codekingpro/portable-devtools

1// Copyright 2011 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4 5//go:build !goexperiment.jsonv26 7package json_test8 9import (10	"bytes"11	"encoding/json"12	"fmt"13	"io"14	"log"15	"os"16	"strings"17)18 19func ExampleMarshal() {20	type ColorGroup struct {21		ID     int22		Name   string23		Colors []string24	}25	group := ColorGroup{26		ID:     1,27		Name:   "Reds",28		Colors: []string{"Crimson", "Red", "Ruby", "Maroon"},29	}30	b, err := json.Marshal(group)31	if err != nil {32		fmt.Println("error:", err)33	}34	os.Stdout.Write(b)35	// Output:36	// {"ID":1,"Name":"Reds","Colors":["Crimson","Red","Ruby","Maroon"]}37}38 39func ExampleUnmarshal() {40	var jsonBlob = []byte(`[41	{"Name": "Platypus", "Order": "Monotremata"},42	{"Name": "Quoll",    "Order": "Dasyuromorphia"}43]`)44	type Animal struct {45		Name  string46		Order string47	}48	var animals []Animal49	err := json.Unmarshal(jsonBlob, &animals)50	if err != nil {51		fmt.Println("error:", err)52	}53	fmt.Printf("%+v", animals)54	// Output:55	// [{Name:Platypus Order:Monotremata} {Name:Quoll Order:Dasyuromorphia}]56}57 58// This example uses a Decoder to decode a stream of distinct JSON values.59func ExampleDecoder() {60	const jsonStream = `61	{"Name": "Ed", "Text": "Knock knock."}62	{"Name": "Sam", "Text": "Who's there?"}63	{"Name": "Ed", "Text": "Go fmt."}64	{"Name": "Sam", "Text": "Go fmt who?"}65	{"Name": "Ed", "Text": "Go fmt yourself!"}66`67	type Message struct {68		Name, Text string69	}70	dec := json.NewDecoder(strings.NewReader(jsonStream))71	for {72		var m Message73		if err := dec.Decode(&m); err == io.EOF {74			break75		} else if err != nil {76			log.Fatal(err)77		}78		fmt.Printf("%s: %s\n", m.Name, m.Text)79	}80	// Output:81	// Ed: Knock knock.82	// Sam: Who's there?83	// Ed: Go fmt.84	// Sam: Go fmt who?85	// Ed: Go fmt yourself!86}87 88// This example uses a Decoder to decode a stream of distinct JSON values.89func ExampleDecoder_Token() {90	const jsonStream = `91	{"Message": "Hello", "Array": [1, 2, 3], "Null": null, "Number": 1.234}92`93	dec := json.NewDecoder(strings.NewReader(jsonStream))94	for {95		t, err := dec.Token()96		if err == io.EOF {97			break98		}99		if err != nil {100			log.Fatal(err)101		}102		fmt.Printf("%T: %v", t, t)103		if dec.More() {104			fmt.Printf(" (more)")105		}106		fmt.Printf("\n")107	}108	// Output:109	// json.Delim: { (more)110	// string: Message (more)111	// string: Hello (more)112	// string: Array (more)113	// json.Delim: [ (more)114	// float64: 1 (more)115	// float64: 2 (more)116	// float64: 3117	// json.Delim: ] (more)118	// string: Null (more)119	// <nil>: <nil> (more)120	// string: Number (more)121	// float64: 1.234122	// json.Delim: }123}124 125// This example uses a Decoder to decode a streaming array of JSON objects.126func ExampleDecoder_Decode_stream() {127	const jsonStream = `128	[129		{"Name": "Ed", "Text": "Knock knock."},130		{"Name": "Sam", "Text": "Who's there?"},131		{"Name": "Ed", "Text": "Go fmt."},132		{"Name": "Sam", "Text": "Go fmt who?"},133		{"Name": "Ed", "Text": "Go fmt yourself!"}134	]135`136	type Message struct {137		Name, Text string138	}139	dec := json.NewDecoder(strings.NewReader(jsonStream))140 141	// read open bracket142	t, err := dec.Token()143	if err != nil {144		log.Fatal(err)145	}146	fmt.Printf("%T: %v\n", t, t)147 148	// while the array contains values149	for dec.More() {150		var m Message151		// decode an array value (Message)152		err := dec.Decode(&m)153		if err != nil {154			log.Fatal(err)155		}156 157		fmt.Printf("%v: %v\n", m.Name, m.Text)158	}159 160	// read closing bracket161	t, err = dec.Token()162	if err != nil {163		log.Fatal(err)164	}165	fmt.Printf("%T: %v\n", t, t)166 167	// Output:168	// json.Delim: [169	// Ed: Knock knock.170	// Sam: Who's there?171	// Ed: Go fmt.172	// Sam: Go fmt who?173	// Ed: Go fmt yourself!174	// json.Delim: ]175}176 177// This example uses RawMessage to delay parsing part of a JSON message.178func ExampleRawMessage_unmarshal() {179	type Color struct {180		Space string181		Point json.RawMessage // delay parsing until we know the color space182	}183	type RGB struct {184		R uint8185		G uint8186		B uint8187	}188	type YCbCr struct {189		Y  uint8190		Cb int8191		Cr int8192	}193 194	var j = []byte(`[195	{"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10}},196	{"Space": "RGB",   "Point": {"R": 98, "G": 218, "B": 255}}197]`)198	var colors []Color199	err := json.Unmarshal(j, &colors)200	if err != nil {201		log.Fatalln("error:", err)202	}203 204	for _, c := range colors {205		var dst any206		switch c.Space {207		case "RGB":208			dst = new(RGB)209		case "YCbCr":210			dst = new(YCbCr)211		}212		err := json.Unmarshal(c.Point, dst)213		if err != nil {214			log.Fatalln("error:", err)215		}216		fmt.Println(c.Space, dst)217	}218	// Output:219	// YCbCr &{255 0 -10}220	// RGB &{98 218 255}221}222 223// This example uses RawMessage to use a precomputed JSON during marshal.224func ExampleRawMessage_marshal() {225	h := json.RawMessage(`{"precomputed": true}`)226 227	c := struct {228		Header *json.RawMessage `json:"header"`229		Body   string           `json:"body"`230	}{Header: &h, Body: "Hello Gophers!"}231 232	b, err := json.MarshalIndent(&c, "", "\t")233	if err != nil {234		fmt.Println("error:", err)235	}236	os.Stdout.Write(b)237 238	// Output:239	// {240	// 	"header": {241	// 		"precomputed": true242	// 	},243	// 	"body": "Hello Gophers!"244	// }245}246 247func ExampleIndent() {248	type Road struct {249		Name   string250		Number int251	}252	roads := []Road{253		{"Diamond Fork", 29},254		{"Sheep Creek", 51},255	}256 257	b, err := json.Marshal(roads)258	if err != nil {259		log.Fatal(err)260	}261 262	var out bytes.Buffer263	json.Indent(&out, b, "=", "\t")264	out.WriteTo(os.Stdout)265	// Output:266	// [267	// =	{268	// =		"Name": "Diamond Fork",269	// =		"Number": 29270	// =	},271	// =	{272	// =		"Name": "Sheep Creek",273	// =		"Number": 51274	// =	}275	// =]276}277 278func ExampleMarshalIndent() {279	data := map[string]int{280		"a": 1,281		"b": 2,282	}283 284	b, err := json.MarshalIndent(data, "<prefix>", "<indent>")285	if err != nil {286		log.Fatal(err)287	}288 289	fmt.Println(string(b))290	// Output:291	// {292	// <prefix><indent>"a": 1,293	// <prefix><indent>"b": 2294	// <prefix>}295}296 297func ExampleValid() {298	goodJSON := `{"example": 1}`299	badJSON := `{"example":2:]}}`300 301	fmt.Println(json.Valid([]byte(goodJSON)), json.Valid([]byte(badJSON)))302	// Output:303	// true false304}305 306func ExampleHTMLEscape() {307	var out bytes.Buffer308	json.HTMLEscape(&out, []byte(`{"Name":"<b>HTML content</b>"}`))309	out.WriteTo(os.Stdout)310	// Output:311	//{"Name":"\u003cb\u003eHTML content\u003c/b\u003e"}312}313