Generic HTTP Web Service Client in C (GHoWSt)

A client written to talk to the Generic HTTP Web Service Server

Design goals

• Use local language semantics to talk to the server without an intermediate language. Unlike with dynamic languages though, the C client will need to be generated manually, but beyond that, the only other things needed are domain object structs, the library, and 3rd party dependencies from vcpkg.json.
• Every call, using a method name convention to map to HTTP methods, gets translated to HTTP requests. Responses are parsed from JSON and mapped back to local structs.

Note

Memory ownership and cleanup is not 100% handled, for the sake of a simpler example. Basic memory management is done when practical, and string safety is decent.

Example code

#include <stdlib.h>

#include "example_http_web_service_client.h"

int main(int argc, char *argv[])
{
    ghowsth ghowst = ghowst_init("http://localhost:8081/generichttpws");

    // Create
    engine_t engine = {
            .name = "CengineGenerated",
            .cylinders = 44,
            .throttle_setting = 49
    };
    int engine_id1 = create_engines(ghowst, engine);

    return EXIT_SUCCESS;
}

Setup

Ensure a compiler (GCC, MSVC were tested) is installed. Ensure vcpkg is installed (it doesn't have to be on the PATH for the CLI build to work). Ensure CMake is installed.

Running the example

First, ensure the server is running. Refer to other grouped GHoWSt projects to get and run the server.

If using the CLI, ensure you are in the project directory. Run:

cmake -S . -B build "-DCMAKE_TOOLCHAIN_FILE=<vcpkg root>/scripts/buildsystems/vcpkg.cmake"
cmake --build build
cd build
./run_example_generic_http_web_service_client

Note

Change <vcpkg root> to match your installation. The last command's forward slash should be a backslash if on Windows.

If using an IDE, ensure it supports CMake and that the project profile configures CMAKE_TOOLCHAIN_FILE to use vcpkg. Now, you should only need to run the below file which should, after the CMake project builds, compile and run for you:

run_example_generic_http_web_service_client.c

The example runs several calls to create, update, replace, read, delete, and do a custom action on resources.

Running the tests

Ensure you are in the build tree. Then,

To run unit tests only:

ctest -R ^unit

To run unit and integration tests:

ctest