Add JSON-Safe serialization modes #1308
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Closes RobotWebTools#1307 - Add SerializationMode type ('typed' | 'plain' | 'json') - Implement message_serialization.js with conversion utilities - Add serializationMode option to createSubscription - Export toJSONSafe and toJSONString utility functions
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@mahmoudalghalayini thanks for submitting the PR with ut and examples, that's great! The overall looks good to me, I will be oof for the rest of the week and will take a closer look early next week. Meanwhile, please feel free to take what we disscussed in #1306, thanks! |
lib/subscription.js
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| this._callback(msg.toPlainObject(this.typedArrayEnabled)); | ||
| let message = msg.toPlainObject(this.typedArrayEnabled); | ||
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| if (this._serializationMode !== 'typed') { |
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I have some concern about the naming typed here, considering when:
this.typedArrayEnabledisfalsethis._serializationModeistyped
The message may contain plain array even if the array can be typed-array, which may cause confusing.
When typedArrayEnabled is true, rclnodejs won't allocate additional memory from C++ side, instead, the typed array is backed by a Buffer if possible, whose memory was allocated by rcl, but I don't have a proper name in my mind now.
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| // Copyright (c) 2024 rclnodejs contributors. All rights reserved. | |||
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I prefer unifying the wording here, you can either:
- Add your name, like https://github.com/RobotWebTools/rclnodejs/blob/develop/lib/parameter_service.js
- Use a general name, like https://github.com/RobotWebTools/rclnodejs/blob/develop/lib/utils.js
It's up to you. nit: it's year of 2025 already :)
minggangw
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minggangw
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lgtm, thanks for submitting the PR!
| * @param {boolean} options.enableTypedArray - The topic will use TypedArray if necessary, default: true. | ||
| * @param {QoS} options.qos - ROS Middleware "quality of service" settings for the subscription, default: QoS.profileDefault. | ||
| * @param {boolean} options.isRaw - The topic is serialized when true, default: false. | ||
| * @param {string} [options.serializationMode='default'] - Controls message serialization format: |
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default makes sence to combine with enableTypedArray
## **Public API Changes**
**New subscription option:**
- `serializationMode: 'default' | 'plain' | 'json'` for `createSubscription()`
**New utility functions:**
- `rclnodejs.toJSONSafe(obj)` - makes objects JSON-friendly
- `rclnodejs.toJSONString(obj)` - converts directly to JSON string
**Fully backward compatible** - existing code works unchanged.
## **Description**
This adds **message serialization modes** to fix a common headache: ROS sensor messages use `TypedArray`s which don't play nice with JSON.
**The Problem:**
If you try to `JSON.stringify()` a LaserScan message, you get `{}` instead of the actual data. This breaks web APIs, logging, and any workflow that needs JSON.
**The Solution:**
Three modes to handle messages differently:
- **`'default'`** Uses native rclnodejs behavior
- **`'plain'`**: Convert TypedArrays to regular arrays - JSON works!
- **`'json'`**: Handle everything (TypedArrays, BigInt, NaN) - fully JSON-safe
[#1307](#1307)
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@mahmoud-ghalayini this change has landed onto latest v1.6.0, thanks for your contribution! |
4 participants
Public API Changes
New subscription option:
serializationMode: 'default' | 'plain' | 'json'forcreateSubscription()New utility functions:
rclnodejs.toJSONSafe(obj)- makes objects JSON-friendlyrclnodejs.toJSONString(obj)- converts directly to JSON stringFully backward compatible - existing code works unchanged.
Description
This adds message serialization modes to fix a common headache: ROS sensor messages use
TypedArrays which don't play nice with JSON.The Problem:
If you try to
JSON.stringify()a LaserScan message, you get{}instead of the actual data. This breaks web APIs, logging, and any workflow that needs JSON.The Solution:
Three modes to handle messages differently:
'default'Uses native rclnodejs behavior'plain': Convert TypedArrays to regular arrays - JSON works!'json': Handle everything (TypedArrays, BigInt, NaN) - fully JSON-safe#1307