Implement automatic downloading facilities

- Fixes emacs-lsp#506

- Implemented base facilities for downloading and installing language servers
- added new field :download-server-fn in lsp--client structure which will be
called with (client callback update?).
- Implemented automatic installation via npm for jsts-ls and ts-ls.
- All servers(when feasible) should be installed under `lsp-server-install-dir`.

@akirak - check the cl-defgenerics in lsp-mode - let me know if they are
sufficient to implement the nix variands.

@razzmatazz - I have ported CSharp implementation but I havent converted it into
async.

@seagle0128 - lsp-python-ms is not ported. In general, it will work as it is but
it will ask to install the server even if you are in different file.

@TOTBWF - F# same as C#.

@kiennq powershell installation is converted to async one.

lsp-clients.el

@@ -158,14 +158,6 @@ This directory shoud contain a file matching groovy-language-server-*.jar"
   :group 'lsp-mode
   :link '(url-link "https://github.com/sourcegraph/javascript-typescript-langserver"))
 
-(defcustom lsp-clients-javascript-typescript-server "javascript-typescript-stdio"
-  "The javascript-typescript-stdio executable to use.
-Leave as just the executable name to use the default behavior of
-finding the executable with variable `exec-path'."
-  :group 'lsp-typescript-javascript
-  :risky t
-  :type 'file)
-
 (defcustom lsp-clients-typescript-javascript-server-args '()
   "Extra arguments for the typescript-language-server language server."
   :group 'lsp-typescript-javascript
@@ -179,13 +171,18 @@ finding the executable with variable `exec-path'."
 
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-stdio-connection (lambda ()
-                                                          (cons lsp-clients-javascript-typescript-server
+                                                          (cons (lsp-package-path :npm "javascript-typescript-langserver" ".bin/javascript-typescript-stdio")
                                                                 lsp-clients-typescript-javascript-server-args)))
                   :activation-fn 'lsp-typescript-javascript-tsx-jsx-activate-p
                   :priority -3
                   :completion-in-comments? t
-                  :ignore-messages '("readFile .*? requested by TypeScript but content not available")
-                  :server-id 'jsts-ls))
+                  :server-id 'jsts-ls
+                  :download-server-fn (lambda (_client callback _update?)
+                                        (lsp-package-ensure
+                                         :npm
+                                         "javascript-typescript-langserver"
+                                         (lambda (success? msg)
+                                           (funcall callback success? msg))))))
 
 
 ;;; TypeScript
@@ -194,14 +191,6 @@ finding the executable with variable `exec-path'."
   :group 'lsp-mode
   :link '(url-link "https://github.com/theia-ide/typescript-language-server"))
 
-(defcustom lsp-clients-typescript-server "typescript-language-server"
-  "The typescript-language-server executable to use.
-Leave as just the executable name to use the default behavior of
-finding the executable with variable `exec-path'."
-  :group 'lsp-typescript
-  :risky t
-  :type 'file)
-
 (defcustom lsp-clients-typescript-server-args '("--stdio")
   "Extra arguments for the typescript-language-server language server."
   :group 'lsp-typescript
@@ -232,16 +221,31 @@ directory containing the package. Example:
 
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-stdio-connection (lambda ()
-                                                          (cons lsp-clients-typescript-server
+                                                          (cons (lsp-package-path :npm
+                                                                                  "typescript-language-server"
+                                                                                  ".bin/typescript-language-server")
                                                                 lsp-clients-typescript-server-args)))
                   :activation-fn 'lsp-typescript-javascript-tsx-jsx-activate-p
                   :priority -2
                   :completion-in-comments? t
                   :initialization-options (lambda ()
                                             (list :plugins lsp-clients-typescript-plugins
-                                                  :logVerbosity lsp-clients-typescript-log-verbosity))
+                                                  :logVerbosity lsp-clients-typescript-log-verbosity
+                                                  :tsServerPath (lsp-package-path :npm "typescript" ".bin/tsserver")))
                   :ignore-messages '("readFile .*? requested by TypeScript but content not available")
-                  :server-id 'ts-ls))
+                  :server-id 'ts-ls
+                  :download-server-fn (lambda (_client callback _update?)
+                                        (lsp-package-ensure
+                                         :npm
+                                         "typescript"
+                                         (lambda (success? msg)
+                                           (if success?
+                                               (lsp-package-ensure
+                                                :npm
+                                                "typescript-language-server"
+                                                (lambda (success? msg)
+                                                  (funcall callback success? msg)))
+                                             (funcall success? msg)))))))
 
 
 
@@ -338,19 +342,18 @@ particular FILE-NAME and MODE."
 
 (defun lsp-php--create-connection ()
   "Create lsp connection."
-  (plist-put
-   (lsp-stdio-connection
-    (lambda () lsp-clients-php-server-command))
-   :test? (lambda ()
-            (if (and (cdr lsp-clients-php-server-command)
-                     (eq (string-match-p "php[0-9.]*\\'" (car lsp-clients-php-server-command)) 0))
-                ;; Start with the php command and the list has more elems. Test the existence of the PHP script.
-                (let ((php-file (nth 1 lsp-clients-php-server-command)))
-                  (or (file-exists-p php-file)
-                      (progn
-                        (lsp-log "%s is not present." php-file)
-                        nil)))
-              t))))
+  (lsp-stdio-connection
+   (lambda () lsp-clients-php-server-command)
+   (lambda ()
+     (if (and (cdr lsp-clients-php-server-command)
+              (eq (string-match-p "php[0-9.]*\\'" (car lsp-clients-php-server-command)) 0))
+         ;; Start with the php command and the list has more elems. Test the existence of the PHP script.
+         (let ((php-file (nth 1 lsp-clients-php-server-command)))
+           (or (file-exists-p php-file)
+               (progn
+                 (lsp-log "%s is not present." php-file)
+                 nil)))
+       t))))
 
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-php--create-connection)
@@ -390,7 +393,9 @@ particular FILE-NAME and MODE."
   "LSP support for OCaml, using ocaml-lsp-server."
   :group 'lsp-mode
   :link '(url-link "https://github.com/ocaml/ocaml-lsp"))
+
 (define-obsolete-variable-alias 'lsp-merlin 'lsp-ocaml-lsp-server)
+(define-obsolete-variable-alias 'lsp-merlin-command 'lsp-ocaml-lsp-server-command)
 
 (defcustom lsp-ocaml-lsp-server-command
   '("ocamllsp")
@@ -400,7 +405,6 @@ particular FILE-NAME and MODE."
           (string :tag "Single string value")
           (repeat :tag "List of string values"
                   string)))
-(define-obsolete-variable-alias 'lsp-merlin-command 'lsp-ocaml-lsp-server-command)
 
 (lsp-register-client
  (make-lsp-client
@@ -734,12 +738,11 @@ responsiveness at the cost of possibile stability issues."
 
 (defun lsp-clients-emmy-lua--create-connection ()
   "Create connection to emmy lua language server."
-  (plist-put
-   (lsp-stdio-connection
-    (lambda ()
-      (list lsp-clients-emmy-lua-java-path "-jar" lsp-clients-emmy-lua-jar-path)))
-   :test? (lambda ()
-            (f-exists? lsp-clients-emmy-lua-jar-path))))
+  (lsp-stdio-connection
+   (lambda ()
+     (list lsp-clients-emmy-lua-java-path "-jar" lsp-clients-emmy-lua-jar-path))
+   (lambda ()
+     (f-exists? lsp-clients-emmy-lua-jar-path))))
 
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-clients-emmy-lua--create-connection)

lsp-csharp.el

@@ -35,7 +35,7 @@ Version 1.34.3 minimum is required."
   :link '(url-link "https://github.com/OmniSharp/omnisharp-roslyn"))
 
 (defcustom lsp-csharp-server-install-dir
-  (locate-user-emacs-file ".cache/omnisharp-roslyn/")
+  (f-join lsp-server-install-dir "omnisharp-roslyn/")
   "Installation directory for OmniSharp Roslyn server."
   :group 'lsp-csharp
   :type 'directory)
@@ -163,14 +163,12 @@ available on github and if so, downloads and installs a newer version."
                                    (format "can be updated, currently installed version is %s" installed-version)
                                  "is not installed")
                                target-version)))
-              (let ((cache-dir (expand-file-name (locate-user-emacs-file ".cache/")))
-                    (o-r-dir (expand-file-name (locate-user-emacs-file ".cache/omnisharp-roslyn/")))
-                    (new-server-dir (lsp-csharp--server-dir target-version))
+              (let ((new-server-dir (lsp-csharp--server-dir target-version))
                     (new-server-bin (lsp-csharp--server-bin target-version))
                     (package-filename (lsp-csharp--server-package-filename))
                     (package-url (lsp-csharp--server-package-url target-version)))
 
-                (f-mkdir cache-dir o-r-dir new-server-dir)
+                (mkdir new-server-dir t)
 
                 (lsp-csharp--extract-server package-url
                                             (f-join new-server-dir package-filename)
@@ -242,13 +240,23 @@ Will attempt to install the server if it is not installed already for the
 current platform."
   (if lsp-csharp-server-path
       (list lsp-csharp-server-path "-lsp")
-    (list (lsp-csharp--get-or-install-server) "-lsp")))
+    (list (lsp-csharp--server-bin (lsp-csharp--latest-installed-version)) "-lsp")))
 
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-stdio-connection
-                                   #'lsp-csharp--language-server-command)
+                                   #'lsp-csharp--language-server-command
+                                   (lambda ()
+                                     (when-let (binary (lsp-csharp--server-bin (lsp-csharp--latest-installed-version)))
+                                       (f-exists? binary))))
+
                   :major-modes '(csharp-mode)
-                  :server-id 'csharp))
+                  :server-id 'csharp
+                  :download-server-fn (lambda (_client callback _update?)
+                                        (condition-case err
+                                            (progn
+                                              (lsp-csharp--install-server nil nil)
+                                              (funcall callback t nil))
+                                          (error (funcall callback nil (error-message-string err)))))))
 
 (provide 'lsp-csharp)
 ;;; lsp-csharp.el ends here

lsp-eslint.el

@@ -198,16 +198,14 @@
   (interactive)
   (lsp-send-execute-command "eslint.applyAllFixes" (vector (lsp--versioned-text-document-identifier))))
 
-
-
 (lsp-register-client
  (make-lsp-client
   :new-connection
-  (plist-put (lsp-stdio-connection
-              (lambda () lsp-eslint-server-command))
-             :test? (lambda ()
-                      (and (cl-second lsp-eslint-server-command)
-                           (file-exists-p (cl-second lsp-eslint-server-command)))))
+  (lsp-stdio-connection
+   (lambda () lsp-eslint-server-command)
+   (lambda ()
+     (and (cl-second lsp-eslint-server-command)
+          (file-exists-p (cl-second lsp-eslint-server-command)))))
   :activation-fn (lambda (filename &optional _)
                    (or (string-match-p (rx (one-or-more anything) "."
                                            (or "ts" "js" "jsx" "tsx" "html" "vue"))

lsp-fsharp.el

@@ -40,7 +40,7 @@
                  (const :tag "Use .Net Framework" net-framework))
   :package-version '(lsp-mode . "6.1"))
 
-(defcustom lsp-fsharp-server-install-dir (locate-user-emacs-file "fsautocomplete/")
+(defcustom lsp-fsharp-server-install-dir (f-join lsp-server-install-dir "fsautocomplete/")
   "Install directory for fsautocomplete server.
 The slash is expected at the end."
   :group 'lsp-fsharp
@@ -179,16 +179,7 @@ disable if `--backgorund-service-enabled' is not used"
                     ".exe")))
     (expand-file-name (concat "fsautocomplete" file-ext) lsp-fsharp-server-install-dir)))
 
-(defun lsp-fsharp--fsac-locate ()
-  "Return the location of the fsautocomplete langauge server."
-  (let ((fsac (lsp-fsharp--fsac-cmd)))
-    (unless (file-exists-p fsac)
-      (if (yes-or-no-p "Server is not installed. Do you want to install it?")
-          (lsp-fsharp--fsac-install)
-        (error "LSP F# cannot be started without FsAutoComplete Server")))
-    fsac))
-
-(defun lsp-fsharp--fsac-install ()
+(defun lsp-fsharp--fsac-install (_client callback _update?)
   "Download the latest version of fsautocomplete and extract it to `lsp-fsharp-server-install-dir'."
   (let* ((temp-file (make-temp-file "fsautocomplete" nil ".zip"))
          (install-dir-full (expand-file-name lsp-fsharp-server-install-dir))
@@ -197,18 +188,19 @@ disable if `--backgorund-service-enabled' is not used"
                              (t (user-error (format "Unable to unzip server - file %s cannot be extracted, please extract it manually" temp-file))))))
     (url-copy-file lsp-fsharp-server-download-url temp-file t)
     (shell-command unzip-script)
-    (shell-command (format "%s %s --version" (lsp-fsharp--fsac-runtime-cmd) (lsp-fsharp--fsac-cmd)))))
+    (shell-command (format "%s %s --version" (lsp-fsharp--fsac-runtime-cmd) (lsp-fsharp--fsac-cmd)))
+    (funcall callback t nil)))
 
 (defun lsp-fsharp-update-fsac ()
   "Update fsautocomplete to the latest version."
   (interactive)
   (-let [install-dir (f-expand lsp-fsharp-server-install-dir)]
     (f-delete install-dir t)
-    (lsp-fsharp--fsac-install)))
+    (lsp-fsharp--fsac-install nil #'ignore t)))
 
 (defun lsp-fsharp--make-launch-cmd ()
   "Build the command required to launch fsautocomplete."
-  (append (list (lsp-fsharp--fsac-runtime-cmd) (lsp-fsharp--fsac-locate) "--background-service-enabled")
+  (append (list (lsp-fsharp--fsac-runtime-cmd) (lsp-fsharp--fsac-cmd) "--background-service-enabled")
           lsp-fsharp-server-args))
 
 (defun lsp-fsharp--project-list ()
@@ -260,7 +252,9 @@ disable if `--backgorund-service-enabled' is not used"
    ("FSharp.EnableReferenceCodeLens" lsp-fsharp-enable-reference-code-lens t)))
 
 (lsp-register-client
- (make-lsp-client :new-connection (lsp-stdio-connection 'lsp-fsharp--make-launch-cmd)
+ (make-lsp-client :new-connection (lsp-stdio-connection
+                                   #'lsp-fsharp--make-launch-cmd
+                                   (lambda () (f-exists? (lsp-fsharp--fsac-cmd))))
                   :major-modes '(fsharp-mode)
                   :notification-handlers (ht ("fsharp/notifyCancel" #'ignore)
                                              ("fsharp/notifyWorkspace" #'ignore)
@@ -275,7 +269,8 @@ disable if `--backgorund-service-enabled' is not used"
                                          (lsp-configuration-section "fsharp"))
                                         (lsp-fsharp--workspace-load
                                          (lsp-fsharp--project-list)))))
-                  :server-id 'fsac))
+                  :server-id 'fsac
+                  :download-server-fn #'lsp-fsharp--fsac-install))
 
 (provide 'lsp-fsharp)
 ;;; lsp-fsharp.el ends here