factorize subprocess based filters

compress/filters/__init__.py

+import subprocess
+
+
 class FilterBase:
     def __init__(self, verbose):
         self.verbose = verbose
@@ -12,3 +15,27 @@ class FilterBase:
 class FilterError(Exception):
     """This exception is raised when a filter fails"""
     pass
+
+
+class SubProcessFilter(FilterBase):
+    def execute_command(self, command, content):
+        pipe = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE,
+            stdin=subprocess.PIPE, stderr=subprocess.PIPE)
+        pipe.stdin.write(content)
+        pipe.stdin.close()
+
+        compressed_content = pipe.stdout.read()
+        pipe.stdout.close()
+
+        error = pipe.stderr.read()
+        pipe.stderr.close()
+
+        if pipe.wait() != 0:
+            if not error:
+                error = "Unable to apply %s filter" % self.__class__.__name__
+            raise FilterError(error)
+
+        if self.verbose:
+            print error
+
+        return compressed_content

compress/filters/closure/__init__.py

-import subprocess
-
 from compress.conf import settings
-from compress.filters import FilterBase, FilterError
+from compress.filters import SubProcessFilter
 
 
-class ClosureCompressorFilter(FilterBase):
+class ClosureCompressorFilter(SubProcessFilter):
     def filter_js(self, js):
         command = '%s %s' % (settings.COMPRESS_CLOSURE_BINARY, settings.COMPRESS_CLOSURE_ARGUMENTS)
-
         if self.verbose:
             command += ' --verbose'
-
-        p = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE,
-            stdin=subprocess.PIPE, stderr=subprocess.PIPE)
-        p.stdin.write(js)
-        p.stdin.close()
-
-        filtered_js = p.stdout.read()
-        p.stdout.close()
-
-        err = p.stderr.read()
-        p.stderr.close()
-
-        if p.wait() != 0:
-            if not err:
-                err = 'Unable to apply Closure Compressor filter'
-
-            raise FilterError(err)
-
-        if self.verbose:
-            print err
-
-        return filtered_js
+        return self.execute_command(command, js)

compress/filters/uglifyjs/__init__.py

-import subprocess
-
 from compress.conf import settings
-from compress.filters import FilterBase, FilterError
+from compress.filters import SubProcessFilter
 
 
-class UglifyJSCompressorFilter(FilterBase):
+class UglifyJSCompressorFilter(SubProcessFilter):
     def filter_js(self, js):
         command = '%s %s' % (settings.COMPRESS_UGLIFYJS_BINARY, settings.COMPRESS_UGLIFYJS_ARGUMENTS)
-
         if self.verbose:
             command += ' --verbose'
-
-        p = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE,
-            stdin=subprocess.PIPE, stderr=subprocess.PIPE)
-        p.stdin.write(js)
-        p.stdin.close()
-
-        filtered_js = p.stdout.read()
-        p.stdout.close()
-
-        err = p.stderr.read()
-        p.stderr.close()
-
-        if p.wait() != 0:
-            if not err:
-                err = 'Unable to apply UglifyJS Compressor filter'
-
-            raise FilterError(err)
-
-        if self.verbose:
-            print err
-
-        return filtered_js
+        return self.execute_command(command, js)

compress/filters/yui/__init__.py

-import subprocess
-
 from compress.conf import settings
-from compress.filters import FilterBase, FilterError
+from compress.filters import SubProcessFilter
 
 
-class YUICompressorFilter(FilterBase):
+class YUICompressorFilter(SubProcessFilter):
     def filter_common(self, content, type_, arguments):
         command = '%s --type=%s %s' % (settings.COMPRESS_YUI_BINARY, type_, arguments)
-
         if self.verbose:
             command += ' --verbose'
-
-        p = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE,
-            stdin=subprocess.PIPE, stderr=subprocess.PIPE)
-        p.stdin.write(content)
-        p.stdin.close()
-
-        compressed_content = p.stdout.read()
-        p.stdout.close()
-
-        err = p.stderr.read()
-        p.stderr.close()
-
-        if p.wait() != 0:
-            if not err:
-                err = 'Unable to apply YUI Compressor filter'
-
-            raise FilterError(err)
-
-        if self.verbose:
-            print err
-
-        return compressed_content
+        return self.execute_command(command, content)
 
     def filter_js(self, js):
         return self.filter_common(js, 'js', settings.COMPRESS_YUI_JS_ARGUMENTS)