Forwarded Headers PathBase extension

Nonstandard pathbase extension

Explicitly add ForwardedParameters.PathBase to Parameters to interpret pathbase; RFC 7239 itself does not define this parameter.

Forwarded: for=192.0.2.60;host="app.example.com:8443";proto=https;pathbase="/gateway"

The value replaces Request.PathBase using ASP.NET Core PathString URI conversion. It never appends to PathBase, strips a prefix from Request.Path, or rewrites Path. The proxy must already forward the intended application path. pathbase="" clears PathBase; a missing parameter leaves the staged value alone.

Use a rooted URI path and quote it as required by HTTP token syntax (a slash requires quoting). Network-path references (//host), non-rooted values, query/fragment suffixes, backslashes, invalid escapes, and controls are invalid. The extension follows the same trust, hop-limit, and error policies as the standard parameters. When disabled it is uninterpreted metadata. Neither X-Forwarded-Prefix nor X-Forwarded-PathBase is read.

ForwardedParameters.All excludes PathBase. See configuration, malformed input handling, and the runnable sample.