From c9eb4f4ff01a467887a32eb6c4d313dfaf5ae099 Mon Sep 17 00:00:00 2001
From: Christian Ege <ch@ege.io>
Date: Wed, 6 Dec 2023 08:50:07 +0100
Subject: [PATCH] feat!: add support for JSON pointers in getSchema

This alows a fine grained access to the getSchema call. But breaks the
API on the other hand since Go does not support multiple signatures of
the same receiving function aka method.

Signed-off-by: Christian Ege <ch@ege.io>
---
 cmd/ovp8xx/cmd/getSchema.go | 55 +++++++++++++++++++++++++++++++++++--
 pkg/ovp8xx/rpc.go           |  8 ++++--
 2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/cmd/ovp8xx/cmd/getSchema.go b/cmd/ovp8xx/cmd/getSchema.go
index 0553410..1a09ee9 100644
--- a/cmd/ovp8xx/cmd/getSchema.go
+++ b/cmd/ovp8xx/cmd/getSchema.go
@@ -12,6 +12,11 @@ import (
 
 func getSchemaCommand(cmd *cobra.Command, args []string) error {
 
+	pointers, err := cmd.Flags().GetStringSlice("pointer")
+	if err != nil {
+		return err
+	}
+
 	host, err := rootCmd.PersistentFlags().GetString("ip")
 	if err != nil {
 		return err
@@ -21,7 +26,7 @@ func getSchemaCommand(cmd *cobra.Command, args []string) error {
 		ovp8xx.WithHost(host),
 	)
 
-	if result, err := o3r.GetSchema(); err != nil {
+	if result, err := o3r.GetSchema(pointers); err != nil {
 		return err
 	} else {
 		fmt.Printf("%s\n", result)
@@ -33,9 +38,55 @@ func getSchemaCommand(cmd *cobra.Command, args []string) error {
 var getSchemaCmd = &cobra.Command{
 	Use:   "getSchema",
 	Short: "Retrieve the currently used JSON schema from the device",
-	RunE:  getSchemaCommand,
+	Long: `The OVP8xx getSchema command accepts a list of JSON pointers.
+The JSON schema provides details about multiple aspects of a paramter. It
+contains information like the type of a parameter and its defaults. It also
+provides information weather a parameter is readOnly or not.
+
+Due to the fact the schema can schema can grow quite big it is possible to
+limit the scope of the query with a query string which is similar to a JSON pointer.
+
+The pointer '/device/swVersion/diagnostics' for example provides this information
+
+{
+	"$schema": "http://json-schema.org/draft-07/schema#",
+	"additionalProperties": false,
+	"properties": {
+	  "device": {
+		"$schema": "http://json-schema.org/draft-07/schema#",
+		"additionalProperties": false,
+		"properties": {
+		  "swVersion": {
+			"additionalProperties": false,
+			"description": "version of software components",
+			"properties": {
+			  "diagnostics": {
+				"readOnly": true,
+				"type": "string"
+			  }
+			},
+			"required": [
+			  "kernel",
+			  "l4t",
+			  "firmware"
+			],
+			"type": "object"
+		  }
+		},
+		"title": "O3R device configuration",
+		"type": "object"
+	  }
+	},
+	"title": "O3R configuration",
+	"type": "object"
+  }
+
+When no query is provided the complete schema is returend.
+`,
+	RunE: getSchemaCommand,
 }
 
 func init() {
 	rootCmd.AddCommand(getSchemaCmd)
+	getSchemaCmd.Flags().StringSliceP("pointer", "p", []string{""}, "A JSON pointer to be queried. This can be used multiple times")
 }
diff --git a/pkg/ovp8xx/rpc.go b/pkg/ovp8xx/rpc.go
index db12bcf..87fb969 100644
--- a/pkg/ovp8xx/rpc.go
+++ b/pkg/ovp8xx/rpc.go
@@ -95,7 +95,7 @@ func (device *Client) FactoryReset(keepNetworkSettings bool) error {
 	return client.Call("factoryReset", arg, nil)
 }
 
-func (device *Client) GetSchema() (string, error) {
+func (device *Client) GetSchema(pointers []string) (string, error) {
 	client, err := xmlrpc.NewClient(device.url)
 	if err != nil {
 		return "", err
@@ -105,8 +105,10 @@ func (device *Client) GetSchema() (string, error) {
 	result := &struct {
 		JSON string
 	}{}
-
-	if err := client.Call("getSchema", nil, result); err != nil {
+	arg := &struct {
+		Pointers []string
+	}{Pointers: pointers}
+	if err := client.Call("getSchema", arg, result); err != nil {
 		return "", err
 	}
 	return result.JSON, nil