iMerge branch 'wip/90-304-image-dnd-paste' into 'mainline'

Inline image drag and drop #90 and image paste from clipboard #304

See merge request GNOME/geary!343

src/client/composer/composer-web-view.vala

@@ -14,7 +14,7 @@ public class ComposerWebView : ClientWebView {
 
     // WebKit message handler names
     private const string CURSOR_CONTEXT_CHANGED = "cursorContextChanged";
-
+    private const string DRAG_DROP_RECEIVED = "dragDropReceived";
 
     /**
      * Encapsulates editing-related state for a specific DOM node.
@@ -108,6 +108,9 @@ public class ComposerWebView : ClientWebView {
     /** Emitted when the cursor's edit context has changed. */
     public signal void cursor_context_changed(EditContext cursor_context);
 
+    /** Emitted when an image file has been dropped on the composer */
+    public signal void image_file_dropped(string filename, string type, uint8[] contents);
+
     /** Workaround for WebView eating the button event */
     internal signal bool button_release_event_done(Gdk.Event event);
 
@@ -121,6 +124,7 @@ public class ComposerWebView : ClientWebView {
         this.user_content_manager.add_script(ComposerWebView.app_script);
 
         register_message_handler(CURSOR_CONTEXT_CHANGED, on_cursor_context_changed);
+        register_message_handler(DRAG_DROP_RECEIVED, on_drag_drop_received);
 
         // XXX this is a bit of a hack given the docs for is_empty,
         // above
@@ -521,4 +525,40 @@ public class ComposerWebView : ClientWebView {
         }
     }
 
+    /**
+     *  Handle a dropped image
+     */
+    private void on_drag_drop_received(WebKit.JavascriptResult result) {
+
+        try {
+            JSC.Value object = result.get_js_value();
+            string filename = Util.JS.to_string(
+                Util.JS.get_property(object, "fileName")
+            );
+            string filename_unescaped = GLib.Uri.unescape_string(filename);
+
+            string file_type = Util.JS.to_string(
+                Util.JS.get_property(object, "fileType")
+            );
+
+            string content_base64 = Util.JS.to_string(
+                Util.JS.get_property(object, "content")
+            );
+            uint8[] image = GLib.Base64.decode(content_base64);
+
+            if (image.length == 0) {
+                warning("%s is empty", filename);
+                return;
+            }
+
+            // A simple check to see if the file looks like an image. A problem here
+            // will be this accepting types which won't be supported by WebKit
+            // or recipients.
+            if (file_type.index_of("image/") == 0) {
+                image_file_dropped(filename_unescaped, file_type, image);
+            }
+        } catch (Util.JS.Error err) {
+            debug("Could not get deceptive link param: %s", err.message);
+        }
+    }
 }

src/client/composer/composer-widget.vala

@@ -179,6 +179,8 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
         _("attach|attaching|attaches|attachment|attachments|attached|enclose|enclosed|enclosing|encloses|enclosure|enclosures");
 
 
+    private const string PASTED_IMAGE_FILENAME_TEMPLATE = "geary-pasted-image-%u.png";
+
     public Geary.Account account { get; private set; }
     private Gee.Map<string, Geary.AccountInformation> accounts;
 
@@ -367,8 +369,8 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
     private AttachPending pending_include = AttachPending.INLINE_ONLY;
     private Gee.Set<File> attached_files = new Gee.HashSet<File>(Geary.Files.nullable_hash,
         Geary.Files.nullable_equal);
-    private Gee.Map<string,File> inline_files = new Gee.HashMap<string,File>();
-    private Gee.Map<string,File> cid_files = new Gee.HashMap<string,File>();
+    private Gee.Map<string,Geary.Memory.Buffer> inline_files = new Gee.HashMap<string,Geary.Memory.Buffer>();
+    private Gee.Map<string,Geary.Memory.Buffer> cid_files = new Gee.HashMap<string,Geary.Memory.Buffer>();
 
     private Geary.App.DraftManager? draft_manager = null;
     private GLib.Cancellable? draft_manager_opening = null;
@@ -524,6 +526,12 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
         this.application.engine.account_unavailable.connect(
             on_account_unavailable
         );
+
+        // Listen for drag and dropped image file
+        this.editor.image_file_dropped.connect(
+            on_image_file_dropped
+        );
+
         // TODO: also listen for account updates to allow adding identities while writing an email
 
         this.from = new Geary.RFC822.MailboxAddresses.single(account.information.primary_mailbox);
@@ -1623,9 +1631,10 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
                         // using a cid: URL anyway, so treat it as an
                         // attachment instead.
                         if (content_id != null) {
-                            this.cid_files[content_id] = file;
+                            Geary.Memory.FileBuffer file_buffer = new Geary.Memory.FileBuffer(file, true);
+                            this.cid_files[content_id] = file_buffer;
                             this.editor.add_internal_resource(
-                                content_id, new Geary.Memory.FileBuffer(file, true)
+                                content_id, file_buffer
                             );
                         } else {
                             type = Geary.Mime.DispositionType.ATTACHMENT;
@@ -1641,7 +1650,10 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
                             !this.attached_files.contains(file) &&
                             !this.inline_files.has_key(content_id)) {
                             if (type == Geary.Mime.DispositionType.INLINE) {
-                                add_inline_part(file, content_id);
+                                check_attachment_file(file);
+                                Geary.Memory.FileBuffer file_buffer = new Geary.Memory.FileBuffer(file, true);
+                                string unused;
+                                add_inline_part(file_buffer, content_id, out unused);
                             } else {
                                 add_attachment_part(file);
                             }
@@ -1690,18 +1702,41 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
         update_attachments_view();
     }
 
-    private void add_inline_part(File target, string content_id)
+    private void add_inline_part(Geary.Memory.Buffer target, string content_id, out string unique_contentid)
         throws AttachmentError {
-        check_attachment_file(target);
-        this.inline_files[content_id] = target;
-        try {
-            this.editor.add_internal_resource(
-                content_id, new Geary.Memory.FileBuffer(target, true)
+
+        const string UNIQUE_RENAME_TEMPLATE = "%s_%02u";
+
+        if (target.size == 0)
+            throw new AttachmentError.FILE(
+                _("“%s” is an empty file.").printf(content_id)
             );
-        } catch (Error err) {
-            // unlikely
-            debug("Failed to re-open file for attachment: %s", err.message);
+
+        // Avoid filename conflicts
+        unique_contentid = content_id;
+        int suffix_index = 0;
+        string unsuffixed_filename = "";
+        while (this.inline_files.has_key(unique_contentid)) {
+            string[] filename_parts = unique_contentid.split(".");
+
+            // Handle no file extension
+            int partindex;
+            if (filename_parts.length > 1) {
+                partindex = filename_parts.length-2;
+            } else {
+                partindex = 0;
+            }
+            if (unsuffixed_filename == "")
+                unsuffixed_filename = filename_parts[partindex];
+            filename_parts[partindex] = UNIQUE_RENAME_TEMPLATE.printf(unsuffixed_filename, suffix_index++);
+
+            unique_contentid = string.joinv(".", filename_parts);
         }
+
+        this.inline_files[unique_contentid] = target;
+        this.editor.add_internal_resource(
+            unique_contentid, target
+        );
     }
 
     private FileInfo check_attachment_file(File target)
@@ -1873,7 +1908,14 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
     private void on_paste(SimpleAction action, Variant? param) {
         if (this.container.get_focus() == this.editor) {
             if (this.editor.is_rich_text) {
-                this.editor.paste_rich_text();
+                // Check for pasted image in clipboard
+                Gtk.Clipboard clipboard = Gtk.Clipboard.get(Gdk.SELECTION_CLIPBOARD);
+                bool has_image = clipboard.wait_is_image_available();
+                if (has_image) {
+                    paste_image();
+                } else {
+                    this.editor.paste_rich_text();
+                }
             } else {
                 this.editor.paste_plain_text();
             }
@@ -1882,6 +1924,39 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
         }
     }
 
+    /**
+     * Handle a pasted image, adding it as an inline attachment
+     */
+    private void paste_image() {
+        // The slow operations here are creating the PNG and, to a lesser extent,
+        // requesting the image from the clipboard
+        this.container.top_window.application.mark_busy();
+
+        get_clipboard(Gdk.SELECTION_CLIPBOARD).request_image((clipboard, pixbuf) => {
+            if (pixbuf != null) {
+                try {
+                    uint8[] buffer;
+                    pixbuf.save_to_buffer(out buffer, "png");
+                    Geary.Memory.ByteBuffer byte_buffer = new Geary.Memory.ByteBuffer(buffer, buffer.length);
+
+                    GLib.DateTime time_now = new GLib.DateTime.now();
+                    string filename = PASTED_IMAGE_FILENAME_TEMPLATE.printf(time_now.hash());
+
+                    string unique_filename;
+                    add_inline_part(byte_buffer, filename, out unique_filename);
+                    this.editor.insert_image(
+                        ClientWebView.INTERNAL_URL_PREFIX + unique_filename
+                    );
+                } catch (Error error) {
+                    warning("Failed to paste image %s", error.message);
+                }
+            } else {
+                warning("Failed to get image from clipboard");
+            }
+            this.container.top_window.application.unmark_busy();
+        });
+    }
+
     private void on_paste_without_formatting(SimpleAction action, Variant? param) {
         if (this.container.get_focus() == this.editor)
             this.editor.paste_plain_text();
@@ -2496,10 +2571,13 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
             dialog.hide();
             foreach (File file in dialog.get_files()) {
                 try {
+                    check_attachment_file(file);
+                    Geary.Memory.FileBuffer file_buffer = new Geary.Memory.FileBuffer(file, true);
                     string path = file.get_path();
-                    add_inline_part(file, path);
+                    string unique_filename;
+                    add_inline_part(file_buffer, path, out unique_filename);
                     this.editor.insert_image(
-                        ClientWebView.INTERNAL_URL_PREFIX + path
+                        ClientWebView.INTERNAL_URL_PREFIX + unique_filename
                     );
                 } catch (Error err) {
                     attachment_failed(err.message);
@@ -2555,4 +2633,21 @@ public class ComposerWidget : Gtk.EventBox, Geary.BaseInterface {
         }
     }
 
+    /**
+     * Handle a dropped image file, adding it as an inline attachment
+     */
+    private void on_image_file_dropped(string filename, string file_type, uint8[] contents) {
+        Geary.Memory.ByteBuffer buffer = new Geary.Memory.ByteBuffer(contents, contents.length);
+        string unique_filename;
+        try {
+            add_inline_part(buffer, filename, out unique_filename);
+        } catch (AttachmentError err) {
+            warning("Couldn't attach dropped empty file %s", filename);
+            return;
+        }
+
+        this.editor.insert_image(
+            ClientWebView.INTERNAL_URL_PREFIX + unique_filename
+        );
+    }
 }

src/client/web-process/web-process-extension.vala

@@ -30,8 +30,7 @@ public void webkit_web_extension_initialize_with_user_data(WebKit.WebExtension e
  */
 public class GearyWebExtension : Object {
 
-
-    private const string[] ALLOWED_SCHEMES = { "cid", "geary", "data" };
+    private const string[] ALLOWED_SCHEMES = { "cid", "geary", "data", "blob" };
 
     private WebKit.WebExtension extension;
 

src/engine/api/geary-composed-email.vala

@@ -38,10 +38,10 @@ public class Geary.ComposedEmail : BaseObject {
 
     public Gee.Set<File> attached_files { get; private set;
         default = new Gee.HashSet<File>(Geary.Files.nullable_hash, Geary.Files.nullable_equal); }
-    public Gee.Map<string,File> inline_files { get; private set;
-        default = new Gee.HashMap<string,File>(); }
-    public Gee.Map<string,File> cid_files { get; private set;
-        default = new Gee.HashMap<string,File>(); }
+    public Gee.Map<string,Memory.Buffer> inline_files { get; private set;
+        default = new Gee.HashMap<string,Memory.Buffer>(); }
+    public Gee.Map<string,Memory.Buffer> cid_files { get; private set;
+        default = new Gee.HashMap<string,Memory.Buffer>(); }
 
     public string img_src_prefix { get; set; default = ""; }
 
@@ -88,18 +88,17 @@ public class Geary.ComposedEmail : BaseObject {
     public bool replace_inline_img_src(string orig, string replacement) {
         // XXX This and contains_inline_img_src are pretty
         // hacky. Should probably be working with a DOM tree.
-        bool ret = false;
+        int index = -1;
         if (this.body_html != null) {
-            string old_body = this.body_html;
-            this.body_html = old_body.replace(
-                IMG_SRC_TEMPLATE.printf(this.img_src_prefix + orig),
-                IMG_SRC_TEMPLATE.printf(replacement)
-            );
-            // Avoid doing a proper comparison so we don't need to scan
-            // the whole string again.
-            ret = this.body_html.length != old_body.length;
+            string prefixed_orig = IMG_SRC_TEMPLATE.printf(this.img_src_prefix + orig);
+            index = this.body_html.index_of(prefixed_orig);
+            if (index != -1) {
+                this.body_html = this.body_html.substring(0, index) +
+                     IMG_SRC_TEMPLATE.printf(replacement) +
+                     this.body_html.substring(index + prefixed_orig.length);
+            }
         }
-        return ret;
+        return index != -1;
     }
 
 }

src/engine/rfc822/rfc822-message.vala

@@ -236,7 +236,7 @@ public class Geary.RFC822.Message : BaseObject, EmailHeaderSet {
                 new Gee.LinkedList<GMime.Object>();
 
             // The files that need to have Content IDs assigned
-            Gee.Map<string,File> inline_files = new Gee.HashMap<string,File>();
+            Gee.Map<string,Memory.Buffer> inline_files = new Gee.HashMap<string,Memory.Buffer>();
             inline_files.set_all(email.inline_files);
 
             // Create parts for inline images, if any, and updating
@@ -248,18 +248,18 @@ public class Geary.RFC822.Message : BaseObject, EmailHeaderSet {
             // assigned
             foreach (string cid in email.cid_files.keys) {
                 if (email.contains_inline_img_src(CID_URL_PREFIX + cid)) {
-                    File file = email.cid_files[cid];
                     GMime.Object? inline_part = null;
                     try {
-                        inline_part = yield get_file_part(
-                            file,
+                        inline_part = yield get_buffer_part(
+                            email.cid_files[cid],
+                            GLib.Path.get_basename(cid),
                             Geary.Mime.DispositionType.INLINE,
                             cancellable
                         );
                     } catch (GLib.Error err) {
                         warning(
                             "Error creating CID part %s: %s",
-                            file.get_path(),
+                            cid,
                             err.message
                         );
                     }
@@ -288,15 +288,16 @@ public class Geary.RFC822.Message : BaseObject, EmailHeaderSet {
                                                      CID_URL_PREFIX + cid)) {
                         GMime.Object? inline_part = null;
                         try {
-                            inline_part = yield get_file_part(
+                            inline_part = yield get_buffer_part(
                                 inline_files[name],
+                                GLib.Path.get_basename(name),
                                 Geary.Mime.DispositionType.INLINE,
                                 cancellable
                             );
                         } catch (GLib.Error err) {
                             warning(
                                 "Error creating inline file part %s: %s",
-                                inline_files[name].get_path(),
+                                name,
                                 err.message
                             );
                         }
@@ -441,6 +442,56 @@ public class Geary.RFC822.Message : BaseObject, EmailHeaderSet {
         GMime.StreamGIO stream = new GMime.StreamGIO(file);
         stream.set_owner(false);
 
+        return yield finalise_attachment_part(stream, part, content_type, cancellable);
+    }
+
+    /**
+     * Create a GMime part for the provided attachment buffer
+     */
+    private async GMime.Part? get_buffer_part(Memory.Buffer buffer,
+                                              string basename,
+                                              Geary.Mime.DispositionType disposition,
+                                              GLib.Cancellable cancellable)
+        throws Error {
+
+        Mime.ContentType? mime_type = Mime.ContentType.guess_type(
+            basename,
+            buffer
+        );
+
+        if (mime_type == null) {
+            throw new RFC822Error.INVALID(
+                _("Could not determine mime type for “%s”.").printf(basename)
+                );
+        }
+
+        GMime.ContentType? content_type = new GMime.ContentType.from_string(mime_type.get_mime_type());
+
+        if (content_type == null) {
+            throw new RFC822Error.INVALID(
+                _("Could not determine content type for mime type “%s” on “%s”.").printf(mime_type.to_string(), basename)
+                );
+        }
+
+        GMime.Part part = new GMime.Part();
+        part.set_disposition(disposition.serialize());
+        part.set_filename(basename);
+        part.set_content_type(content_type);
+
+        GMime.StreamMem stream = Utils.create_stream_mem(buffer);
+
+        return yield finalise_attachment_part(stream, part, content_type, cancellable);
+    }
+
+    /**
+     * Set encoding and content object on GMime part
+     */
+    private async GMime.Part finalise_attachment_part(GMime.Stream stream,
+                                                      GMime.Part part,
+                                                      GMime.ContentType content_type,
+                                                      GLib.Cancellable cancellable)
+        throws Error {
+
         // Text parts should be scanned fully to determine best
         // (i.e. most compact) transport encoding to use, but
         // that's usually fine since they tend to be

test/data/org.gnome.GearyTest.gresource.xml

@@ -6,5 +6,6 @@
     <file>basic-multipart-alternative.eml</file>
     <file>basic-multipart-tnef.eml</file>
     <file>geary-0.6-db.tar.xz</file>
+    <file>test-attachment-image.png</file>
   </gresource>
 </gresources>

test/engine/api/geary-composed-email-test.vala

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2016-2018 Michael Gratton <mike@vee.net>
+ *
+ * This software is licensed under the GNU Lesser General Public License
+ * (version 2.1 or later). See the COPYING file in this distribution.
+ */
+
+class Geary.ComposedEmailTest: TestCase {
+
+    private const string IMG_CONTAINING_HTML_BODY = "<img src=\"test.png\" />";
+
+    public ComposedEmailTest() {
+        base("Geary.ComposedEmailTest");
+        add_test("contains_inline_img_src", contains_inline_img_src);
+        add_test("replace_inline_img_src", replace_inline_img_src);
+    }
+
+    public void contains_inline_img_src() throws Error {
+        ComposedEmail composed = build_composed_with_img_src();
+        assert_true(composed.contains_inline_img_src("test.png"), "Expected matched image source");
+        assert_false(composed.contains_inline_img_src("missing.png"), "Expected missing image");
+    }
+
+    public void replace_inline_img_src() throws Error {
+        ComposedEmail composed = build_composed_with_img_src();
+        assert_true(composed.replace_inline_img_src("test.png", "updated.png"), "Expected replacement success");
+        assert_false(composed.replace_inline_img_src("missing.png", "updated.png"), "Expected replacement failure");
+        assert_true(composed.contains_inline_img_src("updated.png"), "Expected new image source");
+
+        assert_true(composed.replace_inline_img_src("updated.png", "1234567.png"), "Expected replacement success for same length filename");
+        assert_true(composed.contains_inline_img_src("1234567.png"), "Expected new same length image source");
+    }
+
+    private ComposedEmail build_composed_with_img_src() {
+        RFC822.MailboxAddress to = new RFC822.MailboxAddress(
+            "Test", "test@example.com"
+        );
+        RFC822.MailboxAddress from = new RFC822.MailboxAddress(
+            "Sender", "sender@example.com"
+        );
+
+        return new Geary.ComposedEmail(
+            new GLib.DateTime.now_local(),
+            new Geary.RFC822.MailboxAddresses.single(from),
+            new Geary.RFC822.MailboxAddresses.single(to),
+            null,
+            null,
+            null,
+            null,
+            IMG_CONTAINING_HTML_BODY
+        );
+    }
+}

test/engine/rfc822-message-test.vala

@@ -29,6 +29,11 @@ This is the second line.
 
 """;
 
+    private static string SIMPLE_MULTIRECIPIENT_TO_CC_BCC = "From: Jill Smith <jill@somewhere.tld>\r\nTo: Jane Doe <jdoe@somewhere.tld>\r\nCc: Jane Doe CC <jdoe_cc@somewhere.tld>\r\nBcc: Jane Doe BCC <jdoe_bcc@somewhere.tld>\r\nSubject: Re: Saying Hello\r\nDate: Fri, 21 Nov 1997 10:01:10 -0600\r\n\r\nThis is a reply to your hello.\r\n\r\n";
+    private static string NETWORK_BUFFER_EXPECTED = "From: Alice <alice@example.net>\r\nSender: Bob <bob@example.net>\r\nTo: Charlie <charlie@example.net>\r\nCC: Dave <dave@example.net>\r\nBCC: Eve <eve@example.net>\r\nReply-To: \"Alice: Personal Account\" <alice@example.org>\r\nSubject: Re: Basic text/plain message\r\nDate: Fri, 21 Nov 1997 10:01:10 -0600\r\nMessage-ID: <3456@example.net>\r\nIn-Reply-To: <1234@local.machine.example>\r\nReferences: <1234@local.machine.example>\r\nX-Mailer: Geary Test Suite 1.0\r\n\r\nThis is the first line.\r\n\r\nThis is the second line.\r\n\r\n";
+
+    private static string TEST_ATTACHMENT_IMAGE_FILENAME = "test-attachment-image.png";
+
     public MessageTest() {
         base("Geary.RFC822.MessageTest");
         add_test("basic_message_from_buffer", basic_message_from_buffer);
@@ -49,6 +54,11 @@ This is the second line.
         add_test("multipart_alternative_as_html",
                  multipart_alternative_as_html);
         add_test("get_preview", get_preview);
+        add_test("get_recipients", get_recipients);
+        add_test("get_searchable_body", get_searchable_body);
+        add_test("get_searchable_recipients", get_searchable_recipients);
+        add_test("get_network_buffer", get_network_buffer);
+        add_test("from_composed_email_inline_attachments", from_composed_email_inline_attachments);
     }
 
     public void basic_message_from_buffer() throws Error {
@@ -169,6 +179,106 @@ This is the second line.
         assert(multipart_signed.get_preview() == MULTIPART_SIGNED_MESSAGE_PREVIEW);
     }
 
+    public void get_recipients() throws Error {
+        Message test = string_to_message(SIMPLE_MULTIRECIPIENT_TO_CC_BCC);
+
+        Gee.List<RFC822.MailboxAddress>? addresses = test.get_recipients();
+
+        Gee.List<string> verify_list = new Gee.ArrayList<string>();
+        verify_list.add("Jane Doe <jdoe@somewhere.tld>");
+        verify_list.add("Jane Doe CC <jdoe_cc@somewhere.tld>");
+        verify_list.add("Jane Doe BCC <jdoe_bcc@somewhere.tld>");
+
+        assert_addresses_list(addresses, verify_list, "get_recipients");
+    }
+
+    public void get_searchable_body() throws Error {
+        Message test = resource_to_message(BASIC_TEXT_HTML);
+        string searchable = test.get_searchable_body();
+        assert_true(searchable.contains("This is the first line"), "Expected body text");
+        assert_false(searchable.contains("<P>"), "Expected html removed");
+    }
+
+    public void get_searchable_recipients() throws Error {
+        Message test = string_to_message(SIMPLE_MULTIRECIPIENT_TO_CC_BCC);
+        string searchable = test.get_searchable_recipients();
+        assert_true(searchable.contains("Jane Doe <jdoe@somewhere.tld>"), "Expected to address");
+        assert_true(searchable.contains("Jane Doe CC <jdoe_cc@somewhere.tld>"), "Expected cc address");
+        assert_true(searchable.contains("Jane Doe BCC <jdoe_bcc@somewhere.tld>"), "Expected bcc address");
+    }
+
+    public void get_network_buffer() throws Error {
+        Message test = resource_to_message(BASIC_TEXT_PLAIN);
+        Memory.Buffer buffer =  test.get_network_buffer(true);
+        assert_true(buffer.to_string() == NETWORK_BUFFER_EXPECTED, "Network buffer differs");
+    }
+
+    public void from_composed_email_inline_attachments() throws Error {
+        RFC822.MailboxAddress to = new RFC822.MailboxAddress(
+            "Test", "test@example.com"
+        );
+        RFC822.MailboxAddress from = new RFC822.MailboxAddress(
+            "Sender", "sender@example.com"
+        );
+
+       Geary.ComposedEmail composed = new Geary.ComposedEmail(
+            new GLib.DateTime.now_local(),
+            new Geary.RFC822.MailboxAddresses.single(from),
+            new Geary.RFC822.MailboxAddresses.single(to),
+            null,
+            null,
+            null,
+            null,
+            "<img src=\"cid:test-attachment-image.png\" /><img src=\"needing_cid.png\" />"
+        );
+
+        GLib.File resource =
+            GLib.File.new_for_uri(RESOURCE_URI).resolve_relative_path(TEST_ATTACHMENT_IMAGE_FILENAME);
+        uint8[] contents;
+        resource.load_contents(null, out contents, null);
+        Geary.Memory.ByteBuffer buffer = new Geary.Memory.ByteBuffer(contents, contents.length);
+        composed.cid_files[TEST_ATTACHMENT_IMAGE_FILENAME] = buffer;
+        Geary.Memory.ByteBuffer buffer2 = new Geary.Memory.ByteBuffer(contents, contents.length);
+        composed.inline_files["needing_cid.png"] = buffer2;
+
+        this.message_from_composed_email.begin(
+            composed,
+            async_complete_full
+        );
+        Geary.RFC822.Message message = message_from_composed_email.end(async_result());
+
+        Gee.List<Part> attachments = message.get_attachments();
+
+        bool found_first = false;
+        bool found_second = false;
+        bool second_id_renamed = false;
+        foreach (Part part in attachments) {
+            if (part.get_clean_filename() == TEST_ATTACHMENT_IMAGE_FILENAME) {
+                found_first = true;
+            } else if (part.get_clean_filename() == "needing_cid.png") {
+                found_second = true;
+                second_id_renamed = part.content_id != "needing_cid.png";
+            }
+        }
+        assert_true(found_first, "Expected CID attachment");
+        assert_true(found_second, "Expected inline attachment");
+        assert_true(second_id_renamed, "Expected inline attachment renamed");
+
+        string html_body = message.get_html_body(null);
+        assert_false(html_body.contains("src=\"needing_cid.png\""), "Expected updated attachment content ID");
+
+        Memory.Buffer out_buffer =  message.get_native_buffer();
+        assert_true(out_buffer.size > (buffer.size+buffer2.size), "Expected sizeable message");
+    }
+
+    private async Geary.RFC822.Message message_from_composed_email(Geary.ComposedEmail composed) {
+        return yield new Geary.RFC822.Message.from_composed_email(
+            composed,
+            GMime.utils_generate_message_id(composed.from.get(0).domain),
+            null
+        );
+    }
+
     private Message resource_to_message(string path) throws Error {
         GLib.File resource =
             GLib.File.new_for_uri(RESOURCE_URI).resolve_relative_path(path);
@@ -208,6 +318,17 @@ This is the second line.
         assert_string(expected, addresses.to_rfc822_string());
     }
 
+    private void assert_addresses_list(Gee.List<RFC822.MailboxAddress>? addresses,
+                                  Gee.List<string> expected,
+                                  string context)
+        throws Error {
+        assert_non_null(addresses, context + " not null");
+        assert_true(addresses.size == expected.size, context + " size");
+        foreach (RFC822.MailboxAddress address in addresses) {
+            assert_true(expected.contains(address.to_rfc822_string()), context + " missing");
+        }
+    }
+
     private void assert_message_id_list(Geary.RFC822.MessageIDList? ids,
                                         string expected)
         throws Error {

test/meson.build

@@ -27,6 +27,7 @@ geary_test_engine_sources = [
   'engine/api/geary-engine-test.vala',
   'engine/api/geary-folder-path-test.vala',
   'engine/api/geary-service-information-test.vala',
+  'engine/api/geary-composed-email-test.vala',
   'engine/app/app-conversation-test.vala',
   'engine/app/app-conversation-monitor-test.vala',
   'engine/app/app-conversation-set-test.vala',

test/test-engine.vala

@@ -76,6 +76,7 @@ int main(string[] args) {
     engine.add_suite(new Geary.RFC822.PartTest().get_suite());
     engine.add_suite(new Geary.RFC822.Utils.Test().get_suite());
     engine.add_suite(new Geary.String.Test().get_suite());
+    engine.add_suite(new Geary.ComposedEmailTest().get_suite());
 
     /*
      * Run the tests

ui/composer-web-view.js

@@ -93,6 +93,12 @@ ComposerPageState.prototype = {
             }
         }, true);
 
+        // Handle file drag & drop
+        document.body.addEventListener("drop", state.handleFileDrop, true);
+        document.body.addEventListener("allowDrop", function(e) {
+            ev.preventDefault();
+        }, true);
+
         // Search for and remove a particular styling when we quote
         // text. If that style exists in the quoted text, we alter it
         // slightly so we don't mess with it later.
@@ -380,6 +386,31 @@ ComposerPageState.prototype = {
             }
         }
         return inPart;
+    },
+    handleFileDrop: function(dropEvent) {
+        dropEvent.preventDefault();
+
+        for (var i = 0; i < dropEvent.dataTransfer.files.length; i++) {
+            const file = dropEvent.dataTransfer.files[i];
+
+            if (!file.type.startsWith('image/'))
+                continue;
+
+            const reader = new FileReader();
+            reader.onload = (function(filename, imageType) { return function(loadEvent) {
+                // Remove prefixed file type and encoding type
+                var parts = loadEvent.target.result.split(",");
+                if (parts.length < 2)
+                    return;
+
+                window.webkit.messageHandlers.dragDropReceived.postMessage({
+                    fileName: encodeURIComponent(filename),
+                    fileType: imageType,
+                    content: parts[1]
+                });
+            }; })(file.name, file.type);
+            reader.readAsDataURL(file);
+        }
     }
 };