Using POST and Auth with Firebase Database and Swift - swift

Question

I need to use REST Api on my iOS app to post/retrieve data from my server. The app is set up with a key generator, which gets me a id token, and then I format my http request with the id. I know something about my url request is wrong, I just don't know what, but I get back a status code 400 whenever I run this. Any ideas where I went wrong?
func postToFB() {
let preURL = "https://myapp.firebaseio.com/"
let url = URL(string: "\(preURL)\(code)/calculatorDisplay.json?auth=\(idToken)")!
var request = URLRequest(url: url)
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpMethod = "PUT"
let parameters: [String: Any] = [
"field1": env.field1,
"field2": env.field2
]
request.httpBody = parameters.percentEncoded()
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data,
let response = response as? HTTPURLResponse,
error == nil else { // check for fundamental networking error
print("postCalcDataButtons error", error ?? "Unknown error")
return
}
guard (200 ... 299) ~= response.statusCode else { // check for http errors
print("postCalcDataButtons = statusCode should be 2xx, but is \(response.statusCode)")
print("postCalcDataButtons response = \(response)")
return
}
let responseString = String(data: data, encoding: .utf8)
print("postCalcDataButtons responseString = \(String(describing: responseString))")
}
task.resume()
}
Here's the extensions that make the above code work:
extension Dictionary {
func percentEncoded() -> Data? {
return map { key, value in
let escapedKey = "\(key)".addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed) ?? ""
let escapedValue = "\(value)".addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed) ?? ""
return escapedKey + "=" + escapedValue
}
.joined(separator: "&")
.data(using: .utf8)
}
}
extension CharacterSet {
static let urlQueryValueAllowed: CharacterSet = {
let generalDelimitersToEncode = ":#[]#" // does not include "?" or "/" due to RFC 3986 - Section 3.4
let subDelimitersToEncode = "!$&'()*+,;="
var allowed = CharacterSet.urlQueryAllowed
allowed.remove(charactersIn: "\(generalDelimitersToEncode)\(subDelimitersToEncode)")
return allowed
}()
}
Here's the response from the server:
<NSHTTPURLResponse: 0x60000110a0a0> { URL: https://calculonapp.firebaseio.com/zlwxrx/calculatorButtons.json?auth=authCode } { Status Code: 400, Headers {
"Access-Control-Allow-Origin" = (
"*"
);
"Cache-Control" = (
"no-cache"
);
Connection = (
"keep-alive"
);
"Content-Length" = (
77
);
"Content-Type" = (
"application/json; charset=utf-8"
);
Date = (
"Fri, 21 Aug 2020 21:16:43 GMT"
);
Server = (
nginx
);
"Strict-Transport-Security" = (
"max-age=31556926; includeSubDomains; preload"
);
} }

Answer 1

I was able to fix this issue by changing the http method when writing data to firebase to "PATCH", then adding JSONSerialization to encode my my upload before running the URLSession...this is the code I used:
if let jsonData = try? JSONSerialization.data(withJSONObject: json, options: []) {
URLSession.shared.uploadTask(with: request, from: jsonData) { (data, response, error) in
if let httpResponse = response as? HTTPURLResponse {
completion(httpResponse.statusCode)
}
}
.resume()
}
You can keep in the guard statements while you test to catch for http error codes and report them to you, but once my code was working I removed them.