https://github.com/git-lfs/gojsonschema
An implementation of JSON Schema, draft v4 - Go language
https://github.com/git-lfs/gojsonschema
Last synced: 5 months ago
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An implementation of JSON Schema, draft v4 - Go language
- Host: GitHub
- URL: https://github.com/git-lfs/gojsonschema
- Owner: git-lfs
- Fork: true (xeipuuv/gojsonschema)
- Created: 2017-02-10T17:39:53.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2017-02-13T16:31:06.000Z (over 9 years ago)
- Last Synced: 2024-06-20T19:21:10.851Z (about 2 years ago)
- Language: Go
- Size: 367 KB
- Stars: 4
- Watchers: 3
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE-APACHE-2.0.txt
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# gojsonschema
## Description
An implementation of JSON Schema, based on IETF's draft v4 - Go language
References :
* http://json-schema.org
* http://json-schema.org/latest/json-schema-core.html
* http://json-schema.org/latest/json-schema-validation.html
## Installation
```
go get github.com/xeipuuv/gojsonschema
```
Dependencies :
* [github.com/xeipuuv/gojsonpointer](https://github.com/xeipuuv/gojsonpointer)
* [github.com/xeipuuv/gojsonreference](https://github.com/xeipuuv/gojsonreference)
* [github.com/stretchr/testify/assert](https://github.com/stretchr/testify#assert-package)
## Usage
### Example
```go
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)
}
}
}
```
#### Loaders
There are various ways to load your JSON data.
In order to load your schemas and documents,
first declare an appropriate loader :
* Web / HTTP, using a reference :
```go
loader := gojsonschema.NewReferenceLoader("http://www.some_host.com/schema.json")
```
* Local file, using a reference :
```go
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.
* JSON strings :
```go
loader := gojsonschema.NewStringLoader(`{"type": "string"}`)
```
* Custom Go types :
```go
m := map[string]interface{}{"type": "string"}
loader := gojsonschema.NewGoLoader(m)
```
And
```go
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)
```
#### Validation
Once the loaders are set, validation is easy :
```go
result, err := gojsonschema.Validate(schemaLoader, documentLoader)
```
Alternatively, you might want to load a schema only once and process to multiple validations :
```go
schema, err := gojsonschema.NewSchema(schemaLoader)
...
result1, err := schema.Validate(documentLoader1)
...
result2, err := schema.Validate(documentLoader2)
...
// etc ...
```
To check the result :
```go
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)
}
}
```
## Working with Errors
The library handles string error codes which you can customize by creating your own gojsonschema.locale and setting it
```go
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. These strings follow the text/template format i.e.
```
{{.field}} must be greater than or equal to {{.min}}
```
## Formats
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:
````json
{"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:
```go
// 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:
````json
{"type": "string", "format": "role"}
````
## Uses
gojsonschema uses the following test suite :
https://github.com/json-schema/JSON-Schema-Test-Suite