make access key optional

Example/Example/SearchResultsCollectionViewController.swift

@@ -84,7 +84,7 @@ class SearchResultsCollectionViewController: UICollectionViewController {
 
         // call tracking api here to register the click
         // alternately, you can present similar images or recommend them to users in the image detail page
-        let params = ViTrackParams(accessKey: ViSearch.sharedInstance.client!.accessKey, reqId: self.reqId, action: "click")
+        let params = ViTrackParams(reqId: self.reqId, action: "click")
         params?.imName = im_name
 
         ViSearch.sharedInstance.track(params: params!) { (success, error) in

README.md

@@ -549,7 +549,7 @@ User action (e.g. click on an image after search) can be sent in this way:
 
 ```swift
 
-let params = ViTrackParams(accessKey: ViSearch.sharedInstance.client!.accessKey, reqId: recentReqId, action: "click" )
+let params = ViTrackParams(reqId: recentReqId, action: "click" )
 
 // You can also append an im_name field
 params.imName = "example_clicked_im_name"

ViSearchSDK/ViSearchSDK/Classes/Request/ViTrackParams.swift

@@ -8,40 +8,45 @@ public class ViTrackParams : ViSearchParamsProtocol{
     public var imName : String?
     public var reqId  : String
     public var cuid   : String?
-    var cid    : String
-
-    //MARK: init
+    var cid    : String?
 
     /// Init tracking parameters. For example, after user search for images, we want to track which image they clicked
     ///
     /// - parameter accessKey: API access key
     /// - parameter reqId: recent request id e.g. search for similar images
     /// - parameter action: tracking action e.g. click, add to cart, etc. Currently only click is supported
-    public init?(accessKey: String, reqId : String , action: String ) {
+    public convenience init?(accessKey: String, reqId : String , action: String ) {
 
         if accessKey.isEmpty {
             print("\(type(of: self)).\(#function)[line:\(#line)] - error: accessKey parameter is missing")
 
             return nil
         }
 
+        self.init(reqId: reqId, action: action)
+
+        self.cid = accessKey
+        self.cuid = nil
+        self.imName = nil
+    }
+
+    /// Init tracking parameters. For example, after user search for images, we want to track which image they clicked
+    /// Assumption: access key will be passed by client later
+    /// - parameter reqId: recent request id e.g. search for similar images
+    /// - parameter action: tracking action e.g. click, add to cart, etc. Currently only click is supported
+    public init?(reqId : String , action: String){
         if reqId.isEmpty {
             print("\(type(of: self)).\(#function)[line:\(#line)] - error: reqId parameter is missing")
-
             return nil
         }
 
         if action.isEmpty {
             print("\(type(of: self)).\(#function)[line:\(#line)] - error: action parameter is missing")
-
             return nil
         }
-
-        self.cid = accessKey
+
         self.reqId = reqId
         self.action = action
-        self.cuid = nil
-        self.imName = nil
     }
 
     //MARK: search protocol

ViSearchSDK/ViSearchSDK/Classes/ViSearch.swift

@@ -92,7 +92,7 @@ open class ViSearch: NSObject {
         return nil
     }
 
-    // track the API calls and various actions
+    /// track the API calls and various actions
     /// Tracking API
     @discardableResult public func track(params: ViTrackParams,
                                          handler:  ( (_ success: Bool, Error?) -> Void )?

ViSearchSDK/ViSearchSDK/Classes/ViSearchClient.swift

@@ -149,6 +149,8 @@ open class ViSearchClient: NSObject, URLSessionDelegate {
                       handler:  ( (_ success: Bool, Error?) -> Void )?
                       ) -> Void {
 
+        params.cid = accessKey
+
         // different url for tracking
         let url = requestSerialization.generateRequestUrl(baseUrl: trackUrl , apiEndPoint: .TRACK , searchParams: params)
         let request = NSMutableURLRequest(url: URL(string: url)! , cachePolicy: .useProtocolCachePolicy , timeoutInterval: timeoutInterval)