now use main()

src/decrypt.py

@@ -1,10 +1,6 @@
 #!/usr/bin/env python3
 import json, sys, zlib, base45, cbor2, optparse, os
 
-# helper functions
-
-def verbosePrint(desc, text):
-    if verboseMode: print("\n[Verbose:] {}\n{}".format(desc, text))
 
 def checkFilePath(file):
     if not( os.path.isfile(file) and os.access(file, os.R_OK)):
@@ -24,73 +20,92 @@ def getSecondParameter(shortOption, longOption):
     else:
         return args[successIndex]
 
-# define cli options
-cli_parser = optparse.OptionParser()
-cli_parser.set_defaults(debug=False)
-cli_parser.add_option('-v', '--verbose', action='store_true', dest='verbose',
-    help='prints status messages to stdout')
-cli_parser.add_option('-i', '--image', action='store_true', dest='image',
-    help='specify an image as input with the next argument')
-cli_parser.add_option('-t', '--text', action='store_true', dest='text',
-    help='specify text as input with the next argument')
-cli_parser.add_option('-f', '--file', action='store_true', dest='file',
-    help='specify a text file as input with the next argument')
-(options, args) = cli_parser.parse_args()
-
-# parse cli options
-
-# check for verbose mode
-if options.verbose:
-    verboseMode = True
-    print('[Verbose:] verbose mode activated')
-else:
-    verboseMode = False
-
-# save/convert input to string 'qrdata'
-if options.image and options.text is None and options.file is None:
-    imageName = getSecondParameter('-i', '--image')
-    checkFilePath(imageName)
-
-    from pyzbar.pyzbar import decode
-    from PIL import Image
+def parseCommandlineArguments():
+    global options
+    global verboseMode
+
+    # define cli options
+    cli_parser = optparse.OptionParser()
+    cli_parser.set_defaults(debug=False)
+    cli_parser.add_option('-v', '--verbose', action='store_true', dest='verbose',
+        help='prints status messages to stdout')
+    cli_parser.add_option('-i', '--image', action='store_true', dest='image',
+        help='specify an image as input with the next argument')
+    cli_parser.add_option('-t', '--text', action='store_true', dest='text',
+        help='specify text as input with the next argument')
+    cli_parser.add_option('-f', '--file', action='store_true', dest='file',
+        help='specify a text file as input with the next argument')
+    (options, args) = cli_parser.parse_args()
+
+    # check for verbose mode
+    if options.verbose:
+        verboseMode = True
+        print('[Verbose:] verbose mode activated')
+    else:
+        verboseMode = False
+
+def getQRcode():
+    if options.image and options.text is None and options.file is None:
+        imageName = getSecondParameter('-i', '--image')
+        checkFilePath(imageName)
+
+        from pyzbar.pyzbar import decode
+        from PIL import Image
+
+        try:
+            img = Image.open(imageName)
+            decode = decode(img.convert('RGBA')) # convert to RBGA image to avoid PIL warning
+            return decode[0].data.decode('ascii')
+        except:
+            print("Error: Error while opening your image. Are you sure it is actually a QR Code?")
+            exit()
+    elif options.text and options.image is None and options.file is None:
+        return getSecondParameter('-t', '--text')
+    elif options.file and options.image is None and options.text is None:
+        fileName = getSecondParameter('-f', '--file')
+        checkFilePath(fileName)
+
+        with open(fileName, 'r') as fileopener:
+            return fileopener.read()
+    else:
+        print("Error: Please specify (only one!) qr code i/o argument\nHint: run 'python decrypt.py -h'")
+        exit(1)
 
+def stripIdentifiers(qrdata):
+    # remove Context Identifier string (usually 'HCI:'), for more information check the official specification:
+    # https://github.com/ehn-dcc-development/hcert-spec/blob/main/hcert_spec.md#422-qr-2d-barcode
+    qrdata = qrdata[qrdata.find(':') + 1:]
+    verbosePrint('raw QR code data', qrdata)
+    return qrdata
+
+def decryptPayload(qrdata):
     try:
-        img = Image.open(imageName)
-        decode = decode(img.convert('RGBA')) # convert to RBGA image to avoid PIL warning
-        qrdata = decode[0].data.decode('ascii')
+        base45data = base45.b45decode(str(qrdata))
+        verbosePrint('Base45 decoded data', base45data)
+        zlibdata = zlib.decompress(base45data)
+        verbosePrint('Zlib decompressed data', base45data)
+        cosedata = cbor2.loads(zlibdata)
+        verbosePrint("COSE 'sign1' signed data", cosedata)
+        payload = cbor2.loads(cosedata.value[2])
     except:
-        print("Error: Error while opening your image. Are you sure it is actually a QR Code?")
-        exit()
-elif options.text and options.image is None and options.file is None:
-    qrdata = getSecondParameter('-t', '--text')
-elif options.file and options.image is None and options.text is None:
-    fileName = getSecondParameter('-f', '--file')
-    checkFilePath(fileName)
-
-    with open(fileName, 'r') as fileopener:
-        qrdata = fileopener.read()
-else:
-    print("Error: Please specify (only one!) qr code i/o argument\nHint: run 'python decrypt.py -h'")
-    exit(1)
-
-# remove Context Identifier string (usually 'HCI:')
-qrdata = qrdata[qrdata.find(':') + 1:]
-verbosePrint('raw QR code data', qrdata)
-
-# decrypt payload
-try:
-    base45data = base45.b45decode(str(qrdata))
-    verbosePrint('Base45 decoded data', base45data)
-    zlibdata = zlib.decompress(base45data)
-    verbosePrint('Zlib decompressed data', base45data)
-    cosedata = cbor2.loads(zlibdata)
-    verbosePrint("COSE 'sign1' signed data", cosedata)
-    payload = cbor2.loads(cosedata.value[2])
-except:
-    print("Error: Error while decrypting your string. Are you sure you entered it correctly?")
-    exit(1)
-
-# print payload as formatted json
-prettyPayload = json.dumps(payload, indent=4, sort_keys=True, ensure_ascii=False).encode('utf8')
-if verboseMode: print('\n[Verbose:] formatted JSON data')
-print(prettyPayload.decode())
+        print("Error: Error while decrypting your string. Are you sure you entered it correctly?")
+        exit(1)
+    return payload
+
+def verbosePrint(desc, text):
+    if verboseMode: print("\n[Verbose:] {}\n{}".format(desc, text))
+
+def printPayload(payload):
+    prettyPayload = json.dumps(payload, indent=4, sort_keys=True, ensure_ascii=False).encode('utf8')
+    if verboseMode: print('\n[Verbose:] formatted JSON data')
+    print(prettyPayload.decode())
+
+
+def main():
+    parseCommandlineArguments()
+    qrcode = stripIdentifiers(getQRcode())
+
+    printPayload(decryptPayload(qrcode))
+
+if __name__ == "__main__":
+    main()