gptel-gh: Change how tokens are managed

Removed the file based persistent storage of the chat token.

Introduced overloadable function variables that determines how a token
is loaded and saved.

Author: marcus-lundgren

gptel-gh.el

@@ -180,26 +180,28 @@
 (cl-defstruct (gptel--gh (:include gptel-openai)
                          (:copier nil)
                          (:constructor gptel--make-gh))
-  token github-token sessionid machineid)
+  sessionid machineid)
 
 (defcustom gptel-gh-github-token-file (expand-file-name ".cache/copilot-chat/github-token"
                                                         user-emacs-directory)
   "File where the GitHub token is stored."
   :type 'string
   :group 'gptel)
 
-(defcustom gptel-gh-token-file (expand-file-name ".cache/copilot-chat/token"
-                                                 user-emacs-directory)
-  "File where the chat token is cached."
-  :type 'string
-  :group 'gptel)
+(defvar gptel-gh-github-token-load 'gptel--gh-restore-from-file
+  "Function to load the current github token.")
+
+(defvar gptel-gh-github-token-save 'gptel--gh-save-to-file
+  "Function to save the new github token.")
 
 (defconst gptel--gh-auth-common-headers
   `(("editor-plugin-version" . "gptel/*")
     ("editor-version" . ,(concat "emacs/" emacs-version))))
 
 (defconst gptel--gh-client-id "Iv1.b507a08c87ecfe98")
 
+(defvar gptel--gh-token nil "Variable that holds the chat token in memory")
+
 ;; https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_(random)
 (defun gptel--gh-uuid ()
   "Generate a UUID v4-1."
@@ -219,25 +221,25 @@
       (setq hex (nconc hex (list (aref hex-chars (random 16))))))
     (apply #'string hex)))
 
-(defun gptel--gh-restore (file)
-  "Restore saved object from FILE."
-  (when (file-exists-p file)
+(defun gptel--gh-restore-from-file ()
+  "Restore saved object from gptel-gh-github-token-file."
+  (when (file-exists-p gptel-gh-github-token-file)
     ;; We set the coding system to `utf-8-auto-dos' when reading so that
     ;; files with CR EOL can still be read properly
     (let ((coding-system-for-read 'utf-8-auto-dos))
       (with-temp-buffer
         (set-buffer-multibyte nil)
-        (insert-file-contents-literally file)
+        (insert-file-contents-literally gptel-gh-github-token-file)
         (goto-char (point-min))
         (read (current-buffer))))))
 
-(defun gptel--gh-save (file obj)
-  "Save OBJ to FILE."
+(defun gptel--gh-save-to-file (obj)
+   "Save OBJ to gptel--gh-save-to-file."
   (let ((print-length nil)
         (print-level nil)
         (coding-system-for-write 'utf-8-unix))
-    (make-directory (file-name-directory file) t)
-    (write-region (prin1-to-string obj) nil file nil :silent)
+    (make-directory (file-name-directory gptel-gh-github-token-file) t)
+    (write-region (prin1-to-string obj) nil gptel-gh-github-token-file nil :silent)
     obj))
 
 (defun gptel-gh-login ()
@@ -249,20 +251,7 @@ In SSH sessions, the URL and code will be displayed for manual entry
 instead of attempting to open a browser automatically."
   (interactive)
   ;; Determine which GitHub backend to use
-  (let ((gh-backend
-         (cond
-          ;; If current backend is GitHub, use it
-          ((and (boundp 'gptel-backend)
-                gptel-backend
-                (gptel--gh-p gptel-backend))
-           gptel-backend)
-          ;; Otherwise, find any GitHub backend
-          ((cl-find-if (lambda (b) (gptel--gh-p b))
-                       (mapcar #'cdr gptel--known-backends)))
-          ;; No GitHub backend found
-          (t (user-error "No GitHub Copilot backend found.  \
-Please set one up with `gptel-make-gh-copilot' first"))))
-        ;; Detect SSH sessions
+  (let (;; Detect SSH sessions
         (in-ssh-session (or (getenv "SSH_CLIENT")
                             (getenv "SSH_CONNECTION")
                             (getenv "SSH_TTY"))))
@@ -287,28 +276,24 @@ in your local browser, enter the code, and authorize.  Press ENTER after authori
          (format "Your one-time code %s is copied. \
 Press ENTER to open GitHub in your browser. \
 If your browser does not open automatically, browse to %s."
-                 user_code verification_uri))
-        (browse-url verification_uri)
-        (read-from-minibuffer "Press ENTER after authorizing. "))
-      ;; Use gh-backend for token storage
-      (thread-last
-        (plist-get
-         (gptel--url-retrieve
-             "https://github.com/login/oauth/access_token"
-           :method 'post
-           :headers gptel--gh-auth-common-headers
-           :data `( :client_id ,gptel--gh-client-id
-                    :device_code ,device_code
-                    :grant_type "urn:ietf:params:oauth:grant-type:device_code"))
-         :access_token)
-        (gptel--gh-save gptel-gh-github-token-file)
-        (setf (gptel--gh-github-token gh-backend))))
-    ;; Check gh-backend for success
-    (if (and (gptel--gh-github-token gh-backend)
-             (not (string-empty-p
-                   (gptel--gh-github-token gh-backend))))
-        (message "Successfully logged in to GitHub Copilot.")
-      (user-error "Error: You might not have access to GitHub Copilot Chat!"))))
+             user_code verification_uri))
+    (browse-url verification_uri)
+    (read-from-minibuffer "Press ENTER after authorizing."))
+    (thread-last
+      (plist-get
+       (gptel--url-retrieve
+           "https://github.com/login/oauth/access_token"
+         :method 'post
+         :headers gptel--gh-auth-common-headers
+         :data `( :client_id ,gptel--gh-client-id
+                  :device_code ,device_code
+                  :grant_type "urn:ietf:params:oauth:grant-type:device_code"))
+       :access_token)
+      (funcall gptel-gh-github-token-save))
+    (let ((github-token (funcall gptel-gh-github-token-load)))
+      (if (and github-token (not (string-empty-p github-token)))
+          (message "Successfully logged in to GitHub Copilot")
+        (user-error "Error: You might not have access to GitHub Copilot Chat!"))))))
 
 (defun gptel--gh-renew-token ()
   "Renew session token."
@@ -317,34 +302,22 @@ If your browser does not open automatically, browse to %s."
              "https://api.github.com/copilot_internal/v2/token"
            :method 'get
            :headers `(("authorization"
-                       . ,(format "token %s" (gptel--gh-github-token gptel-backend)))
+                       . ,(format "token %s" (funcall gptel-gh-github-token-load)))
                       ,@gptel--gh-auth-common-headers))))
     (if (not (plist-get token :token))
-        (progn
-          (setf (gptel--gh-github-token gptel-backend) nil)
-          (user-error "Error: You might not have access to GitHub Copilot Chat!"))
-      (thread-last
-        (gptel--gh-save gptel-gh-token-file token)
-        (setf (gptel--gh-token gptel-backend))))))
+        (user-error "Error: You might not have access to GitHub Copilot Chat!")
+      (setq gptel--gh-token token))))
 
 (defun gptel--gh-auth ()
   "Authenticate with GitHub Copilot API.
 
 We first need github authorization (github token).
 Then we need a session token."
-  (unless (gptel--gh-github-token gptel-backend)
-    (let ((token (gptel--gh-restore gptel-gh-github-token-file)))
-      (if token
-          (setf (gptel--gh-github-token gptel-backend) token)
-        (gptel-gh-login))))
-
-  (when (null (gptel--gh-token gptel-backend))
-    ;; try to load token from `gptel-gh-token-file'
-    (setf (gptel--gh-token gptel-backend)
-          (gptel--gh-restore gptel-gh-token-file)))
+  (unless (funcall gptel-gh-github-token-load)
+    (gptel-gh-login))
 
   (pcase-let (((map :token :expires_at)
-               (gptel--gh-token gptel-backend)))
+               gptel--gh-token))
     (when (or (null token)
               (and expires_at
                    (> (round (float-time)) expires_at)))
@@ -356,8 +329,7 @@ Then we need a session token."
           (header (lambda ()
                     (gptel--gh-auth)
                     `(("openai-intent" . "conversation-panel")
-                      ("authorization" . ,(concat "Bearer "
-                                           (plist-get (gptel--gh-token gptel-backend) :token)))
+                      ("authorization" . ,(concat "Bearer " (plist-get gptel--gh-token :token)))
                       ("x-request-id" . ,(gptel--gh-uuid))
                       ("vscode-sessionid" . ,(or (gptel--gh-sessionid gptel-backend) ""))
                       ("vscode-machineid" . ,(or (gptel--gh-machineid gptel-backend) ""))