Swift4: Error while decoding json from file - ios

Question

This is my first post, so I hope everything is as structured as it should be.
I hope anybody can help me to solve my issue.
I have the following issue while decoding JSON in Swift from a downloaded file:
The vocabulary.json file contains the following:
[
{
"english": "one",
"deutsch": "eins",
"theme": "numbers"
},
{
"english": "two",
"deutsch": "zwei",
"theme": "numbers"
}
]
JSON in file
My swift 4 - code:
public struct Vocabulary: Codable{
let english: String
let deutsch: String
let theme: String
}
func decodeData(){
DataManager.getJSONFromURL("vokabeln") { (data, error) in
guard let data = data else {
return
}
let decoder = JSONDecoder()
do {
let vocabulary = try decoder.decode(Vocabulary.self, from: data)
print(vocabulary)
} catch let e {
print("failed to convert data \(e)")
}
}
}
public final class DataManager {
public static func getJSONFromURL(_ resource:String, completion:#escaping (_ data:Data?, _ error:Error?) -> Void) {
DispatchQueue.global(qos: .background).async {
let url = URL(string: "https://onedrive.live.com/xxxxx/vokabeln.json")
let data = try! Data(contentsOf: url!, options: .uncached)
completion(data, nil)
}
}
}
If I decode the Json from the following multi string:
public let vokabeln: String = """
[
{
"english": "one",
"deutsch": "eins",
"theme": "numbers"
},
{
"english": "two",
"deutsch": "zwei",
"theme": "numbers"
}
]
"""
it works, but if I try to decode it from the file I receive the following error message:
failed to convert data dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.})))
Thank you in advance.
Kind regards,
Kai

Answer 1

Change this
let vocabulary = try decoder.decode(Vocabulary.self, from: data)
to this
let vocabulary = try decoder.decode([Vocabulary].self, from: data)
It will give an array of Vocabulary just like [Vocabulary].
I hope this will help you.

Answer 2

I was getting a very similar error:
caught: dataCorrupted(Swift.DecodingError.Context(codingPath: [],
debugDescription: "The given data was not valid JSON.",
underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840
"Badly formed object around character 64."
UserInfo={NSDebugDescription=Badly formed object around character
64.})))
But for a completely different reason:
My local json was created like this:
"""
{
"name": "Durian",
"rate": 600,
"city": "Cali"
"description": "A fruit with a distinctive scent."
}
"""
The error message is quite obvious. I had forgot to place , after "Cali".
If I understand this correctly, to count 64 characters you have to start counting from the beginning of the line where "name" is. Meaning there are 4 empty characters before in each line. Hence the number ~64. You don't need to count the spaces at the line of { :)
Placing the comma resolved the issue.