Validate IoT device metadata upon submit

package.json

@@ -87,6 +87,7 @@
         "@types/passport-local": "^1.0.33",
         "@types/supertest": "^2.0.10",
         "@types/validator": "^13.7.1",
+        "@types/ws": "^8.5.2",
         "@typescript-eslint/eslint-plugin": "^4.10.0",
         "@typescript-eslint/parser": "^4.10.0",
         "eslint": "^7.15.0",

src/entities/dto/create-iot-device.dto.ts

@@ -16,6 +16,8 @@ import { IoTDeviceType } from "@enum/device-type.enum";
 
 import { CreateLoRaWANSettingsDto } from "./create-lorawan-settings.dto";
 import { CreateSigFoxSettingsDto } from "./create-sigfox-settings.dto";
+import { IsMetadataJson } from "@helpers/is-metadata-json.validator";
+import { nameof } from "@helpers/type-helper";
 
 export class CreateIoTDeviceDto {
     @ApiProperty({ required: true })
@@ -60,6 +62,7 @@ export class CreateIoTDeviceDto {
 
     @ApiProperty({ required: false })
     @IsOptional()
+    @IsMetadataJson(nameof<CreateIoTDeviceDto>("metadata"))
     metadata?: JSON;
 
     @ApiProperty({ required: false })

src/entities/enum/error-codes.enum.ts

@@ -42,4 +42,6 @@ export enum ErrorCodes {
     ApplicationDoesNotExist = "MESSAGE.APPLICATION-DOES-NOT-EXIST",
     FailedToCreateOrUpdateIotDevice = "MESSAGE.FAILED-TO-CREATE-OR-UPDATE-IOT-DEVICE",
     DeviceModelDoesNotExist = "MESSAGE.DEVICE-MODEL-DOES-NOT-EXIST",
+    InvalidKeyInKeyValuePair = "MESSAGE.INVALID-KEY-IN-KEY-VALUE-PAIR",
+    InvalidValueInKeyValuePair = "MESSAGE.INVALID-VALUE-IN-KEY-VALUE-PAIR",
 }

src/helpers/is-metadata-json.validator.ts

@@ -0,0 +1,57 @@
+import { ErrorCodes } from "@enum/error-codes.enum";
+import {
+    registerDecorator,
+    ValidationArguments,
+    ValidationOptions,
+    ValidatorConstraint,
+    ValidatorConstraintInterface,
+} from "class-validator";
+
+@ValidatorConstraint({ name: "isMetadataJson", async: false })
+export class IsMetadataJsonConstraint implements ValidatorConstraintInterface {
+    private message = "";
+
+    public validate(value: string, args: ValidationArguments): boolean {
+        const [propertyName] = args.constraints;
+        this.message = `${propertyName} must be a valid list of metadata keys and values`;
+
+        if (typeof value !== "string") {
+            return false;
+        }
+        try {
+            const json = JSON.parse(value) as Record<string, string>;
+
+            for (const key of Object.keys(json)) {
+                if (typeof key !== "string" || key.trim() === "") {
+                    this.message = ErrorCodes.InvalidKeyInKeyValuePair;
+                    return false;
+                }
+                if (typeof json[key] !== "string" || json[key].trim() === "") {
+                    this.message = ErrorCodes.InvalidValueInKeyValuePair;
+                    return false;
+                }
+            }
+        } catch (error) {
+            return false;
+        }
+
+        return true;
+    }
+
+    public defaultMessage(_args: ValidationArguments): string {
+        return this.message;
+    }
+}
+
+export function IsMetadataJson(property: string, validationOptions?: ValidationOptions) {
+    return function (object: unknown, propertyName: string): void {
+        registerDecorator({
+            name: "isMetadataJson",
+            target: object.constructor,
+            propertyName: propertyName,
+            constraints: [property],
+            options: validationOptions,
+            validator: IsMetadataJsonConstraint,
+        });
+    };
+}