Note: these tuturials are for WebSync 2 only.

If you are using WebSync 3, you want our WebSync 3 tutorials.

WebSync 2 Tutorials

On-Demand:

Basic

On-Demand: Advanced

Take full control over your data by using private keys in conjunction with a WebSync proxy. With private keys, you can require that your server be used as the "middle-man" for any relevant WebSync requests while leaving the heavy-duty lifting for the WebSync servers themselves. This puts you in the driver's seat for any sort of permissions or access control you may want to implement.

Note that this tutorial is specific to .NET (C#), but the principles are the same for any language. For PHP, the proxy used in this tutorial is available as part of the WebSync On-Demand PHP download.

Prerequisites

You have completed the WebSync On-Demand: Basic tutorial.
You have completed the WebSync On-Demand: Proxies tutorial.

Configuring your project

Before you can start coding, you need to have the correct project references.

Add a reference to FM.WebSync.Core (available as part of the WebSync On-Demand .NET download).

Configuring the client

To start, the client has to send connect requests to the proxy and include some user credentials for us to authenticate.

Modify the HTML page created in the WebSync On-Demand: Basic tutorial.
1. Add a url property to the connect() call and specify the path to the proxy.
2. Add an ext property to the connect() call and specify an object with email and password properties.

client.connect({
    ...
    url: '/RequestProxy.aspx', // your proxy path
    ext: {
        email: 'jsmith@isp.com',
        password: 'websync'
    },
    ...
});

The data in ext will be available in the proxy for authentication.

Performing authentication in the proxy

Since you already have a proxy up and running, adding authentication is a breeze.

Modify the proxy created in the WebSync On-Demand: Proxies tutorial.
1. Pass in your private key as the second parameter to Proxy.Invoke().
2. Define an Ext class for the purpose of deserialization.
3. Iterate over the messages and check the ext property.

[DataContract]
private class Data
{
    [DataMember(Name = "text")]
    public string Text { get; set; }
}

[DataContract]
private class Ext
{
    [DataMember(Name = "email")]
    public string Email { get; set; }
    
    [DataMember(Name = "password")]
    public string Password { get; set; }
}

protected void Page_Load(object sender, EventArgs e)
{
    ProxyCallback callback = new ProxyCallback((args) =>
    {
        foreach (Message message in args.Messages)
        {
            if (message.IsPublish()) // type detection
            {
                // deserialize, modify, then reserialize the data
                Data data = JSON.Deserialize<Data>(message.Data);
                data.Text = data.Text.ToUpperInvariant();
                message.Data = JSON.Serialize(data);
            }
            
            if (message.IsConnect()) // type detection
            {
                // check for null credentials
                if (string.IsNullOrEmpty(message.Ext))
                {
                    message.Successful = false;
                    message.Error = "No user credentials supplied.";
                    continue;
                }

                // deserialize credentials
                Ext ext = JSON.Deserialize<Ext>(message.Ext);

                // verify password
                if (ext.Password != "websync")
                {
                    message.Successful = false;
                    message.Error = "Invalid password.";
                }
            }
        }
    });
    
    Proxy.Invoke(
        callback,
        "22222222-2222-2222-2222-222222222222" // your private key
    );
}

Any requests that go through this proxy will now undergo verification that the supplied password equals "websync". This is trival, of course. In a real scenario, you would likely load up a user record based on the email and check the individual password.

Configuring your domain

There is one final step, and that is to lock down any connect requests that slip around your proxy.

Visit the Portal and opt to require the private key for connect requests.

Only requests that use your private key (i.e. through your proxy) will now be allowed.

Testing

Open the page in a few browsers. Try changing the client password and refreshing the page to see the access denied.