respond: An extra for sending messages to the printer host. (#1053)

I have made one change to `gcode.py` to support quoted parameter
values.

I have added support for the basic `M118` command (see
https://reprap.org/wiki/G-code#M118:_Echo_message_on_host). I have
also added a `RESPOND` command that takes extended parameters.
`ECHO` might be a better name than `RESPOND` but is already defined
in `gcode.py`.

Signed-off-by: Alec B. Plumb <alec@etherwalker.com>

config/example-extras.cfg

@@ -1051,3 +1051,15 @@
 # Replicape support - see the generic-replicape.cfg file for further
 # details.
 #[replicape]
+
+# Enable the "M118" and "RESPOND" extended commands.
+# [respond]
+# default_type: echo
+#    Sets the default prefix of the "M118" and "RESPOND" output to one of
+#    the following:
+#        echo: "echo: " (This is the default)
+#        command: "// "
+#        error: "!! "
+# default_prefix: echo:
+#    Directly sets the default prefix. If present, this value will override
+#    the "default_type".

docs/G-Codes.md

@@ -273,3 +273,19 @@ section is enabled:
   may lead to internal software errors. This command may invalidate
   future boundary checks; issue a G28 afterwards to reset the
   kinematics.
+
+## Send message (respond) to host
+
+The following commands are availabe when the "respond" config section is
+enabled.
+  - `M118 <message>`: echo the message prepended with the configured default
+    prefix (or `echo: ` if no prefix is configured).
+  - `RESPOND MSG="<message>"`: echo the message prepended with the configured default
+    prefix (or `echo: ` if no prefix is configured).
+  - `RESPOND TYPE=echo MSG="<message>"`: echo the message prepended with `echo: `.
+  - `RESPOND TYPE=command MSG="<message>"`: echo the message prepended with `// `.
+    Octopint can be configured to respond to these messages (e.g.
+    `RESPOND TYPE=command MSG=action:pause`).
+  - `RESPOND TYPE=error MSG="<message>"`: echo the message prepended with `!! `.
+  - `RESPOND PREFIX=<prefix> MSG="<message>"`: echo the message prepended with `<prefix>`
+    (The `PREFIX` parameter will take priority over the `TYPE` parameter)

klippy/extras/respond.py

@@ -0,0 +1,51 @@
+# Add 'RESPOND' and 'M118' commands for sending messages to the host
+#
+# Copyright (C) 2018  Alec Plumb <alec@etherwalker.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+respond_types = {
+    'echo': 'echo:',
+    'command': '//',
+    'error' : '!!',
+}
+
+class HostResponder:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.reactor = self.printer.get_reactor()
+        self.default_prefix = config.getchoice('default_type', respond_types, 'echo')
+        self.default_prefix = config.get('default_prefix', self.default_prefix)
+        self.gcode = self.printer.lookup_object('gcode')
+        self.cmd_M118_help = "Send a message to the host prefixed with '%s'" % self.default_prefix
+        self.gcode.register_command(
+            'M118', self.cmd_M118, True, desc=self.cmd_M118_help)
+        self.gcode.register_command('RESPOND', self.cmd_RESPOND, True)
+    def cmd_M118(self, params):
+        if '#original' in params:
+            msg = params['#original']
+            if not msg.startswith('M118'):
+                # Parse out additional info if M118 recd during a print
+                start = msg.find('M118')
+                end = msg.rfind('*')
+                msg = msg[start:end]
+            if len(msg) > 5:
+                msg = msg[5:]
+            else:
+                msg = ''
+            self.gcode.respond("%s %s" %(self.default_prefix, msg))
+    def cmd_RESPOND(self, params):
+        respond_type = self.gcode.get_str('TYPE', params, None)
+        prefix = self.default_prefix
+        if(respond_type != None):
+            respond_type = respond_type.lower()
+            if(respond_type in respond_types):
+                prefix = respond_types[respond_type]
+            else:
+                raise self.gcode.error("RESPOND TYPE '%s' is invalid. Must be one of 'echo', 'command', or 'error'" % respond_type)
+        prefix = self.gcode.get_str('PREFIX', params, prefix)
+        msg = self.gcode.get_str('MSG', params, '')
+        self.gcode.respond("%s %s" %(prefix, msg))
+
+def load_config(config):
+    return HostResponder(config)

klippy/gcode.py

@@ -3,7 +3,7 @@
 # Copyright (C) 2016-2018  Kevin O'Connor <kevin@koconnor.net>
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
-import os, re, logging, collections
+import os, re, logging, collections, shlex
 import homing, kinematics.extruder
 
 class error(Exception):
@@ -356,7 +356,7 @@ class GCodeParser:
             return params
         eargs = m.group('args')
         try:
-            eparams = [earg.split('=', 1) for earg in eargs.split()]
+            eparams = [earg.split('=', 1) for earg in shlex.split(eargs)]
             eparams = { k.upper(): v for k, v in eparams }
             eparams.update({k: params[k] for k in params if k.startswith('#')})
             return eparams