---
title: "JSON Utilities"
description: "JSON parsing utility functions for safe field extraction from ArduinoJSON objects"
keywords: ["json", "parsing", "arduino", "utilities", "type safety"]
---

# JSON Utilities

**Path**: [`src/json.h`](src/json.h)

**Revision History**: Initial documentation

A collection of inline utility functions for safe JSON field parsing with ArduinoJSON. These functions provide type checking, default value fallback, and graceful error handling for JSON data extraction.

## REQUIREMENTS

- No specific hardware pins required
- ArduinoJSON library
- ArduinoLog library

## FEATURES

- Safe type-checked JSON field parsing for uint32_t, uint8_t, and bool data types
- Graceful error handling with default value fallback
- Comprehensive logging with component and field name information
- Inline functions for optimal performance
- Robust null value handling

## DEPENDENCIES

- [ArduinoJSON](https://github.com/bblanchard/ArduinoJSON)
- [ArduinoLog](https://github.com/thijse/Arduino-Log)

```mermaid
graph TD
    json["JSON Utilities"] --> arduinojson[ArduinoJSON]
    json --> arduinolog[Arduino-Log]
```

## BEHAVIOUR

```mermaid
graph TD
    jsonobject["JSON Object"] --> check["Type Check"]
    check --> valid["Valid"]
    check --> invalid["Invalid"]
    valid --> update["Update Target Value"]
    invalid --> logwarn[Log Warning]
    update --> complete["Completed"]
    logwarn --> complete
```

## TODOS

### PERFORMANCE

- Consider using function templates to reduce code duplication across data types
- Add support for floating and string data types
- Implement validation range checking for numeric types

### SECURITY

- No immediate security risks identified
- JSON input injection attacks - explicit field and component names should be validated to prevent log injection
- Input sanitization recommended prior to working with JSON data

### COMPLIANCE

- No specific compliance requirements
- C++17 minimal security practices

### RECOMMENDATIONS

- Use with the correct component and field names in logging
- Provide reasonable default values for all fields
- Validate JSON structure before combining with these utilities
- Ensure adequate error handling in upper-layer application code

## EXAMPLE

This example demonstrates the usage of the JSON extraction utilities:

```cpp
using namespace JsonUtils;

void parseSettings(const char* jsonStr) {
    staticJsonDocument<512> doc;
    DeserializationError error = deserializeJson(doc, jsonStr);

    if (error) {
        Log.errorln("Failed to parse JSON: %s", error.f_str());
        return;
    }

    // Default values
    uint32_t baudRate = 115200;
    uint8_t retryCount = 3;
    bool debugEnabled = false;

    // Safe parsing with default fallback
    parseJsonFieldUint32(doc, "baud_rate", baudRate, "Baud Rate", "Settings");
    parseJsonFieldUint8(doc, "retry_count", retryCount, "Retry Count", "Settings");
    parseJsonFieldBool(doc, "debug_enabled", debugEnabled, "Debug Enabled", "Settings");

    // Use the parsed values
    Log.infoln(F("Settings loaded: Baud=%lu, Retry=%d, Debug=%s"),
               baudRate, retryCount, debugEnabled ? "YES" : "NO");
}
```

### References

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