README
¶
Jason is an easy-to-use JSON library for Go.
About
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. API Documentation can be found on godoc.org.
Install
go get github.com/antonholmquist/jason
Import
import (
"github.com/antonholmquist/jason"
)
Data types
The following golang values are used to represent JSON data types. It is consistent with how encoding/json uses primitive types.
bool, for JSON booleansjson.Number/float64/int64, for JSON numbersstring, for JSON strings[]*Value, for JSON arraysmap[string]*Value, for JSON objectsnilfor JSON null
Examples
Create from bytes
Create object from bytes. Returns an error if the bytes are not valid JSON.
v, err := jason.NewObjectFromBytes(b)
If the root object is not an array, use this method instead. It can then be cased to the expected type with one of the As-Methods.
v, err := jason.NewValueFromBytes(b)
Create from a reader (like a http response)
Create value from a io.reader. Returns an error if the string couldn't be parsed.
v, err := jason.NewObjectFromReader(res.Body)
Read values
Reading values is easy. If the key path is invalid or type doesn't match, it will return an error and the default value.
name, err := v.GetString("name")
age, err := v.GetInt64("age")
verified, err := v.GetBoolean("verified")
education, err := v.GetObject("education")
friends, err := v.GetObjectArray("friends")
interests, err := v.GetStringArray("interests")
Read nested values
Reading nested values is easy. If the path is invalid or type doesn't match, it will return the default value and an error.
name, err := v.GetString("person", "name")
age, err := v.GetInt64("person", "age")
verified, err := v.GetBoolean("person", "verified")
education, err := v.GetObject("person", "education")
friends, err := v.GetObjectArray("person", "friends")
Loop through array
Looping through an array is done with GetValueArray() or GetObjectArray(). It returns an error if the value at that keypath is null (or something else than an array).
friends, err := person.GetObjectArray("friends")
for _, friend := range friends {
name, err := friend.GetString("name")
age, err := friend.GetNumber("age")
}
Loop through object
Looping through an object is easy. GetObject() 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() {
...
}
Sample App
Example project:
package main
import (
"github.com/antonholmquist/jason"
"log"
)
func main() {
exampleJSON := `{
"name": "Walter White",
"age": 51,
"children": [
"junior",
"holly"
],
"other": {
"occupation": "chemist",
"years": 23
}
}`
v, _ := jason.NewObjectFromBytes([]byte(exampleJSON))
name, _ := v.GetString("name")
age, _ := v.GetNumber("age")
occupation, _ := v.GetString("other", "occupation")
years, _ := v.GetNumber("other", "years")
log.Println("age:", age)
log.Println("name:", name)
log.Println("occupation:", occupation)
log.Println("years:", years)
children, _ := v.GetStringArray("children")
for i, child := range children {
log.Printf("child %d: %s", i, child)
}
others, _ := v.GetObject("other")
for _, value := range others.Map() {
s, sErr := value.String()
n, nErr := value.Number()
if sErr == nil {
log.Println("string value: ", s)
} else if nErr == nil {
log.Println("number value: ", n)
}
}
}
Documentation
Documentation can be found a godoc:
https://godoc.org/github.com/antonholmquist/jason
Test
To run the project tests:
go test
Compatibility
Go 1.1 and up.
Where does the name come from?
I remebered it from an email one of our projects managers sent a couple of years ago.
"Don't worry. We can handle both XML and Jason"
Author
Anton Holmquist, http://twitter.com/antonholmquist
Documentation
¶
Overview ¶
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() {
...
}
Index ¶
- type Object
- func (v *Object) GetBoolean(keys ...string) (bool, error)
- func (v *Object) GetBooleanArray(keys ...string) ([]bool, error)
- func (v *Object) GetFloat64(keys ...string) (float64, error)
- func (v *Object) GetFloat64Array(keys ...string) ([]float64, error)
- func (v *Object) GetInt64(keys ...string) (int64, error)
- func (v *Object) GetInt64Array(keys ...string) ([]int64, error)
- func (v *Object) GetNull(keys ...string) error
- func (v *Object) GetNullArray(keys ...string) (int64, error)
- func (v *Object) GetNumber(keys ...string) (json.Number, error)
- func (v *Object) GetNumberArray(keys ...string) ([]json.Number, error)
- func (v *Object) GetObject(keys ...string) (*Object, error)
- func (v *Object) GetObjectArray(keys ...string) ([]*Object, error)
- func (v *Object) GetString(keys ...string) (string, error)
- func (v *Object) GetStringArray(keys ...string) ([]string, error)
- func (v *Object) GetValue(keys ...string) (*Value, error)
- func (v *Object) GetValueArray(keys ...string) ([]*Value, error)
- func (v *Object) Map() map[string]*Value
- func (v *Object) String() string
- type Value
- func (v *Value) Array() ([]*Value, error)
- func (v *Value) Boolean() (bool, error)
- func (v *Value) Float64() (float64, error)
- func (v *Value) Int64() (int64, error)
- func (v *Value) Marshal() ([]byte, error)
- func (v *Value) Null() error
- func (v *Value) Number() (json.Number, error)
- func (v *Value) Object() (*Object, error)
- func (v *Value) String() (string, error)
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Object ¶
type Object struct {
Value
// contains filtered or unexported fields
}
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.
func NewObjectFromBytes ¶
func (*Object) GetBoolean ¶
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 (*Object) GetBooleanArray ¶
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 (*Object) GetFloat64 ¶
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 (*Object) GetFloat64Array ¶
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 (*Object) GetInt64 ¶
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 (*Object) GetInt64Array ¶
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 (*Object) GetNull ¶
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 (*Object) GetNullArray ¶
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 (*Object) GetNumber ¶
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 (*Object) GetNumberArray ¶
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 (*Object) GetObject ¶
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 (*Object) GetObjectArray ¶
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 (*Object) GetString ¶
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 (*Object) GetStringArray ¶
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 (*Object) GetValue ¶
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 (*Object) GetValueArray ¶
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
}
type Value ¶
type Value struct {
// contains filtered or unexported fields
}
Value represents an arbitrary JSON value. It may contain a bool, number, string, object, array or null.
func NewValueFromBytes ¶
Creates a new value from bytes. Returns an error if the bytes are not valid json.
func NewValueFromReader ¶
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 (*Value) Array ¶
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 (*Value) Boolean ¶
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 (*Value) Float64 ¶
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 (*Value) Int64 ¶
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 (*Value) Number ¶
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()
Source Files