Detect unsupported DFT terminals

README.md

@@ -1,22 +1,31 @@
 # oec
 
-IBM 3270 terminal controller - an open replacement for the IBM 3174 Establishment Controller.
+IBM 3270 terminal controller - a replacement for the IBM 3174.
 
 ![IBM 3278 terminal and oec](.images/hero.jpg)
 
 ## Features
 
-This is a work in progress - as of now it only provides basic TN3270 and VT100 emulation.
+The goal of this project is to create an open replacement for the IBM 3174 Establishment Controller, specifically for users looking to connect a IBM 3270 type terminal to the Hercules emulator. It is a work in progress and is far from providing all the features of the 3174, but it does provide basic TN3270 and VT100 emulation.
 
-- [x] TN3270
+  - [x] TN3270
-    - [x] Basic TN3270
+      - [x] Basic TN3270
-    - [ ] EAB
+      - [ ] TN3270E
-    - [ ] TN3270E
+      - [ ] EAB (Extended Attribute Buffer)
-    - [ ] SSL/TLS
+      - [ ] SSL/TLS
-    - [ ] Non-English character sets
+      - [ ] Non-English character sets
-- [x] VT100
+  - [x] VT100
-- [ ] Connection menu
+  - [ ] Connection menu
-- [ ] Multiple logical terminals
+  - [ ] MLT (Multiple Logical Terminals)
+
+## Supported Terminals
+
+Only CUT (Control Unit Terminal) type terminals are supported. I have tested oec with the following terminals:
+
+  * IBM 3278-2
+  * IBM 3483-V (InfoWindow II)
+
+You may have to modify the key mapping to support your specific terminal configuration.
 
 ## Usage
 
@@ -27,7 +36,7 @@ Then configure a Python virtual environment and install dependencies:
 ```
 python -m venv VIRTUALENV
 . VIRTUALENV/bin/activate
-pip install -r requirements.txt --no-deps
+pip install -r requirements.txt
 ```
 
 Assuming your interface is connected to `/dev/ttyACM0` and you want to connect to a TN3270 host named `mainframe`:

oec/controller.py

@@ -6,9 +6,10 @@ oec.controller
 import time
 import logging
 from coax import poll, poll_ack, load_control_register, PollAction, \
-                 KeystrokePollResponse, ReceiveTimeout, ReceiveError, ProtocolError
+                 KeystrokePollResponse, TerminalType, ReceiveTimeout, \
+                 ReceiveError, ProtocolError
 
-from .terminal import Terminal, read_terminal_ids
+from .terminal import Terminal, UnsupportedTerminalError, read_terminal_ids
 from .keyboard import Key
 from .session import SessionDisconnectedError
 
@@ -76,7 +77,11 @@ class Controller:
             return
 
         if not self.terminal:
-            self._handle_terminal_attached(poll_response)
+            try:
+                self._handle_terminal_attached(poll_response)
+            except UnsupportedTerminalError as error:
+                self.logger.error(f'Unsupported terminal: {error}')
+                return
 
         if poll_response:
             self._handle_poll_response(poll_response)
@@ -89,6 +94,9 @@ class Controller:
 
         self.logger.info(f'Terminal ID = {terminal_id}, Extended ID = {extended_id}')
 
+        if terminal_id.type != TerminalType.CUT:
+            raise UnsupportedTerminalError('Only CUT type terminals are supported')
+
         # Get the keymap.
         keymap = self.get_keymap(terminal_id, extended_id)
 

oec/terminal.py

@@ -93,3 +93,6 @@ class Terminal:
                           cursor_blink=self.display.cursor_blink)
 
         return control
+
+class UnsupportedTerminalError(Exception):
+    """Unsupported terminal."""

requirements.txt

@@ -1,8 +1,8 @@
 ptyprocess==0.6.0
-pycoax==0.3.1
+pycoax==0.4.0
 pyserial==3.4
 pyte==0.8.0
 pytn3270==0.5.0
-sliplib==0.3.0
+sliplib==0.5.0
 sortedcontainers==2.1.0
 wcwidth==0.1.7

tests/test_controller.py

@@ -10,7 +10,8 @@ from oec.session import SessionDisconnectedError
 from oec.keyboard import KeyboardModifiers, Key
 from oec.keymap_3278_2 import KEYMAP as KEYMAP_3278_2
 
-TERMINAL_IDS = (TerminalId(0b11110100), 'c1348300')
+CUT_TERMINAL_IDS = (TerminalId(0b11110100), 'c1348300')
+DFT_TERMINAL_IDS = (TerminalId(0b00000001), None)
 
 class RunLoopTestCase(unittest.TestCase):
     def setUp(self):
@@ -21,6 +22,8 @@ class RunLoopTestCase(unittest.TestCase):
 
         self.controller = Controller(self.interface, lambda terminal_id, extended_id: KEYMAP_3278_2, self.create_session_mock)
 
+        self.controller.logger = Mock()
+
         self.controller.connected_poll_period = 1
 
         patcher = patch('oec.controller.poll')
@@ -35,7 +38,7 @@ class RunLoopTestCase(unittest.TestCase):
 
         self.read_terminal_ids_mock = patcher.start()
 
-        self.read_terminal_ids_mock.return_value = TERMINAL_IDS
+        self.read_terminal_ids_mock.return_value = CUT_TERMINAL_IDS
 
         patcher = patch('oec.controller.load_control_register')
 
@@ -80,6 +83,14 @@ class RunLoopTestCase(unittest.TestCase):
 
         self.controller.session.handle_host.assert_called()
 
+    def test_unsupported_terminal_attached(self):
+        self.read_terminal_ids_mock.return_value = DFT_TERMINAL_IDS
+
+        self._assert_run_loop(0, PowerOnResetCompletePollResponse(0xa), 0, True)
+
+        self.assertIsNone(self.controller.terminal)
+        self.assertIsNone(self.controller.session)
+
     def test_keystroke(self):
         self._assert_run_loop(0, PowerOnResetCompletePollResponse(0xa), 0, True)
         self._assert_run_loop(0, KeystrokePollResponse(0b0110000010), 0, True)