Appendix B — plumber: The Missing Manual

B.1 Introduction

This is an appendix. I hope to not need this, but for now I’m planning to document things in plumber that aren’t well-documented by plumber itself. These are things that I had to dig through code to find.

B.2 Response Methods

The res object that’s available in most plumber functions is an R6 object defined in PlumberResponse. It has these public methods (partially documented in the Rendering Output Vignette:

  • setHeader(name, value)
  • toResponse() (hidden inputs: self$headers, self$body, self$status)
  • setCookie(name, value, path = NULL, expiration = FALSE, http = FALSE, secure = FALSE, same_site = FALSE)
    • Kinda documented in session_cookie() (and related docs), but it isn’t clear until you dig.
  • removeCookies(name, path = NULL, http = FALSE, secure = FALSE, same_site = FALSE, ...)
    • ... isn’t used
    • Sends a directive to expire the cookie “Thu, 01 Jan 1970 00:00:00 GMT”, which hopefully results in the cookie being deleted.