tailscale/tsweb/jsonhandler.go

74 lines
1.9 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tsweb
import (
"encoding/json"
"net/http"
)
type response struct {
Status string `json:"status"`
Error string `json:"error,omitempty"`
Data interface{} `json:"data,omitempty"`
}
// TODO: Header
// JSONHandlerFunc only take *http.Request as argument to avoid any misuse of http.ResponseWriter.
// The function's results must be (status int, data interface{}, err error).
// Return a HTTPError to show an error message, otherwise JSONHandler will only show "internal server error".
type JSONHandlerFunc func(r *http.Request) (status int, data interface{}, err error)
// ServeHTTP calls the JSONHandlerFunc and automatically marshals http responses.
//
// Use the following code to unmarshal the request body
// body := new(DataType)
// if err := json.NewDecoder(r.Body).Decode(body); err != nil {
// return http.StatusBadRequest, nil, err
// }
//
// Check jsonhandler_text.go for examples
func (fn JSONHandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
var resp *response
status, data, err := fn(r)
if status == 0 {
status = http.StatusInternalServerError
resp = &response{
Status: "error",
Error: "internal server error",
}
} else if err == nil {
resp = &response{
Status: "success",
Data: data,
}
} else {
if werr, ok := err.(HTTPError); ok {
resp = &response{
Status: "error",
Error: werr.Msg,
Data: data,
}
} else {
resp = &response{
Status: "error",
Error: "internal server error",
}
}
}
b, err := json.Marshal(resp)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(`{"status":"error","error":"json marshal error"}`))
return
}
w.WriteHeader(status)
w.Write(b)
}