json

package
v2.21.0 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Oct 29, 2021 License: MIT, MIT Imports: 15 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var (
	DefaultColorScheme = &ColorScheme{
		Int:       createColorFormat(fgHiMagentaColor),
		Uint:      createColorFormat(fgHiMagentaColor),
		Float:     createColorFormat(fgHiMagentaColor),
		Bool:      createColorFormat(fgHiYellowColor),
		String:    createColorFormat(fgHiGreenColor),
		Binary:    createColorFormat(fgHiRedColor),
		ObjectKey: createColorFormat(fgHiCyanColor),
		Null:      createColorFormat(fgBlueColor),
	}
)

Functions

func Compact 

func Compact(dst *bytes.Buffer, src []byte) error

Compact appends to dst the JSON-encoded src with insignificant space characters elided.

func HTMLEscape 

func HTMLEscape(dst *bytes.Buffer, src []byte)

HTMLEscape appends to dst the JSON-encoded src with <, >, &, U+2028 and U+2029 characters inside string literals changed to \u003c, \u003e, \u0026, \u2028, \u2029 so that the JSON will be safe to embed inside HTML <script> tags. For historical reasons, web browsers don't honor standard HTML escaping within <script> tags, so an alternative JSON encoding must be used.

func Indent 

func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error

Indent appends to dst an indented form of the JSON-encoded src. Each element in a JSON object or array begins on a new, indented line beginning with prefix followed by one or more copies of indent according to the indentation nesting. The data appended to dst does not begin with the prefix nor any indentation, to make it easier to embed inside other formatted JSON data. Although leading space characters (space, tab, carriage return, newline) at the beginning of src are dropped, trailing space characters at the end of src are preserved and copied to dst. For example, if src has no trailing spaces, neither will dst; if src ends in a trailing newline, so will dst.

func Marshal 

func Marshal(v interface{}) ([]byte, error)

Marshal returns the JSON encoding of v.

Marshal traverses the value v recursively. If an encountered value implements the Marshaler interface and is not a nil pointer, Marshal calls its MarshalJSON method to produce JSON. If no MarshalJSON method is present but the value implements encoding.TextMarshaler instead, Marshal calls its MarshalText method and encodes the result as a JSON string. The nil pointer exception is not strictly necessary but mimics a similar, necessary exception in the behavior of UnmarshalJSON.

Otherwise, Marshal uses the following type-dependent default encodings:

Boolean values encode as JSON booleans.

Floating point, integer, and Number values encode as JSON numbers.

String values encode as JSON strings coerced to valid UTF-8, replacing invalid bytes with the Unicode replacement rune. The angle brackets "<" and ">" are escaped to "\u003c" and "\u003e" to keep some browsers from misinterpreting JSON output as HTML. Ampersand "&" is also escaped to "\u0026" for the same reason. This escaping can be disabled using an Encoder that had SetEscapeHTML(false) called on it.

Array and slice values encode as JSON arrays, except that []byte encodes as a base64-encoded string, and a nil slice encodes as the null JSON value.

Struct values encode as JSON objects. Each exported struct field becomes a member of the object, using the field name as the object key, unless the field is omitted for one of the reasons given below.

The encoding of each struct field can be customized by the format string stored under the "json" key in the struct field's tag. The format string gives the name of the field, possibly followed by a comma-separated list of options. The name may be empty in order to specify options without overriding the default field name.

The "omitempty" option specifies that the field should be omitted from the encoding if the field has an empty value, defined as false, 0, a nil pointer, a nil interface value, and any empty array, slice, map, or string.

As a special case, if the field tag is "-", the field is always omitted. Note that a field with name "-" can still be generated using the tag "-,".

Examples of struct field tags and their meanings: 

// Field appears in JSON as key "myName".
Field int `json:"myName"`

// Field appears in JSON as key "myName" and
// the field is omitted from the object if its value is empty,
// as defined above.
Field int `json:"myName,omitempty"`

// Field appears in JSON as key "Field" (the default), but
// the field is skipped if empty.
// Note the leading comma.
Field int `json:",omitempty"`

// Field is ignored by this package.
Field int `json:"-"`

// Field appears in JSON as key "-".
Field int `json:"-,"`

The "string" option signals that a field is stored as JSON inside a JSON-encoded string. It applies only to fields of string, floating point, integer, or boolean types. This extra level of encoding is sometimes used when communicating with JavaScript programs: 

Int64String int64 `json:",string"`

The key name will be used if it's a non-empty string consisting of only Unicode letters, digits, and ASCII punctuation except quotation marks, backslash, and comma.

Anonymous struct fields are usually marshaled as if their inner exported fields were fields in the outer struct, subject to the usual Go visibility rules amended as described in the next paragraph. An anonymous struct field with a name given in its JSON tag is treated as having that name, rather than being anonymous. An anonymous struct field of interface type is treated the same as having that type as its name, rather than being anonymous.

The Go visibility rules for struct fields are amended for JSON when deciding which field to marshal or unmarshal. If there are multiple fields at the same level, and that level is the least nested (and would therefore be the nesting level selected by the usual Go rules), the following extra rules apply:

1) Of those fields, if any are JSON-tagged, only tagged fields are considered, even if there are multiple untagged fields that would otherwise conflict.

2) If there is exactly one field (tagged or not according to the first rule), that is selected.

3) Otherwise there are multiple fields, and all are ignored; no error occurs.

Handling of anonymous struct fields is new in Go 1.1. Prior to Go 1.1, anonymous struct fields were ignored. To force ignoring of an anonymous struct field in both current and earlier versions, give the field a JSON tag of "-".

Map values encode as JSON objects. The map's key type must either be a string, an integer type, or implement encoding.TextMarshaler. The map keys are sorted and used as JSON object keys by applying the following rules, subject to the UTF-8 coercion described for string values above:

  • string keys are used directly
  • encoding.TextMarshalers are marshaled
  • integer keys are converted to strings

Pointer values encode as the value pointed to. A nil pointer encodes as the null JSON value.

Interface values encode as the value contained in the interface. A nil interface value encodes as the null JSON value.

Channel, complex, and function values cannot be encoded in JSON. Attempting to encode such a value causes Marshal to return an UnsupportedTypeError.

JSON cannot represent cyclic data structures and Marshal does not handle them. Passing cyclic structures to Marshal will result in an infinite recursion.

func MarshalContext 

func MarshalContext(ctx context.Context, v interface{}, optFuncs ...EncodeOptionFunc) ([]byte, error)

MarshalContext returns the JSON encoding of v with context.Context and EncodeOption.

func MarshalIndent 

func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error)

MarshalIndent is like Marshal but applies Indent to format the output. Each JSON element in the output will begin on a new line beginning with prefix followed by one or more copies of indent according to the indentation nesting.

func MarshalIndentWithOption 

func MarshalIndentWithOption(v interface{}, prefix, indent string, optFuncs ...EncodeOptionFunc) ([]byte, error)

MarshalIndentWithOption is like Marshal but applies Indent to format the output with EncodeOption.

func MarshalNoEscape 

func MarshalNoEscape(v interface{}) ([]byte, error)

MarshalNoEscape returns the JSON encoding of v and doesn't escape v.

func MarshalWithOption 

func MarshalWithOption(v interface{}, optFuncs ...EncodeOptionFunc) ([]byte, error)

MarshalWithOption returns the JSON encoding of v with EncodeOption.

func Unmarshal 

func Unmarshal(data []byte, v interface{}) error

Unmarshal parses the JSON-encoded data and stores the result in the value pointed to by v. If v is nil or not a pointer, Unmarshal returns an InvalidUnmarshalError.

Unmarshal uses the inverse of the encodings that Marshal uses, allocating maps, slices, and pointers as necessary, with the following additional rules:

To unmarshal JSON into a pointer, Unmarshal first handles the case of the JSON being the JSON literal null. In that case, Unmarshal sets the pointer to nil. Otherwise, Unmarshal unmarshals the JSON into the value pointed at by the pointer. If the pointer is nil, Unmarshal allocates a new value for it to point to.

To unmarshal JSON into a value implementing the Unmarshaler interface, Unmarshal calls that value's UnmarshalJSON method, including when the input is a JSON null. Otherwise, if the value implements encoding.TextUnmarshaler and the input is a JSON quoted string, Unmarshal calls that value's UnmarshalText method with the unquoted form of the string.

To unmarshal JSON into a struct, Unmarshal matches incoming object keys to the keys used by Marshal (either the struct field name or its tag), preferring an exact match but also accepting a case-insensitive match. By default, object keys which don't have a corresponding struct field are ignored (see Decoder.DisallowUnknownFields for an alternative).

To unmarshal JSON into an interface value, Unmarshal stores one of these in the interface value: 

bool, for JSON booleans
float64, for JSON numbers
string, for JSON strings
[]interface{}, for JSON arrays
map[string]interface{}, for JSON objects
nil for JSON null

To unmarshal a JSON array into a slice, Unmarshal resets the slice length to zero and then appends each element to the slice. As a special case, to unmarshal an empty JSON array into a slice, Unmarshal replaces the slice with a new empty slice.

To unmarshal a JSON array into a Go array, Unmarshal decodes JSON array elements into corresponding Go array elements. If the Go array is smaller than the JSON array, the additional JSON array elements are discarded. If the JSON array is smaller than the Go array, the additional Go array elements are set to zero values.

To unmarshal a JSON object into a map, Unmarshal first establishes a map to use. If the map is nil, Unmarshal allocates a new map. Otherwise Unmarshal reuses the existing map, keeping existing entries. Unmarshal then stores key-value pairs from the JSON object into the map. The map's key type must either be any string type, an integer, implement json.Unmarshaler, or implement encoding.TextUnmarshaler.

If a JSON value is not appropriate for a given target type, or if a JSON number overflows the target type, Unmarshal skips that field and completes the unmarshaling as best it can. If no more serious errors are encountered, Unmarshal returns an UnmarshalTypeError describing the earliest such error. In any case, it's not guaranteed that all the remaining fields following the problematic one will be unmarshaled into the target object.

The JSON null value unmarshals into an interface, map, pointer, or slice by setting that Go value to nil. Because null is often used in JSON to mean “not present,” unmarshaling a JSON null into any other Go type has no effect on the value and produces no error.

When unmarshaling quoted strings, invalid UTF-8 or invalid UTF-16 surrogate pairs are not treated as an error. Instead, they are replaced by the Unicode replacement character U+FFFD.

func UnmarshalContext 

func UnmarshalContext(ctx context.Context, data []byte, v interface{}, optFuncs ...DecodeOptionFunc) error

UnmarshalContext parses the JSON-encoded data and stores the result in the value pointed to by v. If you implement the UnmarshalerContext interface, call it with ctx as an argument.

func UnmarshalNoEscape 

func UnmarshalNoEscape(data []byte, v interface{}, optFuncs ...DecodeOptionFunc) error

func UnmarshalWithOption 

func UnmarshalWithOption(data []byte, v interface{}, optFuncs ...DecodeOptionFunc) error

func Valid 

func Valid(data []byte) bool

Valid reports whether data is a valid JSON encoding.

Types

type ColorFormat 

type ColorFormat = encoder.ColorFormat

type ColorScheme 

type ColorScheme = encoder.ColorScheme

type DecodeOption 

type DecodeOption = decoder.Option

type DecodeOptionFunc 

type DecodeOptionFunc func(*DecodeOption)

func DecodeFieldPriorityFirstWin 

func DecodeFieldPriorityFirstWin() DecodeOptionFunc

DecodeFieldPriorityFirstWin in the default behavior, go-json, like encoding/json, will reflect the result of the last evaluation when a field with the same name exists. This option allow you to change this behavior. this option reflects the result of the first evaluation if a field with the same name exists. This behavior has a performance advantage as it allows the subsequent strings to be skipped if all fields have been evaluated.

type Decoder 

type Decoder struct {
	// contains filtered or unexported fields
}

func NewDecoder 

func NewDecoder(r io.Reader) *Decoder

NewDecoder returns a new decoder that reads from r.

The decoder introduces its own buffering and may read data from r beyond the JSON values requested.

func (*Decoder) Buffered 

func (d *Decoder) Buffered() io.Reader

Buffered returns a reader of the data remaining in the Decoder's buffer. The reader is valid until the next call to Decode.

func (*Decoder) Decode 

func (d *Decoder) Decode(v interface{}) error

Decode reads the next JSON-encoded value from its input and stores it in the value pointed to by v.

See the documentation for Unmarshal for details about the conversion of JSON into a Go value.

func (*Decoder) DecodeContext 

func (d *Decoder) DecodeContext(ctx context.Context, v interface{}) error

DecodeContext reads the next JSON-encoded value from its input and stores it in the value pointed to by v with context.Context.

func (*Decoder) DecodeWithOption 

func (d *Decoder) DecodeWithOption(v interface{}, optFuncs ...DecodeOptionFunc) error

func (*Decoder) DisallowUnknownFields 

func (d *Decoder) DisallowUnknownFields()

DisallowUnknownFields causes the Decoder to return an error when the destination is a struct and the input contains object keys which do not match any non-ignored, exported fields in the destination.

func (*Decoder) InputOffset 

func (d *Decoder) InputOffset() int64

func (*Decoder) More 

func (d *Decoder) More() bool

func (*Decoder) Token 

func (d *Decoder) Token() (Token, error)

func (*Decoder) UseNumber 

func (d *Decoder) UseNumber()

UseNumber causes the Decoder to unmarshal a number into an interface{} as a Number instead of as a float64.

type Delim 

type Delim = json.Delim

A Delim is a JSON array or object delimiter, one of [ ] { or }.

type EncodeOption 

type EncodeOption = encoder.Option

type EncodeOptionFunc 

type EncodeOptionFunc func(*EncodeOption)

func Colorize 

func Colorize(scheme *ColorScheme) EncodeOptionFunc

Colorize add an identifier for coloring to the string of the encoded result.

func Debug 

func Debug() EncodeOptionFunc

Debug outputs debug information when panic occurs during encoding.

func UnorderedMap 

func UnorderedMap() EncodeOptionFunc

UnorderedMap doesn't sort when encoding map type.

type Encoder 

type Encoder struct {
	// contains filtered or unexported fields
}

An Encoder writes JSON values to an output stream.

func NewEncoder 

func NewEncoder(w io.Writer) *Encoder

NewEncoder returns a new encoder that writes to w.

func (*Encoder) Encode 

func (e *Encoder) Encode(v interface{}) error

Encode writes the JSON encoding of v to the stream, followed by a newline character.

See the documentation for Marshal for details about the conversion of Go values to JSON.

func (*Encoder) EncodeContext 

func (e *Encoder) EncodeContext(ctx context.Context, v interface{}, optFuncs ...EncodeOptionFunc) error

EncodeContext call Encode with context.Context and EncodeOption.

func (*Encoder) EncodeWithOption 

func (e *Encoder) EncodeWithOption(v interface{}, optFuncs ...EncodeOptionFunc) error

EncodeWithOption call Encode with EncodeOption.

func (*Encoder) SetEscapeHTML 

func (e *Encoder) SetEscapeHTML(on bool)

SetEscapeHTML specifies whether problematic HTML characters should be escaped inside JSON quoted strings. The default behavior is to escape &, <, and > to \u0026, \u003c, and \u003e to avoid certain safety problems that can arise when embedding JSON in HTML.

In non-HTML settings where the escaping interferes with the readability of the output, SetEscapeHTML(false) disables this behavior.

func (*Encoder) SetIndent 

func (e *Encoder) SetIndent(prefix, indent string)

SetIndent instructs the encoder to format each subsequent encoded value as if indented by the package-level function Indent(dst, src, prefix, indent). Calling SetIndent("", "") disables indentation.

type InvalidUTF8Error deprecated 

type InvalidUTF8Error = errors.InvalidUTF8Error

Before Go 1.2, an InvalidUTF8Error was returned by Marshal when attempting to encode a string value with invalid UTF-8 sequences. As of Go 1.2, Marshal instead coerces the string to valid UTF-8 by replacing invalid bytes with the Unicode replacement rune U+FFFD.

Deprecated: No longer used; kept for compatibility.

type InvalidUnmarshalError 

type InvalidUnmarshalError = errors.InvalidUnmarshalError

An InvalidUnmarshalError describes an invalid argument passed to Unmarshal. (The argument to Unmarshal must be a non-nil pointer.)

type Marshaler 

type Marshaler interface {
	MarshalJSON() ([]byte, error)
}

Marshaler is the interface implemented by types that can marshal themselves into valid JSON.

type MarshalerContext 

type MarshalerContext interface {
	MarshalJSON(context.Context) ([]byte, error)
}

MarshalerContext is the interface implemented by types that can marshal themselves into valid JSON with context.Context.

type MarshalerError 

type MarshalerError = errors.MarshalerError

A MarshalerError represents an error from calling a MarshalJSON or MarshalText method.

type Number 

type Number = json.Number

A Number represents a JSON number literal.

type RawMessage 

type RawMessage = json.RawMessage

RawMessage is a raw encoded JSON value. It implements Marshaler and Unmarshaler and can be used to delay JSON decoding or precompute a JSON encoding.

type SyntaxError 

type SyntaxError = errors.SyntaxError

A SyntaxError is a description of a JSON syntax error.

type Token 

type Token = json.Token

A Token holds a value of one of these types: 

Delim, for the four JSON delimiters [ ] { }
bool, for JSON booleans
float64, for JSON numbers
Number, for JSON numbers
string, for JSON string literals
nil, for JSON null

type UnmarshalFieldError deprecated 

type UnmarshalFieldError = errors.UnmarshalFieldError //nolint:staticcheck

An UnmarshalFieldError describes a JSON object key that led to an unexported (and therefore unwritable) struct field.

Deprecated: No longer used; kept for compatibility.

type UnmarshalTypeError 

type UnmarshalTypeError = errors.UnmarshalTypeError

An UnmarshalTypeError describes a JSON value that was not appropriate for a value of a specific Go type.

type Unmarshaler 

type Unmarshaler interface {
	UnmarshalJSON([]byte) error
}

Unmarshaler is the interface implemented by types that can unmarshal a JSON description of themselves. The input can be assumed to be a valid encoding of a JSON value. UnmarshalJSON must copy the JSON data if it wishes to retain the data after returning.

By convention, to approximate the behavior of Unmarshal itself, Unmarshalers implement UnmarshalJSON([]byte("null")) as a no-op.

type UnmarshalerContext 

type UnmarshalerContext interface {
	UnmarshalJSON(context.Context, []byte) error
}

UnmarshalerContext is the interface implemented by types that can unmarshal with context.Context a JSON description of themselves.

type UnsupportedTypeError 

type UnsupportedTypeError = errors.UnsupportedTypeError

An UnsupportedTypeError is returned by Marshal when attempting to encode an unsupported value type.

type UnsupportedValueError 

type UnsupportedValueError = errors.UnsupportedValueError

Source Files

View all Source files

Directories

Path Synopsis
cmd
generator
Code generated by internal/cmd/generator.
 Code generated by internal/cmd/generator.
vm
Code generated by internal/cmd/generator.
 Code generated by internal/cmd/generator.
vm_color
Code generated by internal/cmd/generator.
 Code generated by internal/cmd/generator.
vm_color_indent
Code generated by internal/cmd/generator.
 Code generated by internal/cmd/generator.
vm_indent
Code generated by internal/cmd/generator.
 Code generated by internal/cmd/generator.

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.