Understanding GetMissingPatches output when invoking with Windows Update Agent (WUA)

Overview

The GetMissingPatches method, when invoking with Windows Update Agent (WUA) (Signature: 1103), works directly with Microsoft’s WUA API. Our SDK sends the appropriate input parameters to Microsoft’s API, retrieves the results, and then converts them into a standardized output format. This standardized output is returned as the json_out object of the GetMissingPatches method.

This article provides a detailed explanation of the fields included in the GetMissingPatches json_out object, helping you correctly interpret their values and integrate them into your application.

Sample output

Below is the sample output of GetMissingPatches (method 1013) when using with WUA (signature 1103).

{

    "result" : {

        "method" : 1013,

        "code" : number,

        "timing" : number,

        "timestamp" : string,

        "patches": [

            {

                "id": string,

                "title": string,

                "description": string,

                "revision": number,

                "product": string,

                "vendor": string,

                "severity": string,

                "category_id": string,

                "category": string,

                "category_description": string,

                "category_parent": string,

                "security_update_id": string,

                "kb_id": string,

                "date": string,

                "size": number,

                "reboot_required": boolean,

                "optional": boolean,

                "deployment_action": number,

                "preview_patch": boolean

            },

            ... 

        ],

        "patches_source": string

    }

 }

We will skip the fields method, code, timing, and timestamp, as they are basic outputs of every method in the SDK.

Understanding patches_source

According to Microsoft’s documentation, Windows Update Agent (WUA) can query updates from several different sources. The patches_source field indicates which source is being used. Possible values might include:

Understanding patches' fields

The patches object contains a list of patch entries. Each entry provides details for a single missing update.

The detailed fields are reported directly from Microsoft’s WUA API, while others are processed by SDK logic to ensure consistency for a standardized output.

1. Fields reported directly from WUA API

These values are passed directly from Microsoft’s WUA API without modification.

Category Values

The values from patches[].category in the SDK output is based on the WUA update classifications defined in Microsoft's documentation. For convenience, the key values are summarized below.

DeploymentAction Values

patches[].deployment_action field in the SDK output is passed directly from the Microsoft Windows Update Agent (WUA) API without modification.

The numeric values map to the WUA constants defined in Microsoft's documentation. For convenience, the key values are summarized below.

2. Fields require further processing by SDK

These fields require additional processing by the SDK to interpret or normalize values.

vendor

• Type: string
• Description: The vendor that provides this update.
• Logic:
  • This field will be omitted if the update a Driver Update.
  • "Microsoft Corporation" if the update is not a driver update and source is Windows Update/Microsoft Update.
  • "unknown" if the source is WSUS/Configuration Manager.

severity

• Type: string
• Description: This will fetch the Microsoft Security Response Center severity rating of the update.
• Logic:
  • This field is primarily reported from WUA API via IUpdate::get_MsrcSeverity (Reference from Microsoft).
  • If severity cannot be retrieved, SDK classifies based on the update category.

optional

• Type: boolean
• Description: Indicates if this is an optional update.
• Logic:
  • This field is derived from deployment_action field. Check the DeploymentAction Values table above for possible values of deployment_action field.
  • It is set to true when deployment_action equals 4, and false otherwise.

preview_patch

• Type: boolean
• Description: __Indicates if this is an preview update.
• Logic: Set by SDK to indicate if update is a preview update.