open-vault/helper/jsonutil/json.go
2018-03-20 14:54:10 -04:00

100 lines
2.9 KiB
Go

package jsonutil
import (
"bytes"
"compress/gzip"
"encoding/json"
"fmt"
"io"
"github.com/hashicorp/vault/helper/compressutil"
)
// Encodes/Marshals the given object into JSON
func EncodeJSON(in interface{}) ([]byte, error) {
if in == nil {
return nil, fmt.Errorf("input for encoding is nil")
}
var buf bytes.Buffer
enc := json.NewEncoder(&buf)
if err := enc.Encode(in); err != nil {
return nil, err
}
return buf.Bytes(), nil
}
// EncodeJSONAndCompress encodes the given input into JSON and compresses the
// encoded value (using Gzip format BestCompression level, by default). A
// canary byte is placed at the beginning of the returned bytes for the logic
// in decompression method to identify compressed input.
func EncodeJSONAndCompress(in interface{}, config *compressutil.CompressionConfig) ([]byte, error) {
if in == nil {
return nil, fmt.Errorf("input for encoding is nil")
}
// First JSON encode the given input
encodedBytes, err := EncodeJSON(in)
if err != nil {
return nil, err
}
if config == nil {
config = &compressutil.CompressionConfig{
Type: compressutil.CompressionTypeGzip,
GzipCompressionLevel: gzip.BestCompression,
}
}
return compressutil.Compress(encodedBytes, config)
}
// DecodeJSON tries to decompress the given data. The call to decompress, fails
// if the content was not compressed in the first place, which is identified by
// a canary byte before the compressed data. If the data is not compressed, it
// is JSON decoded directly. Otherwise the decompressed data will be JSON
// decoded.
func DecodeJSON(data []byte, out interface{}) error {
if data == nil || len(data) == 0 {
return fmt.Errorf("'data' being decoded is nil")
}
if out == nil {
return fmt.Errorf("output parameter 'out' is nil")
}
// Decompress the data if it was compressed in the first place
decompressedBytes, uncompressed, err := compressutil.Decompress(data)
if err != nil {
return fmt.Errorf("failed to decompress JSON: err: %v", err)
}
if !uncompressed && (decompressedBytes == nil || len(decompressedBytes) == 0) {
return fmt.Errorf("decompressed data being decoded is invalid")
}
// If the input supplied failed to contain the compression canary, it
// will be notified by the compression utility. Decode the decompressed
// input.
if !uncompressed {
data = decompressedBytes
}
return DecodeJSONFromReader(bytes.NewReader(data), out)
}
// Decodes/Unmarshals the given io.Reader pointing to a JSON, into a desired object
func DecodeJSONFromReader(r io.Reader, out interface{}) error {
if r == nil {
return fmt.Errorf("'io.Reader' being decoded is nil")
}
if out == nil {
return fmt.Errorf("output parameter 'out' is nil")
}
dec := json.NewDecoder(r)
// While decoding JSON values, interpret the integer values as `json.Number`s instead of `float64`.
dec.UseNumber()
// Since 'out' is an interface representing a pointer, pass it to the decoder without an '&'
return dec.Decode(out)
}