php小编苹果为大家带来了关于Go语言中如何使用上下文的介绍。在Go语言开发中，上下文(Context)是一个非常重要的概念，它可以在多个goroutine之间传递请求的信息。本文将详细介绍上下文的作用、使用场景以及如何在Go语言中使用上下文。无论你是初学者还是有一定经验的开发者，通过阅读本文，你都能够更好地理解和应用上下文在Go语言开发中的重要性。
问题内容
我正在尝试通过 imagekit sdk 将图像从 golang 后端上传到 imagekit。我面临着理解 context api 用途的问题。
目前，我并没有真正在后端使用上下文，而是在构造函数中传递所有依赖项。
我遇到了异常：
2023/01/04 09:53:56 http: panic serving 127.0.0.1:50780: runtime error: invalid memory address or nil pointer dereference
goroutine 20 [running]:
net/http.(*conn).serve.func1()
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:1850 +0xbf
panic({0x1005836c0, 0x10092b820})
/usr/local/cellar/go/1.19.3/libexec/src/runtime/panic.go:890 +0x262
github.com/bolzfieber/bolzfieber-backend/internal/controllers.pitchescontroller.createandupdatepitch({0xc0001f7530?, 0x0?}, {0x1006a94e8, 0xc0000ca000}, 0xc0000d4000)
/users/pbahr/dev/bolzfieber/be/bolzfieber-backend/internal/controllers/pitches.go:91 +0x5ae
net/http.handlerfunc.servehttp(0x100580980?, {0x1006a94e8?, 0xc0000ca000?}, 0xc0000be048?)
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:2109 +0x2f
github.com/go-chi/chi/v5.(*mux).routehttp(0xc00007c600, {0x1006a94e8, 0xc0000ca000}, 0xc0000d4000)
/users/pbahr/go/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:442 +0x216
net/http.handlerfunc.servehttp(0xc0000b00c0?, {0x1006a94e8?, 0xc0000ca000?}, 0xc00011b918?)
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:2109 +0x2f
github.com/go-chi/chi/v5.(*mux).servehttp(0xc00007c600, {0x1006a94e8, 0xc0000ca000}, 0xc0000d4000)
/users/pbahr/go/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:71 +0x355
github.com/go-chi/chi/v5.(*mux).mount.func1({0x1006a94e8, 0xc0000ca000}, 0xc0000d4000)
/users/pbahr/go/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:314 +0x19c
net/http.handlerfunc.servehttp(0x100580980?, {0x1006a94e8?, 0xc0000ca000?}, 0xc0000aa005?)
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:2109 +0x2f
github.com/go-chi/chi/v5.(*mux).routehttp(0xc00007c420, {0x1006a94e8, 0xc0000ca000}, 0xc0000d4000)
/users/pbahr/go/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:442 +0x216
net/http.handlerfunc.servehttp(0x1006a9bf8?, {0x1006a94e8?, 0xc0000ca000?}, 0x10092b640?)
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:2109 +0x2f
github.com/go-chi/chi/v5.(*mux).servehttp(0xc00007c420, {0x1006a94e8, 0xc0000ca000}, 0xc000332000)
/users/pbahr/go/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:88 +0x310
net/http.serverhandler.servehttp({0x1006a84d0?}, {0x1006a94e8, 0xc0000ca000}, 0xc000332000)
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:2947 +0x30c
net/http.(*conn).serve(0xc00032c000, {0x1006a9ca0, 0xc000318270})
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:1991 +0x607
created by net/http.(*server).serve
/usr/local/cellar/go/1.19.3/libexec/src/net/http/server.go:3102 +0x4db
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而第91行是imagekit的上传行。所以我认为空指针是上下文。
我当前的方法如下：
func (c PitchesController) CreateAndUpdatePitch(w http.ResponseWriter, r *http.Request) {
var pitchUpload models.PitchUpload
err := json.NewDecoder(r.Body).Decode(&pitchUpload)
if err != nil {
fmt.Printf("Error: %vn", err)
utils.RespondWithError(w, http.StatusBadRequest, "Bad request")
return
}
var pitch = models.Pitch{
Name: pitchUpload.Name,
Address: pitchUpload.Address,
Author: pitchUpload.Author,
PitchType: pitchUpload.PitchType,
PitchSize: pitchUpload.PitchSize,
GoalSize: pitchUpload.GoalSize,
GoalType: pitchUpload.GoalType,
LocationScopeId: pitchUpload.LocationScopeId,
Coordinates: pitchUpload.Coordinates,
Rating: pitchUpload.Rating,
}
for i, image := range pitchUpload.Images {
fmt.Printf("pitch: %vn", pitchUpload.Name)
response, uploadErr := c.Ik.Uploader.Upload(r.Context(), image, uploader.UploadParam{
FileName: pitchUpload.Name + "_" + string(rune(i)),
UseUniqueFileName: newTrue(),
Tags: "pitch",
Folder: "/pitches/" + pitchUpload.Name,
})
if uploadErr != nil {
fmt.Printf("Error: %vn", uploadErr)
utils.RespondWithError(w, http.StatusBadRequest, "Bad request")
return
}
pitch.Images = append(pitch.Images, models.PitchImage{FileUrl: response.Data.Url})
}
c.Db.Save(&pitch)
utils.RespondWithJSON(w, http.StatusCreated, "Created successfully")
}
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以下步骤适用：
解决方法
在这一行得到一个 nil 指针可能意味着 c.Ik。或 c.Ik.Uploader。或河。或上传者。是零。我们可以轻松消除一些嫌疑人。
以上就是Imagekit - Go 语言 |如何使用上下文的详细内容，更多请关注每日运维网(www.mryunwei.com)其它相关文章！
