DocumentDB .Net client using connection string

I created a class for parsing connection string similar to how the CloudStorageAccount.Parse works. I tried to follow their pattern as closely as possible in case they ever decide to open source it, this could hopefully be contribed without much change.

public static class DocumentDbAccount
{
    public static DocumentClient Parse(string connectionString)
    {
        DocumentClient ret;

        if (String.IsNullOrWhiteSpace(connectionString))
        {
            throw new ArgumentException("Connection string cannot be empty.");
        }

        if(ParseImpl(connectionString, out ret, err => { throw new FormatException(err); }))
        {
            return ret;
        }

        throw new ArgumentException($"Connection string was not able to be parsed into a document client.");
    }

    public static bool TryParse(string connectionString, out DocumentClient documentClient)
    {
        if (String.IsNullOrWhiteSpace(connectionString))
        {
            documentClient = null;
            return false;
        }

        try
        {
            return ParseImpl(connectionString, out documentClient, err => { });
        }
        catch (Exception)
        {
            documentClient = null;
            return false;
        }
    }

    private const string AccountEndpointKey = "AccountEndpoint";
    private const string AccountKeyKey = "AccountKey";
    private static readonly HashSet<string> RequireSettings = new HashSet<string>(new [] { AccountEndpointKey, AccountKeyKey }, StringComparer.OrdinalIgnoreCase);

    internal static bool ParseImpl(string connectionString, out DocumentClient documentClient, Action<string> error)
    {
        IDictionary<string, string> settings = ParseStringIntoSettings(connectionString, error);

        if (settings == null)
        {
            documentClient = null;
            return false;
        }

        if (!RequireSettings.IsSubsetOf(settings.Keys))
        {
            documentClient = null;
            return false;
        }

        documentClient = new DocumentClient(new Uri(settings[AccountEndpointKey]), settings[AccountKeyKey]);
        return true;
    }

    /// <summary>
    /// Tokenizes input and stores name value pairs.
    /// </summary>
    /// <param name="connectionString">The string to parse.</param>
    /// <param name="error">Error reporting delegate.</param>
    /// <returns>Tokenized collection.</returns>
    private static IDictionary<string, string> ParseStringIntoSettings(string connectionString, Action<string> error)
    {
        IDictionary<string, string> settings = new Dictionary<string, string>();
        string[] splitted = connectionString.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);

        foreach (string nameValue in splitted)
        {
            string[] splittedNameValue = nameValue.Split(new char[] { '=' }, 2);

            if (splittedNameValue.Length != 2)
            {
                error("Settings must be of the form \"name=value\".");
                return null;
            }

            if (settings.ContainsKey(splittedNameValue[0]))
            {
                error(string.Format(CultureInfo.InvariantCulture, "Duplicate setting '{0}' found.", splittedNameValue[0]));
                return null;
            }

            settings.Add(splittedNameValue[0], splittedNameValue[1]);
        }

        return settings;
    }
}

You can actually do this in a roundabout way.

internal class CosmosDBConnectionString
{
    public CosmosDBConnectionString(string connectionString)
    {
        // Use this generic builder to parse the connection string
        DbConnectionStringBuilder builder = new DbConnectionStringBuilder
        {
            ConnectionString = connectionString
        };

        if (builder.TryGetValue("AccountKey", out object key))
        {
            AuthKey = key.ToString();
        }

        if (builder.TryGetValue("AccountEndpoint", out object uri))
        {
            ServiceEndpoint = new Uri(uri.ToString());
        }
    }

    public Uri ServiceEndpoint { get; set; }

    public string AuthKey { get; set; }
}

Then

var cosmosDBConnectionString = new CosmosDBConnectionString(connectionString)
var client = new DocumentClient(
            cosmosDBConnectionString.ServiceEndpoint,
            cosmosDBConnectionString.AuthKey)

This is taken from the Azure WebJobs Extensions SDK, which is how Azure Functions V2 is able to work with just a connection string. Saves having to try and parse the string yourself.