I am working on certificate verification code for a NSURLSession in Swift. I would like to automatically adjust the trust settings for our own certificate which is used by a server.
The relevant code section is shown below:
SecCertificateAddToKeychain(firstCertificate, nil)
let sslTrust: [NSObject: AnyObject] = [kSecTrustSettingsPolicy: SecPolicyCreateSSL(true, nil)]
let result = SecTrustSettingsSetTrustSettings(firstCertificate, .User, sslTrust)
if (result == errSecSuccess) {
// success
} else {
print("Could not set trust settings \(result)")
}
I always get the result -50, which is errSecParam stating "One or more parameters passed to the function were not valid.".
If I replace the dictionary with an empty array [], the function returns success, so the problem is this last parameter.
How do I correctly use this function in swift?
Related
I'm getting an error saving an encoded value to keychain at the point of SecItemAdd. I'm fairly new to working with Keychain and not sure how to return the error to see what I'm doing incorrectly.
let encoder = JSONEncoder()
func initiateLogin(forceReconnect: Bool = false, completion: #escaping (Bool)->Void) {
Task {
await loginUser(forceReconnect: forceReconnect, completion: { user in
if let encoded = try? self.encoder.encode(user) {
// MARK: - keychain
let attributes: [String: Any] = [
kSecClass as String: kSecClassGenericPassword,
kSecAttrAccount as String: "johnDoe",
kSecValueData as String: encoded,
]
if SecItemAdd(attributes as CFDictionary, nil) == noErr {
print("\(#function) 😀 user saved successfully in keychain")
} else {
print("\(#function) ⚠️ something went wrong")
}
self.initClient(withCredentials: user)
completion(true)
}
})
}
}
You didn't specify which error you are getting (it should be a return value of SecItemAdd), but the most common mistake is this: as documentation states:
The operation might fail, for example, if an item with the given attributes already exists.
In other words: your code will only work once for each unique kSecAttrAccount.
Instead, you need to check if an item already exists, and if yes, update it (or delete the previous one and create a new one).
How to update the items or delete them is explained here.
Side note: it's also a good idea to put keychain management into a separate class (a wrapper), which you can call from anywhere in your code to save / load data from keychain. Here's a good tutorial on how to create such wrapper.
I am working with a poorly designed API (I don't have control over it) where even if the access token is expired, it still returns a HTTP success code but includes the 401 Unauthorized in the actual response body. So simply checking the HTTP status code isn't sufficient and I need to check the actual response.
I am making many network requests in my app to this API and when I receive the response, I need to first check whether the response is an array or a dictionary. If array, then we are good. If it's a dictionary, then I need to check the "error" field in the response dictionary which will have the 401 Unauthorized.
So every time I receive the JSON response, I have the following piece of code to return out of the function if it's an error dictionary:
guard !(myJSON is NSDictionary) && (myJSON as! NSDictionary).value(forKey: "error") != nil else {
print("Error: ", MyAppError.accessTokenExpired)
return
}
I am wondering if there is a way to prevent duplicating this piece of code in every network request function I have? Can I have this somewhere and simply call it without duplicating these lines of code each time?
Wrap it in a function like this one
func isErrorResponse(_ response: Any) -> Bool {
if let dict = response as? [String: Any], let error = dict["error"] {
print("Error: \(MyAppError.accessTokenExpired)")
return true
}
return false
}
You should use the swift data types if you are using Swift language. Although if myJSON validates with Dictionary then it will definitely be validated with [String: Any].
Create function like:
func isValidResponse(_ json: Any) -> Bool {
guard let jsonDict = json as? [String: Any], let let error = dict["error"] else { return true }
print("Error: \(error.localizedDescription)")
return false
}
Use it as:
guard YourClass.isValidResponse(myJSON) else { return }
// Valid Response - Code here...
Right below the second comment, I receive an error of "Result of call to 'taskForDeleteMethod' is unused. Why is this when I use the results and error in the closure following the call?
func deleteSession(_ completionHandlerForDeleteSession: #escaping (_ success: Bool, _ error: NSError?) -> Void) {
/* 1. Specify parameters, method (if has {key}), and HTTP body (if POST) */
// There are none...
/* 2. Make the request */
taskForDELETEMethod { (results, error) in
/* 3. Send the desired value(s) to completion handler */
if let error = error {
print("Post error: \(error)")
completionHandlerForDeleteSession(false, error)
} else {
guard let session = results![JSONKeys.session] as? [String: AnyObject] else {
print("No key '\(JSONKeys.session)' in \(results)")
return
}
if let id = session[JSONKeys.id] as? String {
print("logout id: \(id)")
completionHandlerForDeleteSession(true, nil)
}
}
}
}
In earlier swift versions, you need not bother about the return value of a method. You may store it in any variable snd use it later or you may ignore it completely. Neither it gave any error nor a warning.
But in swift 3.0 you need to specify whether you want to ignore the returned value or use it.
1. If you want to use the returned value, you can create a variable/constant and store the value in it, i.e
let value = taskForDELETEMethod {
// Your code goes here
}
2. If you want to ignore the returned value, you can use _ ,i.e
let _ = taskForDELETEMethod {
// Your code goes here
}
You are confusing the results variable, which is, indeed, used inside the closure, and the result of the taskForDELETEMethod call itself, which is NSURLSessionDataTask object.
From the examples of using taskForDELETEMethod that I was able to find online it looks like it is perfectly OK to ignore the return value, so you can avoid this warning by assigning the result to _ variable, i.e.
let _ = taskForDELETEMethod {
... // The rest of your code goes here
}
I'm trying to use Alamofire and passing my parameters to a function I made.
Here's my code:
let msisdn : AnyObject = textFields[0].text!
//let msisdn = textFields[0].text!
let userId = "MyID"
let params = [
"msisidn":msisdn /*as AnyObject*/,
"denom_id":self.selectedGameDetail.Id /*as AnyObject*/,
"game_id":self.selectedGameDetail.GameId /*as AnyObject*/
]
print(params)
showEZLoading(true)
su.postEpins(userId, params: params, completion:{ (result, error) -> Void in
self.hideEZLoading()
if (error != nil){
print("DEBUG: API Response Error")
Utility.displayAlert(self, msg: "There's an errror fetching data from server.")
}
else {
print("DEBUG: API Response Success")
}
})
Everything in selectedGameDetail is a String.
And here's the postEpins function:
func postEpins(msisdn: String, params: [String: AnyObject]?, completion:(result: JSON, error: NSError?) -> Void) {
print("POST EPINS")
}
Doesn't do anything yet. But, whenever the app gets to the function call, I get this:
fatal error: unexpectedly found nil while unwrapping an Optional value
I'm positive it has something to do with the params, but I'm 100% sure. Yes, params has stuff in it. Check below.
What I've tried:
Well, if you see a comment in my code, I've pretty much tried those. And I have no idea what else to do.
For reference, that exact same code works on another part of the app, minus the userID - and I also tried removing that, but it still gave me the above error.
I found this regarding the params:
I noticed that one of the values is an NSTaggedPointerString, whereas everything else is an AnyObject. Is this an issue?
I am trying to get learn how to use AlamoFire and I am having trouble.
My method so far is as follows:
func siteInfo()->String?{
var info:NSDictionary!
var str:String!
Alamofire.request(.GET, MY_API_END_POINT).responseJSON {(request, response, JSON, error) in
info = JSON as NSDictionary
str = info["access_key"] as String
//return str
}
return str
}
This returns nil which is a problem. From what I have read here, this is because the request can take a while so the closure doesn't execute till after the return. The suggested solution of moving the return into the closure does not work for me and the compiler just yells (adding ->String after (request,response,JSON,error) which gives "'String' is not a subtype of void"). Same goes for the other solution provided.
Any ideas? Even some source code that is not related to this problem, that uses AlamoFire, would be helpful.
Thanks!
One way to handle this is to pass a closure (I usually call it a completionHandler) to your siteInfo function and call that inside Alamofire.request's closure:
func siteInfo(completionHandler: (String?, NSError?) -> ()) -> () {
Alamofire.request(.GET, MY_API_END_POINT).responseJSON {
(request, response, JSON, error) in
let info = JSON as? NSDictionary // info will be nil if it's not an NSDictionary
let str = info?["access_key"] as? String // str will be nil if info is nil or the value for "access_key" is not a String
completionHandler(str, error)
}
}
Then call it like this (don't forget error handling):
siteInfo { (str, error) in
if str != nil {
// Use str value
} else {
// Handle error / nil value
}
}
In the comments you asked:
So how would you save the info you collect from the get request if you
can only do stuff inside the closure and not effect objects outside of
the closure? Also, how to keep track to know when the request has
finished?
You can save the result of the get request to an instance variable in your class from inside the closure; there's nothing about the closure stopping you from doing that. What you do from there really depends on, well, what you want to do with that data.
How about an example?
Since it looks like you're getting an access key form that get request, maybe you need that for future requests made in other functions.
In that case, you can do something like this:
Note: Asynchronous programming is a huge topic; way too much to cover here. This is just one example of how you might handle the data you get back from your asynchronous request.
public class Site {
private var _accessKey: String?
private func getAccessKey(completionHandler: (String?, NSError?) -> ()) -> () {
// If we already have an access key, call the completion handler with it immediately
if let accessKey = self._accessKey {
completionHandler(accessKey, nil)
} else { // Otherwise request one
Alamofire.request(.GET, MY_API_END_POINT).responseJSON {
(request, response, JSON, error) in
let info = JSON as? NSDictionary // info will be nil if it's not an NSDictionary
let accessKey = info?["access_key"] as? String // accessKey will be nil if info is nil or the value for "access_key" is not a String
self._accessKey = accessKey
completionHandler(accessKey, error)
}
}
}
public func somethingNeedingAccessKey() {
getAccessKey { (accessKey, error) in
if accessKey != nil {
// Use accessKey however you'd like here
println(accessKey)
} else {
// Handle error / nil accessKey here
}
}
}
}
With that setup, calling somethingNeedingAccessKey() the first time will trigger a request to get the access key. Any calls to somethingNeedingAccessKey() after that will use the value already stored in self._accessKey. If you do the rest of somethingNeedingAccessKey's work inside the closure being passed to getAccessKey, you can be sure that your accessKey will always be valid. If you need another function that needs accessKey, just write it the same way somethingNeedingAccessKey is written.
public func somethingElse() {
getAccessKey { (accessKey, error) in
if accessKey != nil {
// Do something else with accessKey
} else {
// Handle nil accessKey / error here
}
}
}