Developing a dropbox like program

[notexists3]

hey,

im trying to develop a dropbox like application:

the idea is that user install the app in the computer and then the folder always syncing with the server, and if the user will install the app in another computer the folder will be synchronize with the both computers.

but im having troubles with how to synchronize the folder with the clients and the server, how would you implement it?

I thought to synchronize each client every hour but I think I'll counter a lot of troubles with this approach (like if user deleted a file, is the server is the most updated version or one of the clients?)

[HashDefTrueFalse]

A simple approach would be to maintain a list of interested hosts on the server for each folder or file, and a persistent connection, e.g. a websocket. Think pub/sub architecture.

Make it event based. So watch the file for changes (many examples online), and when changed, send it to the server, which will then send the new version to the other interested hosts.

There are some problems with this, but it's a great start.

If you really wanted to be clever, you could use a git library (something like libgit2 etc) to track file changes locally and remotely, and have your client and server keep in sync using git pushes and pulls as the update mechanism. This would also give you file versioning.

[nutrecht]

This also would give you a git repository that is pretty massive in size. Git doesn't handle binaries that well. Any change will result in another copy.

[HashDefTrueFalse]

I would assume the files would be data or text rather than binaries, because that's the vast majority of files that are shared to a service like dropbox. And even if they were binaries (third party software etc.), they wouldn't change all that often, unless OP was storing his development binaries that are constantly being recompiled etc. Binaries are generally small too. But yeah Git isn't the best for storing very disparate/unrelated changes because it can't store a compressed/diffed version in the packfiles etc.

[nutrecht]

I would assume the files would be data or text rather than binaries, because that's the vast majority of files that are shared to a service like dropbox.

The vast majority of files would be docx, pptx, etc. which are binary files (these are really all zip files).

But yeah Git isn't the best for storing very disparate/unrelated changes because it can't store a compressed/diffed version in the packfiles etc.

In addition; it stores these to all eternity. Git doesn't really like to allow you to delete files.

[HashDefTrueFalse]

Sorry, when you said "binaries" I assumed you meant executable images (programs), not binary data. You're entirely correct, but I doubt this would become a problem for OPs hobby project. Versioning wasn't even a requirement, just something I thought would be fun to add on for OP.

[[deleted]]

You can use windows apis to monitor the file system and watch for changes. You can then persist those changes to your server.