Revised compression.decompress.decompress.

py_tools_ds/compression/decompress.py

@@ -3,22 +3,31 @@
 import os
 import zipfile
 import tarfile
-from logging import Logger
+import gzip
+from logging import getLogger
+import shutil
 
 __author__ = 'Daniel Scheffler'
 
 
-def decompress(compressed_file, outputpath=None, logger=Logger('decompressor')):
-    """Decompresses ZIP, TAR, TAR.GZ and TGZ archives to a given output path.
+def decompress(compressed_file, outputpath=None, logger=getLogger('decompressor')):
+    """Decompresses ZIP, TAR, TAR.GZ, TGZ and GZ archives to a given output path.
     :param compressed_file:
     :param outputpath:
     :param logger:      instance of logging.Logger
     """
-    filepath, filename = os.path.split(compressed_file)
-    logger.info('Extracting ' + filename + '...')
-    outputpath = outputpath or os.path.join(filepath, filename.partition(".")[0])
-    if not os.path.exists(outputpath):
-        os.makedirs(outputpath)
+    # define output folder and filename
+    in_folder, in_filename = os.path.split(compressed_file)
+    out_folder, out_filename = os.path.split(outputpath) if outputpath else ('', '')
+    out_filename = out_filename or in_filename.partition(".")[0]
+    out_folder = out_folder or in_folder
+    outputpath = os.path.join(out_folder, out_filename)
+
+    # decompress
+    logger.info('Extracting ' + in_filename + '...')
+
+    if not os.path.isdir(out_folder):
+        os.makedirs(out_folder)
 
     if compressed_file.endswith(".zip"):
         assert zipfile.is_zipfile(compressed_file), \
@@ -30,7 +39,7 @@ def decompress(compressed_file, outputpath=None, logger=Logger('decompressor')):
             if os.path.exists(os.path.join(outputpath, n)) and \
                     zipfile.ZipFile.getinfo(zf, n).file_size == os.stat(os.path.join(outputpath, n)).st_size:
                 logger.warning("file '%s' from '%s' already exists in the directory: '%s'"
-                               % (n, filename, outputpath))
+                               % (n, in_filename, outputpath))
             else:
                 written = 0
                 while written == 0:
@@ -45,12 +54,12 @@ def decompress(compressed_file, outputpath=None, logger=Logger('decompressor')):
                         else:
                             raise
         if count_extracted == 0:
-            logger.warning("No files of %s have been decompressed.\n" % filename)
+            logger.warning("No files of %s have been decompressed.\n" % in_filename)
         else:
-            logger.info("Extraction of '" + filename + " was successful\n")
+            logger.info("Extraction of '" + in_filename + " was successful\n")
         zf.close()
 
-    elif compressed_file.endswith(".tar") or compressed_file.endswith(".tar.gz") or compressed_file.endswith(".tgz"):
+    elif compressed_file.endswith((".tar", ".tar.gz", ".tgz")):
         tf = tarfile.open(compressed_file)
         names, members = tf.getnames(), tf.getmembers()
         count_extracted = 0
@@ -58,7 +67,7 @@ def decompress(compressed_file, outputpath=None, logger=Logger('decompressor')):
             if os.path.exists(os.path.join(outputpath, n)) and \
                     m.size == os.stat(os.path.join(outputpath, n)).st_size:
                 logger.warning("file '%s' from '%s' already exists in the directory: '%s'"
-                               % (n, filename, outputpath))
+                               % (n, in_filename, outputpath))
             else:
                 written = 0
                 while written == 0:
@@ -73,7 +82,16 @@ def decompress(compressed_file, outputpath=None, logger=Logger('decompressor')):
                         else:
                             raise
         if count_extracted == 0:
-            logger.warning("No files of %s have been decompressed.\n" % filename)
+            logger.warning("No files of %s have been decompressed.\n" % in_filename)
         else:
-            logger.info("Extraction of '" + filename + " was successful\n")
+            logger.info("Extraction of '" + in_filename + " was successful\n")
         tf.close()
+
+    elif compressed_file.endswith(".gz"):
+        with gzip.open(compressed_file, 'rb') as f_in:
+            with open(outputpath, 'wb') as f_out:
+                shutil.copyfileobj(f_in, f_out)
+
+    else:
+        raise ValueError('Unexpected file extension of compressed file. Supported file extensions are: '
+                         '*.zip, *.tar and *.tgz')