twilio A 'From' phone number is required swift - ios

Question

I'm trying to get sms from twilio service but keep getting this error.
Request:
func SMSRequest(countryCode:String, phoneNumber: String) {
let accountSid = "ACc4d9785419f144412823ff2034660c3d"
let authToken = "a2293a42841f8999caa237er363" // changed
let phoneNumber = "[phone]"
let toNumber = "[phone]"
let url = URL(string: "https://\(accountSid):\(authToken)#api.twilio.com/2010-04-01/Accounts/\(accountSid)/SMS/Messages")
print("url", url!)
let parameters = [
"From": phoneNumber,
"To": toNumber,
"Body":"Hi daddy"
]
Alamofire.request(url!, method: .post, parameters: parameters,
encoding: JSONEncoding.default, headers: [:]).responseJSON { response in
let response = String(describing: response.result.ifFailure({
print(response)
if let data = response.data, let utf8Text = String(data: data, encoding: .utf8) {print("Data: \(utf8Text)")}
}))
}
}
Error:
<TwilioResponse><RestException><Code>21603</Code><Message>A 'From' phone number is required.</Message><MoreInfo>https://www.twilio.com/docs/errors/21603</MoreInfo><Status>400</Status></RestException></TwilioResponse>
All the credentials I get from here
Solution:
use utf8 encoding.

Answer 1

Twilio developer evangelist here.
It's important to note that, even though you have solved your problem, you are building a fundamentally insecure application. I left this comment on your other question, but I need to point it out here too.
We do not recommend that you make requests to the Twilio API directly from your native application. To do so, you would need to store or retrieve your account SID and auth token in the application somewhere. If you do this, then a malicious attacker could get access to your credentials and abuse your Twilio account.
This is actually known as the Eavesdropper vulnerability and was written about earlier this year.
Instead we recommend that you create a web application and send the API requests from there. There is a blog post on how to do that here: https://www.twilio.com/blog/2016/11/how-to-send-an-sms-from-ios-in-swift.html

Answer 2

Update for Swift 4 - you don't really need to specify encoding, just leave it as a default.
Regarding the Twilio answer, they shouldn't say that people "shouldn't" make requests to their API, but rather remove that functionality per se and make a proper authentication service on their SDK. For now this works as the best solution I found.
let accountSID = "BOB"
let authToken = "BOB'S PASSWORD"
let url = "https://api.twilio.com/2010-04-01/Accounts/\(accountSID)/Messages" as URLConvertible
let parameters = ["From": "SENDER", "To": "RECIPIENT", "Body": "Hello world!"]
Alamofire.request(url, method: .post, parameters: parameters)
.authenticate(user: accountSID, password: authToken)
.responseString { response in
debugPrint(response)
}