Support Location-Independent Identifier $refs

[hooke]

With jsonschema v.2.6.0, I couldn't manage to use id's of subschemas in $ref in the same file.

test.json with schema:

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "Test Schema",
  "description": "A test for subschemes' relative URIs",
  "type": "object",
"additionalProperties": false,
  "properties": {
    "prop1": { "$ref": "#smth"}
  },
  "definitions": {
    "smth": {
      "$id": "#smth",
      "type": "object",
      "properties": {
        "some_field": {
          "type": "string"
        }
      }
    }
  }
}

test_sample.json with JSON to test:

{
  "prop1": {
    "some_field": "a text"
  }
}

The python code:

import os
import jsonschema, json
from pprint import pprint

schema_absolute_path = "/home/hooke/prj/MK/python-test/example/"
schema_file_name = "test.json"

with open(schema_absolute_path + schema_file_name) as schema_file:    
    schema = json.load(schema_file)

try:
    jsonschema.Draft4Validator.check_schema(schema)
    print "Valid draft 4 schema"
except jsonschema.exceptions.SchemaError: 
    print "Invalid schema"

schema_absolute_uri = 'file://' + schema_absolute_path + schema_file_name

resolver = jsonschema.RefResolver(base_uri = schema_absolute_uri, referrer = schema)



validator = jsonschema.Draft4Validator(
        schema, resolver=resolver)

instance_file_name = "test_sample.json"
with open(schema_absolute_path + instance_file_name) as data_file:    
    data = json.load(data_file)

try:
    validator.validate(data, schema)
    print "Properly accepted object"
except jsonschema.exceptions.RefResolutionError as e: 
    print e
except jsonschema.exceptions.ValidationError: 
    print "Failed to accept object"

Result:

$ python example_test.py 
Valid draft 4 schema
Unresolvable JSON pointer: u'smth'

The aforementioned schema was validated successfully on jsonschemalint.com with draft-04, and with https://github.com/epoberezkin/ajv validator.

[Julian]

Hi -- still haven't gotten a chance to look at this fully, but as-is, that definitely is not a valid reference, so if it validates successfully elsewhere, it sounds like those places have bugs.

In draft4, id is spelled that way, not $id. It's only Draft 6 and later where it uses a $.

[willson-chen]

@hooke Hi, I have tested #717 could solve this problem.

[Julian]

This appears to work at this point (the code you pasted correctly validates the instance). Closing, but feel free to follow up if there are still any issues.