I use url-retrieve-synchronously to download a JSON file from a remote server. This function returns a buffer which contains the entire content of the response, including HTTP headers. However, I'm just interested in the body.

Now, short of parsing a HTTP response manually, how can I jump to the beginning of the body? I have found the variable url-http-end-of-headers, which works, but it's not documented at all, and using it feels “dirty”. Is there a proper API for this purpose?

3 Answers 3


With respect to a "proper API", I think the short answer, at present, is "no" -- unless you are willing to rely on an external library. url-http-end-of-headers seems to be as good as it gets, although it isn't mentioned in the URL Programmer's Manual nor does it appear to be documented in emacs source.


Since there is a newline after the HTTP headers, the only alternative I'm aware of is using a re-search-forward:

    (url-retrieve-synchronously my-url)
  (goto-char (point-min))
  (re-search-forward "^$")
  (delete-region (point) (point-min))
  • 1
    Well, that's “parsing HTTP” for me, and I think url-http-end-of-headers is preferable to this approach. I had really hoped for something like url-http-goto-body or so :(
    – user227
    Commented May 17, 2015 at 18:34

A higher-level alternative to using url-http-end-of-headers, but equally undocumented, is url-insert-file-contents:

  (json-parse-buffer :object-type 'alist))

or equivalently, prior to Emacs 27 compiled with native JSON support:

(require 'json)
  (let ((json-false :false))

These result in:

((items .
  [((tags .
     ["url" "http"])
     (reputation . 10741)
     (user_id . 227)
     (user_type . "registered")
     (accept_rate . 89)
     (profile_image . "https://i.sstatic.net/ebO5J.jpg?s=128&g=1")
     (display_name . "lunaryorn")
     (link . "https://emacs.stackexchange.com/users/227/lunaryorn"))
    (is_answered . t)
    (view_count . 867)
    (accepted_answer_id . 29798)
    (answer_count . 3)
    (score . 4)
    (last_activity_date . 1517363132)
    (creation_date . 1431861037)
    (question_id . 12464)
    (link . "https://emacs.stackexchange.com/questions/12464/go-to-body-after-url-retrieve-synchronously")
    (title . "Go to body after url-retrieve-synchronously"))])
 (has_more . :false)
 (quota_max . 300)
 (quota_remaining . 276))

The function url-insert-file-contents wraps the better-documented functions url-insert-buffer-contents and url-insert and thus comes with the following goodies:

  1. Autoloaded by default.
  2. Exists since at least as far back as Emacs 21.
  3. Simple HTTP response error handling via url-http-response-status.
  4. Decodes data.

FWIW, it also comes with the guarantee of being used by lisp/emacs-lisp/package.el.

  • I had a lot of trouble with using url-http-end-of-headers and I must say url-insert-file-contents is a much easier way, if all you care about is the payload. Thanks for the tip! Commented Feb 17, 2021 at 15:23
  • 1
    Is url-insert-file-contents synchronous like the url-retrieve-synchronously?
    – scribe
    Commented May 30, 2021 at 0:38
  • 1
    @scribe Yes, M-x find-function RET url-insert-file-contents RET reveals that url-retrieve-synchronously is the first thing that url-insert-file-contents does.
    – Basil
    Commented May 30, 2021 at 0:48

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