ShipDict : gestion de l'option -z (--gzip) de merger.py

resolves flotpython#45

data/compare.py

@@ -8,7 +8,7 @@
 
 class Compare(object):
     """
-    An object for comparing a file with its reference version
+    A class for comparing a file with its reference version
     that is expected to be found in <filename>.ref
     """
 
@@ -17,15 +17,8 @@ class Compare(object):
         re.compile("<color>[0-9a-f]+</color>"),
     ]
 
-    def __init__(self, filename, ref_name=None):
-        """
-        create object from its filename
-        compute reference filename if not specified
-        """
-        self.filename = filename
-        self.ref_name = ref_name or f"{self.filename}.ref"
-
-    def _bool_compare(self):
+    @staticmethod
+    def _bool_compare(fn_fm, fnref_fm):
         """
         returns True if both files match - modulo ignored portions
         - and False otherwise
@@ -37,13 +30,13 @@ def _bool_compare(self):
         # contents[1] for the reference version
         contents = [None, None]
 
-        for i, name in enumerate((self.filename, self.ref_name)):
+        for i, (name, fm) in enumerate((fn_fm, fnref_fm)):
             try:
-                with open(name, "r", newline="\n") as input:
+                with fm.open(name, mode=fm.READ) as input:
                     full = input.read()
-                    # remove ignored portions
-                    for ignore in self.ignore_regexps:
-                        full = re.sub(ignore, '', full)
+                # remove ignored portions
+                for ignore in Compare.ignore_regexps:
+                    full = ignore.sub('', full)
                 contents[i] = full
             # if anything goes wrong we just return False
             except Exception as e:
@@ -52,13 +45,22 @@ def _bool_compare(self):
             # result is True if both contents match
         return contents[0] == contents[1]
 
-    def compare_and_print(self):
+    @staticmethod
+    def compare_and_print(fn_fm, fnref_fm):
         """
         Checks for equality and prints a one-liner
         returns a boolean that says if both files indeed are equal
+
+        Args:
+            fn_fm: tuple of filename to test and filemanager
+            fnref_fm: tuple of filename of reference and filemanager
         """
-        bool_result = self._bool_compare()
+        filename, _ = fn_fm
+        ref_name, fm = fnref_fm
+        # compute reference filename if not specified
+        ref_name = ref_name or f"{filename}.ref"
+        bool_result = Compare._bool_compare(fn_fm, (ref_name, fm))
         status = "OK" if bool_result else "KO"
-        message = f"Comparing {self.filename} and {self.ref_name} -> {status}"
+        message = f"Comparing {filename} and {ref_name} -> {status}"
         print(message)
         return bool_result

data/factory.py

@@ -0,0 +1,24 @@
+import abc
+
+# application import
+import file_manager
+
+
+class Factory(abc.ABC):
+
+    @staticmethod
+    @abc.abstractmethod
+    def make_filemanager():
+        pass
+
+class GzipFileManagerFactory(Factory):
+
+    @staticmethod
+    def make_filemanager():
+        return file_manager.GzipFileManager()
+
+class TextFileManagerFactory(Factory):
+
+    @staticmethod
+    def make_filemanager():
+        return file_manager.TextFileManager()

data/file_manager.py

@@ -0,0 +1,41 @@
+import abc
+import gzip
+import contextlib
+
+
+class FileManager(abc.ABC):
+
+    @staticmethod
+    @abc.abstractmethod
+    def open(filename, mode):
+        pass
+
+
+class GzipFileManager(FileManager):
+
+    READ = "rt"
+    WRITE = "wt"
+
+    @staticmethod
+    @contextlib.contextmanager
+    def open(filename, mode):
+        file = gzip.open(filename, encoding="UTF-8", mode=mode, newline="\n")
+        try:
+            yield file
+        finally:
+            file.close()
+
+
+class TextFileManager(FileManager):
+
+    READ = "r"
+    WRITE = "w"
+
+    @staticmethod
+    @contextlib.contextmanager
+    def open(filename, mode):
+        file = open(filename, encoding="UTF-8", mode=mode, newline="\n")
+        try:
+            yield file
+        finally:
+            file.close()

data/merger.py

@@ -1,16 +1,14 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-# Version : 3.0
-
 # standard library imports
-import gzip
 import json
 import glob
 from argparse import ArgumentParser
 #
 
 # application imports
+import factory
 from shipdict import ShipDict
 from kml import KML
 from compare import Compare
@@ -50,6 +48,11 @@ def __init__(self):
 
         self.ship_dict = ShipDict()
 
+        if self.args.gzip:
+            self.factory = factory.GzipFileManagerFactory()
+        else:
+            self.factory = factory.TextFileManagerFactory()
+
     def merge(self, json_filenames):
         """
         given a list of json filenames, decode the JSON content
@@ -95,7 +98,8 @@ def write_ships_summary(self, ships, out_name):
 
         print(f"Opening {filename} for listing ships")
 
-        with open(filename, 'w', newline="\n") as summary:
+        tfm = factory.TextFileManagerFactory.make_filemanager()
+        with tfm.open(filename, tfm.WRITE) as summary:
             # one line to say how many ships we have seen
             summary.write(f"Found {len(ships)} ships\n")
             # ships are expected to be sorted already
@@ -131,8 +135,8 @@ def write_kml_output(self, ships, out_name):
         # message
         print(f"Opening {kml_filename} for ship {out_name}")
         # open a plain file or compressed file as requested
-        with gzip.open(kml_filename, 'w', newline="\n") if self.args.gzip \
-                else open(kml_filename, 'w', newline="\n") as out:
+        fm = self.factory.make_filemanager()
+        with fm.open(kml_filename, mode=fm.WRITE) as out:
             out.write(contents)
         # return filename
         return kml_filename
@@ -199,8 +203,13 @@ def main(self):
             else:
                 # for each of the 2 files, compare contents with the reference
                 # that is expected to be in this directory with a .ref extension
-                ok_summary = Compare(summary_filename).compare_and_print()
-                ok_kml = Compare(kml_filename).compare_and_print()
+                tfm = factory.TextFileManagerFactory.make_filemanager()
+                ok_summary = Compare.compare_and_print(
+                  (summary_filename, tfm),
+                  (None, tfm))
+                ok_kml = Compare.compare_and_print(
+                  (kml_filename, self.factory.make_filemanager()),
+                  ("ALL_SHIPS.kml.ref", tfm))
                 # is everything fine ?
                 ok = ok_summary and ok_kml
             # if so return 0 otherwise 1

w6/w6-s8-x1-classes-merger.md

@@ -97,7 +97,7 @@ Dans les exercices de cette semaine-là nous avions uniquement utilisé des type
 
 +++
 
-On a écrit une application complète, constituée de 4 modules ; on vous donne le code de trois de ces modules et vous devez écrire le module manquant.
+On a écrit une application complète, constituée de 6 modules ; on vous donne le code de cinq de ces modules et vous devez écrire le module manquant.
 
 +++
 
@@ -175,11 +175,13 @@ Quel que soit le format choisi, une fois installé ceci doit vous donner trois f
 
 +++
 
-Vous pouvez à présent aller chercher les 3 modules suivants :
+Vous pouvez à présent aller chercher les 5 modules suivants :
 
 * [`merger.py`](data/merger.py)
 * [`compare.py`](data/compare.py)
 * [`kml.py`](data/kml.py)
+* [`file_manager.py`](data/file_manager.py)
+* [`factory.py`](data/factory.py)
 
 et les sauver dans le même répertoire.
 
@@ -203,7 +205,7 @@ Votre but dans cet exercice est d'écrire le module manquant `shipdict.py` qui p
 
 Le point d'entrée s'appelle `merger.py`
 
-Il utilise trois modules annexes, qui sont :
+Il utilise cinq modules annexes, qui sont :
 
 * `shipdict.py`, qui implémente les classes
   * `Position` qui contient une latitude, une longitude, et un timestamp
@@ -216,6 +218,14 @@ Il utilise trois modules annexes, qui sont :
 * `kml.py` qui implémente
   * la classe `KML` dans laquelle sont concentrées les fonctions liées à la génération de KML ; c'est notamment en fonction de nos objectifs pédagogiques que ce choix a été fait.
 
+* `file_manager.py`, au travers du module `factory`, qui implémente
+  * la classe `TextFileManager` qui gère l'ouverture et la fermeture de simples fichiers texte
+  * la classe `GzipFileManager` qui gère l'ouverture et la fermeture de fichiers texte compressés avec le logiciel gzip
+
+* `factory.py` qui implémente
+  * la classe `TextFileManagerFactory` qui crée des objets de type `TextFileManager`
+  * la classe `GzipFileManagerFactory` qui crée des objets de type `GzipFileManager`
+
 +++
 
 ##### Lancement