Transforms.md

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Transformation introduction

Model values can be transformed by your own custom implementation of IModelTransformer or one of the ones we created.

System Transformers

System transformers will help us transform model with commonly used values. Enable it with the following:

builder.UseSystemModelTransformers();

See below for a list of System transformers.

AutoId

AutoId will generated a GUID for a field such as a key field. Use the following code to enable AutoId on your field.

[AutoId]
[Key]
[Description("Id")]
public string Id { get; set; }

Use a placeholder value @ in place of a replacement value.

AutoDateTime.

AutoDateTime will generated a current UTC date for your DateTime field. Use the following code to enable AutoDate on your field.

[AutoDateTime(AutoDateTimeTypes.UtcToday)]
[ModelField(false)]
[Description("FieldDateTimeToday")]
public DateTime FieldDateTimeToday { get; set; }

ValueFromRequestContextGenerator

ValueFromRequestContextGenerator will pull some values from the request context to populate. Use the following code to

builder.UseValueFromRequestContextGenerator();

In order to leverage ValueFromRequestContextGenerator, you will need to implement IRequestContextValueExtractor interface. An example of the interface implementation is below.

public class TrustFrameworkPolicyRequestContextValueExtractor : IRequestContextValueExtractor
{
	public Task<object> GetValueAsync(IGraphRequestContext graphRequestContext, Member member)
	{
		if (graphRequestContext.HttpRequest.Security != null)
		{
			var tfpClaim = graphRequestContext.HttpRequest.Security.ClaimsPrincipal.FindFirst(x => x.Type == "tfp");
			if (tfpClaim != null)
			{
				return Task.FromResult((object) tfpClaim.Value);
			}
		}

		throw new InvalidOperationException("Unable to get Trust Framework Policy (tfp) claim.");
	}
}

You can enable your custom implementation on the field.

[RequestContextValue(typeof(TrustFrameworkPolicyRequestContextValueExtractor))]
[ModelField(false)]
[Description("FieldFromTrustFrameworkPolicy")]
public string FieldFromTrustFrameworkPolicy { get; set; }