automatic handle of cache migration

CHANGELOG

@@ -21,6 +21,7 @@ This is an an experimental and potentially unstable release. Bug reports are wel
 - "file" is now marked as a dependency (thank Guillaume Loret)
 - "--images-mode" allow to choose at startup which images should be dowloaded (none,readable,full)
 - Support for multi-format rendering (such as RSS feeds with html elements)
+- The cache is now automatically upgraded if needed (see .version in your cache)
 
 ## 1.10 - July 31st 2023
 - IMPORTANT : new optional dependency : python-chardet

cache_migration.py

@@ -18,30 +18,14 @@ import os
 import os.path
 
 
-def v1_10_0(cache_dir: str) -> None:
+def upgrade_to_1(cache_dir: str) -> None:
     """
     Rename index.txt to gophermap in the Gopher protocol cache.
     """
+    print("Upgrading cache to version 1: migrating index.txt to gophermap")
     for root, _, files in os.walk(os.path.join(cache_dir, 'gopher')):
         for f in files:
             if f == 'index.txt':
                 src = os.path.join(root, f)
                 dst = os.path.join(root, 'gophermap')
                 os.rename(src, dst)
-
-
-if __name__ == '__main__':
-    # Compute the default offpunk cache directory.
-    xdg_cache_home = os.environ.get('XDG_CACHE_HOME')
-    if xdg_cache_home:
-        default_cache_dir = os.path.join(xdg_cache_home, 'offpunk')
-    else:
-        default_cache_dir = os.path.join(os.path.expanduser('~'), '.cache/offpunk')
-    # Parse command line arguments.
-    parser = argparse.ArgumentParser(
-        description='Migrate the offpunk cache to a newer version.')
-    parser.add_argument('cache_dir', metavar='CACHE_DIR', nargs='?',
-        default=default_cache_dir, help='the path to the cache')
-    args = parser.parse_args()
-    # Run the cache migration functions from the oldest to the newest version.
-    v1_10_0(args.cache_dir)

man/migrate-offpunk-cache.1

@@ -1,44 +0,0 @@
-.Dd August 11, 2023
-.Dt MIGRATE-OFFPUNK-CACHE 1
-.Os
-.
-.Sh NAME
-.Nm migrate-offpunk-cache
-.Nd migrate offpunk cache to the newest version
-.
-.Sh SYNOPSIS
-.Nm
-.Op Ar CACHE_DIR
-.Nm
-.Fl h | \-help
-.
-.Sh DESCRIPTION
-For each new version of offpunk that requires changes to the cache,
-a migration function is provided.
-All migration functions will be called by this script,
-from the oldest to the newest version.
-.Ss Positional arguments
-.Bl -tag -width Ds -offset indent
-.It CACHE_DIR
-This is the path to the cache.
-The default value will point to $XDG_CACHE_HOME,
-or $HOME/.cache/offpunk if undefined.
-.El
-.Ss Keyword arguments
-.Bl -tag -width Ds -offset indent
-.It Fl h , \-help
-Show a help message and exit
-.El
-.
-.Sh EXIT STATUS
-.Ex -std
-.
-.Sh SEE ALSO
-.Xr ansicat 1 ,
-.Xr netcache 1 ,
-.Xr offpunk 1 ,
-.Xr opnk 1 ,
-.Lk https://sr.ht/~lioploum/offpunk/
-.
-.Sh AUTHORS
-.An Lionel Dricot (Ploum) Aq Mt offpunk2 at ploum.eu

offutils.py

@@ -13,6 +13,9 @@ import shutil
 import shlex
 import urllib.parse
 import urllib.parse
+import cache_migration
+
+CACHE_VERSION = 1
 
 ## Config directories
 ## We implement our own python-xdg to avoid conflict with existing libraries.
@@ -34,6 +37,30 @@ cache_home = os.environ.get('XDG_CACHE_HOME') or\
                 os.path.join(_home,'.cache')
 _CACHE_PATH = os.path.join(os.path.expanduser(cache_home),"offpunk/")
 
+#Let’s read current version of the cache
+version_path = _CACHE_PATH + ".version"
+current_version = 0
+if os.path.exists(version_path):
+    current_str = None
+    with open(version_path) as f:
+        current_str = f.read()
+        f.close()
+    try:
+        current_version = int(current_str)
+    except:
+        current_version = 0
+
+#Now, let’s upgrade the cache if needed
+while current_version < CACHE_VERSION:
+    current_version += 1
+    upgrade_func = getattr(cache_migration,"upgrade_to_"+str(current_version))
+    upgrade_func(_CACHE_PATH)
+    with open(version_path,"w") as f:
+        f.write(str(current_version))
+        f.close()
+
+
+
 ## Those two functions add/remove the mode to the
 # URLs. This is a gross hack to remember the mode
 def mode_url(url,mode):