public override async IAsyncEnumerable <Path> ComputePaths(EvaluationContext ctx)
{
_entityPaths ??= EntityCandidate.ComputePaths(ctx);
await foreach (var path in _entityPaths)
{
yield return(path.Append(PropertyName)); // <-- Best guess, since we don't know if the property is simple or nav
}
}
public override async IAsyncEnumerable <Path> ComputeSelect(EvaluationContext ctx)
{
await foreach (var select in EntityCandidate.ComputeSelect(ctx))
{
yield return(select);
}
_entityPaths ??= EntityCandidate.ComputePaths(ctx);
await foreach (var path in _entityPaths)
{
yield return(path.Append(PropertyName));
}
}
public override async Task <object> Evaluate(EvaluationContext ctx)
{
var entityCandidate = await EntityCandidate.Evaluate(ctx);
if (entityCandidate == null)
{
// Template property access implements null propagation out of the box
return(null);
}
if (entityCandidate is Entity entity)
{
if (entity is EntityWithKey entityWithKey && PropertyName == "Id")
{
return(entityWithKey.GetId());
}
var entityType = entity.GetType();
var propInfo = entityType.GetProperty(PropertyName);
if (propInfo == null || propInfo.GetCustomAttribute <NotMappedAttribute>() != null)
{
throw new TemplateException($"Property '{PropertyName}' does not exist on type {entityType.Name}.");
}
else if (!entity.EntityMetadata.TryGetValue(PropertyName, out FieldMetadata meta))
{
// Developer mistake
throw new InvalidOperationException($"Property '{PropertyName}' on type {entityType.Name} was not loaded correctly.");
}
else if (meta == FieldMetadata.Restricted)
{
throw new TemplateException($"Your account is not granted access to property '{PropertyName}' on type '{entityType.Name}'.");
}
else if (meta == FieldMetadata.Loaded)
{
return(propInfo.GetValue(entity));
}
else
{
// For future proofing
throw new InvalidOperationException($"Unknown FieldMetadata value '{meta}'.");
}
}
else
{
throw new TemplateException($"Property access '.{PropertyName}' is only valid on model entities.");
}
}
