README
¶
This project is a work in progress.
Documentation
¶
Overview ¶
Package json provides a JSON scanner and writer.
Index ¶
- func DecodeValue(s *Scanner) (interface{}, error)
- type Kind
- type NumberValue
- type Scanner
- type SyntaxError
- type Writer
- func (w *Writer) Bool(b bool) error
- func (w *Writer) EndArray() error
- func (w *Writer) EndObject() error
- func (w *Writer) Err() error
- func (w *Writer) Float(f float64) error
- func (w *Writer) Int(i int64) error
- func (w *Writer) Name(name string) error
- func (w *Writer) QuotedInt(i int64) error
- func (w *Writer) QuotedUint(u uint64) error
- func (w *Writer) StartArray() error
- func (w *Writer) StartObject() error
- func (w *Writer) String(s string) error
- func (w *Writer) StringBytes(p []byte) error
- func (w *Writer) Uint(u uint64) error
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func DecodeValue ¶
DecodeValue decodes the current scanner value to to Go types as follows:
JSON Go
null nil
object map[string]interface{}
array []interface{}
string string
bolean bool
number NumberValue
Types ¶
type Kind ¶
type Kind int
Kind represents the kind a JSON document element.
const ( // Null represents a JSON null. Null Kind = iota // Bool represents a JSON bool. Bool // String represents a JSON string. String // Number represents a JSON number. Number // Array represents the start of a JSON array. Array // Object represents the start of a JSON object. Object // End represents the end of an object or array. End )
type NumberValue ¶
type NumberValue string
A NumberValue represents a JSON number literal.
func (NumberValue) Float64 ¶
func (n NumberValue) Float64() (float64, error)
Float64 returns the number as a float64.
func (NumberValue) Int64 ¶
func (n NumberValue) Int64() (int64, error)
Int64 returns the number as an int64.
func (NumberValue) String ¶
func (n NumberValue) String() string
String returns the literal text of the number.
func (NumberValue) Uint ¶
func (n NumberValue) Uint() (uint, error)
Uint returns the number as an uint.
func (NumberValue) Uint64 ¶
func (n NumberValue) Uint64() (uint64, error)
Uint64 returns the number as an uint64.
type Scanner ¶
type Scanner struct {
// contains filtered or unexported fields
}
Scanner reads a JSON document from an io.Reader. Successive calls to the Scan method step through the elements of the document as follows:
element = Null | Bool | Number | String | object | array array = Array element* End object = Object element* End
Scanning stops unrecoverably at EOF, the first I/O error, or a syntax error. When a scan stops, the reader may have advanced arbitrarily far past the last token.
When scanning 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.
Example ¶
This example shows how to decode a JSON value to a tree of maps and slices.
package main
import (
"fmt"
"strconv"
"strings"
"github.com/garyburd/json"
)
const jsonText = `
[
{
"name": "redigo",
"keywords": ["database", "redis"],
"imports": 10
},
{
"name": "mgo",
"keywords": ["database", "mongodb"],
"imports": 22
}
]
`
func decodeValue(s *json.Scanner) (interface{}, error) {
switch s.Kind() {
case json.Number:
return strconv.ParseFloat(string(s.Value()), 64)
case json.String:
return string(s.Value()), nil
case json.Array:
v := []interface{}{}
n := s.NestingLevel()
for s.ScanAtLevel(n) {
subv, err := decodeValue(s)
if err != nil {
return v, err
}
v = append(v, subv)
}
return v, s.Err()
case json.Object:
v := make(map[string]interface{})
n := s.NestingLevel()
for s.ScanAtLevel(n) {
name := string(s.Name())
subv, err := decodeValue(s)
if err != nil {
return v, err
}
v[name] = subv
}
return v, s.Err()
case json.Bool:
return s.Value()[0] == 't', nil
case json.Null:
return nil, nil
default:
return nil, fmt.Errorf("unexpected %v", s.Kind())
}
}
// This example shows how to decode a JSON value to a tree of maps and slices.
func main() {
s := json.NewScanner(strings.NewReader(jsonText))
if !s.Scan() {
fmt.Printf("error %v\n", s.Err())
return
}
v, err := decodeValue(s)
if err != nil {
fmt.Printf("error %v\n", err)
return
}
s.Scan()
if s.Err() != nil {
fmt.Printf("error %v\n", s.Err())
return
}
fmt.Println(v)
}
Output: [map[name:redigo keywords:[database redis] imports:10] map[name:mgo keywords:[database mongodb] imports:22]]
func NewScanner ¶
NewScanner allocates and initializes a new scanner.
func (*Scanner) AllowMultple ¶
func (s *Scanner) AllowMultple()
AllowMultple enables scanning multiple JSON values. If this method is not called, then the scanner expects to find exactly one JSON value.
func (*Scanner) Name ¶
Name returns the object member name of the current value. The underlying array may point to data that will be overwritten by a subsequent call to Scan.
func (*Scanner) NestingLevel ¶
NestingLevel returns the scanner's current nesting level for objects and array.
func (*Scanner) Scan ¶
Scan advances the Scanner to the next element, which will then be available through the Kind and Value methods. Scan returns false if there are no more elements in the input or an error is encountered. The Err method returns the error if any.
func (*Scanner) ScanAtLevel ¶
ScanAtLevel advances to the next element at the current nesting level, possibly skipping over nested elements. ScanAtLevel returns false at the End element for the current level or if an error is encountered.
type SyntaxError ¶
type SyntaxError struct {
Pos int
// contains filtered or unexported fields
}
func (*SyntaxError) Error ¶
func (e *SyntaxError) Error() string
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
Source Files