Swift SQL POST method - Why does it always create a response with <null> as the string? - sql

Question

I'm trying to set up POST requests to connect my Swift Project to my SQL server. I found a lot of good resources on how to create the POST requests, and my code seems to create the request fine. However, it always returns a null string instead of the desired output string. How can I get the request to submit with the correct string?
My POST function:
func addString() {
// declare the parameter as a dictionary that contains string as key and value combination. considering inputs are valid
let parameters: [String: Any] = ["textstring":"Testing..."]
// create the url with URL
let url = URL(string: "http://localhost:3000/strings")! // change server url accordingly
// create the session object
let session = URLSession.shared
// now create the URLRequest object using the url object
var request = URLRequest(url: url)
request.httpMethod = "POST" //set http method as POST
// add headers for the request
request.addValue("application/json", forHTTPHeaderField: "Content-Type") // change as per server requirements
do {
// convert parameters to Data and assign dictionary to httpBody of request
request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: .prettyPrinted)
} catch let error {
print(error.localizedDescription)
return
}
// create dataTask using the session object to send data to the server
let task = session.dataTask(with: request) { data, response, error in
if let error = error {
print("Post Request Error: \(error.localizedDescription)")
return
}
// ensure there is valid response code returned from this HTTP response
guard let httpResponse = response as? HTTPURLResponse,
(200...299).contains(httpResponse.statusCode)
else {
print("Invalid Response received from the server")
return
}
// ensure there is data returned
guard let responseData = data else {
print("nil Data received from the server")
return
}
do {
// create json object from data or use JSONDecoder to convert to Model struct
if let jsonResponse = try JSONSerialization.jsonObject(with: responseData, options: .mutableContainers) as? [String: Any] {
print(jsonResponse)
// handle json response
} else {
print("data maybe corrupted or in wrong format")
throw URLError(.badServerResponse)
}
} catch let error {
print(error.localizedDescription)
}
}
// perform the task
task.resume()
}
My Object TextString that emulates the SQL table (Table "strings" has two columns: "id" (SERIAL PRIMARY KEY) and "textstring" (VARCHAR(255))
struct TextString: Codable, Hashable, Identifiable {
var id: Int
var textString: String
enum CodingKeys: String, CodingKey {
case id = "string_id"
case textString = "textstring"
}}
My response output:
["string_id": 28, "textstring": <null>]
I'm thinking that the issue is with the serialization but the code is taken almost directly from a youtube video where the test cases are shown and they work. Does anyone know why the output returns "textstring" as null and not "Testing..."?
Thanks in advance!