Undo / Redo APIs

Hypi supports the Versioning of saved data on the object level. You can roll back data to a specific version. It is also possible to restore the rolled-back data.

@versioned

The @versioned directive tracks the version of each object that holds a data of certain type . Declare the data type using the @versioned directive as below.

type VersionedObj @versioned {
 data: String 
}

The version field in the hypi object automatically generates a version for each object created for a data type. Or you can create an object with a unique version number.

mutation {
  upsert(values: { VersionedObj: { data: "abc", hypi: { version: 1 } } }) {
    id
  }
}
#result
{
  "data": {
    "upsert": [
      {
        "id": "01GCBVD8J5Y9H94HC23CTWR8J7"
      }
    ]
  }
}

Update the object data by changing the version number. The version number gets automatically generated if not specified.

mutation {
  upsert(
    values: {
      VersionedObj: {
        data: "xyz"
        hypi: { id: "01GCBVD8J5Y9H94HC23CTWR8J7", version: 2 }
      }
    }
  ) {
    id
  }
}

This way version saves different copies of the data inserted in an object. Hypi facilitates navigation through these copies or versions using undo and redo functions.

undo

The undo function rolls back the data to a previous version or a specified version. Provide the object hypi.id and data type as parameters to the function. To roll back the data to a specific version, provide the version number as well.

Let's check the undo function.

undo(
	type: String!
	id: ID!
	version: Long
): Boolean

Parameter	Description	Example
type	Data type	"VersionedObj"
id	hypi.id of the object to roll back data from	"01GCBVD8J5Y9H94HC23CTWR8J7"
version	Version number to roll back data to. This is an optional parameter. If it isn't provided, data gets rolled back to the previous version.	1
Let's execute the function on the data previously inserted.

mutation {
  undo(type: "VersionedObj", id: "01GCBVD8J5Y9H94HC23CTWR8J7", version: 1)
}
#result
{
  "data": {
    "undo": true
  }
}

Retrieving the data shows data from version 1.

{
  get(type: VersionedObj, id: "01gceewc1yp1wcz1j7d8p9tn2k") {
    ... on VersionedObj {
      hypi {
        id
        version
      }
      data
    }
  }
}
#result
{
  "data": {
    "get": {
      "hypi": {
        "id": "01gceewc1yp1wcz1j7d8p9tn2k",
        "version": 1
      },
      "data": "abc"
    }
  }
}

redo

The redo function restores the rolled back data. Provide the object hypi.id and data type as parameters to the function. To restore the data to a specific version, provide the version number as well.

Let's check the redo function.

redo(
	type: String!
	id: ID!
	version: Long
): Boolean

Parameter	Description	Example
type	Data type	"VersionedObj"
id	hypi.id of the object for which the data needs to be restored	"01GCBVD8J5Y9H94HC23CTWR8J7"
version	Version number to restore data to. This is an optional parameter. If it isn't provided, data gets restored to the previous version.	2
Let's execute the function to restore previously rolled back data.

mutation {
  redo(type: "VersionedObj", id: "01GCBVD8J5Y9H94HC23CTWR8J7", version: 2)
}
#result
{
  "data": {
    "redo": true
  }
}