在输出标头之前获取WordPress元数据值

Question

I'm writing a sort of 301 redirecting plugin for WordPress, which adds a metabox for each page, where you can enter a URL you want to redirect that page to. The value of this field has to be obtained before the header is output or else it's too late to redirect. Is it possible to get a metabox value before the header is output? How?

Answer 1

The ideal place to do this is with a hook into the template_redirect action. The WP object is already set up, and no output has been generated yet.