Preserve JSON Key Order

[homestar9]

Summary

I'm not sure if this is possible, but being able to preserve the JSON key order to exactly match the source .json files would make a huge improvement to legibility, consistency, and easier to follow documentation.

Detailed Description

Currently, when you create a .json document which will be exported by cbswagger, the resulting JSON file struct key order appears to be random.

For example, in this schema json file example:

{
	"type": "object",
	"properties": {
		"address": {
			"type": "string"
		},
		"city": {
			"type": "integer"
		},
		"state": {
			"type": "integer"
		},
		"zip": {
			"type": "integer"
		}
       }
}

When processed by cbswagger, results in the final JSON looking like this:

{
	"type": "object",
	"properties": {
		"zip": {
			"type": "integer"
		},
		"city": {
			"type": "integer"
		},
		"address": {
			"type": "string"
		},
		"state": {
			"type": "integer"
		}
       }
}

Possible Implementation Ideas

I know ColdFusion has the ability to preserve struct order by using a Java LinkedHashMap, which works a lot like structs. Perhaps the JSON struct conversion could be done using a Java-based JSON parser which uses hash maps, so the resulting order is preserved in the final output.

[homestar9]

Just checking to see if there's been any update on this issue. I attempted to tackle this on my own, and based on what I discovered, the parser indeed deserializes everything into a CF struct, and the order is preserved. However, the order shifts somewhere between parsing and the final serialized call. I can't pinpoint the exact moment that the key order changes.

[lmajano]

Hi @homestar9 . Yes, structs are ordered by internal hash and order is never guaranteed. If you want order, you need an "ordered" struct. Is this for which section?

[homestar9]

Hey @lmajano, your comment has great timing. I spent a good part of last week trying to figure out how to preserve the JSON key order when generating Swagger JSON. The good news is that the cbswagger-sdk parser uses an ordered struct by default, and the order is preserved all the way to the point where cbswagger calls serializeJson(). The resulting JSON is in a different order than the original struct.

I looked for an alternative serializer and discovered Jackson. According to what I have read, Jackson can convert a Java object to JSON and has the ability to preserve the original key order. Since CFML structs are just Java Objects under the hood, I believe something like Jackson could work.

Unfortunately, getting Jackson to work with CFML isn't as straightforward as including a JAR in my lib paths. The library is split into several jar-modules that declare dependencies between each other and frankly it's beyond my understanding of Java currently.

If there was a way to use this third-party serializer and create a Forgebox module, it could open up the doors to many great serialization opportunities, including, but not limited to, cbswagger.

[lmajano]

We use jackson jr in boxlang and we preserve order already by default. Not sure how this would pan out in ACF to tell you the truth.

[homestar9]

Do you have a compiled JAR of Jackson I could take a look at? Having a portable dependency in JAR format would allow me to continue my exploration. This would help users on Lucee and ACF.

[lmajano]

You can download jars from here: https://jar-download.com/