CurlThin

CurlThin is a NET Standard compatible binding library against libcurl. It includes a modern wrapper for curl_multi interface which uses polling with libuv library instead of using inefficient select.

CurlThin has a very thin abstraction layer, which means that writing the code is as close as possible to writing purely in libcurl. libcurl has extensive documentation and relatively strong support of community and not having additional abstraction layer makes it easier to search solutions for your problems.

Using this library is very much like working with cURL's raw C API.

License

Library is MIT licensed. NuGet icon made by Freepik and is licensed by CC 3.0 BY

Installation

Package	NuGet	MyGet	Description
CurlThin			The C# wrapper for libcurl.
CurlThin.Native			Contains embedded libcurl native binaries for x86 and x64 Windows.

If you have libcurl or libcurl.dll already in your PATH directory, you don't need to install CurlThin.Native package. Once you have installed CurlThin.Native NuGet package, call following method just once before you use cURL:

CurlResources.Init();

It will extract following files to your application output directory

Windows x86	Windows x64	Description
libcurl.dll	libcurl.dll	The multiprotocol file transfer library.
libssl-1_1.dll	libssl-1_1-x64.dll	Portion of OpenSSL which supports TLS ( SSL and TLS Protocols), and depends on libcrypto.
libcrypto-1_1.dll	libcrypto-1_1-x64.dll	Provides the fundamental cryptographic routines used by libssl.
curl-ca-bundle.crt	curl-ca-bundle.crt	Certificate Authority (CA) bundle. You can use it via CURLOPT_CAINFO.

Examples

Easy interface

GET request

// curl_global_init() with default flags.
var global = CurlNative.Init();

// curl_easy_init() to create easy handle.
var easy = CurlNative.Easy.Init();
try
{
    CurlNative.Easy.SetOpt(easy, CURLoption.URL, "http://httpbin.org/ip");

    var stream = new MemoryStream();
    CurlNative.Easy.SetOpt(easy, CURLoption.WRITEFUNCTION, (data, size, nmemb, user) =>
    {
        var length = (int) size * (int) nmemb;
        var buffer = new byte[length];
        Marshal.Copy(data, buffer, 0, length);
        stream.Write(buffer, 0, length);
        return (UIntPtr) length;
    });

    var result = CurlNative.Easy.Perform(easy);

    Console.WriteLine($"Result code: {result}.");
    Console.WriteLine();
    Console.WriteLine("Response body:");
    Console.WriteLine(Encoding.UTF8.GetString(stream.ToArray()));
}
finally
{
    easy.Dispose();

    if (global == CURLcode.OK)
    {
        CurlNative.Cleanup();
    }
}

POST request

// curl_global_init() with default flags.
var global = CurlNative.Init();

// curl_easy_init() to create easy handle.
var easy = CurlNative.Easy.Init();
try
{
    var postData = "fieldname1=fieldvalue1&fieldname2=fieldvalue2";

    CurlNative.Easy.SetOpt(easy, CURLoption.URL, "http://httpbin.org/post");

    // This one has to be called before setting COPYPOSTFIELDS.
    CurlNative.Easy.SetOpt(easy, CURLoption.POSTFIELDSIZE, Encoding.ASCII.GetByteCount(postData));
    CurlNative.Easy.SetOpt(easy, CURLoption.COPYPOSTFIELDS, postData);
    
    var stream = new MemoryStream();
    CurlNative.Easy.SetOpt(easy, CURLoption.WRITEFUNCTION, (data, size, nmemb, user) =>
    {
        var length = (int) size * (int) nmemb;
        var buffer = new byte[length];
        Marshal.Copy(data, buffer, 0, length);
        stream.Write(buffer, 0, length);
        return (UIntPtr) length;
    });

    var result = CurlNative.Easy.Perform(easy);

    Console.WriteLine($"Result code: {result}.");
    Console.WriteLine();
    Console.WriteLine("Response body:");
    Console.WriteLine(Encoding.UTF8.GetString(stream.ToArray()));
}
finally
{
    easy.Dispose();

    if (global == CURLcode.OK)
    {
        CurlNative.Cleanup();
    }
}

Multi interface

Web scrape StackOverflow questions

See Multi/HyperSample.cs.