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auto backing up of wallet.dat

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I started posting in the other topic but I'll repeat here, this thread seems more specific to the topic.

The main backup improvement will be a pre-generated pool of keys and a rescan at load to scrape missed transactions from the block history.  Then a backup will last forward for a long time.

I was starting to post the same idea you said nelisky.

How about a json-rpc command that locks the wallet, flushes it, copies wallet.dat to a location you specified, then unlocks it?  That would be a smaller project than the pooled keys, so maybe it could be done first.

What's the simplest portable way to copy a file?  Is there something in Boost?

What should it be named?  maybe:
backupwallet <destination>

If you read it into memory and write it out, it could fail in tight memory situations.

I'm looking for something like copyfile(const char* from, const char* to) or copyfile(path from, path to), preferably something in Boost if it has it.  If you find it for me, it's more likely I'll get to implementing it.

As for the file copy, why add to the boost dependency? I for one would love to get a core lib with very little deps.
We require Boost for JSON and a dozen things replacing dependencies on wxWidgets.  Boost is good, portable stuff, we should not shy away from it.
I doubt there's an mmap(2) on Windows.  I'd rather call an existing file copy function than make and test my own.

But if you are already using features from boost::filesystem you can use copy_file from that. I just think that, if not already required for something else, it's a tad overkill.
Thanks.  I thought it would be in there somewhere.

We already use boost::filesystem in a dozen places.  It's not a new added dependency.  It gives us a lot of portable stuff that we would otherwise have to have a #ifdef for each OS and test everywhere.
Sorry, I've been so busy lately I've been skimming messages and I still can't keep up.

We want to avoid Windows API calls whenever possible.  They usually take about 6-8 parameters and a lot of testing to get right, it takes a page of code to do something simple.

I usually shy away from iostreams.  Seems like I too often hit limitations.  They kind of botched the C++ streams standard in the 90's, which is too bad, streams can be very powerful and useful when done right.  Using it in rpc.cpp may still turn out to be a mistake.

Bottom line is I'd rather call an existing file copy function than make and test my own.
rpc backupwallet <destination> is in SVN rev 147.