META manipulation now goes into Metafile class

persoconf/main.py

@@ -2,10 +2,11 @@
 
 import argparse
 import logging
-import json
 import os, os.path
 import shutil
 
+from metafile import Metafile, MalformedMetafileError, NoPathDefinedError
+
 # FUNCTIONS
 ########################################
 def yes_no_question(question="Yes or no?", default=False):
@@ -153,28 +154,29 @@ if args.command == "add":
     confpath = appdir + "/" + confname
 
     # Load app META file
-    metafile = appdir + "/" + args.metafile
-
     try:
-        appmeta = json.load( open(metafile) )
+        appmeta = Metafile(json_path = appdir + "/" + args.metafile)
+
     except FileNotFoundError:
         log.info("Metafile %s does not exist for app %s" % (args.metafile, args.app))
-        appmeta = { "name" : args.app, "depends": {}, "files": {} }
+        appmeta = Metafile( name=args.app )
+
+    except MalformedMetafileError:
+        log.error("Malformed metafile %s in app %s" % (args.metafile, args.app) )
+        exit(1)
 
     # Check that the file is really new
     absconf = contractuser( os.path.abspath(os.path.expanduser(args.conf)) )
 
     try:
-        destslist = {}
+        dstdic  = appmeta.get_files_dst2src()
 
-        for (fname,finfo) in appmeta["files"].items():
-            destslist[finfo["dest"]] = fname
-    except KeyError:
+    except MalformedMetafileError:
         log.error("Malformed metafile %s in app %s" % (args.metafile, args.app) )
         exit(1)
-
-    if absconf in destslist:
-        log.error("File %s already exists as %s in app %s" % (absconf, destslist[absconf], args.app))
+        
+    if absconf in dstdic:
+        log.error("File %s already exists as %s in app %s" % (absconf, dstdic[absconf], args.app))
         exit(1)
 
     # Copy the conf dir
@@ -207,7 +209,6 @@ if args.command == "add":
         try:
             log.info("Copying conf file")
             shutil.copyfile(args.conf, confpath)
-
             log.info("New conf file '%s' associated with app '%s'" % (confname, args.app))
 
         except PermissionError:
@@ -217,12 +218,16 @@ if args.command == "add":
     # Add the file to META
     # Update META data
     log.debug("adding meta data for %s in %s" % (confname, args.app))
-    appmeta["files"][confname] = { "dest": absconf }
+    appmeta.add_file( confname, dest=absconf )
 
     # Write to the metafile
-    log.debug("Wrinting to metafile")
-    json.dump(appmeta, open(metafile, 'w'))
+    try:
+        log.debug("Writing to metafile")
+        appmeta.save()
     
+    except NoPathDefinedError:
+        log.error("Unable to save json Metafile for app %s : no path defined" % appmeta.name)
+        exit(1)
 
 
 ########################################

persoconf/metafile.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+
+import json
+
+class Metafile():
+    """Representation of a metafile (default name META), containing (as its
+    name implies) metadata."""
+
+
+    def __init__(self, json_path=None, name=None):
+
+        self.name = name
+
+        # json_path  given => we load it ; otherwise fill with default
+        if json_path is not None:
+            self.load_json(json_path) # raise FileNotFoundError
+        else:
+            self.load_default()
+
+    def load_default(self):
+        self.json_path = None
+        self.depends   = {}
+        self.files     = {}
+        # (Note that name is already written in __init__)
+
+    def load_json(self, json_path):
+        self.json_path = json_path
+
+        tmp = json.load( open(self.json_path) ) # Can raise a FileNotFoundError
+
+        try:
+            self.name    = tmp["name"]
+            self.depends = tmp["depends"]
+            self.files   = tmp["files"]
+        except KeyError:
+            raise MalformedMetafileError("Missing attribute (name, depends or files)")
+    
+    def save(self):
+        if self.json_path is None:
+            raise NoPathDefinedError("json_path is not defined")
+
+        json.dump( { "name": self.name, "depends": self.depends, "files": self.files }, open(self.json_path, 'w') )
+
+
+    def get_files_dst2src(self):
+        dstdic = {}
+
+        try:
+            for (fname, finfo) in self.files.items():
+                dstdic[ finfo["dest"] ] = fname
+        except KeyError:
+            raise MalformedMetafileError("Missing 'dest' attribute in files infos")
+
+        return dstdic
+    
+    def add_file(self, name, dest):
+        self.files[name] = { "dest": dest }
+
+
+
+# Exceptions
+########################################
+class MalformedMetafileError(Exception):
+    """A custom exception to alert that the metafile is malformed"""
+
+    def __init__(self, message):
+        Exception.__init__(self, message)
+        
+
+class NoPathDefinedError(Exception):
+    """A custom exception to alert that the json_path properties of the
+    Metafile is not defined, therefore we cannot write the data."""
+
+    def __init__(self, message):
+        Exception.__init__(self, message)
+        
+
+