Differentiate between different drafts and metaschema validation

README.md

@@ -55,7 +55,6 @@ func main() {
             fmt.Printf("- %s\n", desc)
         }
     }
-
 }
 
 
@@ -149,6 +148,7 @@ To check the result :
     }
 ```
 
+
 ## Loading local schemas
 
 By default `file` and `http(s)` references to external schemas are loaded automatically via the file system or via http(s). An external schema can also be loaded using a `SchemaLoader`.
@@ -189,10 +189,45 @@ It's also possible to pass a `ReferenceLoader` to the `Compile` function that re
 
 ```go
 err = sl.AddSchemas(loader3)
-schema,err := sl.Compile(NewReferenceLoader("http://some_host.com/main.json"))
+schema, err := sl.Compile(gojsonschema.NewReferenceLoader("http://some_host.com/main.json"))
+``` 
+
+Schemas added by `AddSchema` and `AddSchemas` are only validated when the entire schema is compiled, unless meta-schema validation is used.
+
+## Using a specific draft
+By default `gojsonschema` will try to detect the draft of a schema by using the `$schema` keyword and parse it in a strict draft-04, draft-06 or draft-07 mode. If `$schema` is missing, or the draft version is not explicitely set, a hybrid mode is used which merges together functionality of all drafts into one mode.
+
+Autodectection can be turned off with the `AutoDetect` property. Specific draft versions can be specified with the `Draft` property.
+
+```go
+sl := gojsonschema.NewSchemaLoader()
+sl.Draft = gojsonschema.Draft7
+sl.AutoDetect = false
+```
+
+If autodetection is on (default), a draft-07 schema can savely reference draft-04 schemas and vice-versa, as long as `$schema` is specified in all schemas.
+
+## Meta-schema validation
+Schemas that are added using the `AddSchema`, `AddSchemas` and `Compile` can be validated against their meta-schema by setting the `Validate` property.
+
+The following example will produce an error as `multipleOf` must be a number. If `Validate` is off (default), this error is only returned at the `Compile` step. 
+
+```go
+sl := gojsonschema.NewSchemaLoader()
+sl.Validate = true
+err := sl.AddSchemas(gojsonschema.NewStringLoader(`{
+     $id" : "http://some_host.com/invalid.json",
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "multipleOf" : true
+}`))
+ ```
 ``` 
+ ```
+
+Errors returned by meta-schema validation are more readable and contain more information, which helps significantly if you are developing a schema.
+
+Meta-schema validation also works with a custom `$schema`. In case `$schema` is missing, or `AutoDetect` is set to `false`, the meta-schema of the used draft is used.
 
-Schemas added by `AddSchema` and `AddSchemas` are only validated when the entire schema is compiled. Returned errors only contain errors about invalid URIs or if a URI is associated with multiple schemas. This may change in the future.
 
 ## Working with Errors
 

draft.go

@@ -0,0 +1,118 @@
+// Copyright 2018 johandorland ( https://github.com/johandorland )
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gojsonschema
+
+import (
+	"errors"
+	"math"
+	"reflect"
+
+	"github.com/xeipuuv/gojsonreference"
+)
+
+type Draft int
+
+const (
+	Draft4 Draft = 4
+	Draft6 Draft = 6
+	Draft7 Draft = 7
+	Hybrid Draft = math.MaxInt32
+)
+
+type draftConfig struct {
+	Version       Draft
+	MetaSchemaURL string
+	MetaSchema    string
+}
+type draftConfigs []draftConfig
+
+var drafts draftConfigs
+
+func init() {
+	drafts = []draftConfig{
+		draftConfig{
+			Version:       Draft4,
+			MetaSchemaURL: "http://json-schema.org/draft-04/schema",
+			MetaSchema:    `{"id":"http://json-schema.org/draft-04/schema#","$schema":"http://json-schema.org/draft-04/schema#","description":"Core schema meta-schema","definitions":{"schemaArray":{"type":"array","minItems":1,"items":{"$ref":"#"}},"positiveInteger":{"type":"integer","minimum":0},"positiveIntegerDefault0":{"allOf":[{"$ref":"#/definitions/positiveInteger"},{"default":0}]},"simpleTypes":{"enum":["array","boolean","integer","null","number","object","string"]},"stringArray":{"type":"array","items":{"type":"string"},"minItems":1,"uniqueItems":true}},"type":"object","properties":{"id":{"type":"string"},"$schema":{"type":"string"},"title":{"type":"string"},"description":{"type":"string"},"default":{},"multipleOf":{"type":"number","minimum":0,"exclusiveMinimum":true},"maximum":{"type":"number"},"exclusiveMaximum":{"type":"boolean","default":false},"minimum":{"type":"number"},"exclusiveMinimum":{"type":"boolean","default":false},"maxLength":{"$ref":"#/definitions/positiveInteger"},"minLength":{"$ref":"#/definitions/positiveIntegerDefault0"},"pattern":{"type":"string","format":"regex"},"additionalItems":{"anyOf":[{"type":"boolean"},{"$ref":"#"}],"default":{}},"items":{"anyOf":[{"$ref":"#"},{"$ref":"#/definitions/schemaArray"}],"default":{}},"maxItems":{"$ref":"#/definitions/positiveInteger"},"minItems":{"$ref":"#/definitions/positiveIntegerDefault0"},"uniqueItems":{"type":"boolean","default":false},"maxProperties":{"$ref":"#/definitions/positiveInteger"},"minProperties":{"$ref":"#/definitions/positiveIntegerDefault0"},"required":{"$ref":"#/definitions/stringArray"},"additionalProperties":{"anyOf":[{"type":"boolean"},{"$ref":"#"}],"default":{}},"definitions":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"properties":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"patternProperties":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"dependencies":{"type":"object","additionalProperties":{"anyOf":[{"$ref":"#"},{"$ref":"#/definitions/stringArray"}]}},"enum":{"type":"array","minItems":1,"uniqueItems":true},"type":{"anyOf":[{"$ref":"#/definitions/simpleTypes"},{"type":"array","items":{"$ref":"#/definitions/simpleTypes"},"minItems":1,"uniqueItems":true}]},"format":{"type":"string"},"allOf":{"$ref":"#/definitions/schemaArray"},"anyOf":{"$ref":"#/definitions/schemaArray"},"oneOf":{"$ref":"#/definitions/schemaArray"},"not":{"$ref":"#"}},"dependencies":{"exclusiveMaximum":["maximum"],"exclusiveMinimum":["minimum"]},"default":{}}`,
+		},
+		draftConfig{
+			Version:       Draft6,
+			MetaSchemaURL: "http://json-schema.org/draft-06/schema",
+			MetaSchema:    `{"$schema":"http://json-schema.org/draft-06/schema#","$id":"http://json-schema.org/draft-06/schema#","title":"Core schema meta-schema","definitions":{"schemaArray":{"type":"array","minItems":1,"items":{"$ref":"#"}},"nonNegativeInteger":{"type":"integer","minimum":0},"nonNegativeIntegerDefault0":{"allOf":[{"$ref":"#/definitions/nonNegativeInteger"},{"default":0}]},"simpleTypes":{"enum":["array","boolean","integer","null","number","object","string"]},"stringArray":{"type":"array","items":{"type":"string"},"uniqueItems":true,"default":[]}},"type":["object","boolean"],"properties":{"$id":{"type":"string","format":"uri-reference"},"$schema":{"type":"string","format":"uri"},"$ref":{"type":"string","format":"uri-reference"},"title":{"type":"string"},"description":{"type":"string"},"default":{},"examples":{"type":"array","items":{}},"multipleOf":{"type":"number","exclusiveMinimum":0},"maximum":{"type":"number"},"exclusiveMaximum":{"type":"number"},"minimum":{"type":"number"},"exclusiveMinimum":{"type":"number"},"maxLength":{"$ref":"#/definitions/nonNegativeInteger"},"minLength":{"$ref":"#/definitions/nonNegativeIntegerDefault0"},"pattern":{"type":"string","format":"regex"},"additionalItems":{"$ref":"#"},"items":{"anyOf":[{"$ref":"#"},{"$ref":"#/definitions/schemaArray"}],"default":{}},"maxItems":{"$ref":"#/definitions/nonNegativeInteger"},"minItems":{"$ref":"#/definitions/nonNegativeIntegerDefault0"},"uniqueItems":{"type":"boolean","default":false},"contains":{"$ref":"#"},"maxProperties":{"$ref":"#/definitions/nonNegativeInteger"},"minProperties":{"$ref":"#/definitions/nonNegativeIntegerDefault0"},"required":{"$ref":"#/definitions/stringArray"},"additionalProperties":{"$ref":"#"},"definitions":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"properties":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"patternProperties":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"dependencies":{"type":"object","additionalProperties":{"anyOf":[{"$ref":"#"},{"$ref":"#/definitions/stringArray"}]}},"propertyNames":{"$ref":"#"},"const":{},"enum":{"type":"array","minItems":1,"uniqueItems":true},"type":{"anyOf":[{"$ref":"#/definitions/simpleTypes"},{"type":"array","items":{"$ref":"#/definitions/simpleTypes"},"minItems":1,"uniqueItems":true}]},"format":{"type":"string"},"allOf":{"$ref":"#/definitions/schemaArray"},"anyOf":{"$ref":"#/definitions/schemaArray"},"oneOf":{"$ref":"#/definitions/schemaArray"},"not":{"$ref":"#"}},"default":{}}`,
+		},
+		draftConfig{
+			Version:       Draft7,
+			MetaSchemaURL: "http://json-schema.org/draft-07/schema",
+			MetaSchema:    `{"$schema":"http://json-schema.org/draft-07/schema#","$id":"http://json-schema.org/draft-07/schema#","title":"Core schema meta-schema","definitions":{"schemaArray":{"type":"array","minItems":1,"items":{"$ref":"#"}},"nonNegativeInteger":{"type":"integer","minimum":0},"nonNegativeIntegerDefault0":{"allOf":[{"$ref":"#/definitions/nonNegativeInteger"},{"default":0}]},"simpleTypes":{"enum":["array","boolean","integer","null","number","object","string"]},"stringArray":{"type":"array","items":{"type":"string"},"uniqueItems":true,"default":[]}},"type":["object","boolean"],"properties":{"$id":{"type":"string","format":"uri-reference"},"$schema":{"type":"string","format":"uri"},"$ref":{"type":"string","format":"uri-reference"},"$comment":{"type":"string"},"title":{"type":"string"},"description":{"type":"string"},"default":true,"readOnly":{"type":"boolean","default":false},"examples":{"type":"array","items":true},"multipleOf":{"type":"number","exclusiveMinimum":0},"maximum":{"type":"number"},"exclusiveMaximum":{"type":"number"},"minimum":{"type":"number"},"exclusiveMinimum":{"type":"number"},"maxLength":{"$ref":"#/definitions/nonNegativeInteger"},"minLength":{"$ref":"#/definitions/nonNegativeIntegerDefault0"},"pattern":{"type":"string","format":"regex"},"additionalItems":{"$ref":"#"},"items":{"anyOf":[{"$ref":"#"},{"$ref":"#/definitions/schemaArray"}],"default":true},"maxItems":{"$ref":"#/definitions/nonNegativeInteger"},"minItems":{"$ref":"#/definitions/nonNegativeIntegerDefault0"},"uniqueItems":{"type":"boolean","default":false},"contains":{"$ref":"#"},"maxProperties":{"$ref":"#/definitions/nonNegativeInteger"},"minProperties":{"$ref":"#/definitions/nonNegativeIntegerDefault0"},"required":{"$ref":"#/definitions/stringArray"},"additionalProperties":{"$ref":"#"},"definitions":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"properties":{"type":"object","additionalProperties":{"$ref":"#"},"default":{}},"patternProperties":{"type":"object","additionalProperties":{"$ref":"#"},"propertyNames":{"format":"regex"},"default":{}},"dependencies":{"type":"object","additionalProperties":{"anyOf":[{"$ref":"#"},{"$ref":"#/definitions/stringArray"}]}},"propertyNames":{"$ref":"#"},"const":true,"enum":{"type":"array","items":true,"minItems":1,"uniqueItems":true},"type":{"anyOf":[{"$ref":"#/definitions/simpleTypes"},{"type":"array","items":{"$ref":"#/definitions/simpleTypes"},"minItems":1,"uniqueItems":true}]},"format":{"type":"string"},"contentMediaType":{"type":"string"},"contentEncoding":{"type":"string"},"if":{"$ref":"#"},"then":{"$ref":"#"},"else":{"$ref":"#"},"allOf":{"$ref":"#/definitions/schemaArray"},"anyOf":{"$ref":"#/definitions/schemaArray"},"oneOf":{"$ref":"#/definitions/schemaArray"},"not":{"$ref":"#"}},"default":true}`,
+		},
+	}
+}
+
+func (dc draftConfigs) GetMetaSchema(url string) string {
+	for _, config := range dc {
+		if config.MetaSchemaURL == url {
+			return config.MetaSchema
+		}
+	}
+	return ""
+}
+func (dc draftConfigs) GetDraftVersion(url string) *Draft {
+	for _, config := range dc {
+		if config.MetaSchemaURL == url {
+			return &config.Version
+		}
+	}
+	return nil
+}
+func (dc draftConfigs) GetSchemaURL(draft Draft) string {
+	for _, config := range dc {
+		if config.Version == draft {
+			return config.MetaSchemaURL
+		}
+	}
+	return ""
+}
+
+func parseSchemaURL(documentNode interface{}) (string, *Draft, error) {
+
+	if isKind(documentNode, reflect.Bool) {
+		return "", nil, nil
+	}
+	m := documentNode.(map[string]interface{})
+
+	if existsMapKey(m, KEY_SCHEMA) {
+		if !isKind(m[KEY_SCHEMA], reflect.String) {
+			return "", nil, errors.New(formatErrorDescription(
+				Locale.MustBeOfType(),
+				ErrorDetails{
+					"key":  KEY_SCHEMA,
+					"type": TYPE_STRING,
+				},
+			))
+		}
+
+		schemaReference, err := gojsonreference.NewJsonReference(m[KEY_SCHEMA].(string))
+
+		if err != nil {
+			return "", nil, err
+		}
+
+		schema := schemaReference.String()
+
+		return schema, drafts.GetDraftVersion(schema), nil
+	}
+
+	return "", nil, nil
+}

jsonLoader.go

@@ -166,6 +166,12 @@ func (l *jsonReferenceLoader) LoadJSON() (interface{}, error) {
 
 func (l *jsonReferenceLoader) loadFromHTTP(address string) (interface{}, error) {
 
+	// returned cached versions for metaschemas for drafts 4, 6 and 7
+	// for performance and allow for easier offline use
+	if metaSchema := drafts.GetMetaSchema(address); metaSchema != "" {
+		return decodeJsonUsingNumber(strings.NewReader(metaSchema))
+	}
+
 	resp, err := http.Get(address)
 	if err != nil {
 		return nil, err
@@ -182,7 +188,6 @@ func (l *jsonReferenceLoader) loadFromHTTP(address string) (interface{}, error)
 	}
 
 	return decodeJsonUsingNumber(bytes.NewReader(bodyBuff))
-
 }
 
 func (l *jsonReferenceLoader) loadFromFile(path string) (interface{}, error) {

jsonschema_test.go

@@ -43,7 +43,12 @@ type jsonSchemaTestCase struct {
 
 //Skip any directories not named appropiately
 // filepath.Walk will also visit files in the root of the test directory
-var testDirectories = regexp.MustCompile(`^draft\d+$`)
+var testDirectories = regexp.MustCompile(`(draft\d+)`)
+var draftMapping = map[string]Draft{
+	"draft4": Draft4,
+	"draft6": Draft6,
+	"draft7": Draft7,
+}
 
 func executeTests(t *testing.T, path string) error {
 	file, err := os.Open(path)
@@ -61,6 +66,11 @@ func executeTests(t *testing.T, path string) error {
 		t.Errorf("Error (%s)\n", err.Error())
 	}
 
+	draft := Hybrid
+	if m := testDirectories.FindString(path); m != "" {
+		draft = draftMapping[m]
+	}
+
 	for _, test := range tests {
 		fmt.Println("    " + test.Description)
 
@@ -69,7 +79,10 @@ func executeTests(t *testing.T, path string) error {
 		}
 
 		testSchemaLoader := NewRawLoader(test.Schema)
-		testSchema, err := NewSchema(testSchemaLoader)
+		sl := NewSchemaLoader()
+		sl.Draft = draft
+		sl.Validate = true
+		testSchema, err := sl.Compile(testSchemaLoader)
 
 		if err != nil {
 			t.Errorf("Error (%s)\n", err.Error())
@@ -129,7 +142,6 @@ func TestSuite(t *testing.T) {
 		if !strings.HasSuffix(fileInfo.Name(), ".json") {
 			return nil
 		}
-
 		return executeTests(t, path)
 	})
 	if err != nil {