Available on NuGet: https://www.nuget.org/packages/modernhttpclient-updated/

This library brings the latest platform-specific networking libraries to Xamarin applications via a custom HttpClient handler. Write your app using System.Net.Http, but drop this library in and it will go drastically faster. This is made possible by:

• On iOS, NSURLSession
• On Android, via OkHttp3
• On UWP, via a custom HttpClientHandler.

Just reference the portable version of ModernHttpClient in your .Net Standard Library, and it will use the correct version on all platforms.

The good news is, you don't have to know either of these two libraries above.

Here's how it works:

var messageHandler = new NativeMessageHandler() {
    Timeout = new TimeSpan(0,0,9),
    EnableUntrustedCertificates = true,
    DisableCaching = true
};
private static HttpClient httpClient = new HttpClient(messageHandler);

SetCookies(IEnumerable<Cookie> cookies): set native cookies

DeleteCookies(): delete all native cookies.

SetCookie(Cookie cookie): set a native cookie.

DeleteCookie(Cookie cookie): delete a native cookie.

SetCookie before making the http call and they will be added to Cookie header in the native client:

var cookieHandler = new NativeCookieHandler();
var messageHandler = new NativeMessageHandler(false, false, cookieHandler) {
    Timeout = new TimeSpan(0,0,9),
    EnableUntrustedCertificates = true,
    DisableCaching = true
};
private static HttpClient httpClient = new HttpClient(messageHandler);

var cookie = new Cookie("cookie1", "value1", "/", "self-signed.badssl.com");
cookieHandler.SetCookie(cookie);

var response = await client.GetAsync(new Uri("https://self-signed.badssl.com"));

Set EnableUntrustedCertificates to true to support self-signed certificates, this is intended for testing environments.

To make it work in iOS, add this to your info.plist:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSExceptionDomains</key>
    <dict>
        <key>your-self-signed.badssl.com</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
    </dict>
</dict>

Hostname Verifier callback parameter has been removed from NativeMessageHandler constructor. Use "verifyHostnameCallback" static property instead.

In your Android project MainActivity:

NativeMessageHandler.verifyHostnameCallback = (hostname, session) =>
{
    // Do something or
    return true;
};

Internally the plugin uses a custom X509TrustManager but to create one for your backend certificate, do this in your Android project MainActivity:

var cf = CertificateFactory.GetInstance("X.509");
var cert = Resources.OpenRawResource(certResourceId);
Certificate ca;
try
{
      ca = cf.GenerateCertificate(cert);
}
finally
{
       cert.Close();
}

var keyStoreType = KeyStore.DefaultType;
var keyStore = KeyStore.GetInstance(keyStoreType);
keyStore.Load(null, null);
keyStore.SetCertificateEntry("ca", ca);

var tmfAlgorithm = TrustManagerFactory.DefaultAlgorithm;
var tmf = TrustManagerFactory.GetInstance(tmfAlgorithm);
tmf.Init(keyStore);

var customTrustManager = tmf.GetTrustManagers()[0] as IX509TrustManager;

NativeMessageHandler.customTrustManager = customTrustManager;

Minimum SSL Protocol parameter has been removed from NativeMessageHandler constructor. Use "minimumSSLProtocol" static property instead.

In your iOS project AppDelegate:

NativeMessageHandler.minimumSSLProtocol = SslProtocol.Tls_1_2;

System.Net.ServicePointManager.SecurityProtocol provides a mechanism for specifying supported protocol types for System.Net. Since iOS only provides an API for a minimum and maximum protocol we are not able to port this configuration directly and instead use the specified minimum value when one is specified.

2.7.2

[Android] Handshake failed (adding customTrustManager static property) #11

2.7.1

[Android] MissingMethodException Method 'ModernHttpClient.NativeMessageHandler..ctor' not found. #9

[iOS] Removing minimumSSLProtocol from NativeMessageHandler ctor

[UWP] Exception on UWP with Xamarin Forms #3

2.7.0

[Update] Migrating to a multi-target project

[Android] Calling HttpClient methods should throw .Net Exception when fail #5

[Android] VerifyHostnameCallback parameter function on constructor (NativeMessageHandler - Android) when customSSLVerification is true #6

[Android] ReasonPhrase is empty under HTTPS #8

2.6.0

[Update] Adding support for UWP

[Update] Adding support for netstandard 2.0

2.5.3

[Update] Cookies set with the native handler will be merged into the Cookie header

2.5.1

[Android] NativeCookieHandler, if provided, is set as the default CookieJar for OkHttpClient

[Update] Adding DeleteCookies, SetCookie and DeleteCookie to NativeCookieHandler

2.5.0

[Android] Updating to Square.OkHttp3

2.4.9

[Android] Calling HttpClient methods should throw .Net Exception when fail #5

[Android] MissingMethodException Method 'ModernHttpClient.NativeMessageHandler..ctor' not found. #9

[Android] VerifyHostnameCallback parameter function on constructor when customSSLVerification is true #6

[Android] ReasonPhrase is empty under HTTPS #8

[Android] Handshake failed (adding customTrustManager static property) #11

[iOS] Removing minimumSSLProtocol from NativeMessageHandler ctor

2.4.7

[Update] Cookies set with the native handler will be merged into the Cookie header

2.4.5

[Android] NativeCookieHandler, if provided, is set as the default cookie handler for OkHttpClient

[Update] Adding DeleteCookies, SetCookie and DeleteCookie to NativeCookieHandler

2.4.4

[Android] SIGABRT after UnknownHostException #229

[iOS] Updating obsolete NSUrlSessionDelegate to INSUrlSessionDelegate

[Update] Adding EnableUntrustedCertificates to support self-signed certificates

2.4.3

[Update] Adding Timeout property

[Android] Updating to Square.OkHttp 2.7.5

[Android] Timeout value is not respected on Android #192