Howest.Prog.Xamarin.UriSourceExtensions 0.0.3-alpha

.NET Standard 2.0
This is a prerelease version of Howest.Prog.Xamarin.UriSourceExtensions. 
dotnet add package Howest.Prog.Xamarin.UriSourceExtensions --version 0.0.3-alpha
NuGet\Install-Package Howest.Prog.Xamarin.UriSourceExtensions -Version 0.0.3-alpha
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="Howest.Prog.Xamarin.UriSourceExtensions" Version="0.0.3-alpha" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
paket add Howest.Prog.Xamarin.UriSourceExtensions --version 0.0.3-alpha
#r "nuget: Howest.Prog.Xamarin.UriSourceExtensions, 0.0.3-alpha"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
// Install Howest.Prog.Xamarin.UriSourceExtensions as a Cake Addin
#addin nuget:?package=Howest.Prog.Xamarin.UriSourceExtensions&version=0.0.3-alpha&prerelease

// Install Howest.Prog.Xamarin.UriSourceExtensions as a Cake Tool
#tool nuget:?package=Howest.Prog.Xamarin.UriSourceExtensions&version=0.0.3-alpha&prerelease

Xamarin Uri Source Extensions

Why

When developing a Xamarin Forms app you are likely debugging on your Android emulator or device. To provide data and online images to your app, you decide to run your own back-end HTTP API locally using a self-signed certificate.

But what's this? Your images fail to load on Android with the error:

java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

or

ImageLoaderSourceHandler: Could not retrieve image or image data was invalid

In this case, this is usually caused by Android preventing to download your images using a self-signed SSL/TLS certifcate.

What

This small library contains a Xamarin Forms behavior to add to your <Image> elements. It allows you to download images from an insecure HTTPS source when debugging.

It does this by using its own HttpClientHandler and downloading the image UriSource as a Stream.

Overview

Property Type Description
IgnoreCertificateErrors bool Ignores any invalid or self-signed certficates when this image uses a UriSource. Only works during debugging.
Token string Bearer token to add to the header of the request when retrieving the resource

Ignoring self-signed certificates

Add the namespace to your Xamarin Forms Page:

<ContentPage 
    ...
    xmlns:urisource="clr-namespace:Howest.Prog.Xamarin.UriSourceExtensions;assembly=Howest.Prog.Xamarin.UriSourceExtensions"
    ... >

Add the behavior to your <Image> element as follows:

<Image Source="{Binding Url}">
    <Image.Behaviors>
        <urisource:TlsSourceBehavior 
            IgnoreCertificateErrors="True" />
    </Image.Behaviors>
</Image>

Note: For security reasons, the behavior will only work when a debugger is attached to prevent this insecure behavior to leak to production code.<br>

Add a Bearer Token

The behavior also allows you to add a Bearer token like so:

<Image Source="{Binding Url}">
    <Image.Behaviors>
        <urisource:TlsSourceBehavior
        IgnoreCertificateErrors="True"
        Token="{Binding BindingContext.AuthenticationToken, Source={x:Reference Name=myProtectedPage}}" />
    </Image.Behaviors>
</Image>

Sample project

A sample project and REST API is provided in the GitHub repository.<br>

Attribution

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last updated
0.0.3-alpha 286 4/22/2022
0.0.2-alpha 137 4/14/2022
0.0.1-alpha 116 4/14/2022