// Package json provides functions for marshaling and unmarshaling JSON in a format that is // backwards-compatible with Amino JSON encoding. This mostly differs from encoding/json in // encoding of integers (64-bit integers are encoded as strings, not numbers), and handling // of interfaces (wrapped in an interface object with type/value keys). // // JSON tags (e.g. `json:"name,omitempty"`) are supported in the same way as encoding/json, as is // custom marshaling overrides via the json.Marshaler and json.Unmarshaler interfaces. // // Note that not all JSON emitted by Tendermint is generated by this library; some is generated by // encoding/json instead, and kept like that for backwards compatibility. // // Encoding of numbers uses strings for 64-bit integers (including unspecified ints), to improve // compatibility with e.g. Javascript (which uses 64-bit floats for numbers, having 53-bit // precision): // // int32(32) // Output: 32 // uint32(32) // Output: 32 // int64(64) // Output: "64" // uint64(64) // Output: "64" // int(64) // Output: "64" // uint(64) // Output: "64" // // Encoding of other scalars follows encoding/json: // // nil // Output: null // true // Output: true // "foo" // Output: "foo" // "" // Output: "" // // Slices and arrays are encoded as encoding/json, including base64-encoding of byte slices // with additional base64-encoding of byte arrays as well: // // []int64(nil) // Output: null // []int64{} // Output: [] // []int64{1, 2, 3} // Output: ["1", "2", "3"] // []int32{1, 2, 3} // Output: [1, 2, 3] // []byte{1, 2, 3} // Output: "AQID" // [3]int64{1, 2, 3} // Output: ["1", "2", "3"] // [3]byte{1, 2, 3} // Output: "AQID" // // Maps are encoded as encoding/json, but only strings are allowed as map keys (nil maps are not // emitted as null, to retain Amino backwards-compatibility): // // map[string]int64(nil) // Output: {} // map[string]int64{} // Output: {} // map[string]int64{"a":1,"b":2} // Output: {"a":"1","b":"2"} // map[string]int32{"a":1,"b":2} // Output: {"a":1,"b":2} // map[bool]int{true:1} // Errors // // Times are encoded as encoding/json, in RFC3339Nano format, but requiring UTC time zone (with zero // times emitted as "0001-01-01T00:00:00Z" as with encoding/json): // // time.Date(2020, 6, 8, 16, 21, 28, 123, time.FixedZone("UTC+2", 2*60*60)) // // Output: "2020-06-08T14:21:28.000000123Z" // time.Time{} // Output: "0001-01-01T00:00:00Z" // (*time.Time)(nil) // Output: null // // Structs are encoded as encoding/json, supporting JSON tags and ignoring private fields: // // type Struct struct{ // Name string // Value int32 `json:"value,omitempty"` // private bool // } // // Struct{Name: "foo", Value: 7, private: true} // Output: {"Name":"foo","value":7} // Struct{} // Output: {"Name":""} // // Registered types are encoded with type wrapper, regardless of whether they are given as interface // or bare struct, but inside structs they are only emitted with type wrapper for interface fields // (this follows Amino behavior): // // type Vehicle interface { // Drive() error // } // // type Car struct { // Wheels int8 // } // // func (c *Car) Drive() error { return nil } // // RegisterType(&Car{}, "vehicle/car") // // Car{Wheels: 4} // Output: {"type":"vehicle/car","value":{"Wheels":4}} // &Car{Wheels: 4} // Output: {"type":"vehicle/car","value":{"Wheels":4}} // (*Car)(nil) // Output: null // Vehicle(Car{Wheels: 4}) // Output: {"type":"vehicle/car","value":{"Wheels":4}} // Vehicle(nil) // Output: null // // type Struct struct { // Car *Car // Vehicle Vehicle // } // // Struct{Car: &Car{Wheels: 4}, Vehicle: &Car{Wheels: 4}} // // Output: {"Car": {"Wheels: 4"}, "Vehicle": {"type":"vehicle/car","value":{"Wheels":4}}} // package json