bug#29565: [PATCH] Support file download and upload (Bug#29565)

[Jaesup Kwak <veshboo@gmail.com>]

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For the MIME types, which ns xwidget webkit cannot show in a view,
'xwidget-webkit-save-as-file' is called via 'response-callback' event.

Ns xwidget webkit presents file open panel to select upload files.

Tighter check for javascript availability.

* lisp/xwidget.el
(xwidget-webkit-callback): Add case for 'response-callback' event.
(xwidget-webkit-download-dir): New variable.
(xwidget-webkit-save-as-file): New function.
* src/nsxwidget.m
(XwWebView::decidePolicyForNavigationResponse): Store the event.  And
tighter check for javascript availability.
(XwWebView::runOpenPanelWithParameters): Select upload files.
* src/xwidget.c
(store_xwidget_response_callback_event): New function.

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From b5e3db090f43734c365f86d92cae1107f8df5398 Mon Sep 17 00:00:00 2001
From: Jaesup Kwak <veshboo@gmail.com>
Date: Thu, 21 Dec 2017 12:36:51 +0900
Subject: [PATCH] Support file download and upload (Bug#29565)

For the MIME types, which ns xwidget webkit cannot show in a view,
'xwidget-webkit-save-as-file' is called via 'response-callback' event.

Ns xwidget webkit presents file open panel to select upload files.

Tighter check for javascript availability.

* lisp/xwidget.el
(xwidget-webkit-callback): Add case for 'response-callback' event.
(xwidget-webkit-download-dir): New variable.
(xwidget-webkit-save-as-file): New function.
* src/nsxwidget.m
(XwWebView::decidePolicyForNavigationResponse): Store the event.  And
tighter check for javascript availability.
(XwWebView::runOpenPanelWithParameters): Select upload files.
* src/xwidget.c
(store_xwidget_response_callback_event): New function.
---
 lisp/xwidget.el | 23 +++++++++++++++++++++++
 src/nsxwidget.m | 36 ++++++++++++++++++++++++++++++++++--
 src/xwidget.c   | 20 ++++++++++++++++++++
 3 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/lisp/xwidget.el b/lisp/xwidget.el
index 901a6be9a2..6c88262e43 100644
--- a/lisp/xwidget.el
+++ b/lisp/xwidget.el
@@ -84,6 +84,7 @@ xwidget-at
 (require 'browse-url)
 (require 'image-mode);;for some image-mode alike functionality
 (require 'seq)
+(require 'url-handlers)
 
 ;;;###autoload
 (defun xwidget-webkit-browse-url (url &optional new-session)
@@ -289,6 +290,12 @@ xwidget-webkit-callback
                    (xwidget-webkit-show-id-or-named-element
                     xwidget
                     (match-string 1 strarg)))))
+;;; TODO: Response handling other than download.
+            ((eq xwidget-event-type 'response-callback)
+             (let ((url  (nth 3 last-input-event))
+                   (mime-type (nth 4 last-input-event))
+                   (file-name (nth 5 last-input-event)))
+               (xwidget-webkit-save-as-file xwidget url mime-type file-name)))
             ((eq xwidget-event-type 'javascript-callback)
              (let ((proc (nth 3 last-input-event))
                    (arg  (nth 4 last-input-event)))
@@ -317,6 +324,22 @@ xwidget-webkit-mode
     ;; Keep track of [vh]scroll when switching buffers
     (image-mode-setup-winprops))
 
+;;; Download, save as file.
+
+(defvar xwidget-webkit-download-dir "~/Downloads/"
+  "Directory where download file saved.")
+
+(defun xwidget-webkit-save-as-file (xwidget url mime-type &optional file-name)
+  "For XWIDGET webkit, save URL resource of MIME-TYPE as FILE-NAME."
+  (ignore xwidget) ;; Not used currently
+  (let ((save-name (read-file-name
+                    (format "Save '%s' file as: " mime-type)
+                    xwidget-webkit-download-dir file-name nil file-name)))
+    (if (file-directory-p save-name)
+        (setq save-name (concat (file-name-as-directory save-name) file-name)))
+    (setq xwidget-webkit-download-dir (file-name-directory save-name))
+    (url-copy-file url save-name t)))
+
 ;;; Bookmarks integration
 
 (defvar xwidget-webkit-bookmark-jump-new-session nil
diff --git a/src/nsxwidget.m b/src/nsxwidget.m
index ee295518b8..22baaecedf 100644
--- a/src/nsxwidget.m
+++ b/src/nsxwidget.m
@@ -33,6 +33,11 @@ void store_xwidget_event_string (struct xwidget *xw,
                                  const char *eventname,
                                  const char *eventstr);
 
+void store_xwidget_response_callback_event (struct xwidget *xw,
+                                            const char *url,
+                                            const char *mimetype,
+                                            const char *filename);
+
 void store_xwidget_js_callback_event (struct xwidget *xw,
                                       Lisp_Object proc,
                                       Lisp_Object argument);
@@ -142,7 +147,15 @@ - (void)webView:(WKWebView *)webView
 {
   if (!navigationResponse.canShowMIMEType)
     {
-      /* TODO: download using NSURLxxx?  */
+      NSString *url = navigationResponse.response.URL.absoluteString;
+      NSString *mimetype = navigationResponse.response.MIMEType;
+      NSString *filename = navigationResponse.response.suggestedFilename;
+      decisionHandler (WKNavigationResponsePolicyCancel);
+      store_xwidget_response_callback_event (self.xw,
+                                             url.UTF8String,
+                                             mimetype.UTF8String,
+                                             filename.UTF8String);
+      return;
     }
   decisionHandler (WKNavigationResponsePolicyAllow);
 
@@ -157,7 +170,10 @@ - (void)webView:(WKWebView *)webView
         {
           /* TODO: Sloppy parsing of 'Content-Security-Policy' value.  */
           NSRange sandbox = [value rangeOfString:@"sandbox"];
-          if (sandbox.location != NSNotFound)
+          if (sandbox.location != NSNotFound
+              && (sandbox.location == 0
+                  || [value characterAtIndex:(sandbox.location - 1)] == ' '
+                  || [value characterAtIndex:(sandbox.location - 1)] == ';'))
             {
               NSRange allowScripts = [value rangeOfString:@"allow-scripts"];
               if (allowScripts.location == NSNotFound
@@ -181,6 +197,22 @@ - (WKWebView *)webView:(WKWebView *)webView
   return nil;
 }
 
+/* Open panel for file upload.  */
+- (void)webView:(WKWebView *)webView
+runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters
+initiatedByFrame:(WKFrameInfo *)frame
+completionHandler:(void (^)(NSArray<NSURL *> *URLs))completionHandler
+{
+  NSOpenPanel *openPanel = [NSOpenPanel openPanel];
+  openPanel.canChooseFiles = YES;
+  openPanel.canChooseDirectories = NO;
+  openPanel.allowsMultipleSelection = parameters.allowsMultipleSelection;
+  if ([openPanel runModal] == NSModalResponseOK)
+    completionHandler (openPanel.URLs);
+  else
+    completionHandler (nil);
+}
+
 /* By forwarding mouse events to emacs view (frame)
    - Mouse click in webview selects the window contains the webview.
    - Correct mouse hand/arrow/I-beam is displayed (TODO: not perfect yet).
diff --git a/src/xwidget.c b/src/xwidget.c
index 60e8260377..c6a8218c56 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -255,6 +255,26 @@ store_xwidget_event_string (struct xwidget *xw, const char *eventname,
   kbd_buffer_store_event (&event);
 }
 
+void
+store_xwidget_response_callback_event (struct xwidget *xw,
+                                       const char *url,
+                                       const char *mimetype,
+                                       const char *filename)
+{
+  struct input_event event;
+  Lisp_Object xwl;
+  XSETXWIDGET (xwl, xw);
+  EVENT_INIT (event);
+  event.kind = XWIDGET_EVENT;
+  event.frame_or_window = Qnil;
+  event.arg = list5 (intern ("response-callback"),
+                     xwl,
+                     build_string (url),
+                     build_string (mimetype),
+                     build_string (filename));
+  kbd_buffer_store_event (&event);
+}
+
 void
 store_xwidget_js_callback_event (struct xwidget *xw,
                                  Lisp_Object proc,
-- 
2.15.0