Delete trailing white space from all projectile project files

Question

Problem

So the problem is pretty straight forward I'm just trying to get delete trailing spaces from all files in a projectile project.

Here's what I've tried so far:

(defun projectile-delete-trailing-white-spaces-from-project-files ()
  "Deletes trailing spaces from all projectile project files."
  (interactive)
  (let* ((list (projectile-current-project-files))
         (buffer (car list)))
    (while buffer
      (message buffer)
      (when
        (when (file-exists-p buffer)
          (set-buffer (find-file-noselect buffer))
          (delete-trailing-whitespace) ;; <-- This isn't working?
          (save-buffer))               ;; <-- This isn't working?
        (setq list (cdr list))
        (setq buffer (car list))
        ))))

Answer 1

Adjusting Jack's answer slightly:

(defun projectile-whitespace-cleanup-project-files ()
  "Run `whitespace-cleanup' on all project files."
  (interactive)
  (dolist (file (projectile-current-project-files))
    (let ((path (concat (projectile-project-root) file)
          (buffer (find-file-noselect path)))
      (when buffer
        (with-current-buffer buffer
          (whitespace-cleanup)
          (save-buffer)
          (kill-buffer)))))

Answer 2

This works for me:

(defun projectile-delete-trailing-white-spaces-from-project-files ()
  "Deletes trailing spaces from all projectile project files."
  (interactive)
  (let ((project-files (projectile-current-project-files)))
    (dolist (pr project-files)
      (when (file-exists-p pr)
        (message "clearing trailing whitespace in %s" pr)
        (with-temp-buffer
          (insert-file-contents pr)
          (delete-trailing-whitespace (point-min) (point-max))
          (write-file pr))))))

Although not certain it's the best way to do it.