.request调用中的额外参数— Alamofire + Swift

Question

I'm trying to make a .request() call using Alamofire 4 and Swift 4. Here's the code I'm using:

static func getPlaceData(url: String, parameters: [String: String]) {
    Alamofire.request(url, method: .get, parameters: parameters, encoding: JSONEncoding.default, headers: headers).responseJSON { (response) in
        if response.result.isSuccess {
            let json: JSON = JSON(response.result.value!)
            print(json)
        } else {
            print("error")
        }
    }
}

where headers is:

let headers: HTTPHeaders = [
        "Authorization": "Bearer /*PRIVATE KEY*/"
]

I am getting the following error: Extra argument 'method' in call , at the Alamofire.request(... line.

I've read through quite a few SO posts about similar issues but none of their solutions have fixed my problem:

• Alamofire Swift 3.0 Extra argument in call
• Swift Alamofire Request Error - Extra Argument in call

I've also read in the this documentation guide and this issues thread on GitHub but neither have solved the issue.

What is the proper syntax for a .request() call with required parameters and headers ?

The code is for making an authenticated call from Swift code using the Yelp Fusion API -- maybe someone can suggest a better method than Alamofire?

Answer 1

I went through the documentations and found out two things

1. The request method signature which is

     public func request( _ url: URLConvertible, method: HTTPMethod = .get, parameters: Parameters? = nil, encoding: ParameterEncoding = URLEncoding.default, headers: HTTPHeaders? = nil) -> DataRequest 

Link to the documentation

2. The Parameter typeAlias is a type of [String:Any] where as you are passing [String:String] which is conflicting.

Link to the Parameter Definition in the DOC

So all you need to do it change the signature and you are good.

Answer 2

I figured out the issue, no thanks to any documentation or GitHub threads.

The logic in the above code snippet (from the question) referenced a constant called headers , which was declared outside of getPlaceData(url:parameters:) . This is because in order to access the Yelp Fusion API you need to include an extra field in the HTTP header you send to include the private API key using the format mentioned here .

I moved the headers data structure inside of getPlaceData(url:parameters:) and it fixed the issue, so my resulting function is as follows:

static func getPlaceData(url: String, parameters: [String: String]) {
  let headers: HTTPHeaders = [
    "Authorization": "Bearer /*PRIVATE KEY*/"
  ]

  Alamofire.request(url, method: .get, parameters: parameters, encoding: 
  JSONEncoding.default, headers: headers).responseJSON { (response) in
    if response.result.isSuccess {
      let json: JSON = JSON(response.result.value!)
      print(json)
    } else {
      print("error")
    }
  }
}

Not sure why this fixed the issue, but the code works now.