825 lines
18 KiB
Go
825 lines
18 KiB
Go
// Use of this source code is governed by a
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// Jason is designed to be convenient for reading arbitrary JSON while still honoring the strictness of the language.
|
|
// Inspired by other libraries and improved to work well for common use cases.
|
|
// It currently focuses on reading JSON data rather than creating it.
|
|
//
|
|
// Examples
|
|
//
|
|
// JSON is a commonly used data transfer format, so usually the data you want to read comes either as bytes or as an io.Reader.
|
|
//
|
|
// Create an object from bytes:
|
|
// v, err := jason.NewObjectFromBytes(b)
|
|
// .. or from a net/http response body:
|
|
// v, err := jason.NewObjectFromReader(res.body)
|
|
//
|
|
// Read values
|
|
//
|
|
// Reading values is done with Get<Type>(keys ...) or the generic Get(keys ...).
|
|
// If the key path is invalid or the type doesn't match, it will return an error and the default value.
|
|
//
|
|
// name, err := v.GetString("name")
|
|
// age, err := v.GetNumber("age")
|
|
// verified, err := v.GetBoolean("verified")
|
|
// education, err := v.GetObject("education")
|
|
// friends, err := v.GetObjectArray("friends")
|
|
//
|
|
// Loop through array
|
|
//
|
|
// Getting an array is done by Get<Type>Array() or the generic GetValueArray(). It returns an error if the value at that keypath is null (or something else than the type).
|
|
//
|
|
// friends, err := person.GetObjectArray("friends")
|
|
// for _, friend := range friends {
|
|
// name, err := friend.GetString("name")
|
|
// age, err := friend.GetNumber("age")
|
|
// }
|
|
//
|
|
// Loop through keys of object
|
|
//
|
|
// Looping through an object is done by first getting it with `GetObject()` and then range on the Map().
|
|
// The GetObject() method returns an error if the value at that keypath is null (or something else than an object).
|
|
//
|
|
// person, err := person.GetObject("person")
|
|
// for key, value := range person.Map() {
|
|
// ...
|
|
// }
|
|
package jason
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/json"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
// Error values returned when validation functions fail
|
|
var (
|
|
ErrNotNull = errors.New("is not null")
|
|
ErrNotArray = errors.New("Not an array")
|
|
ErrNotNumber = errors.New("not a number")
|
|
ErrNotBool = errors.New("no bool")
|
|
ErrNotObject = errors.New("not an object")
|
|
ErrNotObjectArray = errors.New("not an object array")
|
|
ErrNotString = errors.New("not a string")
|
|
)
|
|
|
|
type KeyNotFoundError struct {
|
|
Key string
|
|
}
|
|
|
|
func (k KeyNotFoundError) Error() string {
|
|
if k.Key != "" {
|
|
return fmt.Sprintf("key '%s' not found", k.Key)
|
|
}
|
|
|
|
return "key not found"
|
|
}
|
|
|
|
// Value represents an arbitrary JSON value.
|
|
// It may contain a bool, number, string, object, array or null.
|
|
type Value struct {
|
|
data interface{}
|
|
exists bool // Used to separate nil and non-existing values
|
|
}
|
|
|
|
// Object represents an object JSON object.
|
|
// It inherets from Value but with an additional method to access
|
|
// a map representation of it's content. It's useful when iterating.
|
|
type Object struct {
|
|
Value
|
|
m map[string]*Value
|
|
valid bool
|
|
}
|
|
|
|
// Returns the golang map.
|
|
// Needed when iterating through the values of the object.
|
|
func (v *Object) Map() map[string]*Value {
|
|
return v.m
|
|
}
|
|
|
|
// Creates a new value from an io.reader.
|
|
// Returns an error if the reader does not contain valid json.
|
|
// Useful for parsing the body of a net/http response.
|
|
// Example: NewFromReader(res.Body)
|
|
func NewValueFromReader(reader io.Reader) (*Value, error) {
|
|
j := new(Value)
|
|
d := json.NewDecoder(reader)
|
|
d.UseNumber()
|
|
err := d.Decode(&j.data)
|
|
return j, err
|
|
}
|
|
|
|
// Creates a new value from bytes.
|
|
// Returns an error if the bytes are not valid json.
|
|
func NewValueFromBytes(b []byte) (*Value, error) {
|
|
r := bytes.NewReader(b)
|
|
return NewValueFromReader(r)
|
|
}
|
|
|
|
func objectFromValue(v *Value, err error) (*Object, error) {
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
o, err := v.Object()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return o, nil
|
|
}
|
|
|
|
func NewObjectFromBytes(b []byte) (*Object, error) {
|
|
return objectFromValue(NewValueFromBytes(b))
|
|
}
|
|
|
|
func NewObjectFromReader(reader io.Reader) (*Object, error) {
|
|
return objectFromValue(NewValueFromReader(reader))
|
|
}
|
|
|
|
// Marshal into bytes.
|
|
func (v *Value) Marshal() ([]byte, error) {
|
|
return json.Marshal(v.data)
|
|
}
|
|
|
|
// Get the interyling data as interface
|
|
func (v *Value) Interface() interface{} {
|
|
return v.data
|
|
}
|
|
|
|
// Private Get
|
|
func (v *Value) get(key string) (*Value, error) {
|
|
|
|
// Assume this is an object
|
|
obj, err := v.Object()
|
|
|
|
if err == nil {
|
|
child, ok := obj.Map()[key]
|
|
if ok {
|
|
return child, nil
|
|
} else {
|
|
return nil, KeyNotFoundError{key}
|
|
}
|
|
}
|
|
|
|
return nil, err
|
|
}
|
|
|
|
// Private get path
|
|
func (v *Value) getPath(keys []string) (*Value, error) {
|
|
current := v
|
|
var err error
|
|
for _, key := range keys {
|
|
current, err = current.get(key)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
return current, nil
|
|
}
|
|
|
|
// Gets the value at key path.
|
|
// Returns error if the value does not exist.
|
|
// Consider using the more specific Get<Type>(..) methods instead.
|
|
// Example:
|
|
// value, err := GetValue("address", "street")
|
|
func (v *Object) GetValue(keys ...string) (*Value, error) {
|
|
return v.getPath(keys)
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an object.
|
|
// Returns error if the value is not a json object.
|
|
// Example:
|
|
// object, err := GetObject("person", "address")
|
|
func (v *Object) GetObject(keys ...string) (*Object, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
obj, err := child.Object()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
return obj, nil
|
|
}
|
|
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into a string.
|
|
// Returns error if the value is not a json string.
|
|
// Example:
|
|
// string, err := GetString("address", "street")
|
|
func (v *Object) GetString(keys ...string) (string, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return "", err
|
|
} else {
|
|
return child.String()
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into null.
|
|
// Returns error if the value is not json null.
|
|
// Example:
|
|
// err := GetNull("address", "street")
|
|
func (v *Object) GetNull(keys ...string) error {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
return child.Null()
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into a number.
|
|
// Returns error if the value is not a json number.
|
|
// Example:
|
|
// n, err := GetNumber("address", "street_number")
|
|
func (v *Object) GetNumber(keys ...string) (json.Number, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return "", err
|
|
} else {
|
|
|
|
n, err := child.Number()
|
|
|
|
if err != nil {
|
|
return "", err
|
|
} else {
|
|
return n, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into a float64.
|
|
// Returns error if the value is not a json number.
|
|
// Example:
|
|
// n, err := GetNumber("address", "street_number")
|
|
func (v *Object) GetFloat64(keys ...string) (float64, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
|
|
n, err := child.Float64()
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
return n, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into a float64.
|
|
// Returns error if the value is not a json number.
|
|
// Example:
|
|
// n, err := GetNumber("address", "street_number")
|
|
func (v *Object) GetInt64(keys ...string) (int64, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
|
|
n, err := child.Int64()
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
return n, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into a float64.
|
|
// Returns error if the value is not a json number.
|
|
// Example:
|
|
// v, err := GetInterface("address", "anything")
|
|
func (v *Object) GetInterface(keys ...string) (interface{}, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
return child.Interface(), nil
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into a bool.
|
|
// Returns error if the value is not a json boolean.
|
|
// Example:
|
|
// married, err := GetBoolean("person", "married")
|
|
func (v *Object) GetBoolean(keys ...string) (bool, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
|
|
return child.Boolean()
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array.
|
|
// Returns error if the value is not a json array.
|
|
// Consider using the more specific Get<Type>Array() since it may reduce later type casts.
|
|
// Example:
|
|
// friends, err := GetValueArray("person", "friends")
|
|
// for i, friend := range friends {
|
|
// ... // friend will be of type Value here
|
|
// }
|
|
func (v *Object) GetValueArray(keys ...string) ([]*Value, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
return child.Array()
|
|
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of objects.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not objects.
|
|
// Example:
|
|
// friends, err := GetObjectArray("person", "friends")
|
|
// for i, friend := range friends {
|
|
// ... // friend will be of type Object here
|
|
// }
|
|
func (v *Object) GetObjectArray(keys ...string) ([]*Object, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
typedArray := make([]*Object, len(array))
|
|
|
|
for index, arrayItem := range array {
|
|
typedArrayItem, err := arrayItem.
|
|
Object()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
typedArray[index] = typedArrayItem
|
|
}
|
|
|
|
}
|
|
return typedArray, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of string.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not strings.
|
|
// Gets the value at key path and attempts to typecast the value into an array of objects.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not objects.
|
|
// Example:
|
|
// friendNames, err := GetStringArray("person", "friend_names")
|
|
// for i, friendName := range friendNames {
|
|
// ... // friendName will be of type string here
|
|
// }
|
|
func (v *Object) GetStringArray(keys ...string) ([]string, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
typedArray := make([]string, len(array))
|
|
|
|
for index, arrayItem := range array {
|
|
typedArrayItem, err := arrayItem.String()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
typedArray[index] = typedArrayItem
|
|
}
|
|
|
|
}
|
|
return typedArray, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of numbers.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not numbers.
|
|
// Example:
|
|
// friendAges, err := GetNumberArray("person", "friend_ages")
|
|
// for i, friendAge := range friendAges {
|
|
// ... // friendAge will be of type float64 here
|
|
// }
|
|
func (v *Object) GetNumberArray(keys ...string) ([]json.Number, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
typedArray := make([]json.Number, len(array))
|
|
|
|
for index, arrayItem := range array {
|
|
typedArrayItem, err := arrayItem.Number()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
typedArray[index] = typedArrayItem
|
|
}
|
|
|
|
}
|
|
return typedArray, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of floats.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not numbers.
|
|
func (v *Object) GetFloat64Array(keys ...string) ([]float64, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
typedArray := make([]float64, len(array))
|
|
|
|
for index, arrayItem := range array {
|
|
typedArrayItem, err := arrayItem.Float64()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
typedArray[index] = typedArrayItem
|
|
}
|
|
|
|
}
|
|
return typedArray, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of ints.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not numbers.
|
|
func (v *Object) GetInt64Array(keys ...string) ([]int64, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
typedArray := make([]int64, len(array))
|
|
|
|
for index, arrayItem := range array {
|
|
typedArrayItem, err := arrayItem.Int64()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
typedArray[index] = typedArrayItem
|
|
}
|
|
|
|
}
|
|
return typedArray, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of bools.
|
|
// Returns error if the value is not a json array or if any of the contained objects are not booleans.
|
|
func (v *Object) GetBooleanArray(keys ...string) ([]bool, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
|
|
typedArray := make([]bool, len(array))
|
|
|
|
for index, arrayItem := range array {
|
|
typedArrayItem, err := arrayItem.Boolean()
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
} else {
|
|
typedArray[index] = typedArrayItem
|
|
}
|
|
|
|
}
|
|
return typedArray, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Gets the value at key path and attempts to typecast the value into an array of nulls.
|
|
// Returns length, or an error if the value is not a json array or if any of the contained objects are not nulls.
|
|
func (v *Object) GetNullArray(keys ...string) (int64, error) {
|
|
child, err := v.getPath(keys)
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
|
|
array, err := child.Array()
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
|
|
var length int64 = 0
|
|
|
|
for _, arrayItem := range array {
|
|
err := arrayItem.Null()
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
} else {
|
|
length++
|
|
}
|
|
|
|
}
|
|
return length, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// Returns an error if the value is not actually null
|
|
func (v *Value) Null() error {
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case nil:
|
|
valid = v.exists // Valid only if j also exists, since other values could possibly also be nil
|
|
break
|
|
}
|
|
|
|
if valid {
|
|
return nil
|
|
}
|
|
|
|
return ErrNotNull
|
|
|
|
}
|
|
|
|
// Attempts to typecast the current value into an array.
|
|
// Returns error if the current value is not a json array.
|
|
// Example:
|
|
// friendsArray, err := friendsValue.Array()
|
|
func (v *Value) Array() ([]*Value, error) {
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case []interface{}:
|
|
valid = true
|
|
break
|
|
}
|
|
|
|
// Unsure if this is a good way to use slices, it's probably not
|
|
var slice []*Value
|
|
|
|
if valid {
|
|
|
|
for _, element := range v.data.([]interface{}) {
|
|
child := Value{element, true}
|
|
slice = append(slice, &child)
|
|
}
|
|
|
|
return slice, nil
|
|
}
|
|
|
|
return slice, ErrNotArray
|
|
|
|
}
|
|
|
|
// Attempts to typecast the current value into a number.
|
|
// Returns error if the current value is not a json number.
|
|
// Example:
|
|
// ageNumber, err := ageValue.Number()
|
|
func (v *Value) Number() (json.Number, error) {
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case json.Number:
|
|
valid = true
|
|
break
|
|
}
|
|
|
|
if valid {
|
|
return v.data.(json.Number), nil
|
|
}
|
|
|
|
return "", ErrNotNumber
|
|
}
|
|
|
|
// Attempts to typecast the current value into a float64.
|
|
// Returns error if the current value is not a json number.
|
|
// Example:
|
|
// percentage, err := v.Float64()
|
|
func (v *Value) Float64() (float64, error) {
|
|
n, err := v.Number()
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return n.Float64()
|
|
}
|
|
|
|
// Attempts to typecast the current value into a int64.
|
|
// Returns error if the current value is not a json number.
|
|
// Example:
|
|
// id, err := v.Int64()
|
|
func (v *Value) Int64() (int64, error) {
|
|
n, err := v.Number()
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return n.Int64()
|
|
}
|
|
|
|
// Attempts to typecast the current value into a bool.
|
|
// Returns error if the current value is not a json boolean.
|
|
// Example:
|
|
// marriedBool, err := marriedValue.Boolean()
|
|
func (v *Value) Boolean() (bool, error) {
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case bool:
|
|
valid = true
|
|
break
|
|
}
|
|
|
|
if valid {
|
|
return v.data.(bool), nil
|
|
}
|
|
|
|
return false, ErrNotBool
|
|
}
|
|
|
|
// Attempts to typecast the current value into an object.
|
|
// Returns error if the current value is not a json object.
|
|
// Example:
|
|
// friendObject, err := friendValue.Object()
|
|
func (v *Value) Object() (*Object, error) {
|
|
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case map[string]interface{}:
|
|
valid = true
|
|
break
|
|
}
|
|
|
|
if valid {
|
|
obj := new(Object)
|
|
obj.valid = valid
|
|
|
|
m := make(map[string]*Value)
|
|
|
|
if valid {
|
|
for key, element := range v.data.(map[string]interface{}) {
|
|
m[key] = &Value{element, true}
|
|
|
|
}
|
|
}
|
|
|
|
obj.data = v.data
|
|
obj.m = m
|
|
|
|
return obj, nil
|
|
}
|
|
|
|
return nil, ErrNotObject
|
|
}
|
|
|
|
// Attempts to typecast the current value into an object arrau.
|
|
// Returns error if the current value is not an array of json objects
|
|
// Example:
|
|
// friendObjects, err := friendValues.ObjectArray()
|
|
func (v *Value) ObjectArray() ([]*Object, error) {
|
|
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case []interface{}:
|
|
valid = true
|
|
break
|
|
}
|
|
|
|
// Unsure if this is a good way to use slices, it's probably not
|
|
var slice []*Object
|
|
|
|
if valid {
|
|
|
|
for _, element := range v.data.([]interface{}) {
|
|
childValue := Value{element, true}
|
|
childObject, err := childValue.Object()
|
|
|
|
if err != nil {
|
|
return nil, ErrNotObjectArray
|
|
}
|
|
slice = append(slice, childObject)
|
|
}
|
|
|
|
return slice, nil
|
|
}
|
|
|
|
return nil, ErrNotObjectArray
|
|
|
|
}
|
|
|
|
// Attempts to typecast the current value into a string.
|
|
// Returns error if the current value is not a json string
|
|
// Example:
|
|
// nameObject, err := nameValue.String()
|
|
func (v *Value) String() (string, error) {
|
|
var valid bool
|
|
|
|
// Check the type of this data
|
|
switch v.data.(type) {
|
|
case string:
|
|
valid = true
|
|
break
|
|
}
|
|
|
|
if valid {
|
|
return v.data.(string), nil
|
|
}
|
|
|
|
return "", ErrNotString
|
|
}
|
|
|
|
// Returns the value a json formatted string.
|
|
// Note: The method named String() is used by golang's log method for logging.
|
|
// Example:
|
|
func (v *Object) String() string {
|
|
|
|
f, err := json.Marshal(v.data)
|
|
if err != nil {
|
|
return err.Error()
|
|
}
|
|
|
|
return string(f)
|
|
|
|
}
|