php小編草為您介紹Golang gin框架中如何接收JSON資料和圖片。在開發過程中，我們經常需要處理前端傳遞過來的JSON資料以及映像檔。 Golang的gin框架提供了簡單易用的方法來接收和處理這些資料。透過本文的介紹，您將了解如何在gin框架中使用結構體來接收JSON數據，以及如何處理上傳的圖像檔案。讓我們一起來探索吧！
我有請求處理程序的程式碼：
func (h *handlers) updateprofile() gin.handlerfunc {
type request struct {
username string `json:"username" binding:"required,min=4,max=20"`
description string `json:"description" binding:"required,max=100"`
}
return func(c *gin.context) {
var updaterequest request
if err := c.bindjson(&updaterequest); err != nil {
var validationerrors validator.validationerrors
if errors.as(err, &validationerrors) {
validateerrors := base.bindingerror(validationerrors)
c.abortwithstatusjson(http.statusbadrequest, gin.h{"error": validateerrors})
} else {
c.abortwitherror(http.statusbadrequest, err)
}
return
}
avatar, err := c.formfile("avatar")
if err != nil {
c.abortwithstatusjson(http.statusbadrequest, gin.h{
"error": "image not contains in request",
})
return
}
log.print(avatar)
if avatar.size > 3<<20 { // if avatar size more than 3mb
c.abortwithstatusjson(http.statusbadrequest, gin.h{
"error": "image is too large",
})
return
}
file, err := avatar.open()
if err != nil {
c.abortwitherror(http.statusinternalservererror, err)
}
session := sessions.default(c)
id := session.get("sessionid")
log.printf("id type: %t", id)
err = h.userservice.updateprofile(fmt.sprintf("%v", id), file, updaterequest.username, updaterequest.description)
if err != nil {
c.abortwithstatusjson(http.statusbadrequest, gin.h{})
return
}
c.indentedjson(http.statusnocontent, gin.h{"message": "succesfull update"})
}
}我對此處理程序進行了單元測試：
func testuser_updateprofile(t *testing.t) {
type testcase struct {
name string
image io.reader
username string
description string
expectedstatuscode int
}
router := gin.default()
memstore := memstore.newstore([]byte("secret"))
router.use(sessions.sessions("session", memstore))
usergroup := router.group("user")
repo := user.newmemory()
service := userservice.new(repo)
userhandlers.register(usergroup, service)
testimage := make([]byte, 100)
rand.read(testimage)
image := bytes.newreader(testimage)
testcases := []testcase{
{
name: "request with image",
image: image,
username: "bobik",
description: "wanna be sharik",
expectedstatuscode: http.statusnocontent,
},
{
name: "request without image",
image: nil,
username: "sharik",
description: "wanna be bobik",
expectedstatuscode: http.statusnocontent,
},
}
for _, tc := range testcases {
t.run(tc.name, func(t *testing.t) {
body := &bytes.buffer{}
writer := multipart.newwriter(body)
imagewriter, err := writer.createformfile("avatar", "test_avatar.jpg")
if err != nil {
t.fatal(err)
}
if _, err := io.copy(imagewriter, image); err != nil {
t.fatal(err)
}
data := map[string]interface{}{
"username": tc.username,
"description": tc.description,
}
jsondata, err := json.marshal(data)
if err != nil {
t.fatal(err)
}
jsonwriter, err := writer.createformfield("json")
if err != nil {
t.fatal(err)
}
if _, err := jsonwriter.write(jsondata); err != nil {
t.fatal(err)
}
writer.close()
// creating request
req := httptest.newrequest(
http.methodpost,
"http://localhost:8080/user/account/updateprofile",
body,
)
req.header.set("content-type", writer.formdatacontenttype())
log.print(req)
w := httptest.newrecorder()
router.servehttp(w, req)
assert.equal(t, tc.expectedstatuscode, w.result().statuscode)
})
}
}在測試過程中出現以下錯誤： 錯誤#01：數字文字中的無效字元“-”
這是請求正文（我用 log.print(req) 列印它）：
&{POST http://localhost:8080/user/account/updateprofile HTTP/1.1 1 1 map[Content-Type:[multipart/form-data; boundary=30b24345de9d8d83ecbdd146262d86894c45b4f3485e4615553621fd2035]] {--30b24345de9d8d83ecbdd146262d86894c45b4f3485e4615553621fd2035
Content-Disposition: form-data; name="avatar"; filename="test_avatar.jpg"
Content-Type: application/octet-stream
--30b24345de9d8d83ecbdd146262d86894c45b4f3485e4615553621fd2035
Content-Disposition: form-data; name="json"
{"description":"wanna be bobik","username":"sharik"}
--30b24345de9d8d83ecbdd146262d86894c45b4f3485e4615553621fd2035--
} <nil> 414 [] false localhost:8080 map[] map[] <nil> map[] 192.0.2.1:1234 http://localhost:8080/user/account/updateprofile <nil> <nil> <nil> <nil>}首先，我只有字串作為 json 資料並將其轉換為位元組。當出現錯誤時，我使用 json.marshal 轉換了 json 數據，但沒有成功。我想用 c.bind 解析 json 資料並用 c.formfile 解析給定圖像，這可能嗎？
更新。我替換了程式碼先取得頭像，然後透過bind結構取得json。現在我有 eof 錯誤。
我們可以定義一個結構體來同時接收json資料和圖像檔案（注意字段標籤）：
var updaterequest struct {
avatar *multipart.fileheader `form:"avatar" binding:"required"`
user struct {
username string `json:"username" binding:"required,min=4,max=20"`
description string `json:"description" binding:"required,max=100"`
} `form:"user" binding:"required"`
}
// c.shouldbind will choose binding.formmultipart based on the content-type header.
// we call c.shouldbindwith to make it explicitly.
if err := c.shouldbindwith(&updaterequest, binding.formmultipart); err != nil {
_ = c.abortwitherror(http.statusbadrequest, err)
return
}
multipart/form-data中的其他內容類型嗎？ 例如，xml 或 yaml。
目前的 gin (@1.9.0) 不會自動解析 multipart/form-data 中的 xml 或 yaml 。 json 很幸運，因為當目標欄位是結構體或對應時，gin 恰好使用 json.unmarshal 解析表單欄位值。請參閱 binding.setwithpropertype。
我們可以像這樣自己解析它們（updaterequest.event 是表單中的字串值）：
var event struct {
at time.time `xml:"time" binding:"required"`
player string `xml:"player" binding:"required"`
action string `xml:"action" binding:"required"`
}
if err := binding.xml.bindbody([]byte(updaterequest.event), &event); err != nil {
_ = c.abortwitherror(http.statusbadrequest, err)
return
}
（請不要與application/xml 請求中的yaml 或application/x-yaml 請求中的xml 混淆。只有當xml 內容或yaml 內容位於 中時才需要這樣做多部分/表單-data 請求） .
c.bindjson 不能用於從 multipart/form-data 讀取 json，因為它假定請求正文以有效的 json 開頭。但它是從一個邊界開始的，看起來像 --30b24345d...。這就是為什麼它失敗並顯示錯誤訊息 invalid character '-' in numeric literal。 c.formfile("avatar") 之後呼叫c.bindjson 不起作用，因為呼叫c.formfile 會使整個請求正文被讀取。而 c.bindjson 後面也沒有什麼可讀的。這就是您看到 eof 錯誤的原因。 這是完整的示範。使用 go test 執行 ./... -v -count 1:
package m
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"mime/multipart"
"net/http"
"net/http/httptest"
"testing"
"time"
"github.com/gin-gonic/gin"
"github.com/gin-gonic/gin/binding"
"github.com/stretchr/testify/assert"
)
func handle(c *gin.Context) {
var updateRequest struct {
Avatar *multipart.FileHeader `form:"avatar" binding:"required"`
User struct {
Username string `json:"username" binding:"required,min=4,max=20"`
Description string `json:"description" binding:"required,max=100"`
} `form:"user" binding:"required"`
Event string `form:"event" binding:"required"`
}
// c.ShouldBind will choose binding.FormMultipart based on the Content-Type header.
// We call c.ShouldBindWith to make it explicitly.
if err := c.ShouldBindWith(&updateRequest, binding.FormMultipart); err != nil {
_ = c.AbortWithError(http.StatusBadRequest, err)
return
}
fmt.Printf("%#v\n", updateRequest)
var event struct {
At time.Time `xml:"time" binding:"required"`
Player string `xml:"player" binding:"required"`
Action string `xml:"action" binding:"required"`
}
if err := binding.XML.BindBody([]byte(updateRequest.Event), &event); err != nil {
_ = c.AbortWithError(http.StatusBadRequest, err)
return
}
fmt.Printf("%#v\n", event)
}
func TestMultipartForm(t *testing.T) {
testImage := make([]byte, 100)
if _, err := rand.Read(testImage); err != nil {
t.Fatal(err)
}
image := bytes.NewReader(testImage)
body := &bytes.Buffer{}
writer := multipart.NewWriter(body)
imageWriter, err := writer.CreateFormFile("avatar", "test_avatar.jpg")
if err != nil {
t.Fatal(err)
}
if _, err := io.Copy(imageWriter, image); err != nil {
t.Fatal(err)
}
if err := writer.WriteField("user", `{"username":"bobik","description":"wanna be sharik"}`); err != nil {
t.Fatal(err)
}
xmlBody := `<?xml version="1.0" encoding="UTF-8"?>
<root>
<time>2023-02-14T19:04:12Z</time>
<player>playerOne</player>
<action>strike (miss)</action>
</root>`
if err := writer.WriteField("event", xmlBody); err != nil {
t.Fatal(err)
}
writer.Close()
req := httptest.NewRequest(
http.MethodPost,
"http://localhost:8080/update",
body,
)
req.Header.Set("Content-Type", writer.FormDataContentType())
fmt.Printf("%v\n", req)
w := httptest.NewRecorder()
c, engine := gin.CreateTestContext(w)
engine.POST("/update", handle)
c.Request = req
engine.HandleContext(c)
assert.Equal(t, 200, w.Result().StatusCode)
}
感謝您的閱讀！
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