fix(binding): Expose validator engine used by the default Validator (#1277)

* fix(binding): Expose validator engine used by the default Validator

- Add func ValidatorEngine for returning the underlying validator engine used
  in the default StructValidator implementation.
- Remove the function RegisterValidation from the StructValidator interface
  which made it immpossible to use a StructValidator implementation without the
  validator.v8 library.
- Update and rename test for registering validation
  Test{RegisterValidation => ValidatorEngine}.
- Update readme and example for registering custom validation.
- Add example for registering struct level validation.
- Add documentation for the following binding funcs/types:
  - Binding interface
  - StructValidator interface
  - Validator instance
  - Binding implementations
  - Default func

* fix(binding): Move validator engine getter inside interface

* docs: rm date cmd from custom validation demo
This commit is contained in:
Suhas Karanth
2018-03-29 12:03:07 +05:30
committed by Bo-Yi Wu
parent 65a65c2edd
commit 6d913fc343
8 changed files with 161 additions and 15 deletions

View File

@ -30,7 +30,11 @@ func bookableDate(
func main() {
route := gin.Default()
binding.Validator.RegisterValidation("bookabledate", bookableDate)
if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
v.RegisterValidation("bookabledate", bookableDate)
}
route.GET("/bookable", getBookable)
route.Run(":8085")
}

View File

@ -0,0 +1,50 @@
## Struct level validations
Validations can also be registered at the `struct` level when field level validations
don't make much sense. This can also be used to solve cross-field validation elegantly.
Additionally, it can be combined with tag validations. Struct Level validations run after
the structs tag validations.
### Example requests
```shell
# Validation errors are generated for struct tags as well as at the struct level
$ curl -s -X POST http://localhost:8085/user \
-H 'content-type: application/json' \
-d '{}' | jq
{
"error": "Key: 'User.Email' Error:Field validation for 'Email' failed on the 'required' tag\nKey: 'User.FirstName' Error:Field validation for 'FirstName' failed on the 'fnameorlname' tag\nKey: 'User.LastName' Error:Field validation for 'LastName' failed on the 'fnameorlname' tag",
"message": "User validation failed!"
}
# Validation fails at the struct level because neither first name nor last name are present
$ curl -s -X POST http://localhost:8085/user \
-H 'content-type: application/json' \
-d '{"email": "george@vandaley.com"}' | jq
{
"error": "Key: 'User.FirstName' Error:Field validation for 'FirstName' failed on the 'fnameorlname' tag\nKey: 'User.LastName' Error:Field validation for 'LastName' failed on the 'fnameorlname' tag",
"message": "User validation failed!"
}
# No validation errors when either first name or last name is present
$ curl -X POST http://localhost:8085/user \
-H 'content-type: application/json' \
-d '{"fname": "George", "email": "george@vandaley.com"}'
{"message":"User validation successful."}
$ curl -X POST http://localhost:8085/user \
-H 'content-type: application/json' \
-d '{"lname": "Contanza", "email": "george@vandaley.com"}'
{"message":"User validation successful."}
$ curl -X POST http://localhost:8085/user \
-H 'content-type: application/json' \
-d '{"fname": "George", "lname": "Costanza", "email": "george@vandaley.com"}'
{"message":"User validation successful."}
```
### Useful links
- Validator docs - https://godoc.org/gopkg.in/go-playground/validator.v8#Validate.RegisterStructValidation
- Struct level example - https://github.com/go-playground/validator/blob/v8.18.2/examples/struct-level/struct_level.go
- Validator release notes - https://github.com/go-playground/validator/releases/tag/v8.7

View File

@ -0,0 +1,64 @@
package main
import (
"net/http"
"reflect"
"github.com/gin-gonic/gin"
"github.com/gin-gonic/gin/binding"
validator "gopkg.in/go-playground/validator.v8"
)
// User contains user information.
type User struct {
FirstName string `json:"fname"`
LastName string `json:"lname"`
Email string `binding:"required,email"`
}
// UserStructLevelValidation contains custom struct level validations that don't always
// make sense at the field validation level. For example, this function validates that either
// FirstName or LastName exist; could have done that with a custom field validation but then
// would have had to add it to both fields duplicating the logic + overhead, this way it's
// only validated once.
//
// NOTE: you may ask why wouldn't not just do this outside of validator. Doing this way
// hooks right into validator and you can combine with validation tags and still have a
// common error output format.
func UserStructLevelValidation(v *validator.Validate, structLevel *validator.StructLevel) {
user := structLevel.CurrentStruct.Interface().(User)
if len(user.FirstName) == 0 && len(user.LastName) == 0 {
structLevel.ReportError(
reflect.ValueOf(user.FirstName), "FirstName", "fname", "fnameorlname",
)
structLevel.ReportError(
reflect.ValueOf(user.LastName), "LastName", "lname", "fnameorlname",
)
}
// plus can to more, even with different tag than "fnameorlname"
}
func main() {
route := gin.Default()
if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
v.RegisterStructValidation(UserStructLevelValidation, User{})
}
route.POST("/user", validateUser)
route.Run(":8085")
}
func validateUser(c *gin.Context) {
var u User
if err := c.ShouldBindJSON(&u); err == nil {
c.JSON(http.StatusOK, gin.H{"message": "User validation successful."})
} else {
c.JSON(http.StatusBadRequest, gin.H{
"message": "User validation failed!",
"error": err.Error(),
})
}
}