Not able to Retrieve back the stored C# object stored as Stream in FileStorage about litedb

[mykemaas]

I was curious, so I tried your sample. It looks like the trouble is that the SerializeToStream method does serialize the object, but leaves the stream's position at the end of the serialized object. You'll need to add this:

stream.Seek(0, SeekOrigin.Begin);

So, ultimately, the method looks like this:

    public static MemoryStream SerializeToStream(object o) {
        MemoryStream stream = new MemoryStream();
        IFormatter formatter = new BinaryFormatter();
        formatter.Serialize(stream, o);
        stream.Seek(0, SeekOrigin.Begin);
        return stream;
    }

This will set the stream position at the beginning, so that when it is persisted in the database, it reads the whole stream.

Hope this helps.

[sherry-ummen]

Very interesting.

How did you find about it?

Sent from my Windows Phone

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From: Mykemailto:[email protected]
Sent: ‎02-‎09-‎2015 23:40
To: mbdavid/LiteDBmailto:[email protected]
Cc: Sherry Ummenmailto:[email protected]
Subject: Re: [LiteDB] Not able to Retrieve back the stored C# object stored as Stream in FileStorage (#54)

I was curious, so I tried your sample. It looks like the trouble is that the SerializeToStream method does serialize the object, but leaves the stream's position at the end of the serialized object. You'll need to add this:

stream.Seek(0, SeekOrigin.Begin);

So, ultimately, the method looks like this:

    public static MemoryStream SerializeToStream(object o) {
        MemoryStream stream = new MemoryStream();
        IFormatter formatter = new BinaryFormatter();
        formatter.Serialize(stream, o);
        stream.Seek(0, SeekOrigin.Begin);
        return stream;
    }

This will set the stream position at the beginning, so that when it is persisted in the database, it reads the whole stream.

Hope this helps.

---

Reply to this email directly or view it on GitHub:
#54 (comment)

[mykemaas]

I've made the same mistake 😄

It's not really an issue with LiteDB... Any library that reads from a stream always reads from the current position. This gives you the ability to set the stream to an appropriate position before passing it in. I've been bitten by this one before in an unrelated case, but that experience let me recognize the issue right off.

[sherry-ummen]

Very nice. I will try this in few hours as its quite late here in Finland n I shoul get some sleep. Thanks

Sent from my Windows Phone

---

From: Mykemailto:[email protected]
Sent: ‎03-‎09-‎2015 00:06
To: mbdavid/LiteDBmailto:[email protected]
Cc: Sherry Ummenmailto:[email protected]
Subject: Re: [LiteDB] Not able to Retrieve back the stored C# object stored as Stream in FileStorage (#54)

I've made the same mistake 😄

It's not really an issue with LiteDB... Any library that reads from a stream always reads from the current position. This gives you the ability to set the stream to an appropriate position before passing it in. I've been bitten by this one before in an unrelated case, but that experience let me recognize the issue right off.

---

Reply to this email directly or view it on GitHub:
#54 (comment)

[mbdavid]

Hi @sherry-ummen! @mykemaas is right, LiteDB use stream from current position. But, the best solution could be implement Write operation in LiteFileStream. It's not a simple think, so I just throw a not implement exception. This custom Stream was a contribution from other old project FileDB that I wrote 5 year ago.

[sherry-ummen]

Great thanks Myke and Mauricio. it worked