How to use .NET CLR Types in Azure API Policy?

By default, Azure imports many basic .NET CLR (Common Language Runtime) types into the API policy execution environment. Imported .NET CLR types can be used in any "@(...)" expressions or "@{...}" expression blocks.

For example, the following "@{...}" expression block retrieves the request header "Authorization" value, performs Base64 decoding on the value, then returns it in UTF8 format:

@{   
    string value;   
    if (context.Request.Headers.TryGetValue("Authorization", out value)) {   
        return Encoding.UTF8.GetString(Convert.FromBase64String(value));
    } else {   
        return null;  
    }
}

Two .NET CLR types are used in the above expression block: "System.Encoding" and "System.Convert".

Here is list of all Imported .NET CLR types:

Newtonsoft.Json.Linq.*
System.Collections.Generic.*
System.Convert
System.DateTime
System.DateTimeKind
System.DateTimeOffset
System.Decimal
System.Double
System.Encoding
System.Guid
System.IEnumerable
System.IEnumerator
System.Int16
System.Int32
System.Int64
System.Linq.Enumerable
System.Math
System.MidpointRounding
System.Nullable
System.Random
System.SByte
System.Security.Cryptography.*
System.Single
System.String
System.StringSplitOptions
System.Text.*
System.TimeSpan
System.Tuple
System.UInt16
System.UInt32
System.UInt64
System.Uri
System.Xml.Linq.*
System.Xml.XmlNodeType

For more information on Imported .NET CLR types, see API Management policy expressions Website.

⇒ 'set-variable' Statement to Create Custom Variables

⇐ Dump Everything from 'context.Request'

⇑ Using Azure API Policy

⇑⇑ Microsoft Azure API Management Tutorials