Add key exporting to account settings

TODO.md

@@ -121,7 +121,6 @@
     - Edit/delete own devices
     - Request room keys from own other devices
     - Auto-trust accounts within the same client
-    - Export keys
   - Uploads & proper http thumbnails
     - Reduce messages ListView cacheBuffer height once http thumbnails
       downloading is implemented 

src/python/matrix_client.py

@@ -338,6 +338,17 @@ class MatrixClient(nio.AsyncClient):
         await self.retry_decrypting_events()
 
 
+    async def export_keys(self, outfile: str, passphrase: str) -> None:
+        path = Path(outfile)
+        path.parent.mkdir(parents=True, exist_ok=True)
+
+        # Remove any existing file
+        # (the QML dialog asks the user if he wants to overwrite before this)
+        path.unlink()
+
+        await super().export_keys(outfile, passphrase)
+
+
     async def clear_import_error(self) -> None:
         self.models[Account][self.user_id].import_error = ("", "", "")
 

src/qml/Base/HPasswordPopup.qml

@@ -28,10 +28,10 @@ Popup {
 
 
     function verifyPassword(pass, callback) {
-        // Implement this function when using this component.
+        // Can be reimplemented when using this component.
-        // Return true on success, false on invalid password, or
+        // Pass to the callback true on success, false on invalid password, or
         // a [error message, translated] array for any other error.
-        return ["Verification not implemented", false]
+        callback(true)
     }
 
 

src/qml/Pages/EditAccount/Encryption.qml

@@ -14,6 +14,19 @@ HLoader {
     property bool importing: false
 
 
+    function exportKeys(file, passphrase, button=null) {
+        if (button) button.loading = true
+
+        let path = file.toString().replace(/^file:\/\//, "")
+
+        py.callClientCoro(
+            editAccount.userId, "export_keys", [path, passphrase], () => {
+                // null: user is on another page
+                if (encryptionUI !== null && button) button.loading = false
+            }
+        )
+    }
+
     function importKeys(file, passphrase, button=null) {
         if (button) button.loading = true
         encryptionUI.importing = true
@@ -22,7 +35,7 @@ HLoader {
 
         py.callClientCoro(
             editAccount.userId, "import_keys", [path, passphrase], () => {
-                if (encryptionUI !== null) {  // null: user is on another page
+                if (encryptionUI !== null) {
                     encryptionUI.importing = false
                     if (button) button.loading = false
                 }

src/qml/Pages/EditAccount/ImportExportKeys.qml

@@ -1,22 +1,27 @@
 import QtQuick 2.12
 import QtQuick.Controls 2.12
 import QtQuick.Layouts 1.12
+import Qt.labs.platform 1.1
 import "../../Base"
 import "../../utils.js" as Utils
 
 HBox {
+    property var exportButton: null
+
     horizontalSpacing: currentSpacing
     verticalSpacing: currentSpacing
 
     buttonModel: [
-        { name: "export", text: qsTr("Export"), iconName: "export-keys",
+        { name: "export", text: qsTr("Export"), iconName: "export-keys"},
-          enabled: false },
         { name: "import", text: qsTr("Import"), iconName: "import-keys"},
     ]
 
     buttonCallbacks: ({
-        export: button => {},
+        export: button => {
-        import: button => { fileDialog.dialog.open() },
+            exportButton = button
+            exportFileDialog.dialog.open()
+        },
+        import: button => { importFileDialog.dialog.open() },
     })
 
 
@@ -24,29 +29,49 @@ HBox {
         wrapMode: Text.Wrap
         text: qsTr(
             "The decryption keys for messages you received in encrypted " +
-            "rooms can be exported to a passphrase-protected file.%1" +
+            "rooms can be exported to a passphrase-protected file.\n" +
-            "You will then be able to import this file in another " +
+            "You can then import this file on another Matrix account or " +
-            "Matrix client."
+            "client, to be able to decrypt these messages again."
-        ).arg(pageLoader.isWide ? "\n" :"\n\n")
+        )
 
         Layout.fillWidth: true
     }
 
     HFileDialogOpener {
-        id: fileDialog
+        id: exportFileDialog
         fill: false
-        dialog.title: qsTr("Select a decryption key file to import")
+        dialog.title: qsTr("Save decryption keys file as...")
+        dialog.fileMode: FileDialog.SaveFile
+        onFileChanged: {
+            exportPasswordPopup.file = file
+            exportPasswordPopup.open()
+        }
+    }
+
+    HFileDialogOpener {
+        id: importFileDialog
+        fill: false
+        dialog.title: qsTr("Select a decryption keys file to import")
         onFileChanged: {
             importPasswordPopup.file = file
             importPasswordPopup.open()
         }
     }
 
+    HPasswordPopup {
+        property url file: ""
+
+        id: exportPasswordPopup
+        label.text: qsTr("Please enter a passphrase to protect this file:")
+        onAcceptedPasswordChanged:
+            encryptionUI.exportKeys(file, acceptedPassword, exportButton)
+    }
+
     HPasswordPopup {
         property url file: ""
 
         function verifyPassword(pass, callback) {
-            return py.callCoro(
+            py.callCoro(
                 "check_exported_keys_passphrase",
                 [file.toString().replace(/^file:\/\//, ""), pass],
                 callback