How to save y-doc in mongdoDB.

1

We are trying to receive a y-doc from the client and store it in MongoDB. After confirming that typeof(doc) was an object, we tried the following three methods.

  1. Convert to string and store: JSON.stringify(doc)
  2. doc.JSON()
  3. Save doc in schema as it is.

we need your help because we failed everything.

How can y-doc be stored in a commercial DB (mongoDB) rather than y-leveldb, y-indexdb?
we are university student

2

Hi @jinh0303,

You can encode the document to a binary object and transform it back to a Yjs document. This process is documented here: Document Updates - Yjs Docs

// encode the document to a binary object: 
storeInDatabase(Y.encodeStateAsUpdate(ydoc))

loadFromDatabase().then(state => {
  const ydoc = new Y.Doc()
  Y.applyUpdate(ydoc)
  ydoc // should now have the same information as the initial document
})
1 Like
3

thank you sir!!

You saved us!

4

Sorry for re opening this thread after so long. For example when I do Y.encodeStateAsUpdate(ydoc1) I get a UInt8Array with value { "0": 1, "1": 1, "2": 136, "3": 145, "4": 193, "5": 243, "6": 6, "7": 0, "8": 4, "9": 1, "10": 11, "11": 99, "12": 111, "13": 110, "14": 116, "15": 101, "16": 110, "17": 116, "18": 72, "19": 84, "20": 77, "21": 76, "22": 1, "23": 100, "24": 0 }

lets store it in foo and do Y.applyUpdate(ydoc2, foo) and boom I get an error.

Unhandled Runtime Error

Error: Unexpected end of array

It happens even if I use the UintArray constructor like this new Uint8Array(foo). I have been banging my head since last week solving this error. What am I missing here?

5

{ "0": 1, "1": 1, "2": 136, "3": 145, "4": 193, "5": 243, "6": 6, "7": 0, "8": 4, "9": 1, "10": 11, "11": 99, "12": 111, "13": 110, "14": 116, "15": 101, "16": 110, "17": 116, "18": 72, "19": 84, "20": 77, "21": 76, "22": 1, "23": 100, "24": 0 }

⇐ This is not a Uint8Array. This is a stringified JSON.stringify’d Uint8Array. There is a section about how you should transmit data over the network: Document Updates | Yjs Docs