Chore: Moves common and response into separate packages (#30298)

* Chore: moves common and response into separate packages

* Chore: moves common and response into separate packages

* Update pkg/api/utils/common.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Chore: changes after PR comments

* Chore: move wrap to routing package

* Chore: move functions in common to response package

* Chore: move functions in common to response package

* Chore: formats imports

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/api/response/response.go

@@ -0,0 +1,216 @@
+package response
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/setting"
+	jsoniter "github.com/json-iterator/go"
+)
+
+// Response is an HTTP response interface.
+type Response interface {
+	// WriteTo writes to a context.
+	WriteTo(ctx *models.ReqContext)
+	// Body gets the response's body.
+	Body() []byte
+	// Status gets the response's status.
+	Status() int
+}
+
+func CreateNormalResponse(header http.Header, body []byte, status int) *NormalResponse {
+	return &NormalResponse{
+		header: header,
+		body:   body,
+		status: status,
+	}
+}
+
+type NormalResponse struct {
+	status     int
+	body       []byte
+	header     http.Header
+	errMessage string
+	err        error
+}
+
+// Status gets the response's status.
+func (r *NormalResponse) Status() int {
+	return r.status
+}
+
+// Body gets the response's body.
+func (r *NormalResponse) Body() []byte {
+	return r.body
+}
+
+// Err gets the response's err.
+func (r *NormalResponse) Err() error {
+	return r.err
+}
+
+// ErrMessage gets the response's errMessage.
+func (r *NormalResponse) ErrMessage() string {
+	return r.errMessage
+}
+
+func (r *NormalResponse) WriteTo(ctx *models.ReqContext) {
+	if r.err != nil {
+		ctx.Logger.Error(r.errMessage, "error", r.err, "remote_addr", ctx.RemoteAddr())
+	}
+
+	header := ctx.Resp.Header()
+	for k, v := range r.header {
+		header[k] = v
+	}
+	ctx.Resp.WriteHeader(r.status)
+	if _, err := ctx.Resp.Write(r.body); err != nil {
+		ctx.Logger.Error("Error writing to response", "err", err)
+	}
+}
+
+func (r *NormalResponse) Header(key, value string) *NormalResponse {
+	r.header.Set(key, value)
+	return r
+}
+
+// StreamingResponse is a response that streams itself back to the client.
+type StreamingResponse struct {
+	body   interface{}
+	status int
+	header http.Header
+}
+
+// Status gets the response's status.
+// Required to implement api.Response.
+func (r StreamingResponse) Status() int {
+	return r.status
+}
+
+// Body gets the response's body.
+// Required to implement api.Response.
+func (r StreamingResponse) Body() []byte {
+	return nil
+}
+
+// WriteTo writes the response to the provided context.
+// Required to implement api.Response.
+func (r StreamingResponse) WriteTo(ctx *models.ReqContext) {
+	header := ctx.Resp.Header()
+	for k, v := range r.header {
+		header[k] = v
+	}
+	ctx.Resp.WriteHeader(r.status)
+	enc := jsoniter.NewEncoder(ctx.Resp)
+	if err := enc.Encode(r.body); err != nil {
+		ctx.Logger.Error("Error writing to response", "err", err)
+	}
+}
+
+// RedirectResponse represents a redirect response.
+type RedirectResponse struct {
+	location string
+}
+
+// WriteTo writes to a response.
+func (r *RedirectResponse) WriteTo(ctx *models.ReqContext) {
+	ctx.Redirect(r.location)
+}
+
+// Status gets the response's status.
+// Required to implement api.Response.
+func (*RedirectResponse) Status() int {
+	return http.StatusFound
+}
+
+// Body gets the response's body.
+// Required to implement api.Response.
+func (r *RedirectResponse) Body() []byte {
+	return nil
+}
+
+// JSON creates a JSON response.
+func JSON(status int, body interface{}) *NormalResponse {
+	return Respond(status, body).Header("Content-Type", "application/json")
+}
+
+// JSONStreaming creates a streaming JSON response.
+func JSONStreaming(status int, body interface{}) StreamingResponse {
+	header := make(http.Header)
+	header.Set("Content-Type", "application/json")
+	return StreamingResponse{
+		body:   body,
+		status: status,
+		header: header,
+	}
+}
+
+// Success create a successful response
+func Success(message string) *NormalResponse {
+	resp := make(map[string]interface{})
+	resp["message"] = message
+	return JSON(200, resp)
+}
+
+// Error creates an error response.
+func Error(status int, message string, err error) *NormalResponse {
+	data := make(map[string]interface{})
+
+	switch status {
+	case 404:
+		data["message"] = "Not Found"
+	case 500:
+		data["message"] = "Internal Server Error"
+	}
+
+	if message != "" {
+		data["message"] = message
+	}
+
+	if err != nil {
+		if setting.Env != setting.Prod {
+			data["error"] = err.Error()
+		}
+	}
+
+	resp := JSON(status, data)
+
+	if err != nil {
+		resp.errMessage = message
+		resp.err = err
+	}
+
+	return resp
+}
+
+// Empty creates an empty NormalResponse.
+func Empty(status int) *NormalResponse {
+	return Respond(status, nil)
+}
+
+// Respond creates a response.
+func Respond(status int, body interface{}) *NormalResponse {
+	var b []byte
+	switch t := body.(type) {
+	case []byte:
+		b = t
+	case string:
+		b = []byte(t)
+	default:
+		var err error
+		if b, err = json.Marshal(body); err != nil {
+			return Error(500, "body json marshal", err)
+		}
+	}
+
+	return &NormalResponse{
+		status: status,
+		body:   b,
+		header: make(http.Header),
+	}
+}
+
+func Redirect(location string) *RedirectResponse {
+	return &RedirectResponse{location: location}
+}