service/vendor/github.com/clbanning/mxj/v2/json.go

324 lines
10 KiB
Go

// Copyright 2012-2014 Charles Banning. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file
package mxj
import (
"bytes"
"encoding/json"
"fmt"
"io"
"time"
)
// ------------------------------ write JSON -----------------------
// Just a wrapper on json.Marshal.
// If option safeEncoding is'true' then safe encoding of '<', '>' and '&'
// is preserved. (see encoding/json#Marshal, encoding/json#Encode)
func (mv Map) Json(safeEncoding ...bool) ([]byte, error) {
var s bool
if len(safeEncoding) == 1 {
s = safeEncoding[0]
}
b, err := json.Marshal(mv)
if !s {
b = bytes.Replace(b, []byte("\\u003c"), []byte("<"), -1)
b = bytes.Replace(b, []byte("\\u003e"), []byte(">"), -1)
b = bytes.Replace(b, []byte("\\u0026"), []byte("&"), -1)
}
return b, err
}
// Just a wrapper on json.MarshalIndent.
// If option safeEncoding is'true' then safe encoding of '<' , '>' and '&'
// is preserved. (see encoding/json#Marshal, encoding/json#Encode)
func (mv Map) JsonIndent(prefix, indent string, safeEncoding ...bool) ([]byte, error) {
var s bool
if len(safeEncoding) == 1 {
s = safeEncoding[0]
}
b, err := json.MarshalIndent(mv, prefix, indent)
if !s {
b = bytes.Replace(b, []byte("\\u003c"), []byte("<"), -1)
b = bytes.Replace(b, []byte("\\u003e"), []byte(">"), -1)
b = bytes.Replace(b, []byte("\\u0026"), []byte("&"), -1)
}
return b, err
}
// The following implementation is provided for symmetry with NewMapJsonReader[Raw]
// The names will also provide a key for the number of return arguments.
// Writes the Map as JSON on the Writer.
// If 'safeEncoding' is 'true', then "safe" encoding of '<', '>' and '&' is preserved.
func (mv Map) JsonWriter(jsonWriter io.Writer, safeEncoding ...bool) error {
b, err := mv.Json(safeEncoding...)
if err != nil {
return err
}
_, err = jsonWriter.Write(b)
return err
}
// Writes the Map as JSON on the Writer. []byte is the raw JSON that was written.
// If 'safeEncoding' is 'true', then "safe" encoding of '<', '>' and '&' is preserved.
func (mv Map) JsonWriterRaw(jsonWriter io.Writer, safeEncoding ...bool) ([]byte, error) {
b, err := mv.Json(safeEncoding...)
if err != nil {
return b, err
}
_, err = jsonWriter.Write(b)
return b, err
}
// Writes the Map as pretty JSON on the Writer.
// If 'safeEncoding' is 'true', then "safe" encoding of '<', '>' and '&' is preserved.
func (mv Map) JsonIndentWriter(jsonWriter io.Writer, prefix, indent string, safeEncoding ...bool) error {
b, err := mv.JsonIndent(prefix, indent, safeEncoding...)
if err != nil {
return err
}
_, err = jsonWriter.Write(b)
return err
}
// Writes the Map as pretty JSON on the Writer. []byte is the raw JSON that was written.
// If 'safeEncoding' is 'true', then "safe" encoding of '<', '>' and '&' is preserved.
func (mv Map) JsonIndentWriterRaw(jsonWriter io.Writer, prefix, indent string, safeEncoding ...bool) ([]byte, error) {
b, err := mv.JsonIndent(prefix, indent, safeEncoding...)
if err != nil {
return b, err
}
_, err = jsonWriter.Write(b)
return b, err
}
// --------------------------- read JSON -----------------------------
// Decode numericvalues as json.Number type Map values - see encoding/json#Number.
// NOTE: this is for decoding JSON into a Map with NewMapJson(), NewMapJsonReader(),
// etc.; it does not affect NewMapXml(), etc. The XML encoders mv.Xml() and mv.XmlIndent()
// do recognize json.Number types; a JSON object can be decoded to a Map with json.Number
// value types and the resulting Map can be correctly encoded into a XML object.
var JsonUseNumber bool
// Just a wrapper on json.Unmarshal
// Converting JSON to XML is a simple as:
// ...
// mapVal, merr := mxj.NewMapJson(jsonVal)
// if merr != nil {
// // handle error
// }
// xmlVal, xerr := mapVal.Xml()
// if xerr != nil {
// // handle error
// }
// NOTE: as a special case, passing a list, e.g., [{"some-null-value":"", "a-non-null-value":"bar"}],
// will be interpreted as having the root key 'object' prepended - {"object":[ ... ]} - to unmarshal to a Map.
// See mxj/j2x/j2x_test.go.
func NewMapJson(jsonVal []byte) (Map, error) {
// empty or nil begets empty
if len(jsonVal) == 0 {
m := make(map[string]interface{}, 0)
return m, nil
}
// handle a goofy case ...
if jsonVal[0] == '[' {
jsonVal = []byte(`{"object":` + string(jsonVal) + `}`)
}
m := make(map[string]interface{})
// err := json.Unmarshal(jsonVal, &m)
buf := bytes.NewReader(jsonVal)
dec := json.NewDecoder(buf)
if JsonUseNumber {
dec.UseNumber()
}
err := dec.Decode(&m)
return m, err
}
// Retrieve a Map value from an io.Reader.
// NOTE: The raw JSON off the reader is buffered to []byte using a ByteReader. If the io.Reader is an
// os.File, there may be significant performance impact. If the io.Reader is wrapping a []byte
// value in-memory, however, such as http.Request.Body you CAN use it to efficiently unmarshal
// a JSON object.
func NewMapJsonReader(jsonReader io.Reader) (Map, error) {
jb, err := getJson(jsonReader)
if err != nil || len(*jb) == 0 {
return nil, err
}
// Unmarshal the 'presumed' JSON string
return NewMapJson(*jb)
}
// Retrieve a Map value and raw JSON - []byte - from an io.Reader.
// NOTE: The raw JSON off the reader is buffered to []byte using a ByteReader. If the io.Reader is an
// os.File, there may be significant performance impact. If the io.Reader is wrapping a []byte
// value in-memory, however, such as http.Request.Body you CAN use it to efficiently unmarshal
// a JSON object and retrieve the raw JSON in a single call.
func NewMapJsonReaderRaw(jsonReader io.Reader) (Map, []byte, error) {
jb, err := getJson(jsonReader)
if err != nil || len(*jb) == 0 {
return nil, *jb, err
}
// Unmarshal the 'presumed' JSON string
m, merr := NewMapJson(*jb)
return m, *jb, merr
}
// Pull the next JSON string off the stream: just read from first '{' to its closing '}'.
// Returning a pointer to the slice saves 16 bytes - maybe unnecessary, but internal to package.
func getJson(rdr io.Reader) (*[]byte, error) {
bval := make([]byte, 1)
jb := make([]byte, 0)
var inQuote, inJson bool
var parenCnt int
var previous byte
// scan the input for a matched set of {...}
// json.Unmarshal will handle syntax checking.
for {
_, err := rdr.Read(bval)
if err != nil {
if err == io.EOF && inJson && parenCnt > 0 {
return &jb, fmt.Errorf("no closing } for JSON string: %s", string(jb))
}
return &jb, err
}
switch bval[0] {
case '{':
if !inQuote {
parenCnt++
inJson = true
}
case '}':
if !inQuote {
parenCnt--
}
if parenCnt < 0 {
return nil, fmt.Errorf("closing } without opening {: %s", string(jb))
}
case '"':
if inQuote {
if previous == '\\' {
break
}
inQuote = false
} else {
inQuote = true
}
case '\n', '\r', '\t', ' ':
if !inQuote {
continue
}
}
if inJson {
jb = append(jb, bval[0])
if parenCnt == 0 {
break
}
}
previous = bval[0]
}
return &jb, nil
}
// ------------------------------- JSON Reader handler via Map values -----------------------
// Default poll delay to keep Handler from spinning on an open stream
// like sitting on os.Stdin waiting for imput.
var jhandlerPollInterval = time.Duration(1e6)
// While unnecessary, we make HandleJsonReader() have the same signature as HandleXmlReader().
// This avoids treating one or other as a special case and discussing the underlying stdlib logic.
// Bulk process JSON using handlers that process a Map value.
// 'rdr' is an io.Reader for the JSON (stream).
// 'mapHandler' is the Map processing handler. Return of 'false' stops io.Reader processing.
// 'errHandler' is the error processor. Return of 'false' stops io.Reader processing and returns the error.
// Note: mapHandler() and errHandler() calls are blocking, so reading and processing of messages is serialized.
// This means that you can stop reading the file on error or after processing a particular message.
// To have reading and handling run concurrently, pass argument to a go routine in handler and return 'true'.
func HandleJsonReader(jsonReader io.Reader, mapHandler func(Map) bool, errHandler func(error) bool) error {
var n int
for {
m, merr := NewMapJsonReader(jsonReader)
n++
// handle error condition with errhandler
if merr != nil && merr != io.EOF {
merr = fmt.Errorf("[jsonReader: %d] %s", n, merr.Error())
if ok := errHandler(merr); !ok {
// caused reader termination
return merr
}
continue
}
// pass to maphandler
if len(m) != 0 {
if ok := mapHandler(m); !ok {
break
}
} else if merr != io.EOF {
<-time.After(jhandlerPollInterval)
}
if merr == io.EOF {
break
}
}
return nil
}
// Bulk process JSON using handlers that process a Map value and the raw JSON.
// 'rdr' is an io.Reader for the JSON (stream).
// 'mapHandler' is the Map and raw JSON - []byte - processor. Return of 'false' stops io.Reader processing.
// 'errHandler' is the error and raw JSON processor. Return of 'false' stops io.Reader processing and returns the error.
// Note: mapHandler() and errHandler() calls are blocking, so reading and processing of messages is serialized.
// This means that you can stop reading the file on error or after processing a particular message.
// To have reading and handling run concurrently, pass argument(s) to a go routine in handler and return 'true'.
func HandleJsonReaderRaw(jsonReader io.Reader, mapHandler func(Map, []byte) bool, errHandler func(error, []byte) bool) error {
var n int
for {
m, raw, merr := NewMapJsonReaderRaw(jsonReader)
n++
// handle error condition with errhandler
if merr != nil && merr != io.EOF {
merr = fmt.Errorf("[jsonReader: %d] %s", n, merr.Error())
if ok := errHandler(merr, raw); !ok {
// caused reader termination
return merr
}
continue
}
// pass to maphandler
if len(m) != 0 {
if ok := mapHandler(m, raw); !ok {
break
}
} else if merr != io.EOF {
<-time.After(jhandlerPollInterval)
}
if merr == io.EOF {
break
}
}
return nil
}