Refactored the Unpacker class

Author: mdxs

unpacker.py

@@ -1,54 +1,52 @@
 #!/usr/bin/env python
 
 import os.path
-import zipfile
-import tempfile
 import random
-import string
-import shutil
 import re
+import shutil
+import string
+import tempfile
+import zipfile
 
-from os.path  import basename
 
 class Unpacker(object):
-   #--------------------------------------------------------------------------
-   # 
-   #--------------------------------------------------------------------------
-   def entropy(self, length):
-       return ''.join(random.choice(string.lowercase) for i in range (length))
-
-   #--------------------------------------------------------------------------
-   # 
-   #--------------------------------------------------------------------------
-   def unpack_zipfile(self, file):
-
-        if not os.path.isfile(file):
-            raise Exception("Error: file, not found!")
-
-        # Create unique working direction into which the zip file is expanded
-        self.unzip_dir = "{0}/{1}_{2}".format(tempfile.gettempdir(), os.path.splitext(basename(file))[0], self.entropy(6))
-
-        datfilename = ""
-        binfilename = ""
-
-        with zipfile.ZipFile(file, 'r') as zip:
-            files = [item.filename for item in zip.infolist()]
-            datfilename = [m.group(0) for f in files for m in [re.search('.*\.dat', f)] if m].pop()
-            binfilename = [m.group(0) for f in files for m in [re.search('.*\.bin', f)] if m].pop()
-
-            zip.extractall(r'{0}'.format(self.unzip_dir))
-
-        datfile = "{0}/{1}".format(self.unzip_dir, datfilename)
-        binfile = "{0}/{1}".format(self.unzip_dir, binfilename)
-
-        # print "DAT file: " + datfile
-        # print "BIN file: " + binfile
-
-        return binfile, datfile
-
-   #--------------------------------------------------------------------------
-   # 
-   #--------------------------------------------------------------------------
-   def delete(self):
-       # delete self.unzip_dir and its contents
-       shutil.rmtree(self.unzip_dir)
+    """
+    Helper class to unpack a nRF5 Device Firmware Update (DFU)
+    based .zip file in a temporary folder and locate the .bin
+    and associated .dat files inside of it.
+    Removes the temporary folder on desctruction of the instance.
+    """
+
+    def __init__(self):
+        self.unzip_dir = ''
+
+    def unpack_zipfile(self, zip_fname):
+        if not os.path.isfile(zip_fname):
+            raise Exception("Error: file '{}' not found!".format(zip_fname))
+        # create unique working directory into which to expand the zip file
+        rnd_str = ''.join(random.choice(string.ascii_lowercase) for i in range(6))
+        self.unzip_dir = '{0}/{1}_{2}'.format( \
+            tempfile.gettempdir(), \
+            os.path.splitext(os.path.basename(zip_fname))[0], \
+            rnd_str)
+        bin_fname = ''
+        dat_fname = ''
+        with zipfile.ZipFile(zip_fname, 'r') as zf:
+            files = [item.filename for item in zf.infolist()]
+            bin_fname = [m.group(0) for f in files
+                         for m in [re.search('.*\.bin', f)] if m].pop()
+            dat_fname = [m.group(0) for f in files
+                         for m in [re.search('.*\.dat', f)] if m].pop()
+            zf.extractall(r'{0}'.format(self.unzip_dir))
+        bin_file = '{0}/{1}'.format(self.unzip_dir, bin_fname)
+        dat_file = '{0}/{1}'.format(self.unzip_dir, dat_fname)
+        return bin_file, dat_file
+
+    def __del__(self):
+        if self.unzip_dir:
+            # delete self.unzip_dir and its contents
+            shutil.rmtree(self.unzip_dir)
+
+    def delete(self):
+        # delete self.unzip_dir and its contents
+        shutil.rmtree(self.unzip_dir)