github.com/SimingLiu/jsonschema/v2

jsonschema v2.1.0

Package jsonschema provides json-schema compilation and validation.

This implementation of JSON Schema, supports draft4, draft6 and draft7.

Passes all tests(including optional) in https://github.com/json-schema/JSON-Schema-Test-Suite

An example of using this package:

schema, err := jsonschema.Compile("schemas/purchaseOrder.json")
if err != nil {
    return err
}
f, err := os.Open("purchaseOrder.json")
if err != nil {
    return err
}
defer f.Close()
if err = schema.Validate(f); err != nil {
    return err
}

The schema is compiled against the version specified in $schema property. If $schema property is missing, it uses latest draft which currently is draft7. You can force to use draft4 when $schema is missing, as follows:

compiler := jsonschema.NewCompiler()
compler.Draft = jsonschema.Draft4

you can also validate go value using schema.ValidateInterface(interface{}) method.
but the argument should not be user-defined struct.

This package supports loading json-schema from filePath and fileURL.

To load json-schema from HTTPURL, add following import:

import _ "github.com/santhosh-tekuri/jsonschema/v2/httploader"

Loading from urls for other schemes (such as ftp), can be plugged in. see package jsonschema/httploader for an example

To load json-schema from in-memory:

data := `{"type": "string"}`
url := "sch.json"
compiler := jsonschema.NewCompiler()
if err := compiler.AddResource(url, strings.NewReader(data)); err != nil {
    return err
}
schema, err := compiler.Compile(url)
if err != nil {
    return err
}
f, err := os.Open("doc.json")
if err != nil {
    return err
}
defer f.Close()
if err = schema.Validate(f); err != nil {
    return err
}

This package supports json string formats:

• date-time
• date
• time
• hostname
• email
• ip-address
• ipv4
• ipv6
• uri
• uriref/uri-reference
• regex
• format
• json-pointer
• relative-json-pointer
• uri-template (limited validation)

Developers can register their own formats by adding them to jsonschema.Formats map.

"base64" contentEncoding is supported. Custom decoders can be registered by adding them to jsonschema.Decoders map.

"application/json" contentMediaType is supported. Custom mediatypes can be registered by adding them to jsonschema.MediaTypes map.

ValidationError

The ValidationError returned by Validate method contains detailed context to understand why and where the error is.

schema.json:

{
      "$ref": "t.json#/definitions/employee"
}

t.json:

{
    "definitions": {
        "employee": {
            "type": "string"
        }
    }
}

doc.json:

1

Validating doc.json with schema.json, gives following ValidationError:

I[#] S[#] doesn't validate with "schema.json#"
  I[#] S[#/$ref] doesn't valide with "t.json#/definitions/employee"
    I[#] S[#/definitions/employee/type] expected string, but got number

Here I stands for instance document and S stands for schema document.
The json-fragments that caused error in instance and schema documents are represented using json-pointer notation.
Nested causes are printed with indent.

CLI

jv <schema-file> [<json-doc>]...

if no <json-doc> arguments are passed, it simply validates the <schema-file>.

exit-code is 1, if there are any validation errors