Use a strategy to decide conflict resolution

PFERD/organizer.py

@@ -7,8 +7,9 @@ import filecmp
 import logging
 import os
 import shutil
+from enum import Enum
 from pathlib import Path, PurePath
-from typing import List, Optional, Set
+from typing import Callable, List, Optional, Set
 
 from .download_summary import DownloadSummary
 from .location import Location
@@ -19,6 +20,25 @@ LOGGER = logging.getLogger(__name__)
 PRETTY = PrettyLogger(LOGGER)
 
 
+class FileConflictResolution(Enum):
+    """
+    The reaction when confronted with a file conflict.
+    """
+
+    OVERWRITE_EXISTING = "overwrite"
+    KEEP_EXISTING = "keep"
+    DEFAULT = "default"
+    PROMPT = "prompt"
+
+
+FileConflictResolver = Callable[[PurePath], FileConflictResolution]
+
+
+def resolve_prompt_user(_path: PurePath) -> FileConflictResolution:
+    """Resolves conflicts by always asking the user."""
+    return FileConflictResolution.PROMPT
+
+
 class FileAcceptException(Exception):
     """An exception while accepting a file."""
 
@@ -26,7 +46,7 @@ class FileAcceptException(Exception):
 class Organizer(Location):
     """A helper for managing downloaded files."""
 
-    def __init__(self, path: Path, no_prompt: bool = False):
+    def __init__(self, path: Path, conflict_resolver: FileConflictResolver = resolve_prompt_user):
         """Create a new organizer for a given path."""
         super().__init__(path)
         self._known_files: Set[Path] = set()
@@ -36,7 +56,7 @@ class Organizer(Location):
 
         self.download_summary = DownloadSummary()
 
-        self.not_prompting = no_prompt
+        self.conflict_resolver = conflict_resolver
 
     def accept_file(self, src: Path, dst: PurePath) -> Optional[Path]:
         """
@@ -69,18 +89,14 @@ class Organizer(Location):
 
         if self._is_marked(dst):
             PRETTY.warning(f"File {str(dst_absolute)!r} was already written!")
-            default_action: bool = False
+            if self._resolve_conflict(f"Overwrite file?", dst_absolute, default=False):
-            if self.not_prompting and not default_action \
-                    or not self.not_prompting and not prompt_yes_no(f"Overwrite file?", default=default_action):
                 PRETTY.ignored_file(dst_absolute, "file was written previously")
                 return None
 
         # Destination file is directory
         if dst_absolute.exists() and dst_absolute.is_dir():
-            default_action: bool = False
+            prompt = f"Overwrite folder {dst_absolute} with file?"
-            if self.not_prompting and default_action \
+            if self._resolve_conflict(prompt, dst_absolute, default=False):
-                    or not self.not_prompting \
-                    and prompt_yes_no(f"Overwrite folder {dst_absolute} with file?", default=default_action):
                 shutil.rmtree(dst_absolute)
             else:
                 PRETTY.warning(f"Could not add file {str(dst_absolute)!r}")
@@ -151,8 +167,20 @@ class Organizer(Location):
     def _delete_file_if_confirmed(self, path: Path) -> None:
         prompt = f"Do you want to delete {path}"
 
-        default_action: bool = False
+        if self._resolve_conflict(prompt, path, default=False):
-        if self.not_prompting and default_action or \
-                not self.not_prompting and prompt_yes_no(prompt, default_action):
             self.download_summary.add_deleted_file(path)
             path.unlink()
+
+    def _resolve_conflict(self, prompt: str, path: Path, default: bool) -> bool:
+        if not self.conflict_resolver:
+            return prompt_yes_no(prompt, default=default)
+
+        result = self.conflict_resolver(path)
+        if result == FileConflictResolution.DEFAULT:
+            return default
+        if result == FileConflictResolution.KEEP_EXISTING:
+            return False
+        if result == FileConflictResolution.OVERWRITE_EXISTING:
+            return True
+
+        return prompt_yes_no(prompt, default=default)

PFERD/pferd.py

@@ -18,7 +18,7 @@ from .ipd import (IpdCrawler, IpdDownloader, IpdDownloadInfo,
                   IpdDownloadStrategy, ipd_download_new_or_modified)
 from .location import Location
 from .logging import PrettyLogger, enable_logging
-from .organizer import Organizer
+from .organizer import FileConflictResolver, Organizer, resolve_prompt_user
 from .tmp_dir import TmpDir
 from .transform import TF, Transform, apply_transform
 from .utils import PathLike, to_path
@@ -76,13 +76,13 @@ class Pferd(Location):
             download_strategy: IliasDownloadStrategy,
             timeout: int,
             clean: bool = True,
-            no_prompt: bool = None
+            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
     ) -> Organizer:
         # pylint: disable=too-many-locals
         cookie_jar = CookieJar(to_path(cookies) if cookies else None)
         session = cookie_jar.create_session()
         tmp_dir = self._tmp_dir.new_subdir()
-        organizer = Organizer(self.resolve(to_path(target)), no_prompt if no_prompt is not None else False)
+        organizer = Organizer(self.resolve(to_path(target)), file_conflict_resolver)
 
         crawler = IliasCrawler(base_url, session, authenticator, dir_filter)
         downloader = IliasDownloader(tmp_dir, organizer, session,
@@ -118,6 +118,7 @@ class Pferd(Location):
             download_strategy: IliasDownloadStrategy = download_modified_or_new,
             clean: bool = True,
             timeout: int = 5,
+            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
     ) -> Organizer:
         """
         Synchronizes a folder with the ILIAS instance of the KIT.
@@ -145,6 +146,8 @@ class Pferd(Location):
             clean {bool} -- Whether to clean up when the method finishes.
             timeout {int} -- The download timeout for opencast videos. Sadly needed due to a
                 requests bug.
+            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
+                with overwriting or deleting files. The default always asks the user.
         """
         # This authenticator only works with the KIT ilias instance.
         authenticator = KitShibbolethAuthenticator(username=username, password=password)
@@ -160,7 +163,8 @@ class Pferd(Location):
             transform=transform,
             download_strategy=download_strategy,
             clean=clean,
-            timeout=timeout
+            timeout=timeout,
+            file_conflict_resolver=file_conflict_resolver
         )
 
         self._download_summary.merge(organizer.download_summary)
@@ -185,6 +189,7 @@ class Pferd(Location):
             download_strategy: IliasDownloadStrategy = download_modified_or_new,
             clean: bool = True,
             timeout: int = 5,
+            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
     ) -> Organizer:
         """
         Synchronizes a folder with the ILIAS instance of the KIT. This method will crawl the ILIAS
@@ -211,6 +216,8 @@ class Pferd(Location):
             clean {bool} -- Whether to clean up when the method finishes.
             timeout {int} -- The download timeout for opencast videos. Sadly needed due to a
                 requests bug.
+            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
+                with overwriting or deleting files. The default always asks the user.
         """
         # This authenticator only works with the KIT ilias instance.
         authenticator = KitShibbolethAuthenticator(username=username, password=password)
@@ -226,7 +233,8 @@ class Pferd(Location):
             transform=transform,
             download_strategy=download_strategy,
             clean=clean,
-            timeout=timeout
+            timeout=timeout,
+            file_conflict_resolver=file_conflict_resolver
         )
 
         self._download_summary.merge(organizer.download_summary)
@@ -246,7 +254,7 @@ class Pferd(Location):
             download_strategy: IliasDownloadStrategy = download_modified_or_new,
             clean: bool = True,
             timeout: int = 5,
-            no_prompt: bool = None
+            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
     ) -> Organizer:
         """
         Synchronizes a folder with a given folder on the ILIAS instance of the KIT.
@@ -273,6 +281,8 @@ class Pferd(Location):
             clean {bool} -- Whether to clean up when the method finishes.
             timeout {int} -- The download timeout for opencast videos. Sadly needed due to a
                 requests bug.
+            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
+                with overwriting or deleting files. The default always asks the user.
         """
         # This authenticator only works with the KIT ilias instance.
         authenticator = KitShibbolethAuthenticator(username=username, password=password)
@@ -292,7 +302,7 @@ class Pferd(Location):
             download_strategy=download_strategy,
             clean=clean,
             timeout=timeout,
-            no_prompt=no_prompt
+            file_conflict_resolver=file_conflict_resolver
         )
 
         self._download_summary.merge(organizer.download_summary)
@@ -306,7 +316,8 @@ class Pferd(Location):
             url: str,
             transform: Transform = lambda x: x,
             download_strategy: IpdDownloadStrategy = ipd_download_new_or_modified,
-            clean: bool = True
+            clean: bool = True,
+            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
     ) -> Organizer:
         """
         Synchronizes a folder with a DIVA playlist.
@@ -322,6 +333,8 @@ class Pferd(Location):
                 be downloaded. Can save bandwidth and reduce the number of requests.
                 (default: {diva_download_new})
             clean {bool} -- Whether to clean up when the method finishes.
+            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
+                with overwriting or deleting files. The default always asks the user.
         """
         tmp_dir = self._tmp_dir.new_subdir()
 
@@ -332,7 +345,7 @@ class Pferd(Location):
         if isinstance(target, Organizer):
             organizer = target
         else:
-            organizer = Organizer(self.resolve(to_path(target)))
+            organizer = Organizer(self.resolve(to_path(target)), file_conflict_resolver)
 
         PRETTY.starting_synchronizer(organizer.path, "IPD", url)
 
@@ -360,7 +373,8 @@ class Pferd(Location):
             playlist_location: str,
             transform: Transform = lambda x: x,
             download_strategy: DivaDownloadStrategy = diva_download_new,
-            clean: bool = True
+            clean: bool = True,
+            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
     ) -> Organizer:
         """
         Synchronizes a folder with a DIVA playlist.
@@ -377,6 +391,8 @@ class Pferd(Location):
                 be downloaded. Can save bandwidth and reduce the number of requests.
                 (default: {diva_download_new})
             clean {bool} -- Whether to clean up when the method finishes.
+            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
+                with overwriting or deleting files. The default always asks the user.
         """
         tmp_dir = self._tmp_dir.new_subdir()
 
@@ -392,7 +408,7 @@ class Pferd(Location):
         if isinstance(target, Organizer):
             organizer = target
         else:
-            organizer = Organizer(self.resolve(to_path(target)))
+            organizer = Organizer(self.resolve(to_path(target)), file_conflict_resolver)
 
         PRETTY.starting_synchronizer(organizer.path, "DIVA", playlist_id)
 

sync_url.py

@@ -5,24 +5,35 @@ A simple script to download a course by name from ILIAS.
 """
 
 import argparse
-from pathlib import Path
+from pathlib import Path, PurePath
 from urllib.parse import urlparse
 
 from PFERD import Pferd
 from PFERD.cookie_jar import CookieJar
 from PFERD.ilias import (IliasCrawler, IliasElementType,
                          KitShibbolethAuthenticator)
+from PFERD.organizer import FileConflictResolution, resolve_prompt_user
 from PFERD.transform import sanitize_windows_path
 from PFERD.utils import to_path
 
 
+def _resolve_overwrite(_path: PurePath) -> FileConflictResolution:
+    return FileConflictResolution.OVERWRITE_EXISTING
+
+
+def _resolve_default(_path: PurePath) -> FileConflictResolution:
+    return FileConflictResolution.DEFAULT
+
+
 def main() -> None:
     parser = argparse.ArgumentParser()
     parser.add_argument("--test-run", action="store_true")
     parser.add_argument('-c', '--cookies', nargs='?', default=None, help="File to store cookies in")
     parser.add_argument('--no-videos', nargs='?', default=None, help="Don't download videos")
-    parser.add_argument('-p', '--passive', action="store_true",
+    parser.add_argument('-d', '--default', action="store_true",
                         help="Don't prompt for confirmations and use sane defaults")
+    parser.add_argument('-r', '--remove', action="store_true",
+                        help="Remove and overwrite files without prompting for confirmation")
     parser.add_argument('url', help="URL to the course page")
     parser.add_argument('folder', nargs='?', default=None, help="Folder to put stuff into")
     args = parser.parse_args()
@@ -39,13 +50,17 @@ def main() -> None:
 
     folder = Path(args.folder)
     if args.folder is None:
-        folder = Path(crawler.find_element_name(args.url))
+        element_name = crawler.find_element_name(args.url)
+        if not element_name:
+            print("Error, could not get element name. Please specify a folder yourself.")
+            return
+        folder = Path(element_name)
         cookie_jar.save_cookies()
 
     # files may not escape the pferd_root with relative paths
     # note: Path(Path.cwd, Path(folder)) == Path(folder) if it is an absolute path
     pferd_root = Path(Path.cwd(), Path(folder)).parent
-    folder = folder.name
+    target = folder.name
     pferd = Pferd(pferd_root, test_run=args.test_run)
 
     def dir_filter(_: Path, element: IliasElementType) -> bool:
@@ -53,15 +68,22 @@ def main() -> None:
             return element not in [IliasElementType.VIDEO_FILE, IliasElementType.VIDEO_FOLDER]
         return True
 
+    if args.default:
+        file_confilict_resolver = _resolve_default
+    elif args.remove:
+        file_confilict_resolver = _resolve_overwrite
+    else:
+        file_confilict_resolver = resolve_prompt_user
+
     pferd.enable_logging()
     # fetch
     pferd.ilias_kit_folder(
-        target=folder,
+        target=target,
         full_url=args.url,
         cookies=args.cookies,
         dir_filter=dir_filter,
         transform=sanitize_windows_path,
-        no_prompt=args.passive
+        file_conflict_resolver=file_confilict_resolver
     )