How to handle empty response using Alamofire and Combine? - ios

I am making a post request, which has an empty response
AF.request(URL(string: "some url")!, method: .post, parameters: parameters, encoding: URLEncoding.default, headers: nil)
.validate()
.publishDecodable(type: T.self)
.value()
.eraseToAnyPublisher()
where T is
struct EmptyResponse: Codable {}
and I am having this error "Response could not be serialized, input data was nil or zero length."
How do I handle a post request with an empty response using Alamofire and Combine?

This error occurs when your backend returns no data but does not return an appropriate HTTP response code (204 or 205). If this is expected behavior for your backend, you can add your response code to the list of acceptable empty response codes when you set up the publisher: .publishDecodable(T.self, emptyResponseCodes: [200]. This also requires T to either conform to Alamofire's EmptyResponse protocol, or for you to expect Alamofire's Empty type as the response.

Found answer somewhere else but it's useful here. Made empty object like that:
struct EmptyEntity: Codable, EmptyResponse {
static func emptyValue() -> EmptyEntity {
return EmptyEntity.init()
}
}
And return publisher like so:
-> AnyPublisher<EmptyEntity, AFError>

AF.request(UrlUtils.base_url, method: .post, parameters: params, encoding: URLEncoding.default, headers: nil).responseJSON { (response:AFDataResponse<Any>) in
switch(response.result) {
case .success(_):
// this case handles http response code 200, so it will be a successful response
break
case .failure(_):
break
}
}

Related

How to use responseDecodable instead of responseJSON using Alamofire 6

One of my apps no longer works due to JSON serialisation failing when using Alamofire.
'responseJSON(queue:dataPreprocessor:emptyResponseCodes:emptyRequestMethods:options:completionHandler:)'
is deprecated: responseJSON deprecated and will be removed in
Alamofire 6. Use responseDecodable instead.
For code with the following lines
AF.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: [:]).responseJSON { response in.. }
When changing to
AF.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: [:])
.responseDecodable { response in... }
Then I get the error
Generic parameter 'T' could not be inferred
So I add the following
AF.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: [:])
.responseDecodable(of: ResponseType.self) { response in.. }
I get the error
Cannot find 'ResponseType' in scope
Does anyone have any suggestions?
Unlike .responseJSON which returns a dictionary or array .responseDecodable deserializes the JSON into structs or classes.
You have to create an appropriate model which conforms to Decodable, in your code it's represented by ResponseType(.self).
The associated value of the success case is the root struct of the model.
But deprecated (in a yellow warning) means the API is still operational.
Side note: A JSON dictionary is never [String: Any?] the value is always non-optional.
In Alamofire -> Documentation/Usage.md, I found the definition of the Decodable, so I try like this, then found working.
struct DecodableType: Decodable {
let url: String
}
AF.request(urlString).responseDecodable(of: DecodableType.self) { response in
switch response.result {
case .success(let dTypes):
print(dTypes.url)
case .failure(let error):
print(error)
}
}

post request with body Alamofire

I am trying to post some data to the API, but I keep getting Response status code was unacceptable: 404 error message.. I have checked, the POST parameters and API Url are all correct, example request works on the postman but it is not working on Xcode..
my POST request Url is in this format: {{API}}/postData/Id/block.
my POST request function with Alamofire is as follows:
func postData(token: String, id: String, category: String, completion: #escaping(_ data: DataTobePost) -> Void) {
let header: HTTPHeaders = ["authorization": token]
let parameter: Parameters = [
"Id": id,
"category": category ]
Alamofire.request(API_Configurator.postData, method: .post, parameters: parameter, encoding: JSONEncoding.default, headers: header).validate().responseData(completionHandler: { response in
switch response.result {
case .success(let val):
do {
let data = try JSONDecoder().decode(DataTobePost.self, from: val)
completion(data)
}catch {
print("[DataTobePost Catch Error while decoding response: \(error.localizedDescription)]")
}
case .failure(let error):
print("[DataTobePost Failure Error : \(error.localizedDescription)]")
}
})
}
and the response is:
{
"success": true
}
where am i going wrong, can anyone help through this. (I am quite new to Alamofire)
There is no way to check what is wrong.
If you got the 404 error it means 2 things:
Code was written correctly(it compiles)
Requested page does not exist (404 error)
I think you need to check your API_Configurator.postData.
Usually, it's something simple like extra characters like "//", " ", "." etc.
Or the problem with API.
The best way to check API uses Postman

Incorrect response from Alamofire?

I am making a request to a server using Alamofire. Here is how i am doing it:
Alamofire.request(url, method: .post, parameters: [:] ,encoding: JSONEncoding.default).responseJSON { response in
print("response=\(response)")
print("Response=:\((response.response?.statusCode)!)")
switch response.result{
case .success :
let passList = AuthenticateSuccess(nibName: "AuthenticateSuccess", bundle: nil)
self.navigationController?.pushViewController(passList, animated: true)
print("connected")
case .failure(let error):
self.showAlertTost("", msg: "Authentication Failed. Authenticate again!", Controller: self)
}
}
This is what prints:
response=SUCCESS: {
message = "Access denied.";
}
Response=:401
connected
I want to know that if 401 is error why is success block being executed? Is failure case in Alamofire handled differently?
As the documentation says:
By default, Alamofire treats any completed request to be successful, regardless of the content of the response. Calling validate() before a response handler causes an error to be generated if the response had an unacceptable status code or MIME type.
E.g.
Alamofire.request(url, method: .post, encoding: JSONEncoding.default)
.validate()
.responseJSON { response in
...
}
With validate, non 2xx responses will now be treated as errors.
response.success depicts that the server has returned the response. Whereas 401 is something that is related to the REST response which your backend system generated. Hence add the check to response code after verifying that you have received the response to provide better information to the end-user.

Alamofire - responseSerializationFailed

I really need help with this one. I'm trying to do POST request using Alamofire, but for some reason I'm always getting an error from the title. When I test in POSTMAN, I'm getting okay response. Here is screenshot from POSTMAN, just to get things clearer:
And this is how I'm calling this API in code:
let parameters: Parameters = [
"data": [
"action":"homeimages"
]
]
print("Params: \(parameters)")
Alamofire.request(Constants.API_URL_2, method: .post, parameters: parameters, encoding: JSONEncoding.default).responseJSON {
response in
print("Response: \(response)")
switch response.result {
case .success(let value):
print("Response: \(value)")
break
case .failure(let error):
print(error)
}
}
As far as I know responseserializationfailed error, mostly error with API itself however as you stated, you are getting response in POSTMAN please check below things :
URL(check small/caps well), parameters are correct(check caps and dictionary format as well)
Sometimes we don't need below (optional) parameter , delete this parameter and check
encoding: JSONEncoding.default

Setting content-type header to use JSON with Swift 3 + AlamoFire

The answers in Alamofire Swift 3.0 Extra parameter in call did not work for me.
Setting header to nil compiles but I need ["Content-Type", "application/json"]. Here I get an error of an extra parameter in th emethod
How do I take
manager.request(url, method: .get, parameters: parameters).responseJSON {
response in
fulfill(response)
}
}
and send JSON content-type?
The documentation shows
Automatic Validation
Automatically validates status code within 200..<300 range, and that the Content-Type header of the response matches the Accept header of the request, if one is provided.
Alamofire.request("https://httpbin.org/get").validate().responseJSON { response in
switch response.result {
case .success:
print("Validation Successful")
case .failure(let error):
print(error)
}
}
I'm using .responseJSON but I'm not getting JSON back. So I think I need to send the Content-Type header.
Try this, there is another method overload that allow pass a dictionary with headers
let request = Alamofire.request(requestUrl, method: .get, parameters: [:], encoding: URLEncoding.queryString, headers: ["Content-Type" :"application/json"]).responseData { (response) in
/***YOUR CODE***/
}
for post JSON data in request check this answer Using manager.request with POST
Hope this helps you

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