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package types
import (
"bytes"
"compress/gzip"
"database/sql/driver"
"encoding/json"
"errors"
"io/ioutil"
)
// GzippedText is a []byte which transparently gzips data being submitted to
// a database and ungzips data being Scanned from a database.
type GzippedText []byte
// Value implements the driver.Valuer interface, gzipping the raw value of
// this GzippedText.
func (g GzippedText) Value() (driver.Value, error) {
b := make([]byte, 0, len(g))
buf := bytes.NewBuffer(b)
w := gzip.NewWriter(buf)
w.Write(g)
w.Close()
return buf.Bytes(), nil
}
// Scan implements the sql.Scanner interface, ungzipping the value coming off
// the wire and storing the raw result in the GzippedText.
func (g *GzippedText) Scan(src interface{}) error {
var source []byte
switch src.(type) {
case string:
source = []byte(src.(string))
case []byte:
source = src.([]byte)
default:
return errors.New("Incompatible type for GzippedText")
}
reader, err := gzip.NewReader(bytes.NewReader(source))
defer reader.Close()
b, err := ioutil.ReadAll(reader)
if err != nil {
return err
}
*g = GzippedText(b)
return nil
}
// JSONText is a json.RawMessage, which is a []byte underneath.
// Value() validates the json format in the source, and returns an error if
// the json is not valid. Scan does no validation. JSONText additionally
// implements `Unmarshal`, which unmarshals the json within to an interface{}
type JSONText json.RawMessage
// MarshalJSON returns the *j as the JSON encoding of j.
func (j *JSONText) MarshalJSON() ([]byte, error) {
return *j, nil
}
// UnmarshalJSON sets *j to a copy of data
func (j *JSONText) UnmarshalJSON(data []byte) error {
if j == nil {
return errors.New("JSONText: UnmarshalJSON on nil pointer")
}
*j = append((*j)[0:0], data...)
return nil
}
// Value returns j as a value. This does a validating unmarshal into another
// RawMessage. If j is invalid json, it returns an error.
func (j JSONText) Value() (driver.Value, error) {
var m json.RawMessage
var err = j.Unmarshal(&m)
if err != nil {
return []byte{}, err
}
return []byte(j), nil
}
// Scan stores the src in *j. No validation is done.
func (j *JSONText) Scan(src interface{}) error {
var source []byte
switch src.(type) {
case string:
source = []byte(src.(string))
case []byte:
source = src.([]byte)
default:
return errors.New("Incompatible type for JSONText")
}
*j = JSONText(append((*j)[0:0], source...))
return nil
}
// Unmarshal unmarshal's the json in j to v, as in json.Unmarshal.
func (j *JSONText) Unmarshal(v interface{}) error {
return json.Unmarshal([]byte(*j), v)
}
// Pretty printing for JSONText types
func (j JSONText) String() string {
return string(j)
}
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