Rebuild JSON string to a different structure, parsing specific fields - json

Question

I receive a JSON like this
{
"raw_content":"very long string"
"mode":"ML",
"user_id":"4000008367",
"user_description":"John Doe",
"model":3,
"dest_contact":"test#email.it",
"order_details":[
"ART.: 214883 PELL GRANI 9 ESPR.BAR SKGR 1000 SGOC.: 1000 GR\nVS.ART: 305920132 COMPOS. PALLET\n36 COLLI PEZ.RA: 6 TOT.PEZZI: 216 B: 12 T: 6\nEU C.L.: 24,230\nCO SCAP- : 16,500 CA SCAP- : 15,000 CO SCCP- : 0,000\nCO SAGV- : 0,00000\nC.N. : 17,200SCAD.MIN.: 25/01/22\nCONDIZIONI PAGAMENTO : 60GG B.B. DT RIC FT FINEMESE ART62\n",
"ART.: 287047 PELLINI BIO100%ARABICALTGR 250 SGOC.: 250 GR\nVS.ART: 315860176 COMPOS. PALLET\n36 COLLI PEZ.RA: 6 TOT.PEZZI: 216 B: 12 T: 3\nEU C.L.: 8,380\nCO SCAP- : 16,500 PR SCAP- : 15,000 CO SCCP- : 0,000\nCO SAGV- : 0,00000\nC.N. : 5,950SCAD.MIN.: 25/01/22\nCONDIZIONI PAGAMENTO : 60GG B.B. DT RIC FT FINEMESE ART62\n",
"ART.: 3137837 CAFFE PELLINI TOP LTGR 250 SGOC.: 250 GR\nVS.ART: 315850175 COMPOS. PALLET\n30 COLLI PEZ.RA: 12 TOT.PEZZI: 360 B: 6 T: 5\nEU C.L.: 6,810\nCO SCAP- : 16,500 PR SCAP- : 12,000 CO SCCP- : 0,000\nCO SAGV- : 0,00000\nC.N. : 5,000SCAD.MIN.: 18/08/21\nCONDIZIONI PAGAMENTO : 60GG B.B. DT RIC FT FINEMESE ART62\n",
"ART.: 7748220 ESPRES.SUP.TRADIZ. MOKPKGR 500 SGOC.: 500 GR\nVS.ART: 315930114 COMPOS. PALLET\n80 COLLI PEZ.RA: 10 TOT.PEZZI: 800 B: 10 T: 6\nEU C.L.: 7,580\nCO SCAP- : 16,500 PR SCAP- : 27,750 CO SCCP- : 0,000\nCO SAGV- : 0,00000\nC.N. : 4,570SCAD.MIN.: 25/01/22\nCONDIZIONI PAGAMENTO : 60GG B.B. DT RIC FT FINEMESE ART62\n"
],
"order_footer":"\nPALLET DA CM. 80X120\nT O T A L E C O L L I 182\n\n- EX D.P.R. 322 - 18/05/82 NON SI ACCETTANO TERMINI MINIMI DI\nCONSERVAZIONE INFERIORI A QUELLI INDICATI\n- CONSEGNA FRANCO BANCHINA, PALLET MONOPRODOTTO\nCOME DA PALLETTIZZAZIONE SPECIFICATA\nCONDIZIONI DI PAGAMENTO : COME DA ACCORDI\n"
}
and I want to reorder it to this
{
id: "32839ds8a32jjdas93193snkkk32jhds-k2j1", // generated, see my implementation
rawContent: "very long string",
parsedContent: {"mode":"ML", "user_id":"4000008367", "user_description":"John Doe", "order_details":[ "....." ], ... } // basically all the fields except raw content
}
How can I do this? I'm trying to work it with maps:
var output map[string]interface{}
var message processing.Document // message is of type struct {ID string, Raw string, Parsed string}
err = json.Unmarshal([]byte(doc), &output)
if err != nil {
// error handling
}
message.ParsedContent = "{"
for key, data := range output {
if key == "raw_content" {
hash := md5.Sum([]byte(data.(string)))
message.ID = hex.EncodeToString(hash[:])
message.RawContent = base64.RawStdEncoding.EncodeToString([]byte(data.(string)))
} else {
temp := fmt.Sprintf("\"%s\": \"%s\", ", key, data)
message.ParsedContent = message.ParsedContent + temp
}
}
message.ParsedContent = message.ParsedContent + "}"
msg, err := json.Marshal(message)
if err != nil {
// error handling
}
fmt.Println(string(msg))
There's a few problem with this. If it was only strings it would be ok, but there are integers and the sprintf doesn't work (the output I get, for example on the field "model" is "model": "%!s(float64=3)". I could do an if key == model and parse it as an int, but as I said the fields are not always the same and there are other integers that sometimes are there and sometimes are not there.
Also, the field "order_footer" has escaped new lines which are somehow deleted in my parsing, and this breaks the validity of the resulting JSON.
How can I solve this issues?
EDIT: As suggested, hand-parsing JSON is a bad idea. I could parse it into a struct, the field "model" actually tells me which struct to use. The struct for "model": 3 for example is:
type MOD3 struct {
Raw string `json:"raw_content"`
Mode string `json:"mode"`
UserID string `json:"user_id"`
UserDes string `json:"user_description"`
Model int `json:"model"`
Heading string `json:"legal_heading"`
DestContact string `json:"dest_contact"`
VendorID string `json:"vendor_id"`
VendorLegal string `json:"vendor_legal"`
OrderID string `json:"order_id"`
OrderDate int64 `json:"order_date"`
OrderReference string `json:"order_reference"`
DeliveryDate int64 `json:"delivery_date"`
OrderDestination string `json:"order_destination"`
OrderDestinationAddress string `json:"order_destination_address"`
Items []string `json:"order_details"`
OrderFooter string `json:"order_footer"`
}
At this point, how can I parse specific fields to the output format?

Answer 1

You should never, ever, ever try to generate JSON by hand. The steps should be:
Get JSON and parse it in a model object.
Create a copy of the model object with all the changes you want.
Convert the copied model object to JSON.
You don't know enough about JSON to modify it on the fly. I know enough, and the only reasonable way is complete parsing, and writing back the complete changes.