Fix #216: Enable to call binding multiple times in some formats (#1341)

* Add interface to read body bytes in binding

* Add BindingBody implementation for some binding

* Fix to use `BindBodyBytesKey` for key

* Revert "Fix to use `BindBodyBytesKey` for key"

This reverts commit 2c82901ceab6ae53730a3cfcd9839bee11a08f13.

* Use private-like key for body bytes

* Add tests for BindingBody & ShouldBindBodyWith

* Add note for README

* Remove redundant space between sentences
This commit is contained in:
JINNOUCHI Yasushi
2018-05-11 11:33:33 +09:00
committed by Bo-Yi Wu
parent 6e09ef03b0
commit 995fa8e9ce
9 changed files with 279 additions and 10 deletions

View File

@ -52,6 +52,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
- [Graceful restart or stop](#graceful-restart-or-stop)
- [Build a single binary with templates](#build-a-single-binary-with-templates)
- [Bind form-data request with custom struct](#bind-form-data-request-with-custom-struct)
- [Try to bind body into different structs](#try-to-bind-body-into-different-structs)
- [Testing](#testing)
- [Users](#users--)
@ -1554,6 +1555,64 @@ type StructZ struct {
In a word, only support nested custom struct which have no `form` now.
### Try to bind body into different structs
The normal methods for binding request body consumes `c.Request.Body` and they
cannot be called multiple times.
```go
type formA struct {
Foo string `json:"foo" xml:"foo" binding:"required"`
}
type formB struct {
Bar string `json:"bar" xml:"bar" binding:"required"`
}
func SomeHandler(c *gin.Context) {
objA := formA{}
objB := formB{}
// This c.ShouldBind consumes c.Request.Body and it cannot be reused.
if errA := c.ShouldBind(&objA); errA == nil {
c.String(http.StatusOK, `the body should be formA`)
// Always an error is occurred by this because c.Request.Body is EOF now.
} else if errB := c.ShouldBind(&objB); errB == nil {
c.String(http.StatusOK, `the body should be formB`)
} else {
...
}
}
```
For this, you can use `c.ShouldBindBodyWith`.
```go
func SomeHandler(c *gin.Context) {
objA := formA{}
objB := formB{}
// This reads c.Request.Body and stores the result into the context.
if errA := c.ShouldBindBodyWith(&objA, binding.JSON); errA == nil {
c.String(http.StatusOK, `the body should be formA`)
// At this time, it reuses body stored in the context.
} else if errB := c.ShouldBindBodyWith(&objB, binding.JSON); errB == nil {
c.String(http.StatusOK, `the body should be formB JSON`)
// And it can accepts other formats
} else if errB2 := c.ShouldBindBodyWith(&objB, binding.XML); errB2 == nil {
c.String(http.StatusOK, `the body should be formB XML`)
} else {
...
}
}
```
* `c.ShouldBindBodyWith` stores body into the context before binding. This has
a slight impact to performance, so you should not use this method if you are
enough to call binding at once.
* This feature is only needed for some formats -- `JSON`, `XML`, `MsgPack`,
`ProtoBuf`. For other formats, `Query`, `Form`, `FormPost`, `FormMultipart`,
can be called by `c.ShouldBind()` multiple times without any damage to
performance (See [#1341](https://github.com/gin-gonic/gin/pull/1341)).
## Testing
The `net/http/httptest` package is preferable way for HTTP testing.