<<std::endl;

        // If you want to print the entire error stack you can do
        error.print_traceback();
    }
    return 0;
}

Here's instead, the creation of an HTTPS POST login form:

#include <string>

#include "curl_easy.h"
#include "curl_pair.h"
#include "curl_form.h"
#include "curl_exception.h"

using std::string;

using curl::curl_form;
using curl::curl_easy;
using curl::curl_pair;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;

int main(int argc, const char * argv[]) {
    curl_form form;
    curl_easy easy;

    // Forms creation
    curl_pair<CURLformoption,string> name_form(CURLFORM_COPYNAME,"user");
    curl_pair<CURLformoption,string> name_cont(CURLFORM_COPYCONTENTS,"you username here");
    curl_pair<CURLformoption,string> pass_form(CURLFORM_COPYNAME,"passw");
    curl_pair<CURLformoption,string> pass_cont(CURLFORM_COPYCONTENTS,"your password here");

    try {
        // Form adding
        form.add(name_form,name_cont);
        form.add(pass_form,pass_cont);

        // Add some options to our request
        easy.add<CURLOPT_URL>("http://<your_url_here>");
        easy.add<CURLOPT_SSL_VERIFYPEER>(false);
        easy.add<CURLOPT_HTTPPOST>(form.get());
        // Execute the request.
        easy.perform();

    } catch (curl_easy_exception &error) {
        // If you want to get the entire error stack we can do:
        curlcpp_traceback errors = error.get_traceback();
        // Otherwise we could print the stack like this:
        error.print_traceback();
    }
    return 0;
}

And if we would like to put the returned content in a file? Nothing easier than:

#include <iostream>
#include <ostream>
#include <fstream>

#include "curl_easy.h"
#include "curl_ios.h"
#include "curl_exception.h"

using std::cout;
using std::endl;
using std::ostream;
using std::ofstream;

using curl::curl_easy;
using curl::curl_ios;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;

int main(int argc, const char * argv[]) {
    // Create a file
    ofstream myfile;
    myfile.open ("/path/to/your/file");

    // Create a curl_ios object to handle the stream
    curl_ios<ostream> writer(myfile);
    // Pass it to the easy constructor and watch the content returned in that file!
    curl_easy easy(writer);

    // Add some option to the easy handle
    easy.add<CURLOPT_URL>("http://<your_url_here>");
    easy.add<CURLOPT_FOLLOWLOCATION>(1L);
    try {
        // Execute the request
        easy.perform();

    } catch (curl_easy_exception &error) {
        // If you want to print the last error.
        std::cerr<<error.what()<<std::endl;

        // If you want to print the entire error stack you can do
        error.print_traceback();
    }
    myfile.close();
    return 0;
}

Not interested in files? So let's put the request's output in a variable!

#include <iostream>
#include <ostream>

#include "curl_easy.h"
#include "curl_form.h"
#include "curl_ios.h"
#include "curl_exception.h"

using std::cout;
using std::endl;
using std::ostringstream;

using curl::curl_easy;
using curl::curl_ios;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;

int main() {
    // Create a stringstream object
    ostringstream str;
    // Create a curl_ios object, passing the stream object.
    curl_ios<ostringstream> writer(str);

    // Pass the writer to the easy constructor and watch the content returned in that variable!
    curl_easy easy(writer);
    // Add some option to the easy handle
    easy.add<CURLOPT_URL>("http://<your_url_here>");
    easy.add<CURLOPT_FOLLOWLOCATION>(1L);

    try {
        easy.perform();

        // Let's print the stream content
        cout<<str.str()<<endl;

    } catch (curl_easy_exception &error) {
        // If you want to print the last error.
        std::cerr<<error.what()<<std::endl;

        // If you want to print the entire error stack you can do
        error.print_traceback();
    }
    return 0;
}

I have implemented a sender and a receiver to make it easy to use send/receive without handling buffers. For example, a very simple send/receiver would be:

#include <iostream>
#include <string>

#include "curl_easy.h"
#include "curl_form.h"
#include "curl_pair.h"
#include "curl_receiver.h"
#include "curl_exception.h"
#include "curl_sender.h"

using std::cout;
using std::endl;
using std::string;

using curl::curl_form;
using curl::curl_easy;
using curl::curl_sender;
using curl::curl_receiver;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;

int main(int argc, const char * argv[]) {
    // Simple request
    string request = "GET / HTTP/1.0\r\nHost: example.com\r\n\r\n";
    // Creation of easy object.
    curl_easy easy;
    try {
        easy.add<CURLOPT_URL>("http://<your_url_here>");
        // Just connect
        easy.add<CURLOPT_CONNECT_ONLY>(true);
        // Execute the request.
        easy.perform();

    } catch (curl_easy_exception &error) {
        // If you want to get the entire error stack we can do:
        curlcpp_traceback errors = error.get_traceback();
        // Otherwise we could print the stack like this:
        error.print_traceback();
    }

    // Creation of a sender. You should wait here using select to check if socket is ready to send.
    curl_sender<string> sender(easy);
    sender.send(request);
    // Prints che sent bytes number.
    cout<<"Sent bytes: "<<sender.get_sent_bytes()<<endl;

    for(;;) {
        // You should wait here to check if socket is ready to receive
        try {
            // Create a receiver
            curl_receiver<char, 1024> receiver;
            // Receive the content on the easy handler
            receiver.receive(easy);
            // Prints the received bytes number.
            cout<<"Receiver bytes: "<<receiver.get_received_bytes()<<endl;

        } catch (curl_easy_exception &error) {
            // If any errors occurs, exit from the loop
            break;
        }
    }
    return 0;
}