How do you hash a string in a PCL project? - xamarin

Question

We've tried using this library: http://msdn.microsoft.com/en-us/library/system.security.cryptography.hashalgorithm(v=vs.110).aspx
And this code:
public static byte[] GetHash(string inputString)
{
HashAlgorithm algorithm = SHA1.Create(); // SHA1.Create()
return algorithm.ComputeHash(Encoding.UTF8.GetBytes(inputString));
}
public static string GetHashString(string inputString)
{
StringBuilder sb = new StringBuilder();
foreach (byte b in GetHash(inputString))
sb.Append(b.ToString("X2"));
return sb.ToString();
}
But the library doesn't seem to be available.

Answer 1

In case certain API is not available in PCL, you would normally create an interface of and inject it in the constructor.
In your example, it would be something like this
PCL library project
public interface IHashService
{
byte[] ComputeHash(byte[] data)
}
Platform specific project
public class Sha1HashService : IHashService
{
public ComputeHash(byte[] data)
{
using(var algorithm = SHA1.Create())
{
var result = algorithm.ComputeHash(data);
return result;
}
}
}
It is good practice not to use static methods and use a dependency injection whenever possible.
Also you probably want your interface to be more generic (takes bytes as an argument) rather than a string, for the very same reason (dependency on the Encoding.UTF8.GetBytes).