Adding raw Data to the encoder - swift

Question

I have an Encodable struct that contains raw Data. This data is expected to be a raw representation of a JSON string.
When I encode this struct, I expect the encoding to have that Data be part of the struct's JSON object.
Here's the playground I have come up with so far, with outlined expected and actual results:
import Foundation
struct Payload: Encodable {
let name: String
let contents: Data
enum CodingKeys: String, CodingKey {
case name
case contents
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(contents, forKey: .contents)
}
}
let payload = Payload(
name: "Hello",
/// Integers corresponding to ASCII values of a valid JSON string: `{"text":"C"}`
contents:Data([123, 34, 116, 101, 120, 116, 34, 58, 34, 67, 34, 125])
)
let encoder = JSONEncoder()
let data = try encoder.encode(payload)
let string = String(data: data, encoding: .utf8)!
print(string)
/// expected: `{"name":"Hello","contents": {"text":"C"} }`
/// actual: `{"name":"Hello","contents":"eyJ0ZXh0IjoiQyJ9"}`
I have also tried to encode contents as a String, but that results in:
{"name":"Hello","contents":"{\"text\":\"C\"}"}
Which is close, but still not what I want

Answer 1

You could try this approach, as shown in the example code, to encode and then recover your Payload contents Data as a String. Use the same approach for non-SwiftUI systems:
struct ContentView: View {
#State var payloadContents = ""
var body: some View {
Text(payloadContents)
.onAppear {
let payload = Payload(
name: "Hello",
/// Integers corresponding to ASCII values of a valid JSON string: `{"text":"C"}`
contents: Data([123, 34, 116, 101, 120, 116, 34, 58, 34, 67, 34, 125])
)
// direct access
// payloadContents = payload.stringContents!
do {
// encode the payload
let data = try JSONEncoder().encode(payload)
// decode the payload
let decoded = try JSONDecoder().decode(Payload.self, from: data)
print("\n---> decoded: \(decoded)") // <-- raw data
// get the `contents` to the desired String
payloadContents = String(data: decoded.contents, encoding: .utf8)!
// alternative
// payloadContents = decoded.stringContents!
print("\n---> payloadContents: \(payloadContents)\n")
} catch {
print(error)
}
}
}
}
struct Payload: Codable { // <-- here
let name: String
let contents: Data
var stringContents: String? {
String(data: contents, encoding: .utf8) // <-- here
}
enum CodingKeys: String, CodingKey {
case name, contents
}
}