Sync Interceptor

The ISyncInterceptor interface lets you modify HTTP requests before they are sent during pull and push operations. The most common use case is adding authentication headers.

Implementing ISyncInterceptor

public class MySyncInterceptor : ISyncInterceptor
{
    readonly IAuthService _auth;

    public MySyncInterceptor(IAuthService auth)
    {
        _auth = auth;
    }

    public async Task BeforePull(Type documentType, DateTimeOffset lastRun, HttpRequestMessage request)
    {
        var token = await _auth.GetAccessTokenAsync();
        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
    }

    public async Task BeforePush(Type documentType, object[] items, HttpRequestMessage request)
    {
        var token = await _auth.GetAccessTokenAsync();
        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
    }
}

Registration

Register as a singleton in your DI container:

builder.Services.AddSingleton<ISyncInterceptor, MySyncInterceptor>();

Tip

Use ISyncInterceptor for auth headers rather than configuring the HttpClient directly — the interceptor is called per-request and can refresh tokens dynamically.

Parameters

Method	Parameters	Description
BeforePull	Type documentType — the entity type being pulled	Called before each pull HTTP request
	DateTimeOffset lastRun — when this entity type was last pulled
	HttpRequestMessage request — the outgoing request to modify
BeforePush	Type documentType — the entity type being pushed	Called before each push HTTP request
	object[] items — the entities about to be pushed
	HttpRequestMessage request — the outgoing request to modify