[Feature] Add MicroSD PSBT File support for SeedSignerOS

src/seedsigner/controller.py

@@ -103,6 +103,7 @@ class Controller(Singleton):
     # TODO: Refactor these flow-related attrs that survive across multiple Screens.
     # TODO: Should all in-memory flow-related attrs get wiped on MainMenuView?
     psbt: 'embit.psbt.PSBT' = None
+    psbt_file: dict = None
     psbt_seed: 'Seed' = None
     psbt_parser: 'PSBTParser' = None
 
@@ -173,6 +174,7 @@ def configure_instance(cls, disable_hardware=False):
 
         # Store one working psbt in memory
         controller.psbt = None
+        controller.psbt_file = None
         controller.psbt_parser = None
 
         # Configure the Renderer

src/seedsigner/hardware/microsd.py

@@ -1,24 +1,30 @@
 import time
+import base64, os, glob
 
 from seedsigner.models.singleton import Singleton
 from seedsigner.models.threads import BaseThread
-from seedsigner.models.settings import Settings
+from seedsigner.models.settings import Settings, SettingsConstants
 #from seedsigner.views.view import MicroSDToastView
 from seedsigner.gui.screens.screen import MicroSDToastScreen
 
 class MicroSD(Singleton, BaseThread):
 
 	ACTION__INSERTED = "add"
 	ACTION__REMOVED = "remove"
+	MOUNT_LOCATION = "/mnt/microsd/"
 
-	settings_handler = None
+	MAGIC = b"psbt\xff"
+	MAGIC_BASE64 = base64.b64encode(MAGIC)[:-1] # remove last byte base64 padding
+	MAGIC_MAX_LENGTH = max(len(MAGIC), len(MAGIC_BASE64))
 
 	@classmethod
 	def get_instance(cls):
 		# This is the only way to access the one and only instance
 		if cls._instance is None:
 			# Instantiate the one and only instance
 			microsd = cls.__new__(cls)
+			microsd.psbt_files = []
+			microsd.find_psbt_files()
 			cls._instance = microsd
 
 			# explicitly call BaseThread __init__ since multiple class inheritance
@@ -50,6 +56,46 @@ def run(self):
 					print(f"fifo message: {action}")
 
 					Settings.microsd_handler(action=action)
+					MicroSD.psbt_files_handler(action=action)
 
 					toastscreen = MicroSDToastScreen(action=action)
 					toastscreen.display()
+
+	def psbt_files_handler(action):
+		from seedsigner.controller import Controller
+		controller: Controller = Controller.get_instance()
+		if action == MicroSD.ACTION__INSERTED:
+			controller.microsd.find_psbt_files()
+		elif action == MicroSD.ACTION__REMOVED:
+			controller.microsd.psbt_files = []
+
+	def find_psbt_files(self):
+		self.psbt_files = []
+		# only populate psbt files from the microsd in seedsigner-os
+		if Settings.HOSTNAME == Settings.SEEDSIGNER_OS:
+			# only populate psbt files if setting is enabled
+			if Settings.get_instance().get_value(SettingsConstants.SETTING__MICROSD_PSBT) == SettingsConstants.OPTION__ENABLED:
+				for filepath in sorted(glob.glob(MicroSD.MOUNT_LOCATION + '*')):
+					if os.path.isfile(filepath):
+						with open(filepath, 'rb') as psbt_file:
+							file_header = psbt_file.read(MicroSD.MAGIC_MAX_LENGTH)
+
+					# binary psbt file check
+					if file_header.startswith(MicroSD.MAGIC):
+						self.psbt_files.append({
+							"name": os.path.splitext(os.path.basename(filepath))[0],
+							"filename": os.path.basename(filepath),
+							"filepath": filepath,
+							"type": "binary"
+						})
+					# base64 psbt file check
+					elif file_header.startswith(MicroSD.MAGIC_BASE64):
+						self.psbt_files.append({
+							"name": os.path.splitext(os.path.basename(filepath))[0],
+							"filename": os.path.basename(filepath),
+							"filepath": filepath,
+							"type": "base64"
+						})
+
+				# sort the list by name of file without extension	
+				self.psbt_files = sorted(self.psbt_files, key=lambda d: d['name']) 

src/seedsigner/models/settings.py

@@ -159,8 +159,14 @@ def set_value(self, attr_name: str, value: any):
                 print(f"Removed {self.SETTINGS_FILENAME}")
             except:
                 print(f"{self.SETTINGS_FILENAME} not found to be removed")
-                
+
         self._data[attr_name] = value
+
+        # Special handling for MicroSD PSBT setting
+        if attr_name == SettingsConstants.SETTING__MICROSD_PSBT:
+            from seedsigner.hardware.microsd import MicroSD
+            MicroSD.get_instance().find_psbt_files()
+
         self.save()
 
 

src/seedsigner/models/settings_definition.py

@@ -159,6 +159,7 @@ def map_network_to_embit(cls, network) -> str:
     SETTING__COMPACT_SEEDQR = "compact_seedqr"
     SETTING__BIP85_CHILD_SEEDS = "bip85_child_seeds"
     SETTING__MESSAGE_SIGNING = "message_signing"
+    SETTING__MICROSD_PSBT = "microsd_psbt"
     SETTING__PRIVACY_WARNINGS = "privacy_warnings"
     SETTING__DIRE_WARNINGS = "dire_warnings"
     SETTING__QR_BRIGHTNESS_TIPS = "qr_brightness_tips"
@@ -461,6 +462,12 @@ class SettingsDefinition:
                       display_name="Message signing",
                       visibility=SettingsConstants.VISIBILITY__ADVANCED,
                       default_value=SettingsConstants.OPTION__DISABLED),
+
+        SettingsEntry(category=SettingsConstants.CATEGORY__FEATURES,
+                              attr_name=SettingsConstants.SETTING__MICROSD_PSBT,
+                              display_name="MicroSD PSBT",
+                              visibility=SettingsConstants.VISIBILITY__ADVANCED,
+                              default_value=SettingsConstants.OPTION__DISABLED),
 
         SettingsEntry(category=SettingsConstants.CATEGORY__FEATURES,
                       attr_name=SettingsConstants.SETTING__PRIVACY_WARNINGS,

src/seedsigner/views/psbt_views.py

@@ -1,18 +1,66 @@
+import os
+from binascii import a2b_base64
 from embit.psbt import PSBT
 from embit import script
 from embit.networks import NETWORKS
 from seedsigner.controller import Controller
 
 from seedsigner.gui.components import FontAwesomeIconConstants, SeedSignerIconConstants
 from seedsigner.models.encode_qr import EncodeQR
+from seedsigner.hardware.microsd import MicroSD
 from seedsigner.models.psbt_parser import PSBTParser
 from seedsigner.models.qr_type import QRType
 from seedsigner.models.settings import SettingsConstants
 from seedsigner.gui.screens.psbt_screens import PSBTOverviewScreen, PSBTMathScreen, PSBTAddressDetailsScreen, PSBTChangeDetailsScreen, PSBTFinalizeScreen
-from seedsigner.gui.screens.screen import (RET_CODE__BACK_BUTTON, ButtonListScreen, WarningScreen, DireWarningScreen, QRDisplayScreen)
+from seedsigner.gui.screens.screen import (RET_CODE__BACK_BUTTON, ButtonListScreen, WarningScreen, DireWarningScreen, QRDisplayScreen, LargeIconStatusScreen)
 from seedsigner.views.view import BackStackView, MainMenuView, NotYetImplementedView, View, Destination
 
 
+class PSBTFileSelectionView(View):
+    def run(self):
+
+        # edge case when file selection menu is selected, but no psbt files are available, re-route to home menu
+        if len(self.controller.microsd.psbt_files) == 0:
+            return Destination(MainMenuView)
+
+        # add button to button list for each psbt file
+        button_data = []
+
+        for psbt_file in self.controller.microsd.psbt_files:
+            if len(psbt_file["filename"]) > 21:
+                button_data.append(psbt_file["filename"][:12] + "..." + psbt_file["filename"][-7:])
+            else:
+                button_data.append(psbt_file["filename"])
+
+        selected_menu_num = ButtonListScreen(
+            title="Select PSBT File",
+            is_button_text_centered=False,
+            button_data=button_data
+        ).display()
+
+        if selected_menu_num == RET_CODE__BACK_BUTTON:
+            return Destination(BackStackView)
+
+        # Read PSBT file select if it exists
+        psbt_file = self.controller.microsd.psbt_files[selected_menu_num]
+        tx = PSBT
+
+        if os.path.exists(psbt_file["filepath"]):
+            with open(psbt_file["filepath"], 'rb') as f:
+                data = f.read()
+
+            if psbt_file["type"] == "binary":
+                tx = PSBT.parse(data)
+            elif psbt_file["type"] == "base64":
+                raw = a2b_base64(data)
+                tx = PSBT.parse(raw)
+            self.controller.psbt = tx
+            self.controller.psbt_parser = None
+            self.controller.psbt_file = psbt_file
+            return Destination(PSBTSelectSeedView)
+        else:
+            # TODO display warning messages that psbt file was not found
+            return Destination(MainMenuView)
 
 class PSBTSelectSeedView(View):
     SCAN_SEED = ("Scan a seed", SeedSignerIconConstants.QRCODE)
@@ -482,7 +530,10 @@ def run(self):
             # Sign PSBT
             sig_cnt = PSBTParser.sig_count(psbt)
             psbt.sign_with(psbt_parser.root)
-            trimmed_psbt = PSBTParser.trim(psbt)
+
+            trimmed_psbt = psbt
+            if self.controller.psbt_file == None: # skip trim when using psbt files from microsd
+                trimmed_psbt = PSBTParser.trim(psbt)
 
             if sig_cnt == PSBTParser.sig_count(trimmed_psbt):
                 # Signing failed / didn't do anything
@@ -492,7 +543,11 @@ def run(self):
 
             else:
                 self.controller.psbt = trimmed_psbt
-                return Destination(PSBTSignedQRDisplayView)
+                # when psbt file is used from microsd, write signed psbt to microsd
+                if self.controller.psbt_file == None:
+                    return Destination(PSBTSignedQRDisplayView)
+                else:
+                    return Destination(PSBTSignedFileDisplayView)
 
 
 
@@ -510,7 +565,66 @@ def run(self):
         #   clears all ephemeral data (except in-memory seeds).
         return Destination(MainMenuView, clear_history=True)
 
-
+class PSBTSignedFileDisplayView(View):
+    def run(self):
+
+        # extract psbt from memory to write to file. The file name of a signed PSBT is appended with "signed" to the original file name.
+        # So "Test 123.psbt" unsigned PSBT will be written to the microsd card as "Test 123 signed.psbt".
+        raw = self.controller.psbt.serialize()
+        filename, extension = os.path.splitext(self.controller.psbt_file["filename"])
+        signed_filename = filename + " signed" + extension
+        signed_filepath = MicroSD.MOUNT_LOCATION + signed_filename
+        increment = 0
+
+        # verify microsd directory exists and is writable, display message warning on failure
+        selected_menu_num = 0
+        while (not os.path.exists(MicroSD.MOUNT_LOCATION) or not os.access(MicroSD.MOUNT_LOCATION, os.W_OK)):
+            selected_menu_num = WarningScreen(
+                status_headline="MicroSD Card Missing!",
+                text="MicroSD Card is required to write out signed PSBT file.",
+                button_data=["Continue", "Exit"],
+            ).display()
+
+            # if users chooses to exit, consider the PSBT workflow complete
+            if selected_menu_num == 1:
+                # We're done with this PSBT. Remove all related data
+                self.controller.psbt = None
+                self.controller.psbt_parser = None
+                self.controller.psbt_seed = None
+                self.controller.psbt_file = None
+                return Destination(MainMenuView)
+
+        # if signed filename already exists on disk, add incremented number to the end of the file name
+        while os.path.exists(signed_filepath):
+            increment += 1
+            signed_filename = filename + " signed" + str(increment) + extension
+            signed_filepath = MicroSD.MOUNT_LOCATION + signed_filename
+
+        # write out psbt file sync and force flush to disk as best as possible
+        with open(signed_filepath, "wb") as f:
+            f.write(raw)
+            f.flush()
+            os.fsync(f.fileno())
+
+        LargeIconStatusScreen(
+            title="PSBT Saved",
+            show_back_button=False,
+            status_headline="Success!",
+            text=signed_filename,
+            button_data=["OK"],
+            allow_text_overflow=True
+        ).display()
+
+        # refresh list of files to include the new signed psbt
+        self.controller.microsd.find_psbt_files()
+
+        # We're done with this PSBT. Remove all related data
+        self.controller.psbt = None
+        self.controller.psbt_parser = None
+        self.controller.psbt_seed = None
+        self.controller.psbt_file = None
+
+        return Destination(MainMenuView)
 
 class PSBTSigningErrorView(View):
     def run(self):

src/seedsigner/views/scan_views.py

@@ -86,6 +86,8 @@ def run(self):
                 psbt = self.decoder.get_psbt()
                 self.controller.psbt = psbt
                 self.controller.psbt_parser = None
+                self.controller.psbt_file = None
+
                 return Destination(PSBTSelectSeedView, skip_current_view=True)
 
             elif self.decoder.is_settings:

src/seedsigner/views/seed_views.py

@@ -427,6 +427,7 @@ def run(self):
 ****************************************************************************"""
 class SeedOptionsView(View):
     SCAN_PSBT = ("Scan PSBT", SeedSignerIconConstants.QRCODE)
+    OPEN_PSBT = "Open PSBT on MicroSD"
     VERIFY_ADDRESS = "Verify Addr"
     EXPORT_XPUB = "Export Xpub"
     EXPLORER = "Address Explorer"
@@ -478,6 +479,9 @@ def run(self):
 
         button_data.append(self.SCAN_PSBT)
 
+        if len(self.controller.microsd.psbt_files) > 0:
+            button_data.append(self.OPEN_PSBT)
+
         if self.settings.get_value(SettingsConstants.SETTING__XPUB_EXPORT) == SettingsConstants.OPTION__ENABLED:
             button_data.append(self.EXPORT_XPUB)
 
@@ -507,6 +511,11 @@ def run(self):
             from seedsigner.views.scan_views import ScanPSBTView
             self.controller.psbt_seed = self.controller.get_seed(self.seed_num)
             return Destination(ScanPSBTView)
+
+        elif button_data[selected_menu_num] == self.OPEN_PSBT:
+            from seedsigner.views.psbt_views import PSBTFileSelectionView
+            self.controller.psbt_seed = self.controller.get_seed(self.seed_num)
+            return Destination(PSBTFileSelectionView)
 
         elif button_data[selected_menu_num] == self.VERIFY_ADDRESS:
             return Destination(SeedAddressVerificationView, view_args=dict(seed_num=self.seed_num))

src/seedsigner/views/tools_views.py

@@ -17,6 +17,7 @@
 from seedsigner.models.seed import Seed
 from seedsigner.models.settings_definition import SettingsConstants
 from seedsigner.views.seed_views import SeedDiscardView, SeedFinalizeView, SeedMnemonicEntryView, SeedWordsWarningView, SeedExportXpubScriptTypeView
+from seedsigner.views.psbt_views import PSBTFileSelectionView
 
 from .view import View, Destination, BackStackView
 
@@ -27,11 +28,15 @@ class ToolsMenuView(View):
     DICE = ("New seed", FontAwesomeIconConstants.DICE)
     KEYBOARD = ("Calc 12th/24th word", FontAwesomeIconConstants.KEYBOARD)
     EXPLORER = "Address Explorer"
+    OPEN_PSBT = "Open PSBT on MicroSD"
     ADDRESS = "Verify address"
 
     def run(self):
         button_data = [self.IMAGE, self.DICE, self.KEYBOARD, self.EXPLORER, self.ADDRESS]
 
+        if len(self.controller.microsd.psbt_files) > 0:
+            button_data.append(self.OPEN_PSBT)
+
         selected_menu_num = self.run_screen(
             ButtonListScreen,
             title="Tools",
@@ -53,6 +58,9 @@ def run(self):
 
         elif button_data[selected_menu_num] == self.EXPLORER:
             return Destination(ToolsAddressExplorerSelectSourceView)
+
+        elif button_data[selected_menu_num] == OPEN_PSBT:
+            return Destination(PSBTFileSelectionView)
 
         elif button_data[selected_menu_num] == self.ADDRESS:
             from seedsigner.views.scan_views import ScanAddressView