Written README. Reordered code. Added exceptions.

README.md

@@ -1,2 +1,18 @@
 # gqrx-fscanner
-Script that drives gqrx via telnet to implement frequency scanning
+> Script that drives gqrx via telnet to implement frequency scanning.
+
+# Setup
+1) **Configure** *Allowed hosts* and *Port* in gqrx from Tools>Remote control settings
+2) **Enable** remote control by checking Tools>Remote control
+3) **Change** `HOST` and `PORT` in the code to match your configuration (default values should work)
+
+# Usage
+## Scan frequencies from file
+`./gqrx-fscanner file.txt`
+
+`file.txt` must contain a list of integer frequencies in Hz, one per line.
+
+## Scan frequencies from gqrx bookmarks
+`./gqrx-fscanner 145000000 148000000`
+
+Scan bookmarked frequencies between 145MHz and 148MHz.

TODO

@@ -1,2 +1,2 @@
-- more checks on operations: read from file, connect to telnet, etc..
 - add connectionreset exception
+- use wait time parameter integrated in telnet instead of manual sleep

gqrx-fscanner.py

@@ -12,17 +12,39 @@
 HOST = "127.0.0.1"
 PORT = 7356
 
-# Send a command via telnet and return the answer
+def parse_bookmarks(lf, hf):
+	'''Parse gqrx bookmark file and extract frequencies between lf and hf'''
+
+	tmp_freq = []
+
+	with open(os.path.expanduser("~")+'/.config/gqrx/bookmarks.csv') as csv_file:
+		csv_reader = csv.reader(csv_file, delimiter=';')
+		for row in csv_reader:
+			if len(row) == 0:
+				continue
+			if row[0][0] == '#':
+				row[0] = row[0][1:]
+				labels = [i.strip() for i in row]	# Strip out all the spaces
+			elif labels != None and len(labels) == len(row) == 5:
+				row = [i.strip() for i in row]		# Strip out all the spaces
+				row = dict(zip(labels,row))
+				if int(row['Frequency']) < hi_freq and int(row['Frequency']) > lo_freq:
+					tmp_freq.append(row['Frequency'])
+
+	return tmp_freq
+
 def send_cmd(s):
+	'''Send a command via telnet and return the answer'''
+
 	cmd = s + '\n'
 	cmd = cmd.encode('UTF-8')
 	tn.write(cmd)
-	sleep(0.1)
+	sleep(0.1)		# Wait answer
 	try:
 		a = tn.read_eager()
 	except EOFError:
 		print("Connection closed")
-		exit(1)
+		sys.exit(1)
 
 	return a.decode('UTF-8')
 
@@ -31,45 +53,37 @@ def send_cmd(s):
 index = 0
 TIME_SLOT = 0.3		# seconds between skips
 
-if   len(sys.argv) == 1:
-	with open("freq.txt", "rt") as f:
+if len(sys.argv) == 2:
+	# Read from txt
+	with open(sys.argv[1], "rt") as f:
 		FREQ = f.read().splitlines()
 elif len(sys.argv) == 3:
 	try:
 		lo_freq = int(sys.argv[1])
 		hi_freq = int(sys.argv[2])
 	except:
 		print("Your argument is invalid!")
-		sys.exit(-1)
+		sys.exit(1)
 
-	# Open bookmark
-	with open(os.path.expanduser("~")+'/.config/gqrx/bookmarks.csv') as csv_file:
-		csv_reader = csv.reader(csv_file, delimiter=';')
-		for row in csv_reader:
-			if len(row) == 0:
-				continue
-			if row[0][0] == '#':
-				row[0] = row[0][1:]
-				labels = [i.strip() for i in row]
-			elif labels != None and len(labels) == len(row):
-				if len(row) == 6:
-					row = [i.strip() for i in row]
-					row = dict(zip(labels,row))
-					if int(row['Frequency']) < hi_freq and int(row['Frequency']) > lo_freq:
-						FREQ.append(row['Frequency'])
-					#elif len(labels) == 2:
+	# Parse gqrx bookmarks
+	FREQ = parse_bookmarks(lo_freq, hi_freq)
+
 else:
 	print("Usage:")
-	print("Read from gqrx bookmarks: ./script low_freq high_freq")
-	print("Read from freq.txt      : ./script\n")
-	sys.exit(-1)
+	print("Read from gqrx bookmarks:   ./script low_freq high_freq")
+	print("Read frequencies from file: ./script path/to/file\n")
+	sys.exit(1)
 
 if len(FREQ) == 0:
     print("No frequencies given")
     sys.exit(1)
 
-tn = telnetlib.Telnet(HOST, PORT)
-
+# Open telnet connection with gqrx
+try:
+	tn = telnetlib.Telnet(HOST, PORT)
+except ConnectionRefusedError:
+	print("Connection refused\nCheck gqrx network settings")
+	sys.exit(1)
 
 while(1):
 	sql = send_cmd("l SQL")			# read SQUELCH level