Litedb: Can it run in memory?

[lidanger]

I mean, when the app begins, LiteDB can load all data into memory, and then LiteDB synchronizes with the local file when the collection change.
Maybe it's not necessary, I only ask a question.

[mbdavid]

Yes it's possible. You can load you file to memory and initialize LiteDB using MemoryStream and when you want persist in disk, write from memory to disk. some like this:
```
var mem = new MemoryStream(File.ReadAllBytes("data.db"));

using (var db = new LiteDatabase(mem))
{
// here, all database are in memory only
}

File.WriteAllBytes("data.db", mem.ToArray());

[lidanger]

Good.

[UweKeim]

Please note that you have to open the memory stream this way, in order to be expandable:

```c#
using (var ms = new MemoryStream())
{
// Do your thing, for example:
m.Attachments[0].ContentStream.CopyTo(ms);

return ms.ToArray(); // This gives you the byte array you want.

}

I.e. you have to call the parameter-less c'tor of `MemoryStream` and later insert the file content into this stream.

----

To catch on to the above example of mbdavid, I've written this function:

```c#
private static MemoryStream readStream(string path)
{
    using (var temp = new MemoryStream(File.ReadAllBytes(path)))
    {
        var ms = new MemoryStream();
        temp.CopyTo(ms);

        return ms;
    }
}

Then, I inserted a call to this function in the example like:

```c#
using (var mem = readStream("data.db"))
{
using (var db = new LiteDatabase(mem))
{
// here, all database are in memory only
}

File.WriteAllBytes("data.db", mem.ToArray());

}
```

(Please note that I've put the memory stream into a using block, too.