Moved the lock related code to commoniface and adapted to the ref imp…

…lementation

See https://github.com/cs3org/cs3apis/blob/main/cs3/storage/provider/v1beta1/resources.proto
And cs3org/cs3apis#160

src/core/commoniface.py

@@ -1,13 +1,16 @@
 '''
 commoniface.py
 
-common entities used by all storage interfaces for the IOP WOPI server
+Common entities used by all storage interfaces for the IOP WOPI server.
+Includes functions to store and retrieve Reva-compatible locks.
 
 Author: Giuseppe.LoPresti@cern.ch, CERN/IT-ST
 '''
 
 import time
 import json
+from base64 import urlsafe_b64encode, urlsafe_b64decode
+
 
 # standard file missing message
 ENOENT_MSG = 'No such file or directory'
@@ -22,5 +25,15 @@
 LOCKKEY = 'user.iop.lock'
 
 def genrevalock(appname, value):
-    '''Return a JSON-formatted lock compatible with the Reva implementation of the CS3 Lock API'''
-    return json.dumps({'h': appname if appname else 'wopi', 't': int(time.time()), 'md': value})
+    '''Return a base64-encoded lock compatible with the Reva implementation of the CS3 Lock API
+       cf. https://github.com/cs3org/cs3apis/blob/main/cs3/storage/provider/v1beta1/resources.proto'''
+    return urlsafe_b64encode(json.dumps(
+        {'type': 'LOCK_TYPE_SHARED',
+         'h': appname if appname else 'wopi',
+         'md': value,
+         'mtime': int(time.time()),
+        }).encode()).decode()
+
+def retrieverevalock(rawlock):
+    '''Restores the JSON payload from a base64-encoded Reva lock'''
+    return json.loads(urlsafe_b64decode(rawlock).decode())

src/core/localiface.py

@@ -10,7 +10,6 @@
 import os
 import warnings
 from stat import S_ISDIR
-import json
 import core.commoniface as common
 
 LOCKKEY = 'user.iop.lock'    # this is to be compatible with the (future) Lock API in Reva
@@ -81,7 +80,7 @@ def setxattr(_endpoint, filepath, _userid, key, value):
     '''Set the extended attribute <key> to <value> on behalf of the given userid'''
     try:
         os.setxattr(_getfilepath(filepath), 'user.' + key, str(value).encode())
-    except (FileNotFoundError, PermissionError, OSError) as e:
+    except OSError as e:
         log.error('msg="Failed to setxattr" filepath="%s" key="%s" exception="%s"' % (filepath, key, e))
         raise IOError(e)
 
@@ -91,7 +90,7 @@ def getxattr(_endpoint, filepath, _userid, key):
     try:
         filepath = _getfilepath(filepath)
         return os.getxattr(filepath, 'user.' + key).decode('UTF-8')
-    except (FileNotFoundError, PermissionError, OSError) as e:
+    except OSError as e:
         log.error('msg="Failed to getxattr" filepath="%s" key="%s" exception="%s"' % (filepath, key, e))
         return None
 
@@ -100,7 +99,7 @@ def rmxattr(_endpoint, filepath, _userid, key):
     '''Remove the extended attribute <key> on behalf of the given userid'''
     try:
         os.removexattr(_getfilepath(filepath), 'user.' + key)
-    except (FileNotFoundError, PermissionError, OSError) as e:
+    except OSError as e:
         log.error('msg="Failed to rmxattr" filepath="%s" key="%s" exception="%s"' % (filepath, key, e))
         raise IOError(e)
 
@@ -118,7 +117,7 @@ def getlock(endpoint, filepath, _userid):
     '''Get the lock metadata as an xattr on behalf of the given userid'''
     l = getxattr(endpoint, filepath, '0:0', common.LOCKKEY)
     if l:
-        return json.loads(l)
+        return common.retrieverevalock(l)
     return None
 
 def refreshlock(endpoint, filepath, _userid, appname, value):

src/core/wopiutils.py

@@ -159,7 +159,8 @@ def generateAccessToken(userid, fileid, viewmode, user, folderurl, endpoint, app
 
 
 def retrieveWopiLock(fileid, operation, lock, acctok, overridefilename=None):
-    '''Retrieves and logs a lock for a given file: returns the lock and its holder, or (None, None) if missing'''
+    '''Retrieves and logs a lock for a given file: returns the lock and its holder, or (None, None) if missing
+       TODO use the native lock metadata (breaking change) such as the `mtime` and return the whole lock'''
     encacctok = flask.request.args['access_token'][-20:] if 'access_token' in flask.request.args else 'N/A'
     lockcontent = st.getlock(acctok['endpoint'], overridefilename if overridefilename else acctok['filename'], acctok['userid'])
     if not lockcontent:
@@ -203,7 +204,8 @@ def retrieveWopiLock(fileid, operation, lock, acctok, overridefilename=None):
 
 
 def _makeLock(lock):
-    '''Generates the lock payload given the raw data'''
+    '''Generates the lock payload given the raw data
+    TODO drop the expiration time in favour of the lock native metadata'''
     lockcontent = {}
     lockcontent['wopilock'] = lock
     # append or overwrite the expiration time

src/core/xrootiface.py

@@ -12,8 +12,6 @@
 from stat import S_ISDIR
 from base64 import b64encode
 from pwd import getpwnam
-from base64 import urlsafe_b64encode, urlsafe_b64decode
-import json
 from XRootD import client as XrdClient
 from XRootD.client.flags import OpenFlags, QueryCode, MkDirFlags, StatInfoFlags
 
@@ -275,8 +273,7 @@ def setlock(endpoint, filepath, userid, appname, value):
     The special option "c" (create-if-not-exists) is used to be atomic'''
     try:
         log.debug('msg="Invoked setlock" filepath="%s"' % filepath)
-        setxattr(endpoint, filepath, userid, common.LOCKKEY, \
-                 urlsafe_b64encode(common.genrevalock(appname, value).encode()).decode() + '&mgm.option=c')
+        setxattr(endpoint, filepath, userid, common.LOCKKEY, common.genrevalock(appname, value) + '&mgm.option=c')
     except IOError as e:
         if EXCL_XATTR_MSG in str(e):
             raise IOError(common.EXCL_ERROR)
@@ -286,7 +283,7 @@ def getlock(endpoint, filepath, userid):
     '''Get the lock metadata as an xattr'''
     l = getxattr(endpoint, filepath, userid, common.LOCKKEY)
     if l:
-        return json.loads(urlsafe_b64decode(l).decode())
+        return common.retrieverevalock(l)
     return None         # no pre-existing lock found, or error attempting to read it: assume it does not exist
 
 
@@ -299,8 +296,7 @@ def refreshlock(endpoint, filepath, userid, appname, value):
     if l['h'] != appname and l['h'] != 'wopi':
         raise IOError('File is locked by %s' % l['h'])
     # this is non-atomic, but the lock was already held
-    setxattr(endpoint, filepath, userid, common.LOCKKEY, \
-             urlsafe_b64encode(common.genrevalock(appname, value).encode()).decode())
+    setxattr(endpoint, filepath, userid, common.LOCKKEY, common.genrevalock(appname, value))
 
 
 def unlock(endpoint, filepath, userid, _appname):