Setting the Automatic Host Header

The Host header is a required header in the HTTP/1.1 protocol. The Host header specifies the hostname and port number of the target server for the request, ensuring that the server can correctly distinguish different domains on the same IP address and handle them accordingly. The framework provides a convenient method for setting it:

HttpRequestBuilder.Get("https://furion.net")    .AutoSetHostHeader();   // EnableHttpRequestBuilder.Get("https://furion.net")    .AutoSetHostHeader(false);   // Disable the automatic Host header

Once enabled, the Host: furion.net header is automatically added when sending an HTTP remote request.

Host Issues Caused by HttpClient Automatic Redirection

When sending an HTTP remote request, if the target server returns a redirect response (such as 301 Moved Permanently or 302 Found), the framework automatically follows the redirect by default. However, when the automatic Host header is enabled, you may encounter an issue where the Host header cannot be updated. In that case, you can disable the AllowAutoRedirect option so that the framework can handle redirection correctly:

// Configure the default clientservices.AddHttpClient(string.Empty)    .ConfigurePrimaryHttpMessageHandler(() => new SocketsHttpHandler    {        AllowAutoRedirect = false    });

In addition, to set the maximum number of redirections for the framework's built-in redirection behavior, you can use the following approach:

services.AddHttpRemote(builder => {})    .ConfigureOptions(options =>    {        MaximumAutomaticRedirections = 20;    });

This way, you can ensure that the redirection behavior meets expectations while avoiding incorrect Host header settings.