How to specify a root directory for `$ref` resolution?

[RyoJerryYu]

Prerequisite

I have a bundle of json schema files on local file system as below:

/path/to/base/dir/
└── schema/
    └── v2/
        ├── named_api_resource.json
        └── pokemon/
            └── $id/
                └── index.json

In schema/v2/pokemon/$id/index.json , There is a $ref to /schema/v2/pokemon/$id/index.json:

{
    "$schema": "http://json-schema.org/schema#",
    "properties": {
        "abilities": {
            "items": {
                "properties": {
                    "ability": {
                        "$ref": "/schema/v2/named_api_resource.json"
                    }
                },
                "required": [
                    "ability"
                ],
                "type": "object"
            },
            "type": "array"
        }
    },
    "required": [
        "abilities"
    ],
    "type": "object"
}

What did you expect to happen?

I want /schema/v2/named_api_resource.json can be correctly resolved to /path/to/base/dir/schema/v2/named_api_resource.json .

These schemas are downloaded from internet and I prefer not to modify these schemas.

What happened?

I tried to generate these schemas using command below:

go-jsonschema -p schema ./schema/v2/pokemon/\$id/index.json ./schema/v2/named_api_resource.json

And of course it failed, with follow message:

go-jsonschema: Failed: could not generate type for field "abilities": could not generate type for field "ability": could not follow $ref "/schema/v2/named_api_resource.json" to file "/schema/v2/named_api_resource.json": error resolving symlinks in : lstat /schema: no such file or directory

Possible Reason

And I think the reason is /schema/v2/named_api_resource.json was resolved as the absolute path to my file system:

go-jsonschema/pkg/generator/generate.go

Lines 187 to 206 in fda3a01

	func (g *Generator) loadSchemaFromFile(fileName, parentFileName string) (*schemas.Schema, error) {
	if !filepath.IsAbs(fileName) {
	fileName = filepath.Join(filepath.Dir(parentFileName), fileName)
	}
	exts := append([]string{""}, g.config.ResolveExtensions...)
	for i, ext := range exts {
	qualified := fileName + ext
	// Poor man's resolving loop.
	if i < len(exts)-1 && !fileExists(qualified) {
	continue
	}
	var err error
	qualified, err = filepath.EvalSymlinks(qualified)
	if err != nil {
	return nil, fmt.Errorf("error resolving symlinks in %s: %w", qualified, err)
	}

Question

Is there any way to specify a root directory for reference resolution? If not, may I contribute to this feature?

[omissis]

Hi @RyoJerryYu , thanks for opening this issue. File resolution is a fairly complex topic in json schema, and one I only recently started to investigate (see https://json-schema.slack.com/archives/CT8QRGTK5/p1696579815116399 and https://json-schema.slack.com/archives/CT8QRGTK5/p1696613711695749).
It'll probably take a long time for me to get to the point I discussed on slack, so I guess that if you want to work on a --schemas-root-dir PR, we could make use of it for the time being, and solve your issue, so please have a go at it :)