yanic/respond/respond.go

82 lines
1.7 KiB
Go

package respond
import (
"bytes"
"compress/flate"
"encoding/json"
"io"
"net"
"github.com/bdlm/log"
"github.com/tidwall/gjson"
"github.com/FreifunkBremen/yanic/data"
)
const (
// default multicast group used by announced
MulticastAddressDefault = "ff05:0:0:0:0:0:2:1001"
// default udp port used by announced
PortDefault = 1001
// maximum receivable size
MaxDataGramSize = 8192
)
// Response of the respond request
type Response struct {
Address *net.UDPAddr
Raw []byte
}
func NewRespone(res *data.ResponseData, addr *net.UDPAddr) (*Response, error) {
buf := new(bytes.Buffer)
flater, err := flate.NewWriter(buf, flate.BestCompression)
if err != nil {
return nil, err
}
defer flater.Close()
if err = json.NewEncoder(flater).Encode(res); err != nil {
return nil, err
}
err = flater.Flush()
return &Response{
Raw: buf.Bytes(),
Address: addr,
}, err
}
func (res *Response) parse(customFields []CustomFieldConfig) (*data.ResponseData, error) {
// Deflate
deflater := flate.NewReader(bytes.NewReader(res.Raw))
defer deflater.Close()
jsonData, err := io.ReadAll(deflater)
if err != nil && err != io.ErrUnexpectedEOF {
return nil, err
}
// Unmarshal
rdata := &data.ResponseData{}
err = json.Unmarshal(jsonData, rdata)
rdata.CustomFields = make(map[string]interface{})
if !gjson.Valid(string(jsonData)) {
log.WithField("jsonData", jsonData).Info("JSON data is invalid")
} else {
jsonParsed := gjson.Parse(string(jsonData))
for _, customField := range customFields {
field := jsonParsed.Get(customField.Path)
if field.Exists() {
rdata.CustomFields[customField.Name] = field.String()
}
}
}
return rdata, err
}