add jsonhttp package for json http api related functions

pkg/jsonhttp/jsonhttp.go

+// Copyright 2020 The Swarm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Most of the code is copied from package resenje.org/jsonresponse.
+
+package jsonhttp
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+var (
+	// DefaultContentTypeHeader is the value of if "Content-Type" header
+	// in HTTP response.
+	DefaultContentTypeHeader = "application/json; charset=utf-8"
+	// EscapeHTML specifies whether problematic HTML characters
+	// should be escaped inside JSON quoted strings.
+	EscapeHTML = false
+)
+
+// Respond writes a JSON-encoded body to http.ResponseWriter.
+func Respond(w http.ResponseWriter, statusCode int, response interface{}) {
+
+	type statusResponse struct {
+		Code    int    `json:"code,omitempty"`
+		Message string `json:"message,omitempty"`
+	}
+
+	if response == nil {
+		response = &statusResponse{
+			Code:    statusCode,
+			Message: http.StatusText(statusCode),
+		}
+	} else if message, ok := response.(string); ok {
+		response = &statusResponse{
+			Code:    statusCode,
+			Message: message,
+		}
+	}
+	var b bytes.Buffer
+	enc := json.NewEncoder(&b)
+	enc.SetEscapeHTML(EscapeHTML)
+	if err := enc.Encode(response); err != nil {
+		panic(err)
+	}
+	if DefaultContentTypeHeader != "" {
+		w.Header().Set("Content-Type", DefaultContentTypeHeader)
+	}
+	w.WriteHeader(statusCode)
+	fmt.Fprintln(w, b.String())
+}
+
+// Continue writes a response with status code 100.
+func Continue(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusContinue, response)
+}
+
+// SwitchingProtocols writes a response with status code 101.
+func SwitchingProtocols(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusSwitchingProtocols, response)
+}
+
+// OK writes a response with status code 200.
+func OK(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusOK, response)
+}
+
+// Created writes a response with status code 201.
+func Created(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusCreated, response)
+}
+
+// Accepted writes a response with status code 202.
+func Accepted(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusAccepted, response)
+}
+
+// NonAuthoritativeInfo writes a response with status code 203.
+func NonAuthoritativeInfo(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusNonAuthoritativeInfo, response)
+}
+
+// ResetContent writes a response with status code 205.
+func ResetContent(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusResetContent, response)
+}
+
+// PartialContent writes a response with status code 206.
+func PartialContent(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusPartialContent, response)
+}
+
+// MultipleChoices writes a response with status code 300.
+func MultipleChoices(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusMultipleChoices, response)
+}
+
+// MovedPermanently writes a response with status code 301.
+func MovedPermanently(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusMovedPermanently, response)
+}
+
+// Found writes a response with status code 302.
+func Found(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusFound, response)
+}
+
+// SeeOther writes a response with status code 303.
+func SeeOther(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusSeeOther, response)
+}
+
+// NotModified writes a response with status code 304.
+func NotModified(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusNotModified, response)
+}
+
+// UseProxy writes a response with status code 305.
+func UseProxy(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusUseProxy, response)
+}
+
+// TemporaryRedirect writes a response with status code 307.
+func TemporaryRedirect(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusTemporaryRedirect, response)
+}
+
+// PermanentRedirect writes a response with status code 308.
+func PermanentRedirect(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusPermanentRedirect, response)
+}
+
+// BadRequest writes a response with status code 400.
+func BadRequest(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusBadRequest, response)
+}
+
+// Unauthorized writes a response with status code 401.
+func Unauthorized(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusUnauthorized, response)
+}
+
+// PaymentRequired writes a response with status code 402.
+func PaymentRequired(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusPaymentRequired, response)
+}
+
+// Forbidden writes a response with status code 403.
+func Forbidden(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusForbidden, response)
+}
+
+// NotFound writes a response with status code 404.
+func NotFound(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusNotFound, response)
+}
+
+// MethodNotAllowed writes a response with status code 405.
+func MethodNotAllowed(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusMethodNotAllowed, response)
+}
+
+// NotAcceptable writes a response with status code 406.
+func NotAcceptable(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusNotAcceptable, response)
+}
+
+// ProxyAuthRequired writes a response with status code 407.
+func ProxyAuthRequired(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusProxyAuthRequired, response)
+}
+
+// RequestTimeout writes a response with status code 408.
+func RequestTimeout(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusRequestTimeout, response)
+}
+
+// Conflict writes a response with status code 409.
+func Conflict(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusConflict, response)
+}
+
+// Gone writes a response with status code 410.
+func Gone(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusGone, response)
+}
+
+// LengthRequired writes a response with status code 411.
+func LengthRequired(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusLengthRequired, response)
+}
+
+// PreconditionFailed writes a response with status code 412.
+func PreconditionFailed(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusPreconditionFailed, response)
+}
+
+// RequestEntityTooLarge writes a response with status code 413.
+func RequestEntityTooLarge(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusRequestEntityTooLarge, response)
+}
+
+// RequestURITooLong writes a response with status code 414.
+func RequestURITooLong(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusRequestURITooLong, response)
+}
+
+// UnsupportedMediaType writes a response with status code 415.
+func UnsupportedMediaType(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusUnsupportedMediaType, response)
+}
+
+// RequestedRangeNotSatisfiable writes a response with status code 416.
+func RequestedRangeNotSatisfiable(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusRequestedRangeNotSatisfiable, response)
+}
+
+// ExpectationFailed writes a response with status code 417.
+func ExpectationFailed(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusExpectationFailed, response)
+}
+
+// Teapot writes a response with status code 418.
+func Teapot(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusTeapot, response)
+}
+
+// UpgradeRequired writes a response with status code 426.
+func UpgradeRequired(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusUpgradeRequired, response)
+}
+
+// PreconditionRequired writes a response with status code 428.
+func PreconditionRequired(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusPreconditionRequired, response)
+}
+
+// TooManyRequests writes a response with status code 429.
+func TooManyRequests(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusTooManyRequests, response)
+}
+
+// RequestHeaderFieldsTooLarge writes a response with status code 431.
+func RequestHeaderFieldsTooLarge(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusRequestHeaderFieldsTooLarge, response)
+}
+
+// UnavailableForLegalReasons writes a response with status code 451.
+func UnavailableForLegalReasons(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusUnavailableForLegalReasons, response)
+}
+
+// InternalServerError writes a response with status code 500.
+func InternalServerError(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusInternalServerError, response)
+}
+
+// NotImplemented writes a response with status code 501.
+func NotImplemented(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusNotImplemented, response)
+}
+
+// BadGateway writes a response with status code 502.
+func BadGateway(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusBadGateway, response)
+}
+
+// ServiceUnavailable writes a response with status code 503.
+func ServiceUnavailable(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusServiceUnavailable, response)
+}
+
+// GatewayTimeout writes a response with status code 504.
+func GatewayTimeout(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusGatewayTimeout, response)
+}
+
+// HTTPVersionNotSupported writes a response with status code 505.
+func HTTPVersionNotSupported(w http.ResponseWriter, response interface{}) {
+	Respond(w, http.StatusHTTPVersionNotSupported, response)
+}