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cpr - C++ Requests

Curl for People

C++ Requests is a simple wrapper around libcurl inspired by the excellent Python Requests project.

Despite its name, libcurl's easy interface is anything but, and making mistakes misusing it is a common source of error and frustration. Using the more expressive language facilities of C++17, this library captures the essence of making network calls into a few concise idioms.

Here's a quick GET request:

{% raw %}

#include <cpr/cpr.h>

int main(int argc, char** argv) {
    cpr::Response r = cpr::Get(cpr::Url{"https://api.github.com/repos/libcpr/cpr/contributors"},
                      cpr::Authentication{"user", "pass", cpr::AuthMode::BASIC},
                      cpr::Parameters{{"anon", "true"}, {"key", "value"}});
    r.status_code;                  // 200
    r.header["content-type"];       // application/json; charset=utf-8
    r.text;                         // JSON text string
}

{% endraw %}

And here's less functional, more complicated code, without cpr.

Features

C++ Requests currently supports:

  • Custom headers
  • Url encoded parameters
  • Url encoded POST values
  • Multipart form POST upload
  • File POST upload
  • Basic authentication
  • Digest authentication
  • NTLM authentication
  • Connection and request timeout specification
  • Timeout for low speed connection
  • Asynchronous requests
  • 🍪 support!
  • Proxy support
  • Callback interfaces
  • PUT methods
  • DELETE methods
  • HEAD methods
  • OPTIONS methods
  • PATCH methods
  • Thread Safe access to libCurl
  • OpenSSL and WinSSL support for HTTPS requests
  • Manual domain name resolution

Planned

Support for the following will be forthcoming (in rough order of implementation priority):

and much more!

Usage

CMake

If you already have a CMake project you need to integrate C++ Requests with, the primary way is to use fetch_content. Add the following to your CMakeLists.txt.

include(FetchContent)
FetchContent_Declare(cpr GIT_REPOSITORY https://github.com/libcpr/cpr.git
                         GIT_TAG 871ed52d350214a034f6ef8a3b8f51c5ce1bd400) # The commit hash for 1.9.0. Replace with the latest from: https://github.com/libcpr/cpr/releases
FetchContent_MakeAvailable(cpr)

This will produce the target cpr::cpr which you can link against the typical way:

target_link_libraries(your_target_name PRIVATE cpr::cpr)

That should do it! There's no need to handle libcurl yourself. All dependencies are taken care of for you.
All of this can be found in an example here.

Bazel

Please refer to hedronvision/bazel-make-cc-https-easy.

Packages for Linux Distributions

Alternatively, you may install a package specific to your Linux distribution. Since so few distributions currently have a package for cpr, most users will not be able to run your program with this approach.

Currently, we are aware of packages for the following distributions:

If there's no package for your distribution, try making one! If you do, and it is added to your distribution's repositories, please submit a pull request to add it to the list above. However, please only do this if you plan to actively maintain the package.

Requirements

The only explicit requirements are:

  • a C++17 compatible compiler such as Clang or GCC. The minimum required version of GCC is unknown, so if anyone has trouble building this library with a specific version of GCC, do let me know
  • If you would like to perform https requests OpenSSL and its development libraries are required.

Building cpr - Using vcpkg

You can download and install cpr using the vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install cpr

The cpr port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

Building cpr - Using Conan

You can download and install cpr using the Conan package manager. Setup your CMakeLists.txt (see Conan documentation on how to use MSBuild, Meson and others). An example can be found here.

The cpr package in Conan is kept up to date by Conan contributors. If the version is out of date, please create an issue or pull request on the conan-center-index repository.

Building cpr with Meson

Meson is available in all Linux/BSD and on Marcos in their main repository. Once installed just make a directory cpr_test and enter it and run:

meson init -l cpp -n cpr-test

It creates a .cpp file in the directory root and a meson.build just like this.

Now to make cpr available to the project, make a subprojects directory and install it with:

meson wrap install cpr

It creates a meson wrap file in subprojects/cpr.wrap, with that we need to it as dependecy in the meson.build file:

project('cpr-test', 'cpp',
  version : '0.1',
  default_options : ['warning_level=3', 'cpp_std=c++17'])

cpr_dep = dependency('cpr')

exe = executable('cpr-test', 'cpr_test.cpp', dependencies: [ cpr_dep ], install: true)

test('basic', exe)

and now just paste the example usage in the top of page in the new .cpp file, do some modification and build/compile the project:

meson setup builddir --wipe
meson compile -C builddir
./builddir/cpr-test

That's it. For more information check out on the Meson website: https://mesonbuild.com

Testing docs in a container image

With your image builder ready, either Docker or Podman, build it like:

podman build . --tag cpr-image
podman run --rm -it -p 4000:4000 -v ${PWD}:/app -w /app cpr-image

Then go to localhost:4000 with your web browser or curl. That's it!

Contributing

Please fork this repository and contribute back using pull requests. Features can be requested using issues. All code, comments, and critiques are greatly appreciated.