A more structured exception handling

pocket_cli/app.py

@@ -3,10 +3,16 @@ import time
 from datetime import datetime
 from operator import itemgetter
 
-from pocket import Pocket, PocketException
+from pocket import (
+    Pocket,
+    PocketException,
+    PocketAutException
+)
+
 from progress.spinner import Spinner
 
 from .config import Configs
+from .exceptions import AppException, AppNotConfigured
 from .storage import Storage
 
 
@@ -49,7 +55,7 @@ class PocketApp:
         try:
             return self._pocket.add(url, title, tags)
         except PocketException as e:
-            return self._check_exception(e)
+            raise self._check_exception(e) from e
 
     def get_articles(self, limit=None, order=None):
         if self._storage.is_empty():
@@ -61,7 +67,7 @@ class PocketApp:
         try:
             self._pocket.archive(int(item_id)).commit()
         except PocketException as e:
-            return self._check_exception(e)
+            raise self._check_exception(e) from e
 
     def find_article(self, item_id):
         index = self._storage.read()
@@ -98,8 +104,7 @@ class PocketApp:
                 )
             except PocketException as e:
                 spinner.finish()
-                self._check_exception(e)
-                return
+                raise self._check_exception(e) from e
 
             if not articles['list']:
                 break
@@ -147,9 +152,7 @@ class PocketApp:
         return int(time.mktime(date.timetuple()))
 
     def _check_exception(self, e):
-        if int(e.error_code) == 136:
-            print('Application is not configured')
-            print('Run `pocket-cli configure` to be able to use this app')
-            return
-        print(e.message)
-        return False
+        if isinstance(e, PocketAutException):
+            raise AppNotConfigured('Application is not configured')
+
+        raise AppException(e.message)

pocket_cli/cli.py

@@ -6,6 +6,7 @@ import webbrowser
 import click
 
 from .app import PocketApp
+from .exceptions import AppNotConfigured, AppException
 from .utils import format_article
 
 
@@ -73,7 +74,19 @@ def add_article(url, title, tags):
               type=click.Choice(['asc', 'desc']),
               help='Order of items to return')
 def list_articles(limit, order):
-    articles = pocket_app.get_articles(limit, order)
+    try:
+        articles = pocket_app.get_articles(limit, order)
+    except AppNotConfigured:
+        app_not_configured()
+        return
+    except AppException as e:
+        exception_occured(e)
+        return
+
+    if not articles:
+        print('Articles index is empty,'
+              'run pocket-cli fetch to index your articles')
+        return
 
     try:
         pager = subprocess.Popen(['less'],
@@ -140,13 +153,35 @@ def random_article(browser, archive):
 
 @click.command()
 def fetch():
-    pocket_app.fetch_articles(True)
+    try:
+        pocket_app.fetch_articles(True)
+    except AppNotConfigured:
+        app_not_configured()
+    except AppException as e:
+        exception_occured(e)
 
 
 @click.command(name='archive')
 @click.argument('article_id')
 def archive_article(article_id):
-    pocket_app.archive_article(int(article_id))
+    try:
+        pocket_app.archive_article(int(article_id))
+    except AppNotConfigured:
+        app_not_configured()
+    except AppException as e:
+        exception_occured(e)
+
+
+def app_not_configured():
+    print('App is not configured')
+    print('Run `pocket-cli configure` to be able to use the app')
+
+
+def exception_occured(exception):
+    print('An error occured while '
+          'trying to perform requested action: {}'.format(
+              exception.message
+          ))
 
 
 main.add_command(configure)

pocket_cli/exceptions.py

@@ -0,0 +1,8 @@
+class AppNotConfigured(Exception):
+    def __init__(self, message):
+        super().__init__(message)
+
+
+class AppException(Exception):
+    def __init__(self, message):
+        super().__init__(message)

pocket_cli/storage.py

@@ -34,6 +34,9 @@ class Storage:
     def read(self, limit=10, order='asc'):
         index = []
 
+        if not os.path.exists(self._filename):
+            return index
+
         row_counter = 0
         with open(self._filename, 'r') as csv_file:
             reader = csv.DictReader(csv_file)