Assembly scanning

By default all assemblies in the endpoint's bin directory are scanned in search of related interfaces so that the endpoint can configure them automatically.

Controlling the assemblies to scan

There are some cases where finer control over which assemblies are loaded is required:

• To limit the number of assemblies being scanned and hence provide improvements to startup time.
• If hosting multiple endpoints out of the same directory each endpoint may require a subset of assemblies to be loaded.

Nested Directories

Nested directories are not scanned for assemblies. Nested directory assembly scanning can be enabled using:

var scanner = endpointConfiguration.AssemblyScanner();
scanner.ScanAssembliesInNestedDirectories = true;

Assemblies to scan

An "Exclude a list" approach is used. This supports that the common scenario removing specific assemblies from scanning without the common side effect of accidentally excluding required assemblies.

Exclude a list approach

Exclude specific assemblies by name:

var scanner = endpointConfiguration.AssemblyScanner();
scanner.ExcludeAssemblies("MyAssembly1.dll", "MyAssembly2.dll");

Exclude assemblies by wildcard:

Multiple assemblies can be excluded by wildcards using the following approach:

var scanner = endpointConfiguration.AssemblyScanner();

var excludeRegexs = new List<string>
{
    @"App_Web_.*\.dll",
    @".*\.resources\.dll"
};

var baseDirectory = AppDomain.CurrentDomain.BaseDirectory;
foreach (var fileName in Directory.EnumerateFiles(baseDirectory, "*.dll")
    .Select(Path.GetFileName))
{
    foreach (var pattern in excludeRegexs)
    {
        if (Regex.IsMatch(fileName, pattern, RegexOptions.IgnoreCase))
        {
            scanner.ExcludeAssemblies(fileName);
            break;
        }
    }
}

Exclude specific types:

var scanner = endpointConfiguration.AssemblyScanner();
scanner.ExcludeTypes(type1, type2);

AppDomain assemblies

By default, the assemblies that are already loaded into the AppDomain, but are not present in the application's base directory, are not scanned. The endpoint can also be configured to scan the AppDomain assemblies:

var scanner = endpointConfiguration.AssemblyScanner();
scanner.ScanAppDomainAssemblies = true;

Suppress scanning exceptions

By default, exceptions occurred during assembly scanning will be re-thrown. Those exceptions can be ignored using the following:

var scanner = endpointConfiguration.AssemblyScanner();
scanner.ThrowExceptions = false;