pwall567
commented
2 years ago Hi - thank you for giving such comprehensive detail on your issue.
The code generator was originally written to accept a list of input files (or directories, which would be scanned recursively), and it would establish a list of target classes to be generated. Then, if a property in one schema used a "$ref" to refer to another schema which was in the list of targets to be generated as a separate class, the generated code for the property in the first class would refer to the second. For example, the "Getting Started" JSON Schema page concludes with the development of two schema files: https://json-schema.org/learn/getting-started-step-by-step.html#references - if these two schema files are presented to the code generator, it recognises the
"$ref": "https://example.com/geographical-location.schema.json"line in the product.schema.json file as referring to a schema for which it is generating a class (in its target list), and it uses that class in the val in the Product class:
val warehouseLocation: GeographicalLocation? = nullIf a property of type object includes the schema definition inline, or uses a "$ref" to a schema which is not part of the target set, the code generator creates a nested class for the object, and uses that in the outer class. This is what happened in your Option 1 - the generator didn't recognise the reference as being in its target list because only the two outer files, not the schema at #/shared/SharedA, were in the target list.
The code generator was subsequently modified to accept a set of schema definitions contained in a composite file such as an OpenAPI file. In this case it creates target entries for each definition in the collection, so individual classes will be created for each schema definition, and references from one to another will be generated as references to the generated classes. It's possible to create a complex target list from multiple files when using the CodeGenerator class programmatically, but this is not covered by the Gradle plugin.
To generate a set of classes from individual files with inter-schema references, you need to ensure that each schema to be referenced in this way is a member of the target list, that is, it is the main object in the file. I changed your files to:
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"foo": {
"type": "string"
}
}
}and:
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"baz": {
"type": "string"
},
"shared": {
"$ref": "shared.json"
}
}
}and the output was (omitting the comments):
package com.example.generated
data class Shared(
val foo: String? = null
)and:
package com.example.generated
data class A(
val baz: String? = null,
val shared: Shared? = null
)The generated class names are derived from the "$id" in the file, or if that is not present, from the filename. There are options for specifying the generated class name in the config file, if the derived names are not satisfactory.
Thank you for persisting with the code generator - I hope this has given you enough information to configure your use of it successfully.
magnusrobertsson
I have an issue with generating data classes from multiple json schema files that reference each other. The idea is to have a shared schema from which other schemas can reuse.
I've tried a couple of options but have ran out of ideas. I'm using the following files:
shared.jsona.jsonOption 1: Specify directory only
This works but generates "ugly" data classes. The classes even get names based on the filename, not from the json schema.
Gradle definition:
Generates this:
Notice that the shared field contains an inner class named Shared instead of SharedA. It also generates another file with the Shared class definition. The inner class is redundant! Not very nice imho.
Option 2: Specify directory and json pointer
The following Gradle definition doesn't work at all.
Gives this error:
It seems like it trying to read the directory as a file.
Option 3: Specify schema file with json pointer
Doesn't work at all.
Gives this error:
Here the code generator doesn't understand that the reference to
shared.jsonis a local file but adds a https prefix to it. I've tried to addfile://but failed to make it work. Even if it had worked I wonder how the plugin would handle the two difference json pointers?Option 4: Put everything in one file with the same json pointer
This works and creates three nice files as expected, but the schema becomes a "monolith". It defies the purpose of having decoupled definitions imho.
When using the json pointer I get nice data classes, i.e. one kotlin source file per definition, but it only allows one file! It seems there is lacking an option to specify multiple files with a json pointer for each file. Or how do I solve this issue?