diff --git a/README.md b/README.md index 72ac99bd..7dd7f734 100644 --- a/README.md +++ b/README.md @@ -564,7 +564,11 @@ 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") } @@ -580,13 +584,16 @@ func getBookable(c *gin.Context) { ``` ```console -$ curl "localhost:8085/bookable?check_in=2017-08-16&check_out=2017-08-17" +$ curl "localhost:8085/bookable?check_in=2018-04-16&check_out=2018-04-17" {"message":"Booking dates are valid!"} -$ curl "localhost:8085/bookable?check_in=2017-08-15&check_out=2017-08-16" +$ curl "localhost:8085/bookable?check_in=2018-03-08&check_out=2018-03-09" {"error":"Key: 'Booking.CheckIn' Error:Field validation for 'CheckIn' failed on the 'bookabledate' tag"} ``` +[Struct level validations](https://github.com/go-playground/validator/releases/tag/v8.7) can also be registed this way. +See the [struct-lvl-validation example](examples/struct-lvl-validations) to learn more. + ### Only Bind Query String `ShouldBindQuery` function only binds the query params and not the post data. See the [detail information](https://github.com/gin-gonic/gin/issues/742#issuecomment-315953017). diff --git a/binding/binding.go b/binding/binding.go index dc32d538..646eb80a 100644 --- a/binding/binding.go +++ b/binding/binding.go @@ -6,8 +6,6 @@ package binding import ( "net/http" - - "gopkg.in/go-playground/validator.v8" ) const ( @@ -23,11 +21,18 @@ const ( MIMEMSGPACK2 = "application/msgpack" ) +// Binding describes the interface which needs to be implemented for binding the +// data present in the request such as JSON request body, query parameters or +// the form POST. type Binding interface { Name() string Bind(*http.Request, interface{}) error } +// StructValidator is the minimal interface which needs to be implemented in +// order for it to be used as the validator engine for ensuring the correctness +// of the reqest. Gin provides a default implementation for this using +// https://github.com/go-playground/validator/tree/v8.18.2. type StructValidator interface { // ValidateStruct can receive any kind of type and it should never panic, even if the configuration is not right. // If the received type is not a struct, any validation should be skipped and nil must be returned. @@ -36,14 +41,18 @@ type StructValidator interface { // Otherwise nil must be returned. ValidateStruct(interface{}) error - // RegisterValidation adds a validation Func to a Validate's map of validators denoted by the key - // NOTE: if the key already exists, the previous validation function will be replaced. - // NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation - RegisterValidation(string, validator.Func) error + // Engine returns the underlying validator engine which powers the + // StructValidator implementation. + Engine() interface{} } +// Validator is the default validator which implements the StructValidator +// interface. It uses https://github.com/go-playground/validator/tree/v8.18.2 +// under the hood. var Validator StructValidator = &defaultValidator{} +// These implement the Binding interface and can be used to bind the data +// present in the request to struct instances. var ( JSON = jsonBinding{} XML = xmlBinding{} @@ -55,6 +64,8 @@ var ( MsgPack = msgpackBinding{} ) +// Default returns the appropriate Binding instance based on the HTTP method +// and the content type. func Default(method, contentType string) Binding { if method == "GET" { return Form diff --git a/binding/default_validator.go b/binding/default_validator.go index 6336bb6e..c67aa8a3 100644 --- a/binding/default_validator.go +++ b/binding/default_validator.go @@ -28,9 +28,13 @@ func (v *defaultValidator) ValidateStruct(obj interface{}) error { return nil } -func (v *defaultValidator) RegisterValidation(key string, fn validator.Func) error { +// Engine returns the underlying validator engine which powers the default +// Validator instance. This is useful if you want to register custom validations +// or struct level validations. See validator GoDoc for more info - +// https://godoc.org/gopkg.in/go-playground/validator.v8 +func (v *defaultValidator) Engine() interface{} { v.lazyinit() - return v.validate.RegisterValidation(key, fn) + return v.validate } func (v *defaultValidator) lazyinit() { diff --git a/binding/json.go b/binding/json.go index b7c856af..e928a8c1 100644 --- a/binding/json.go +++ b/binding/json.go @@ -10,6 +10,9 @@ import ( "github.com/gin-gonic/gin/json" ) +// EnableDecoderUseNumber is used to call the UseNumber method on the JSON +// Decoder instance. UseNumber causes the Decoder to unmarshal a number into an +// interface{} as a Number instead of as a float64. var EnableDecoderUseNumber = false type jsonBinding struct{} diff --git a/binding/validate_test.go b/binding/validate_test.go index 8ca79989..cb76063c 100644 --- a/binding/validate_test.go +++ b/binding/validate_test.go @@ -214,11 +214,14 @@ func notOne( return false } -func TestRegisterValidation(t *testing.T) { +func TestValidatorEngine(t *testing.T) { // This validates that the function `notOne` matches // the expected function signature by `defaultValidator` // and by extension the validator library. - err := Validator.RegisterValidation("notone", notOne) + engine, ok := Validator.Engine().(*validator.Validate) + assert.True(t, ok) + + err := engine.RegisterValidation("notone", notOne) // Check that we can register custom validation without error assert.Nil(t, err) @@ -228,6 +231,6 @@ func TestRegisterValidation(t *testing.T) { // Check that we got back non-nil errs assert.NotNil(t, errs) - // Check that the error matches expactation + // Check that the error matches expectation assert.Error(t, errs, "", "", "notone") } diff --git a/examples/custom-validation/server.go b/examples/custom-validation/server.go index 31d449f0..dea0c302 100644 --- a/examples/custom-validation/server.go +++ b/examples/custom-validation/server.go @@ -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") } diff --git a/examples/struct-lvl-validations/README.md b/examples/struct-lvl-validations/README.md new file mode 100644 index 00000000..1bd57f03 --- /dev/null +++ b/examples/struct-lvl-validations/README.md @@ -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 diff --git a/examples/struct-lvl-validations/server.go b/examples/struct-lvl-validations/server.go new file mode 100644 index 00000000..be807b78 --- /dev/null +++ b/examples/struct-lvl-validations/server.go @@ -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(), + }) + } +}