fix(nextflow): Improve async download of large files

Avoids hanging and blocking the UI on large files
This doesn't happen with small files (1.9MB Magik) but does happen with
large files (12.6MB Nextflow)

Author: edmundmiller

clients/lsp-nextflow.el

@@ -21,8 +21,6 @@
 ;;; Commentary:
 
 ;; LSP Clients for the Nextflow Programming Language.
-;;
-;; The language server JAR will be automatically downloaded from GitHub releases.
 
 ;;; Code:
 
@@ -61,29 +59,9 @@
   :type 'file
   :package-version '(lsp-mode . "9.0.0"))
 
-(defun lsp-nextflow--async-download (callback error-callback)
-  "Asynchronously download Nextflow language server JAR file."
-  (let ((download-buffer (url-retrieve 
-                          lsp-nextflow-server-download-url
-                          (lambda (status callback error-callback)
-                            (if (plist-get status :error)
-                                (progn
-                                  (message "Nextflow LSP download failed: %s" (plist-get status :error))
-                                  (funcall error-callback (plist-get status :error)))
-                              (unwind-protect
-                                  (progn
-                                    (goto-char (point-min))
-                                    (re-search-forward "\n\n" nil 'noerror)
-                                    (let ((jar-content (buffer-substring (point) (point-max))))
-                                      (mkdir (f-parent lsp-nextflow-server-file) t)
-                                      (with-temp-file lsp-nextflow-server-file
-                                        (set-buffer-file-coding-system 'binary)
-                                        (insert jar-content))
-                                      (message "Nextflow LSP download completed: %s" lsp-nextflow-server-file)
-                                      (funcall callback)))
-                                (kill-buffer (current-buffer)))))
-                          (list callback error-callback))))
-    (message "Downloading Nextflow LSP server from %s..." lsp-nextflow-server-download-url)))
+(lsp-dependency 'nextflow-language-server
+                `(:download :url lsp-nextflow-server-download-url
+                           :store-path lsp-nextflow-server-file))
 
 (defun lsp-nextflow-server-command ()
   "Startup command for Nextflow language server."
@@ -140,7 +118,7 @@ find Java automatically."
 (lsp-register-client
  (make-lsp-client
   :download-server-fn (lambda (_client callback error-callback _update?)
-                        (lsp-nextflow--async-download callback error-callback))
+                        (lsp-package-ensure 'nextflow-language-server callback error-callback))
   :new-connection (lsp-stdio-connection
                    (lambda ()
                      (list

lsp-mode.el

@@ -8468,6 +8468,72 @@ nil."
 
 
 ;; Download URL handling
+
+(defun lsp-download-install--url-retrieve (url file callback error-callback)
+  "Download URL to FILE using url-retrieve asynchronously.
+Call CALLBACK on success or ERROR-CALLBACK on failure."
+  (url-retrieve
+   url
+   (lambda (status &rest args)
+     (cond
+      ;; Check for errors
+      ((plist-get status :error)
+       (lsp--error "Download failed: %s" (plist-get status :error))
+       (funcall error-callback (plist-get status :error)))
+
+      ;; Success - save to file
+      (t
+       (condition-case err
+           (progn
+             ;; Move past HTTP headers
+             (goto-char (point-min))
+             (re-search-forward "\n\n" nil t)
+
+             ;; Write content to file
+             (let ((coding-system-for-write 'binary))
+               (write-region (point) (point-max) file nil 'silent))
+
+             ;; Clean up and call success callback
+             (kill-buffer)
+             (funcall callback))
+         (error
+          (lsp--error "Failed to save downloaded file: %s" err)
+          (funcall error-callback err))))))
+   nil 'silent 'inhibit-cookies))
+
+(defun lsp-download-install--verify-signature (main-url main-file asc-url pgp-key)
+  "Verify GPG signature for MAIN-FILE.
+Download signature from ASC-URL and verify with PGP-KEY.
+This is a synchronous operation that should be called after the main download."
+  (if (executable-find epg-gpg-program)
+      (let ((asc-download-path (concat main-file ".asc"))
+            (context (epg-make-context))
+            (fingerprint)
+            (signature))
+        (when (f-exists? asc-download-path)
+          (f-delete asc-download-path))
+
+        ;; Download signature file - using synchronous download for simplicity
+        ;; since signature files are typically very small
+        (lsp--info "Downloading signature from %s..." asc-url)
+        (url-copy-file asc-url asc-download-path)
+        (lsp--info "Downloaded signature file")
+
+        ;; Import and verify
+        (epg-import-keys-from-string context pgp-key)
+        (setq fingerprint (epg-import-status-fingerprint
+                           (car
+                            (epg-import-result-imports
+                             (epg-context-result-for context 'import)))))
+        (lsp--info "Verifying signature %s..." asc-download-path)
+        (epg-verify-file context asc-download-path main-file)
+        (setq signature (car (epg-context-result-for context 'verify)))
+        (unless (and
+                 (eq (epg-signature-status signature) 'good)
+                 (equal (epg-signature-fingerprint signature) fingerprint))
+          (error "Failed to verify GPG signature: %s" (epg-signature-to-string signature))))
+    (lsp--warn "GPG is not installed, skipping the signature check.")))
+
 (cl-defun lsp-download-install (callback error-callback &key url asc-url pgp-key store-path decompress &allow-other-keys)
   (let* ((url (lsp-resolve-value url))
          (store-path (lsp-resolve-value store-path))
@@ -8479,52 +8545,44 @@ nil."
             (:targz (concat store-path ".tar.gz"))
             (`nil store-path)
             (_ (error ":decompress must be `:gzip', `:zip', `:targz' or `nil'")))))
-    (make-thread
+    ;; Clean up any existing files
+    (when (f-exists? download-path)
+      (f-delete download-path))
+    (when (and (f-exists? store-path) (not (equal download-path store-path)))
+      (f-delete store-path))
+
+    ;; Create parent directory if needed
+    (mkdir (f-parent download-path) t)
+
+    ;; Start async download
+    (lsp--info "Starting to download %s to %s..." url download-path)
+    (lsp-download-install--url-retrieve
+     url
+     download-path
      (lambda ()
+       ;; Success handler - continue with decompression and verification
+       (lsp--info "Finished downloading %s..." download-path)
        (condition-case err
            (progn
-             (when (f-exists? download-path)
-               (f-delete download-path))
-             (when (f-exists? store-path)
-               (f-delete store-path))
-             (lsp--info "Starting to download %s to %s..." url download-path)
-             (mkdir (f-parent download-path) t)
-             (url-copy-file url download-path)
-             (lsp--info "Finished downloading %s..." download-path)
+             ;; Handle signature verification if requested
              (when (and lsp-verify-signature asc-url pgp-key)
-               (if (executable-find epg-gpg-program)
-                   (let ((asc-download-path (concat download-path ".asc"))
-                         (context (epg-make-context))
-                         (fingerprint)
-                         (signature))
-                     (when (f-exists? asc-download-path)
-                       (f-delete asc-download-path))
-                     (lsp--info "Starting to download %s to %s..." asc-url asc-download-path)
-                     (url-copy-file asc-url asc-download-path)
-                     (lsp--info "Finished downloading %s..." asc-download-path)
-                     (epg-import-keys-from-string context pgp-key)
-                     (setq fingerprint (epg-import-status-fingerprint
-                                        (car
-                                         (epg-import-result-imports
-                                          (epg-context-result-for context 'import)))))
-                     (lsp--info "Verifying signature %s..." asc-download-path)
-                     (epg-verify-file context asc-download-path download-path)
-                     (setq signature (car (epg-context-result-for context 'verify)))
-                     (unless (and
-                              (eq (epg-signature-status signature) 'good)
-                              (equal (epg-signature-fingerprint signature) fingerprint))
-                       (error "Failed to verify GPG signature: %s" (epg-signature-to-string signature))))
-                 (lsp--warn "GPG is not installed, skipping the signature check.")))
+               (lsp-download-install--verify-signature url download-path asc-url pgp-key))
+
+             ;; Handle decompression if needed
              (when decompress
                (lsp--info "Decompressing %s..." download-path)
                (pcase decompress
-                 (:gzip
-                  (lsp-gunzip download-path))
+                 (:gzip (lsp-gunzip download-path))
                  (:zip (lsp-unzip download-path (f-parent store-path)))
                  (:targz (lsp-tar-gz-decompress download-path (f-parent store-path))))
                (lsp--info "Decompressed %s..." store-path))
+
+             ;; Call success callback
              (funcall callback))
-         (error (funcall error-callback err)))))))
+         (error
+          (lsp--error "Error in post-download processing: %s" err)
+          (funcall error-callback err))))
+     error-callback)))
 
 (cl-defun lsp-download-path (&key store-path binary-path set-executable? &allow-other-keys)
   "Download URL and store it into STORE-PATH.