Cloudant function-clause error at HTTP GET request - swift

Question

This is my first question here and I have not much experience in coding so please bear with me. Thanks!
I defined some documents in my Bluemix Cloudant account with different cars which have different characteristics. I want to get one entry from an IOS Swift front-end App.
This is an example query url:
https://$ACCOUNT-bluemix.cloudant.com/cars/_design/car_index/_search/car_index_name?q=size:small
Now the problem: If I use this url in a browser I get the correct results in JSON format back without any error. But if the app makes the request a function-clause error is logged while the request itself seems to be successful.
I read that a function_clause error is caused by some bug in the Javascript Cloudant uses for indexing the documents. The Javascript I'm using is exactely the same as Cloudant states it in the tutorials.
Has anyone an idea why it works in the browser but not in the App?
Thank you very much for any help!
Here is all the code:
This is the method I use in swift to make the request:
func databaseRequest(size: String, interior: String, fuel: String) {
let baseURL = "https://$ACCOUNT-bluemix.cloudant.com/cars/_design/car_index/_search/car_index_name?q="
let queryURL = "size:\(size)"
let completeURL: String = baseURL + queryURL
let completeURLModified = completeURL.addingPercentEncoding(withAllowedCharacters: NSCharacterSet.urlQueryAllowed)
let requestURL = URL(string: completeURLModified!)
var request = URLRequest(url: requestURL!)
request.httpMethod = "GET"
request.setValue("Basic \(credentials)", forHTTPHeaderField: "Authorization")
let task = URLSession.shared.dataTask(with: request){data, response, error in
guard error == nil else{
print("There was an error:", error as Any)
return
}
guard data == data else{
print("Data is empty")
return
}
let jsonResponse = try! JSONSerialization.jsonObject(with: data!, options: [])
print("This is JSON Response", jsonResponse)
}; task.resume()
}
This is the response from the JSON answer:
This is JSON Response {
error = "unknown_error";
reason = "function_clause";
ref = 1944801346;
}
The rest of log from http headers if this is helpful:
Optional(<NSHTTPURLResponse: 0x6080000349c0> { URL: https://$ACCOUNT-bluemix.cloudant.com/cars/_design/car_index/_search/car_index_name?q=size:small } { status code: 500, headers {
"Cache-Control" = "must-revalidate";
"Content-Length" = 70;
"Content-Type" = "application/json";
Date = "Thu, 24 Nov 2016 04:41:03 GMT";
Server = "CouchDB/2.0.0 (Erlang OTP/17)";
"Strict-Transport-Security" = "max-age=31536000";
Via = "1.1 lb1.bm-cc-dal-01 (Glum/1.31.3)";
"X-Cloudant-Backend" = "bm-cc-dal-01";
"X-Content-Type-Options" = nosniff;
"X-Couch-Request-ID" = 51e5e0b5e1;
"X-Couch-Stack-Hash" = 1944801346;
"X-CouchDB-Body-Time" = 0;
Last but not least the Javascript file I use as Index in the design document in Cloudant:
function (doc) {
index("name", doc.name, {"store": true});
if (doc.fuel){ index("fuel", doc.fuel, {"store": true});}
if (doc.interior){ index("interior", doc.interior, {"store": true});}
if (doc.size){index("size", doc.size, {"store": true});
}}

Answer 1

I think this error is due to cloudant trying to decode whatever you passed as \(credentials) as a base64 encoded string. If \(credentials) is not a valid base64 encoded string (e.g. contains characters other than a-z, A-Z, 0-9, +, / and =), then my guess is that cloudant's base64 decoding function fails with the above error.
You need to make sure that \(credentials) is the string <your_username>:<your_password> encoded correctly. E.g. if your username is john and your password is doe, then \(credentials) should be am9objpkb2U=.