GripDev Json Schema Validator

Overview

A simple wrapper around Newtonsoft.Json.Schema as CLI or PowerShell Module.

It gives full details about the line, position, value, schemaid for any schema errors

As JSON scripts:

{
  "Valid": false,
  "Errors": [
    {
      "UserMessage": "\n❌ Error Details:\n   └─ Message: Required properties are missing from object: city.\n   └─ Location: Line 4, Position 14\n   └─ Path: address\n   └─ "
      "Message": "String '12345' does not match regex pattern '^[0-9]{10}$'.",
      "LineNumber": 10,
      "LinePosition": 20,
      "Path": "contact.phone",
      "Value": "12345",
      "SchemaId": "#/properties/contact/properties/phone",
      "SchemaBaseUri": null,
      "ErrorType": "pattern",
      "ChildErrors": []
    }
  ]
}

Or Pretty printed output for users 👀 even handling if-then-else and sub errors nicely!

 ❌ Error Details:
   └─ Message: JSON does not match schema from 'then'.
   └─ Location: Line 151, Position 14
   └─ Path: mingw
   └─ Value: 
   └─ Related Issues:
      ↳ Required properties are missing from object: pinnedDetails.

You can easily use this to output annotations onto files during Pull Requests, for example, with GitHub Actions. The Write-Host ::error line tells actions to add an annotation with the user message to the right file and line.

    $validationResult = Test-JsonSchema -SchemaPath $schemaFilePath -JsonPath $file.FullName -PrettyPrint $false

    if ($validationResult.Valid) {
        Write-Host "✅ JSON is valid." -ForegroundColor Green
    } else {
        # File has been modified since the commit, enforce validation
        $toolsetHasErrors = $true
        Write-Host "`n❌ JSON validation failed!" -ForegroundColor Red
        Write-Host "   Found the following errors:`n" -ForegroundColor Yellow

        $validationResult.Errors | ForEach-Object {
            Write-Host $_.UserMessage
            if ($env:GITHUB_ACTIONS -eq 'true') {
                Write-Host "Adding annotation"
                Write-Host "::error file=$($file.Name),line=$($_.LineNumber)::$($_.UserMessage.Replace("`n", '%0A'))"
            }
        }
    }

Big shout out to James King (Newtonsoft) for the heavy lifting here using the AGPL version of his library. See pricing for non agpl version on their site.

Installation

To install the NewtonsoftJsonSchemaTool, use the following command:

dotnet tool install --global GripDevJsonSchemaValidator

Usage

To use the NewtonsoftJsonSchemaTool, run the following command:

GripDevJsonSchemaValidator <schema-file> <json-file>

Replace <schema-file> with the path to your JSON schema file and <json-file> with the path to your JSON file to validate.

Example

Here is an example of how to use the NewtonsoftJsonSchemaTool:

1. Create a JSON schema file (schema.json):

{
  "type": "object",
  "properties": {
    "name": {
      "type": "string"
    },
    "age": {
      "type": "integer"
    }
  },
  "required": ["name", "age"]
}

2. Create a JSON file to validate (data.json):

{
  "name": "John Doe",
  "age": "twenty-five"
}

3. Run the GripDevJsonSchemaValidator:

GripDevJsonSchemaValidator schema.json data.json

4. The output will be a JSON array of errors with full details, including line numbers for each error:

{
  "Valid": false,
  "Errors": [
    {
      "Message": "Invalid type. Expected Integer but got String.",
      "LineNumber": 3,
      "LinePosition": 12,
      "Path": "age"
    }
  ]
}

Powershell Module

In addition to the dotnet CLI tool, a Powershell module is also available for running Newtonsoft schema validation on input JSON schema and files to validate. The Powershell module returns a well-typed array of error objects exposing the JSON schema validation error type.

Installation

To install the Powershell module, use the following command:

Install-Module -Name GripDevJsonSchemaValidator

Usage

To use the Powershell module, import the module and run the Test-JsonSchema cmdlet:

Import-Module GripDevJsonSchemaValidator

$validationResult = Test-JsonSchema -SchemaPath ./some/schema.json -JsonPath ./data.json

if ($validationResult.Valid) {
    Write-Output "JSON is valid."
} else {
    Write-Output "JSON is invalid. Errors:"
    $validationResult.Errors | ForEach-Object {
        Write-Output "Message: $($_.Message)"
        if ($_.ChildErrors) {
            $_.ChildErrors | ForEach-Object {
                Write-Output "  Child Error: $($_.Message)"
            }
        }
        Write-Output "LineNumber: $($_.LineNumber)"
        Write-Output "LinePosition: $($_.LinePosition)"
        Write-Output "Path: $($_.Path)"
        Write-Output "Value: $($_.Value)"
    }
}