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Source file src/encoding/json/stream_test.go

Documentation: encoding/json

     1  // Copyright 2010 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package json
     6  
     7  import (
     8  	"bytes"
     9  	"io"
    10  	"io/ioutil"
    11  	"log"
    12  	"net"
    13  	"net/http"
    14  	"net/http/httptest"
    15  	"reflect"
    16  	"strings"
    17  	"testing"
    18  )
    19  
    20  // Test values for the stream test.
    21  // One of each JSON kind.
    22  var streamTest = []interface{}{
    23  	0.1,
    24  	"hello",
    25  	nil,
    26  	true,
    27  	false,
    28  	[]interface{}{"a", "b", "c"},
    29  	map[string]interface{}{"K": "Kelvin", "ß": "long s"},
    30  	3.14, // another value to make sure something can follow map
    31  }
    32  
    33  var streamEncoded = `0.1
    34  "hello"
    35  null
    36  true
    37  false
    38  ["a","b","c"]
    39  {"ß":"long s","K":"Kelvin"}
    40  3.14
    41  `
    42  
    43  func TestEncoder(t *testing.T) {
    44  	for i := 0; i <= len(streamTest); i++ {
    45  		var buf bytes.Buffer
    46  		enc := NewEncoder(&buf)
    47  		// Check that enc.SetIndent("", "") turns off indentation.
    48  		enc.SetIndent(">", ".")
    49  		enc.SetIndent("", "")
    50  		for j, v := range streamTest[0:i] {
    51  			if err := enc.Encode(v); err != nil {
    52  				t.Fatalf("encode #%d: %v", j, err)
    53  			}
    54  		}
    55  		if have, want := buf.String(), nlines(streamEncoded, i); have != want {
    56  			t.Errorf("encoding %d items: mismatch", i)
    57  			diff(t, []byte(have), []byte(want))
    58  			break
    59  		}
    60  	}
    61  }
    62  
    63  var streamEncodedIndent = `0.1
    64  "hello"
    65  null
    66  true
    67  false
    68  [
    69  >."a",
    70  >."b",
    71  >."c"
    72  >]
    73  {
    74  >."ß": "long s",
    75  >."K": "Kelvin"
    76  >}
    77  3.14
    78  `
    79  
    80  func TestEncoderIndent(t *testing.T) {
    81  	var buf bytes.Buffer
    82  	enc := NewEncoder(&buf)
    83  	enc.SetIndent(">", ".")
    84  	for _, v := range streamTest {
    85  		enc.Encode(v)
    86  	}
    87  	if have, want := buf.String(), streamEncodedIndent; have != want {
    88  		t.Error("indented encoding mismatch")
    89  		diff(t, []byte(have), []byte(want))
    90  	}
    91  }
    92  
    93  func TestEncoderSetEscapeHTML(t *testing.T) {
    94  	var c C
    95  	var ct CText
    96  	var tagStruct struct {
    97  		Valid   int `json:"<>&#! "`
    98  		Invalid int `json:"\\"`
    99  	}
   100  	for _, tt := range []struct {
   101  		name       string
   102  		v          interface{}
   103  		wantEscape string
   104  		want       string
   105  	}{
   106  		{"c", c, `"\u003c\u0026\u003e"`, `"<&>"`},
   107  		{"ct", ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
   108  		{`"<&>"`, "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
   109  		{
   110  			"tagStruct", tagStruct,
   111  			`{"\u003c\u003e\u0026#! ":0,"Invalid":0}`,
   112  			`{"<>&#! ":0,"Invalid":0}`,
   113  		},
   114  	} {
   115  		var buf bytes.Buffer
   116  		enc := NewEncoder(&buf)
   117  		if err := enc.Encode(tt.v); err != nil {
   118  			t.Fatalf("Encode(%s): %s", tt.name, err)
   119  		}
   120  		if got := strings.TrimSpace(buf.String()); got != tt.wantEscape {
   121  			t.Errorf("Encode(%s) = %#q, want %#q", tt.name, got, tt.wantEscape)
   122  		}
   123  		buf.Reset()
   124  		enc.SetEscapeHTML(false)
   125  		if err := enc.Encode(tt.v); err != nil {
   126  			t.Fatalf("SetEscapeHTML(false) Encode(%s): %s", tt.name, err)
   127  		}
   128  		if got := strings.TrimSpace(buf.String()); got != tt.want {
   129  			t.Errorf("SetEscapeHTML(false) Encode(%s) = %#q, want %#q",
   130  				tt.name, got, tt.want)
   131  		}
   132  	}
   133  }
   134  
   135  func TestDecoder(t *testing.T) {
   136  	for i := 0; i <= len(streamTest); i++ {
   137  		// Use stream without newlines as input,
   138  		// just to stress the decoder even more.
   139  		// Our test input does not include back-to-back numbers.
   140  		// Otherwise stripping the newlines would
   141  		// merge two adjacent JSON values.
   142  		var buf bytes.Buffer
   143  		for _, c := range nlines(streamEncoded, i) {
   144  			if c != '\n' {
   145  				buf.WriteRune(c)
   146  			}
   147  		}
   148  		out := make([]interface{}, i)
   149  		dec := NewDecoder(&buf)
   150  		for j := range out {
   151  			if err := dec.Decode(&out[j]); err != nil {
   152  				t.Fatalf("decode #%d/%d: %v", j, i, err)
   153  			}
   154  		}
   155  		if !reflect.DeepEqual(out, streamTest[0:i]) {
   156  			t.Errorf("decoding %d items: mismatch", i)
   157  			for j := range out {
   158  				if !reflect.DeepEqual(out[j], streamTest[j]) {
   159  					t.Errorf("#%d: have %v want %v", j, out[j], streamTest[j])
   160  				}
   161  			}
   162  			break
   163  		}
   164  	}
   165  }
   166  
   167  func TestDecoderBuffered(t *testing.T) {
   168  	r := strings.NewReader(`{"Name": "Gopher"} extra `)
   169  	var m struct {
   170  		Name string
   171  	}
   172  	d := NewDecoder(r)
   173  	err := d.Decode(&m)
   174  	if err != nil {
   175  		t.Fatal(err)
   176  	}
   177  	if m.Name != "Gopher" {
   178  		t.Errorf("Name = %q; want Gopher", m.Name)
   179  	}
   180  	rest, err := ioutil.ReadAll(d.Buffered())
   181  	if err != nil {
   182  		t.Fatal(err)
   183  	}
   184  	if g, w := string(rest), " extra "; g != w {
   185  		t.Errorf("Remaining = %q; want %q", g, w)
   186  	}
   187  }
   188  
   189  func nlines(s string, n int) string {
   190  	if n <= 0 {
   191  		return ""
   192  	}
   193  	for i, c := range s {
   194  		if c == '\n' {
   195  			if n--; n == 0 {
   196  				return s[0 : i+1]
   197  			}
   198  		}
   199  	}
   200  	return s
   201  }
   202  
   203  func TestRawMessage(t *testing.T) {
   204  	var data struct {
   205  		X  float64
   206  		Id RawMessage
   207  		Y  float32
   208  	}
   209  	const raw = `["\u0056",null]`
   210  	const msg = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
   211  	err := Unmarshal([]byte(msg), &data)
   212  	if err != nil {
   213  		t.Fatalf("Unmarshal: %v", err)
   214  	}
   215  	if string([]byte(data.Id)) != raw {
   216  		t.Fatalf("Raw mismatch: have %#q want %#q", []byte(data.Id), raw)
   217  	}
   218  	b, err := Marshal(&data)
   219  	if err != nil {
   220  		t.Fatalf("Marshal: %v", err)
   221  	}
   222  	if string(b) != msg {
   223  		t.Fatalf("Marshal: have %#q want %#q", b, msg)
   224  	}
   225  }
   226  
   227  func TestNullRawMessage(t *testing.T) {
   228  	var data struct {
   229  		X     float64
   230  		Id    RawMessage
   231  		IdPtr *RawMessage
   232  		Y     float32
   233  	}
   234  	const msg = `{"X":0.1,"Id":null,"IdPtr":null,"Y":0.2}`
   235  	err := Unmarshal([]byte(msg), &data)
   236  	if err != nil {
   237  		t.Fatalf("Unmarshal: %v", err)
   238  	}
   239  	if want, got := "null", string(data.Id); want != got {
   240  		t.Fatalf("Raw mismatch: have %q, want %q", got, want)
   241  	}
   242  	if data.IdPtr != nil {
   243  		t.Fatalf("Raw pointer mismatch: have non-nil, want nil")
   244  	}
   245  	b, err := Marshal(&data)
   246  	if err != nil {
   247  		t.Fatalf("Marshal: %v", err)
   248  	}
   249  	if string(b) != msg {
   250  		t.Fatalf("Marshal: have %#q want %#q", b, msg)
   251  	}
   252  }
   253  
   254  var blockingTests = []string{
   255  	`{"x": 1}`,
   256  	`[1, 2, 3]`,
   257  }
   258  
   259  func TestBlocking(t *testing.T) {
   260  	for _, enc := range blockingTests {
   261  		r, w := net.Pipe()
   262  		go w.Write([]byte(enc))
   263  		var val interface{}
   264  
   265  		// If Decode reads beyond what w.Write writes above,
   266  		// it will block, and the test will deadlock.
   267  		if err := NewDecoder(r).Decode(&val); err != nil {
   268  			t.Errorf("decoding %s: %v", enc, err)
   269  		}
   270  		r.Close()
   271  		w.Close()
   272  	}
   273  }
   274  
   275  func BenchmarkEncoderEncode(b *testing.B) {
   276  	b.ReportAllocs()
   277  	type T struct {
   278  		X, Y string
   279  	}
   280  	v := &T{"foo", "bar"}
   281  	b.RunParallel(func(pb *testing.PB) {
   282  		for pb.Next() {
   283  			if err := NewEncoder(ioutil.Discard).Encode(v); err != nil {
   284  				b.Fatal(err)
   285  			}
   286  		}
   287  	})
   288  }
   289  
   290  type tokenStreamCase struct {
   291  	json      string
   292  	expTokens []interface{}
   293  }
   294  
   295  type decodeThis struct {
   296  	v interface{}
   297  }
   298  
   299  var tokenStreamCases []tokenStreamCase = []tokenStreamCase{
   300  	// streaming token cases
   301  	{json: `10`, expTokens: []interface{}{float64(10)}},
   302  	{json: ` [10] `, expTokens: []interface{}{
   303  		Delim('['), float64(10), Delim(']')}},
   304  	{json: ` [false,10,"b"] `, expTokens: []interface{}{
   305  		Delim('['), false, float64(10), "b", Delim(']')}},
   306  	{json: `{ "a": 1 }`, expTokens: []interface{}{
   307  		Delim('{'), "a", float64(1), Delim('}')}},
   308  	{json: `{"a": 1, "b":"3"}`, expTokens: []interface{}{
   309  		Delim('{'), "a", float64(1), "b", "3", Delim('}')}},
   310  	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []interface{}{
   311  		Delim('['),
   312  		Delim('{'), "a", float64(1), Delim('}'),
   313  		Delim('{'), "a", float64(2), Delim('}'),
   314  		Delim(']')}},
   315  	{json: `{"obj": {"a": 1}}`, expTokens: []interface{}{
   316  		Delim('{'), "obj", Delim('{'), "a", float64(1), Delim('}'),
   317  		Delim('}')}},
   318  	{json: `{"obj": [{"a": 1}]}`, expTokens: []interface{}{
   319  		Delim('{'), "obj", Delim('['),
   320  		Delim('{'), "a", float64(1), Delim('}'),
   321  		Delim(']'), Delim('}')}},
   322  
   323  	// streaming tokens with intermittent Decode()
   324  	{json: `{ "a": 1 }`, expTokens: []interface{}{
   325  		Delim('{'), "a",
   326  		decodeThis{float64(1)},
   327  		Delim('}')}},
   328  	{json: ` [ { "a" : 1 } ] `, expTokens: []interface{}{
   329  		Delim('['),
   330  		decodeThis{map[string]interface{}{"a": float64(1)}},
   331  		Delim(']')}},
   332  	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []interface{}{
   333  		Delim('['),
   334  		decodeThis{map[string]interface{}{"a": float64(1)}},
   335  		decodeThis{map[string]interface{}{"a": float64(2)}},
   336  		Delim(']')}},
   337  	{json: `{ "obj" : [ { "a" : 1 } ] }`, expTokens: []interface{}{
   338  		Delim('{'), "obj", Delim('['),
   339  		decodeThis{map[string]interface{}{"a": float64(1)}},
   340  		Delim(']'), Delim('}')}},
   341  
   342  	{json: `{"obj": {"a": 1}}`, expTokens: []interface{}{
   343  		Delim('{'), "obj",
   344  		decodeThis{map[string]interface{}{"a": float64(1)}},
   345  		Delim('}')}},
   346  	{json: `{"obj": [{"a": 1}]}`, expTokens: []interface{}{
   347  		Delim('{'), "obj",
   348  		decodeThis{[]interface{}{
   349  			map[string]interface{}{"a": float64(1)},
   350  		}},
   351  		Delim('}')}},
   352  	{json: ` [{"a": 1} {"a": 2}] `, expTokens: []interface{}{
   353  		Delim('['),
   354  		decodeThis{map[string]interface{}{"a": float64(1)}},
   355  		decodeThis{&SyntaxError{"expected comma after array element", 11}},
   356  	}},
   357  	{json: `{ "` + strings.Repeat("a", 513) + `" 1 }`, expTokens: []interface{}{
   358  		Delim('{'), strings.Repeat("a", 513),
   359  		decodeThis{&SyntaxError{"expected colon after object key", 518}},
   360  	}},
   361  	{json: `{ "\a" }`, expTokens: []interface{}{
   362  		Delim('{'),
   363  		&SyntaxError{"invalid character 'a' in string escape code", 3},
   364  	}},
   365  	{json: ` \a`, expTokens: []interface{}{
   366  		&SyntaxError{"invalid character '\\\\' looking for beginning of value", 1},
   367  	}},
   368  }
   369  
   370  func TestDecodeInStream(t *testing.T) {
   371  
   372  	for ci, tcase := range tokenStreamCases {
   373  
   374  		dec := NewDecoder(strings.NewReader(tcase.json))
   375  		for i, etk := range tcase.expTokens {
   376  
   377  			var tk interface{}
   378  			var err error
   379  
   380  			if dt, ok := etk.(decodeThis); ok {
   381  				etk = dt.v
   382  				err = dec.Decode(&tk)
   383  			} else {
   384  				tk, err = dec.Token()
   385  			}
   386  			if experr, ok := etk.(error); ok {
   387  				if err == nil || !reflect.DeepEqual(err, experr) {
   388  					t.Errorf("case %v: Expected error %#v in %q, but was %#v", ci, experr, tcase.json, err)
   389  				}
   390  				break
   391  			} else if err == io.EOF {
   392  				t.Errorf("case %v: Unexpected EOF in %q", ci, tcase.json)
   393  				break
   394  			} else if err != nil {
   395  				t.Errorf("case %v: Unexpected error '%#v' in %q", ci, err, tcase.json)
   396  				break
   397  			}
   398  			if !reflect.DeepEqual(tk, etk) {
   399  				t.Errorf(`case %v: %q @ %v expected %T(%v) was %T(%v)`, ci, tcase.json, i, etk, etk, tk, tk)
   400  				break
   401  			}
   402  		}
   403  	}
   404  
   405  }
   406  
   407  // Test from golang.org/issue/11893
   408  func TestHTTPDecoding(t *testing.T) {
   409  	const raw = `{ "foo": "bar" }`
   410  
   411  	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
   412  		w.Write([]byte(raw))
   413  	}))
   414  	defer ts.Close()
   415  	res, err := http.Get(ts.URL)
   416  	if err != nil {
   417  		log.Fatalf("GET failed: %v", err)
   418  	}
   419  	defer res.Body.Close()
   420  
   421  	foo := struct {
   422  		Foo string
   423  	}{}
   424  
   425  	d := NewDecoder(res.Body)
   426  	err = d.Decode(&foo)
   427  	if err != nil {
   428  		t.Fatalf("Decode: %v", err)
   429  	}
   430  	if foo.Foo != "bar" {
   431  		t.Errorf("decoded %q; want \"bar\"", foo.Foo)
   432  	}
   433  
   434  	// make sure we get the EOF the second time
   435  	err = d.Decode(&foo)
   436  	if err != io.EOF {
   437  		t.Errorf("err = %v; want io.EOF", err)
   438  	}
   439  }
   440  

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