| commit | 9c0294d600f8555b76d64e3e7e65c726d8676d7a | [log] [tgz] |
|---|---|---|
| author | Sergiusz Urbaniak <sergiusz.urbaniak@gmail.com> | Fri May 06 13:44:43 2016 +0200 |
| committer | Sergiusz Urbaniak <sergiusz.urbaniak@gmail.com> | Fri May 06 13:44:43 2016 +0200 |
| tree | bad079ef2aa45a633e5dca94a3123687e13f1b32 | |
| parent | 93e72a773fade158921402d6a24c819b48aba29d [diff] |
jsonLoader: add support for http.FileSystem Currently jsonReferenceLoader only supports raw filesystem lookups. This introduces a new constructor NewReferenceLoaderFileSystem which takes a http.FileSystem. This allows to embed JSON schema files in binaries.
An implementation of JSON Schema, based on IETF's draft v4 - Go language
References :
go get github.com/xeipuuv/gojsonschema
Dependencies :
package main import ( "fmt" "github.com/xeipuuv/gojsonschema" ) func main() { schemaLoader := gojsonschema.NewReferenceLoader("file:///home/me/schema.json") documentLoader := gojsonschema.NewReferenceLoader("file:///home/me/document.json") result, err := gojsonschema.Validate(schemaLoader, documentLoader) if err != nil { panic(err.Error()) } if result.Valid() { fmt.Printf("The document is valid\n") } else { fmt.Printf("The document is not valid. see errors :\n") for _, desc := range result.Errors() { fmt.Printf("- %s\n", desc) } } }
There are various ways to load your JSON data. In order to load your schemas and documents, first declare an appropriate loader :
loader := gojsonschema.NewReferenceLoader("http://www.some_host.com/schema.json")
loader := gojsonschema.NewReferenceLoader("file:///home/me/schema.json")
References use the URI scheme, the prefix (file://) and a full path to the file are required.
loader := gojsonschema.NewStringLoader(`{"type": "string"}`)
m := map[string]interface{}{"type": "string"}
loader := gojsonschema.NewGoLoader(m)
And
type Root struct {
Users []User `json:"users"`
}
type User struct {
Name string `json:"name"`
}
...
data := Root{}
data.Users = append(data.Users, User{"John"})
data.Users = append(data.Users, User{"Sophia"})
data.Users = append(data.Users, User{"Bill"})
loader := gojsonschema.NewGoLoader(data)
Once the loaders are set, validation is easy :
result, err := gojsonschema.Validate(schemaLoader, documentLoader)
Alternatively, you might want to load a schema only once and process to multiple validations :
schema, err := gojsonschema.NewSchema(schemaLoader) ... result1, err := schema.Validate(documentLoader1) ... result2, err := schema.Validate(documentLoader2) ... // etc ...
To check the result :
if result.Valid() { fmt.Printf("The document is valid\n") } else { fmt.Printf("The document is not valid. see errors :\n") for _, err := range result.Errors() { // Err implements the ResultError interface fmt.Printf("- %s\n", err) } }
The library handles string error codes which you can customize by creating your own gojsonschema.locale and setting it
gojsonschema.Locale = YourCustomLocale{}
However, each error contains additional contextual information.
err.Type(): string Returns the “type” of error that occurred. Note you can also type check. See below
Note: An error of RequiredType has an err.Type() return value of “required”
"required": RequiredError "invalid_type": InvalidTypeError "number_any_of": NumberAnyOfError "number_one_of": NumberOneOfError "number_all_of": NumberAllOfError "number_not": NumberNotError "missing_dependency": MissingDependencyError "internal": InternalError "enum": EnumError "array_no_additional_items": ArrayNoAdditionalItemsError "array_min_items": ArrayMinItemsError "array_max_items": ArrayMaxItemsError "unique": ItemsMustBeUniqueError "array_min_properties": ArrayMinPropertiesError "array_max_properties": ArrayMaxPropertiesError "additional_property_not_allowed": AdditionalPropertyNotAllowedError "invalid_property_pattern": InvalidPropertyPatternError "string_gte": StringLengthGTEError "string_lte": StringLengthLTEError "pattern": DoesNotMatchPatternError "multiple_of": MultipleOfError "number_gte": NumberGTEError "number_gt": NumberGTError "number_lte": NumberLTEError "number_lt": NumberLTError
err.Value(): interface{} Returns the value given
err.Context(): gojsonschema.jsonContext Returns the context. This has a String() method that will print something like this: (root).firstName
err.Field(): string Returns the fieldname in the format firstName, or for embedded properties, person.firstName. This returns the same as the String() method on err.Context() but removes the (root). prefix.
err.Description(): string The error description. This is based on the locale you are using. See the beginning of this section for overwriting the locale with a custom implementation.
err.Details(): gojsonschema.ErrorDetails Returns a map[string]interface{} of additional error details specific to the error. For example, GTE errors will have a “min” value, LTE will have a “max” value. See errors.go for a full description of all the error details. Every error always contains a “field” key that holds the value of err.Field()
Note in most cases, the err.Details() will be used to generate replacement strings in your locales. and not used directly i.e.
%field% must be greater than or equal to %min%
JSON Schema allows for optional “format” property to validate strings against well-known formats. gojsonschema ships with all of the formats defined in the spec that you can use like this:
{"type": "string", "format": "email"}
Available formats: date-time, hostname, email, ipv4, ipv6, uri.
For repetitive or more complex formats, you can create custom format checkers and add them to gojsonschema like this:
// Define the format checker type RoleFormatChecker struct {} // Ensure it meets the gojsonschema.FormatChecker interface func (f RoleFormatChecker) IsFormat(input string) bool { return strings.HasPrefix("ROLE_", input) } // Add it to the library gojsonschema.FormatCheckers.Add("role", RoleFormatChecker{})
Now to use in your json schema:
{"type": "string", "format": "role"}
gojsonschema uses the following test suite :