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copied!<p>There is a simple solution (with full copy on open for read access and full copy on close with write access):</p> <pre><code>import os import shutil from tempfile import mkstemp class CachedFileObject(object): def __init__(self, cache_dir="/tmp"): self.cache_dir = cache_dir self.local_file = None self.local_path = None self.remote_path = None self.mode = None def open(self, path, mode="r", buffering=-1): if self.local_file and not self.local_file.closed: raise ValueError("Already open") fd, self.local_path = mkstemp(dir=self.cache_dir) os.close(fd) try: if "r" in mode and not os.path.exists(path): raise ValueError("No such remote file") if os.path.exists(path): # have remote file self._cache_remote(path, self.local_path) self.local_file = open(self.local_path, mode=mode, buffering=buffering) self.mode = mode self.remote_path = path except Exception as e: os.unlink(self.local_path) raise return self def close(self): self.local_file.close() try: if set("wa+").intersection(set(self.mode)): # have writes, sync file back to remote side self._sync_remote(self.remote_path, self.local_path) finally: os.unlink(self.local_path) def _cache_remote(self, remote_path, local_path): # simple cp shutil.copy(remote_path, local_path) def _sync_remote(self, remote_path, local_path): shutil.copy(local_path, remote_path) def __getattr__(self, attr): if self.local_file is not None: return getattr(self.local_file, attr) else: raise ValueError("File is not opened") </code></pre> <p>Created object will behavior as regular file, and just copy/sync on open/close.</p> <p>Usage:</p> <pre><code>f = CachedFileObject(cache_dir="/your/tmp/dir") f.open("/path/to/remote/file") # ..your f.read()'s here.. f.close() </code></pre>

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