Adds autodiscovery and status via 9101

src/tsp100_print/main.py

@@ -6,36 +6,86 @@
 from PIL import Image, ImageOps, UnidentifiedImageError
 
 
+SOCKET_BUFFER_SIZE = 1024
+
 logging.basicConfig(level=logging.INFO)
 log = logging.getLogger(__name__)
 
 
+# This was discovered by capturing network traffic from the futurePRNT software.
+# We can discover printers on the local network by broadcasting a certain bytestring on port 22222.
+# Printers will respond back to us, with a similar bytestring, plus some additional data about the
+# printer, such as model name, mac address, how it's configured (DHCP/STATIC), et.c.
+def discover_printers():
+    msg = b'STR_BCAST' + bytes([0x00] * 7) + b'RQ1.0.0' + bytes([0x00, 0x00, 0x1c, 0x64, 0x31])
+
+    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
+    sock.settimeout(1)
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+
+    # NOTE: Ideally we should send to the broadcast address of each connected network instead.
+    sock.sendto(msg, ("255.255.255.255", 22222))
+
+    try:
+        _data, sender = sock.recvfrom(SOCKET_BUFFER_SIZE)
+        return sender
+
+    except TimeoutError:
+        return None
+
+    finally:
+        sock.close()
+
+
+# This was discovered by capturing network traffic from the futurePRNT software.
+# NOTE: The status bytestring received from the printer is duplicated for some reason.
+def get_printer_status(host):
+    sock = socket.create_connection((host, 9101), timeout=1)
+    sock.settimeout(1)
+    sock.sendall(b'0' + bytes([0x00] * 50))
+    response = sock.recv(1024)
+    return response
+
+
 @click.command(context_settings={'show_default': True})
+@click.option('--autodiscover', is_flag=True, default=False, help='Try to autodiscover the printer on the network via broadcasting')
 @click.option('--cut/--no-cut', default=True, help='Whether or not to cut receipt after printing')
-@click.option('--density', default=3, type=click.IntRange(0, 6), help='0 = Highest density, 6 = Lowest density')
+@click.option('-d', '--density', default=3, type=click.IntRange(0, 6), help='0 = Highest density, 6 = Lowest density')
 @click.option('--dither', default='NONE', type=click.Choice(['NONE', 'FLOYDSTEINBERG'], case_sensitive=False))
+@click.option('-h', '--host', help='Hostname or IP-address of the printer')
 @click.option('--margin-top', default=0)
 @click.option('--margin-bottom', default=9)
 @click.option('--resize-width', type=int, help='Resizes input image to the given width while preserving aspect ratio')
-@click.option('--speed', default=2, type=click.IntRange(0, 2), help='0 = Fastest, 2 = Slowest')
-@click.argument('printer-ip')
+@click.option('-s', '--speed', default=2, type=click.IntRange(0, 2), help='0 = Fastest, 2 = Slowest')
 @click.argument('input', type=click.File('rb'))
-def print_image(printer_ip, input, cut, density, dither, margin_top, margin_bottom, resize_width, speed):
+def print_image(input, autodiscover, cut, density, dither, host, margin_top, margin_bottom, resize_width, speed):
     '''
     This is a small utility for sending raster images to Star Micronics TSP100 / TSP143 receipt printers.
 
     The program expects bilevel (black and white) images, at most 576 pixels wide. Wider images will be cropped.
     '''
 
+    if host:
+        pass
+
+    elif autodiscover:
+        host = discover_printers()
+
+        if not host:
+            raise click.ClickException('Could not autodiscover any printer')
+
+    else:
+        raise click.UsageError('You need to specify either --autodiscover or -h/--host <printer-hostname-or-ip>')
+
     try:
         image = Image.open(input)
     except UnidentifiedImageError:
         raise click.ClickException(f'Could not open {input.name} as an image, unknown format')
-    
+
     histogram = image.histogram()
     if any(histogram[1:-1]):
         log.warning('More than 2 levels (black/white), data will be lost via thresholding')
-    
+
     image = image.convert("1", dither=getattr(Image.Dither, dither.upper()))
     image = ImageOps.invert(image)
 
@@ -70,14 +120,14 @@ def print_image(printer_ip, input, cut, density, dither, margin_top, margin_bott
 
     # Connect to the printer
     try:
-        connection = socket.create_connection((printer_ip, 9100), timeout=1)
+        connection = socket.create_connection((host, 9100), timeout=1)
     except TimeoutError:
-        raise click.ClickException(f'Timed out while trying to connect to {printer_ip}, make sure that the printer is online')
+        raise click.ClickException(f'Timed out while trying to connect to {host}, make sure that the printer is online')
     except OSError as e:
-        raise click.ClickException(f'Could not connect to {printer_ip}: {e}')
+        raise click.ClickException(f'Could not connect to {host}: {e}')
 
     # Read printer status
-    data = connection.recv(1024)
+    data = connection.recv(SOCKET_BUFFER_SIZE)
     log.debug(f'ASB: {repr([hex(x) for x in data])}')
 
     if any(data[2:]):
@@ -110,7 +160,6 @@ def print_image(printer_ip, input, cut, density, dither, margin_top, margin_bott
     if not cut:
         connection.sendall(bytes([0x1b, ord(b'*'), ord(b'r'), ord(b'E'), 1, 0x00])) # End of Transmission cut behaviour
 
-    connection.sendall(bytes([0x1b, ord(b'*'), ord(b'r'), ord(b'Q'), 2, 0x00])) # Raster quality, not sure if this does anything
     connection.sendall(bytes([0x1b, ord(b'*'), ord(b'r'), ord(b'm'), ord(b'l'), 0, 0x00])) # No left margin
     connection.sendall(bytes([0x1b, ord(b'*'), ord(b'r'), ord(b'm'), ord(b'r'), 0, 0x00])) # No right margin
     connection.sendall(bytes([0x1b, ord(b'*'), ord(b'r'), ord(b'P'), ord(b'0'), 0x00])) # Set raster length to continuous
@@ -141,14 +190,14 @@ def print_image(printer_ip, input, cut, density, dither, margin_top, margin_bott
     # Try to reconnect to the printer to check status
     for _ in range(10):
         try:
-            connection = socket.create_connection((printer_ip, 9100), timeout=1)
+            connection = socket.create_connection((host, 9100), timeout=1)
         except (TimeoutError, OSError):
             time.sleep(1)
             continue
-        
-        data = connection.recv(1024)
+
+        data = connection.recv(SOCKET_BUFFER_SIZE)
         log.debug(f'Print verification ASB: {repr([hex(x) for x in data])}')
-    
+
         if any(data[2:]):
             raise click.ClickException('Print might have failed, check printer')