Storing custom data within the data model

Managed by | Updated 3 years ago.

Background

This article describes how to add custom data to the data model using a hook script. Once the custom values are in the data model they can be accessed from a Freemarker template.

Custom data elements in the data model

If you need to store variables within the data model there are several customData maps that exist for this purpose:

• transaction.question.customData[]: Custom data to attach to the search question. Values can be added in a pre-process hook script.
• transaction.response.customData[]: Custom data to attach to the search response. Values can be added in a post-process hook script.
• transaction.response.results[n].customData[]: Result-specific custom data. Per result values can be added in a post-process hook script.
• transaction.customData[]: Global custom data. Note: this is not currently accessible from Freemarker so don't use this element.

Adding custom data

The following example shows how to set a few different types of variables in a post process hook script and write these to the response.customData[] list in the data model:

// Define some variables of different types
def number = 3
def string = "This is a string value"
def map=[ident1:"val1", ident2:"val2"]
def list=["item","another item"]
// Add these to custom data in the data model
transaction.response.customData["number"] = number
transaction.response.customData["string"] = string
transaction.response.customData["list"] = list
transaction.response.customData["map"] = map

This results in a data model structure like the following (note: some of the data model elements have been collapsed for clarity in the example:

{
    question: { ... },
    extraSearchesTerminated: false,
    response: {
        resultPacket: { ... },
        returnCode: 0,
        untruncatedPadreOutputSize: 11906,
        facets: [ ... ],
        customData: {
            number: 3,
            string: "This is a string value",
            list: [
                "item",
                "another item"
                ],
            map: {
                ident1: "val1",
                ident2: "val2"
                }
        },
        optimiserModel: null,
        curator: { ... },
        performanceMetrics: { ... }
    },
    session: { ... },
    QueryString: "collection=mycollection&query=!showall",
    error: null
}