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  type strMarshaler string
    94  
    95  func (s strMarshaler) MarshalJSON() ([]byte, error) {
    96  	return []byte(s), nil
    97  }
    98  
    99  type strPtrMarshaler string
   100  
   101  func (s *strPtrMarshaler) MarshalJSON() ([]byte, error) {
   102  	return []byte(*s), nil
   103  }
   104  
   105  func TestEncoderSetEscapeHTML(t *testing.T) {
   106  	var c C
   107  	var ct CText
   108  	var tagStruct struct {
   109  		Valid   int `json:"<>&#! "`
   110  		Invalid int `json:"\\"`
   111  	}
   112  
   113  	// This case is particularly interesting, as we force the encoder to
   114  	// take the address of the Ptr field to use its MarshalJSON method. This
   115  	// is why the '&' is important.
   116  	marshalerStruct := &struct {
   117  		NonPtr strMarshaler
   118  		Ptr    strPtrMarshaler
   119  	}{`"<str>"`, `"<str>"`}
   120  
   121  	for _, tt := range []struct {
   122  		name       string
   123  		v          interface{}
   124  		wantEscape string
   125  		want       string
   126  	}{
   127  		{"c", c, `"\u003c\u0026\u003e"`, `"<&>"`},
   128  		{"ct", ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
   129  		{`"<&>"`, "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
   130  		{
   131  			"tagStruct", tagStruct,
   132  			`{"\u003c\u003e\u0026#! ":0,"Invalid":0}`,
   133  			`{"<>&#! ":0,"Invalid":0}`,
   134  		},
   135  		{
   136  			`"<str>"`, marshalerStruct,
   137  			`{"NonPtr":"\u003cstr\u003e","Ptr":"\u003cstr\u003e"}`,
   138  			`{"NonPtr":"<str>","Ptr":"<str>"}`,
   139  		},
   140  	} {
   141  		var buf bytes.Buffer
   142  		enc := NewEncoder(&buf)
   143  		if err := enc.Encode(tt.v); err != nil {
   144  			t.Fatalf("Encode(%s): %s", tt.name, err)
   145  		}
   146  		if got := strings.TrimSpace(buf.String()); got != tt.wantEscape {
   147  			t.Errorf("Encode(%s) = %#q, want %#q", tt.name, got, tt.wantEscape)
   148  		}
   149  		buf.Reset()
   150  		enc.SetEscapeHTML(false)
   151  		if err := enc.Encode(tt.v); err != nil {
   152  			t.Fatalf("SetEscapeHTML(false) Encode(%s): %s", tt.name, err)
   153  		}
   154  		if got := strings.TrimSpace(buf.String()); got != tt.want {
   155  			t.Errorf("SetEscapeHTML(false) Encode(%s) = %#q, want %#q",
   156  				tt.name, got, tt.want)
   157  		}
   158  	}
   159  }
   160  
   161  func TestDecoder(t *testing.T) {
   162  	for i := 0; i <= len(streamTest); i++ {
   163  		// Use stream without newlines as input,
   164  		// just to stress the decoder even more.
   165  		// Our test input does not include back-to-back numbers.
   166  		// Otherwise stripping the newlines would
   167  		// merge two adjacent JSON values.
   168  		var buf bytes.Buffer
   169  		for _, c := range nlines(streamEncoded, i) {
   170  			if c != '\n' {
   171  				buf.WriteRune(c)
   172  			}
   173  		}
   174  		out := make([]interface{}, i)
   175  		dec := NewDecoder(&buf)
   176  		for j := range out {
   177  			if err := dec.Decode(&out[j]); err != nil {
   178  				t.Fatalf("decode #%d/%d: %v", j, i, err)
   179  			}
   180  		}
   181  		if !reflect.DeepEqual(out, streamTest[0:i]) {
   182  			t.Errorf("decoding %d items: mismatch", i)
   183  			for j := range out {
   184  				if !reflect.DeepEqual(out[j], streamTest[j]) {
   185  					t.Errorf("#%d: have %v want %v", j, out[j], streamTest[j])
   186  				}
   187  			}
   188  			break
   189  		}
   190  	}
   191  }
   192  
   193  func TestDecoderBuffered(t *testing.T) {
   194  	r := strings.NewReader(`{"Name": "Gopher"} extra `)
   195  	var m struct {
   196  		Name string
   197  	}
   198  	d := NewDecoder(r)
   199  	err := d.Decode(&m)
   200  	if err != nil {
   201  		t.Fatal(err)
   202  	}
   203  	if m.Name != "Gopher" {
   204  		t.Errorf("Name = %q; want Gopher", m.Name)
   205  	}
   206  	rest, err := ioutil.ReadAll(d.Buffered())
   207  	if err != nil {
   208  		t.Fatal(err)
   209  	}
   210  	if g, w := string(rest), " extra "; g != w {
   211  		t.Errorf("Remaining = %q; want %q", g, w)
   212  	}
   213  }
   214  
   215  func nlines(s string, n int) string {
   216  	if n <= 0 {
   217  		return ""
   218  	}
   219  	for i, c := range s {
   220  		if c == '\n' {
   221  			if n--; n == 0 {
   222  				return s[0 : i+1]
   223  			}
   224  		}
   225  	}
   226  	return s
   227  }
   228  
   229  func TestRawMessage(t *testing.T) {
   230  	var data struct {
   231  		X  float64
   232  		Id RawMessage
   233  		Y  float32
   234  	}
   235  	const raw = `["\u0056",null]`
   236  	const msg = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
   237  	err := Unmarshal([]byte(msg), &data)
   238  	if err != nil {
   239  		t.Fatalf("Unmarshal: %v", err)
   240  	}
   241  	if string([]byte(data.Id)) != raw {
   242  		t.Fatalf("Raw mismatch: have %#q want %#q", []byte(data.Id), raw)
   243  	}
   244  	b, err := Marshal(&data)
   245  	if err != nil {
   246  		t.Fatalf("Marshal: %v", err)
   247  	}
   248  	if string(b) != msg {
   249  		t.Fatalf("Marshal: have %#q want %#q", b, msg)
   250  	}
   251  }
   252  
   253  func TestNullRawMessage(t *testing.T) {
   254  	var data struct {
   255  		X     float64
   256  		Id    RawMessage
   257  		IdPtr *RawMessage
   258  		Y     float32
   259  	}
   260  	const msg = `{"X":0.1,"Id":null,"IdPtr":null,"Y":0.2}`
   261  	err := Unmarshal([]byte(msg), &data)
   262  	if err != nil {
   263  		t.Fatalf("Unmarshal: %v", err)
   264  	}
   265  	if want, got := "null", string(data.Id); want != got {
   266  		t.Fatalf("Raw mismatch: have %q, want %q", got, want)
   267  	}
   268  	if data.IdPtr != nil {
   269  		t.Fatalf("Raw pointer mismatch: have non-nil, want nil")
   270  	}
   271  	b, err := Marshal(&data)
   272  	if err != nil {
   273  		t.Fatalf("Marshal: %v", err)
   274  	}
   275  	if string(b) != msg {
   276  		t.Fatalf("Marshal: have %#q want %#q", b, msg)
   277  	}
   278  }
   279  
   280  var blockingTests = []string{
   281  	`{"x": 1}`,
   282  	`[1, 2, 3]`,
   283  }
   284  
   285  func TestBlocking(t *testing.T) {
   286  	for _, enc := range blockingTests {
   287  		r, w := net.Pipe()
   288  		go w.Write([]byte(enc))
   289  		var val interface{}
   290  
   291  		// If Decode reads beyond what w.Write writes above,
   292  		// it will block, and the test will deadlock.
   293  		if err := NewDecoder(r).Decode(&val); err != nil {
   294  			t.Errorf("decoding %s: %v", enc, err)
   295  		}
   296  		r.Close()
   297  		w.Close()
   298  	}
   299  }
   300  
   301  func BenchmarkEncoderEncode(b *testing.B) {
   302  	b.ReportAllocs()
   303  	type T struct {
   304  		X, Y string
   305  	}
   306  	v := &T{"foo", "bar"}
   307  	b.RunParallel(func(pb *testing.PB) {
   308  		for pb.Next() {
   309  			if err := NewEncoder(ioutil.Discard).Encode(v); err != nil {
   310  				b.Fatal(err)
   311  			}
   312  		}
   313  	})
   314  }
   315  
   316  type tokenStreamCase struct {
   317  	json      string
   318  	expTokens []interface{}
   319  }
   320  
   321  type decodeThis struct {
   322  	v interface{}
   323  }
   324  
   325  var tokenStreamCases = []tokenStreamCase{
   326  	// streaming token cases
   327  	{json: `10`, expTokens: []interface{}{float64(10)}},
   328  	{json: ` [10] `, expTokens: []interface{}{
   329  		Delim('['), float64(10), Delim(']')}},
   330  	{json: ` [false,10,"b"] `, expTokens: []interface{}{
   331  		Delim('['), false, float64(10), "b", Delim(']')}},
   332  	{json: `{ "a": 1 }`, expTokens: []interface{}{
   333  		Delim('{'), "a", float64(1), Delim('}')}},
   334  	{json: `{"a": 1, "b":"3"}`, expTokens: []interface{}{
   335  		Delim('{'), "a", float64(1), "b", "3", Delim('}')}},
   336  	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []interface{}{
   337  		Delim('['),
   338  		Delim('{'), "a", float64(1), Delim('}'),
   339  		Delim('{'), "a", float64(2), Delim('}'),
   340  		Delim(']')}},
   341  	{json: `{"obj": {"a": 1}}`, expTokens: []interface{}{
   342  		Delim('{'), "obj", Delim('{'), "a", float64(1), Delim('}'),
   343  		Delim('}')}},
   344  	{json: `{"obj": [{"a": 1}]}`, expTokens: []interface{}{
   345  		Delim('{'), "obj", Delim('['),
   346  		Delim('{'), "a", float64(1), Delim('}'),
   347  		Delim(']'), Delim('}')}},
   348  
   349  	// streaming tokens with intermittent Decode()
   350  	{json: `{ "a": 1 }`, expTokens: []interface{}{
   351  		Delim('{'), "a",
   352  		decodeThis{float64(1)},
   353  		Delim('}')}},
   354  	{json: ` [ { "a" : 1 } ] `, expTokens: []interface{}{
   355  		Delim('['),
   356  		decodeThis{map[string]interface{}{"a": float64(1)}},
   357  		Delim(']')}},
   358  	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []interface{}{
   359  		Delim('['),
   360  		decodeThis{map[string]interface{}{"a": float64(1)}},
   361  		decodeThis{map[string]interface{}{"a": float64(2)}},
   362  		Delim(']')}},
   363  	{json: `{ "obj" : [ { "a" : 1 } ] }`, expTokens: []interface{}{
   364  		Delim('{'), "obj", Delim('['),
   365  		decodeThis{map[string]interface{}{"a": float64(1)}},
   366  		Delim(']'), Delim('}')}},
   367  
   368  	{json: `{"obj": {"a": 1}}`, expTokens: []interface{}{
   369  		Delim('{'), "obj",
   370  		decodeThis{map[string]interface{}{"a": float64(1)}},
   371  		Delim('}')}},
   372  	{json: `{"obj": [{"a": 1}]}`, expTokens: []interface{}{
   373  		Delim('{'), "obj",
   374  		decodeThis{[]interface{}{
   375  			map[string]interface{}{"a": float64(1)},
   376  		}},
   377  		Delim('}')}},
   378  	{json: ` [{"a": 1} {"a": 2}] `, expTokens: []interface{}{
   379  		Delim('['),
   380  		decodeThis{map[string]interface{}{"a": float64(1)}},
   381  		decodeThis{&SyntaxError{"expected comma after array element", 11}},
   382  	}},
   383  	{json: `{ "` + strings.Repeat("a", 513) + `" 1 }`, expTokens: []interface{}{
   384  		Delim('{'), strings.Repeat("a", 513),
   385  		decodeThis{&SyntaxError{"expected colon after object key", 518}},
   386  	}},
   387  	{json: `{ "\a" }`, expTokens: []interface{}{
   388  		Delim('{'),
   389  		&SyntaxError{"invalid character 'a' in string escape code", 3},
   390  	}},
   391  	{json: ` \a`, expTokens: []interface{}{
   392  		&SyntaxError{"invalid character '\\\\' looking for beginning of value", 1},
   393  	}},
   394  }
   395  
   396  func TestDecodeInStream(t *testing.T) {
   397  	for ci, tcase := range tokenStreamCases {
   398  
   399  		dec := NewDecoder(strings.NewReader(tcase.json))
   400  		for i, etk := range tcase.expTokens {
   401  
   402  			var tk interface{}
   403  			var err error
   404  
   405  			if dt, ok := etk.(decodeThis); ok {
   406  				etk = dt.v
   407  				err = dec.Decode(&tk)
   408  			} else {
   409  				tk, err = dec.Token()
   410  			}
   411  			if experr, ok := etk.(error); ok {
   412  				if err == nil || !reflect.DeepEqual(err, experr) {
   413  					t.Errorf("case %v: Expected error %#v in %q, but was %#v", ci, experr, tcase.json, err)
   414  				}
   415  				break
   416  			} else if err == io.EOF {
   417  				t.Errorf("case %v: Unexpected EOF in %q", ci, tcase.json)
   418  				break
   419  			} else if err != nil {
   420  				t.Errorf("case %v: Unexpected error '%#v' in %q", ci, err, tcase.json)
   421  				break
   422  			}
   423  			if !reflect.DeepEqual(tk, etk) {
   424  				t.Errorf(`case %v: %q @ %v expected %T(%v) was %T(%v)`, ci, tcase.json, i, etk, etk, tk, tk)
   425  				break
   426  			}
   427  		}
   428  	}
   429  }
   430  
   431  // Test from golang.org/issue/11893
   432  func TestHTTPDecoding(t *testing.T) {
   433  	const raw = `{ "foo": "bar" }`
   434  
   435  	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
   436  		w.Write([]byte(raw))
   437  	}))
   438  	defer ts.Close()
   439  	res, err := http.Get(ts.URL)
   440  	if err != nil {
   441  		log.Fatalf("GET failed: %v", err)
   442  	}
   443  	defer res.Body.Close()
   444  
   445  	foo := struct {
   446  		Foo string
   447  	}{}
   448  
   449  	d := NewDecoder(res.Body)
   450  	err = d.Decode(&foo)
   451  	if err != nil {
   452  		t.Fatalf("Decode: %v", err)
   453  	}
   454  	if foo.Foo != "bar" {
   455  		t.Errorf("decoded %q; want \"bar\"", foo.Foo)
   456  	}
   457  
   458  	// make sure we get the EOF the second time
   459  	err = d.Decode(&foo)
   460  	if err != io.EOF {
   461  		t.Errorf("err = %v; want io.EOF", err)
   462  	}
   463  }
   464  

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