Changing connection string at runtime for OData/WCF Data Service which uses basic authentication

4
votes

I have an ODATA services with a single schema. These point to a development database, and is served through a WCF Data Service which is then used by clients running Excel/Powerpivot to fetch their own data for reports and such.

The service is secured at runtime through pretty much the same basic authentication explained here: http://msdn.microsoft.com/en-us/data/gg192997

Now how this needs to work in the live environment is sit on the server and connect to different databases based on the username/password supplied. the Users will be typing in 'username@clientID' and 'password'. 'username@clientID' is then split() and username/password is checked against the SQL database. But the database server URL to check against will be determined by ClientID.

Also, once it is authorized the WCF data service needs to return data from the Database corresponding to the ClientID.

The approach I tried was to modify the connection string in the web.config file, but this doesn't work because it says the file is read-only. I'm not even sure if this would have worked at all. What I need to do is get the EDMX/WCF Data service to return the data from the correct database. Here's what I tried to do:

    private static bool TryAuthenticate(string user, string password, out IPrincipal principal)
    {

        Configuration myWebConfig = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
        myWebConfig.AppSettings.Settings["test"].Value = "Hello";
        myWebConfig.Save();

        string newConnStr = myWebConfig.ConnectionStrings.ConnectionStrings["IntelCorpEntities"].ToString();
        newConnStr.ToString().Replace("SERGEIX01", "SERVERX01");
        myWebConfig.ConnectionStrings.ConnectionStrings["IntelCorpEntities"].ConnectionString = newConnStr;            
        myWebConfig.Save();

        if (user.ToLower().Equals("admin") && password.Equals("password"))
        {
            principal = new GenericPrincipal(new GenericIdentity(user), new string[] { "Users" });
            return true;
        }
        else
        {
            principal = null;
            return false;
        }
    }
2
wcfauthenticationconnectionodataedmx

2 Answers

6
votes

In your DataService derived class override the CreateDataSource method and in it figure out the right connect string, create a new instance of the EF object context for the connection string and return it. The WCF DS Service will not use the default constructor on the EF object context then, it's completely up to you construct the instance with the right connection string.

1
votes

In your svc.cs file add following :

protected override NorthWindEntity CreateDataSource()
{
    System.Data.EntityClient.EntityConnection connection = new System.Data.EntityClient.EntityConnection();
    connection.ConnectionString = "";
    NorthWindEntity ctx = new NorthWindEntity(connection);
    return ctx;
}