/// <summary>
/// Create the .NET class for a particular projection type from its name
/// </summary>
/// <param name="projectionName">
/// The "business" name of the projection to map to a .NET class
/// </param>
public IProjection CreateProjectionClass(string projectionName)
{
if (string.IsNullOrWhiteSpace(projectionName))
{
// No idea what projection is being sought
return(null);
}
if (AllMaps.ContainsKey(projectionName))
{
return(AllMaps[projectionName].CreateProjectionClass());
}
else
{
// maybe the projection name already is the .NET class (bad practice)
var type = Type.GetType(projectionName, false);
if (null == type)
{
if (!EventMaps.TryFindType(projectionName, out type))
{
// Unable to create an event class for the name
return(null);
}
}
if (null != type)
{
return((IProjection)Activator.CreateInstance(type));
}
}
// Unable to create an event class for the name
return(null);
}
/// <summary>
/// Create an event map that is the default for this application
/// </summary>
/// <remarks>
/// This uses both the configuration and reflection to build the maps - if you need faster
/// spin-up you should create a hard-coded map and use dependency injection to load it
/// </remarks>
public static IEventMaps CreateDefaultEventMaps()
{
if (null == _defaultEventMaps)
{
_defaultEventMaps = new EventMaps();
_defaultEventMaps.LoadFromConfig();
_defaultEventMaps.LoadByReflection();
}
return(_defaultEventMaps);
}
/// <summary>
/// Load the projection maps as stored in any configuration files
/// </summary>
public void LoadFromConfig(string basePath = null)
{
if (string.IsNullOrWhiteSpace(basePath))
{
basePath = Environment.GetEnvironmentVariable("AzureWebJobsScriptRoot") // local_root
?? (Environment.GetEnvironmentVariable("HOME") == null
? Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)
: $"{Environment.GetEnvironmentVariable("HOME")}/site/wwwroot"); // azure_root
}
ConfigurationBuilder builder = new ConfigurationBuilder();
if (!string.IsNullOrWhiteSpace(basePath))
{
builder.SetBasePath(basePath);
}
builder.AddJsonFile("appsettings.json", true)
.AddJsonFile("config.local.json", true)
.AddJsonFile("config.json", true)
.AddJsonFile("connectionstrings.json", true)
.AddEnvironmentVariables();
IConfigurationRoot config = builder.Build();
// Get the [ProjectionMaps] section
IConfigurationSection projectionMapSection = config.GetSection("ProjectionMaps");
if (null != projectionMapSection)
{
if (projectionMapSection.Exists())
{
var configProjectionMaps = projectionMapSection.Get <List <ProjectionMap> >(c => c.BindNonPublicProperties = true);
if (null != configProjectionMaps)
{
foreach (ProjectionMap map in configProjectionMaps)
{
if (null != map)
{
if (!AllMaps.ContainsKey(map.ProjectionName))
{
Type eventType = null;
if (EventMaps.TryFindType(map.ProjectionImplementationClassName, out eventType))
{
AllMaps.Add(map.ProjectionName,
new ProjectionMap(map.ProjectionName, eventType.FullName));
}
}
}
}
}
}
}
}
public IProjection CreateProjectionClass()
{
if (!string.IsNullOrWhiteSpace(ProjectionImplementationClassName))
{
Type typeRet;
if (EventMaps.TryFindType(ProjectionImplementationClassName, out typeRet))
{
return((IProjection)(Activator.CreateInstance(typeRet)));
}
}
// Could not create any instance
return(null);
}
