Print improvements: don't print unprintable filetypes, improve PDF conversion and mimetype detection

.github/workflows/ci.yml

@@ -83,7 +83,7 @@ jobs:
       - name: Install dependencies
         run: |
           poetry -C ${{ matrix.component }} install
-          if [[ "${{ matrix.component }}" == "client" ]]; then
+          if [[ "${{ matrix.component }}" == "client" || "${{ matrix.component }}" == "export" ]]; then
             make -C ${{ matrix.component }} ci-install-deps
           fi
       - name: Run lint

.github/workflows/test.yml

@@ -47,6 +47,9 @@ jobs:
         if: ${{ matrix.component == 'proxy' }}
       - name: Install dependencies
         run: |
+          if [[ "${{ matrix.component }}" == "export" ]]; then
+            make -C ${{ matrix.component }} ci-install-deps
+          fi
           sudo -u user poetry -C ${{ matrix.component }} install
       - name: Run test
         run: |

client/securedrop_client/export.py

@@ -268,7 +268,7 @@ def _on_print_prefight_error(self) -> None:
         if self.process:
             err = self.process.readAllStandardError().data().decode("utf-8").strip()
             logger.debug(f"Print preflight error: {err}")
-        self.print_preflight_check_failed.emit(ExportStatus.ERROR_PRINT)
+        self.print_preflight_check_failed.emit(ExportStatus.CALLED_PROCESS_ERROR)
 
     def _on_print_complete(self) -> None:
         """
@@ -303,15 +303,15 @@ def end_process(self) -> None:
 
     def _on_print_error(self) -> None:
         """
-        Error callback for print qrexec.
+        Error callback for print qrexec. Called if QProcess fails.
         """
         self._cleanup_tmpdir()
         if self.process:
             err = self.process.readAllStandardError()
             logger.debug(f"Print error: {err}")
         else:
             logger.error("Print error (stderr unavailable)")
-        self.print_failed.emit(ExportStatus.ERROR_PRINT)
+        self.print_failed.emit(ExportStatus.CALLED_PROCESS_ERROR)
 
     def print(self, filepaths: list[str]) -> None:
         """
@@ -332,8 +332,8 @@ def print(self, filepaths: list[str]) -> None:
             self._run_qrexec_export(archive_path, self._on_print_complete, self._on_print_error)
 
         except OSError as e:
-            logger.error("Export failed")
-            logger.debug(f"Export failed: {e}")
+            logger.error("Print failed")
+            logger.debug(f"Print failed: {e}")
             self.print_failed.emit(ExportStatus.ERROR_PRINT)
 
         # ExportStatus.ERROR_MISSING_FILES

client/securedrop_client/export_status.py

@@ -47,6 +47,9 @@ class ExportStatus(Enum):
 
     # Print error
     ERROR_PRINT = "ERROR_PRINT"
+    ERROR_UNPRINTABLE_TYPE = "ERROR_UNPRINTABLE_TYPE"
+    ERROR_MIMETYPE_UNKNOWN = "ERROR_MIMETYPE_UNKNOWN"
+    ERROR_MIMETYPE_DISCOVERY = "ERROR_MIMETYPE_DISCOVERY"
 
     # New
     PRINT_PREFLIGHT_SUCCESS = "PRINTER_PREFLIGHT_SUCCESS"

client/securedrop_client/gui/conversation/export/print_dialog.py

@@ -19,8 +19,12 @@ def __init__(self, device: Export, file_name: str, filepaths: list[str]) -> None
         self.file_name = SecureQLabel(
             file_name, wordwrap=False, max_length=self.FILENAME_WIDTH_PX
         ).text()
-        # Hold onto the error status we receive from the Export VM
-        self.error_status: ExportStatus | None = None
+
+        # Hold onto the error status we receive from the Export VM. Only required
+        # because we're reusing the same modal dialog with different text depending
+        # on conditions, and need to pass methods to Qt handlers with a predefined
+        # message signature.
+        self.status: ExportStatus | None = None
 
         # Connect device signals to slots
         self._device.print_preflight_check_succeeded.connect(
@@ -61,6 +65,7 @@ def __init__(self, device: Export, file_name: str, filepaths: list[str]) -> None
         )
         self.insert_usb_message = _("Please connect your printer to a USB port.")
         self.generic_error_message = _("See your administrator for help.")
+        self.unprintable_type_error_message = _("This file type cannot be printed.")
 
         self._show_starting_instructions()
         self.start_animate_header()
@@ -80,14 +85,38 @@ def _show_insert_usb_message(self) -> None:
         self.error_details.hide()
         self.adjustSize()
 
+    def _show_unprintable_message(self) -> None:
+        self.continue_button.clicked.disconnect()
+        self.continue_button.clicked.connect(self.close)
+        self.header.setText(self.error_header)
+        self.body.setText(self.unprintable_type_error_message)
+        self.error_details.hide()
+        self.adjustSize()
+
     def _show_generic_error_message(self) -> None:
+        self._show_error_message()
+
+    def _show_error_message(self) -> None:
+        """
+        Show error message based on ExportStatus returned.
+        """
         self.continue_button.clicked.disconnect()
         self.continue_button.clicked.connect(self.close)
         self.continue_button.setText(_("DONE"))
         self.header.setText(self.error_header)
-        self.body.setText(  # nosemgrep: semgrep.untranslated-gui-string
-            f"{self.error_status}: {self.generic_error_message}"
-        )
+        if self.status == ExportStatus.ERROR_UNPRINTABLE_TYPE:
+            body_text = self.unprintable_type_error_message
+        else:
+            body_text = self.generic_error_message
+
+        if self.status:
+            self.body.setText(  # nosemgrep: semgrep.untranslated-gui-string
+                f"{self.status.value}: {body_text}"
+            )
+        else:
+            self.body.setText(  # nosemgrep: semgrep.untranslated-gui-string
+                body_text
+            )
         self.error_details.hide()
         self.adjustSize()
 
@@ -100,20 +129,30 @@ def _print_file(self) -> None:
         self.start_animate_activestate()
         self._device.print(self.filepaths)
 
-    @pyqtSlot()
-    def _on_print_complete(self) -> None:
+    @pyqtSlot(object)
+    def _on_print_complete(self, status: ExportStatus) -> None:
         """
-        Send a signal to close the print dialog.
+        Send a signal to close the print dialog or display
+        an appropriate error message.
         """
+        self.status = status
         self.stop_animate_activestate()
-        self.close()
+        if status == ExportStatus.PRINT_SUCCESS:
+            self.close()
+        elif self.status == ExportStatus.ERROR_PRINTER_NOT_FOUND:
+            self._show_insert_usb_message()
+        elif self.status == ExportStatus.ERROR_UNPRINTABLE_TYPE:
+            self._show_unprintable_message()
+        else:
+            self._show_error_message()
 
     @pyqtSlot(object)
     def _on_print_preflight_check_succeeded(self, status: ExportStatus) -> None:
         # We don't use the ExportStatus for now for "success" status,
         # but in future work we will migrate towards a wizard-style dialog, where
         # success and intermediate status values all use the same PyQt slot.
         # If the continue button is disabled then this is the result of a background preflight check
+        self.status = status
         self.stop_animate_header()
         self.header_icon.update_image("printer.svg", svg_size=QSize(64, 64))
         self.header.setText(self.ready_header)
@@ -128,20 +167,20 @@ def _on_print_preflight_check_succeeded(self, status: ExportStatus) -> None:
 
     @pyqtSlot(object)
     def _on_print_preflight_check_failed(self, status: ExportStatus) -> None:
+        self.status = status
         self.stop_animate_header()
         self.header_icon.update_image("printer.svg", svg_size=QSize(64, 64))
-        self.error_status = status
         # If the continue button is disabled then this is the result of a background preflight check
         if not self.continue_button.isEnabled():
             self.continue_button.clicked.disconnect()
             if status == ExportStatus.ERROR_PRINTER_NOT_FOUND:
                 self.continue_button.clicked.connect(self._show_insert_usb_message)
             else:
-                self.continue_button.clicked.connect(self._show_generic_error_message)
+                self.continue_button.clicked.connect(self._show_error_message)
 
             self.continue_button.setEnabled(True)
             self.continue_button.setFocus()
         elif status == ExportStatus.ERROR_PRINTER_NOT_FOUND:
             self._show_insert_usb_message()
         else:
-            self._show_generic_error_message()
+            self._show_error_message()

client/securedrop_client/locale/messages.pot

@@ -14,7 +14,7 @@ msgstr ""
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=utf-8\n"
 "Content-Transfer-Encoding: 8bit\n"
-"Generated-By: Babel 2.12.1\n"
+"Generated-By: Babel 2.15.0\n"
 
 msgid "{application_name} is already running"
 msgstr ""
@@ -366,6 +366,9 @@ msgstr ""
 msgid "See your administrator for help."
 msgstr ""
 
+msgid "This file type cannot be printed."
+msgstr ""
+
 msgid "YES, DELETE ENTIRE SOURCE ACCOUNT"
 msgstr ""