Dactyloidae iOS initial commit

mobile/ios/Client/Frontend/Browser/SearchSuggestClient.swift

@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import Alamofire
+import Foundation
+import Shared
+
+let SearchSuggestClientErrorDomain = "org.mozilla.firefox.SearchSuggestClient"
+let SearchSuggestClientErrorInvalidEngine = 0
+let SearchSuggestClientErrorInvalidResponse = 1
+
+/*
+ * Clients of SearchSuggestionClient should retain the object during the 
+ * lifetime of the search suggestion query, as requests are canceled during destruction.
+ * 
+ * Query callbacks that must run even if they are cancelled should wrap their contents in `withExtendendLifetime`.
+ */
+class SearchSuggestClient {
+    fileprivate let searchEngine: OpenSearchEngine
+    fileprivate weak var request: Request?
+    fileprivate let userAgent: String
+
+    lazy fileprivate var alamofire: SessionManager = {
+        let configuration = URLSessionConfiguration.ephemeral
+        var defaultHeaders = SessionManager.default.session.configuration.httpAdditionalHeaders ?? [:]
+        defaultHeaders["User-Agent"] = self.userAgent
+        configuration.httpAdditionalHeaders = defaultHeaders
+        return SessionManager(configuration: configuration)
+    }()
+
+    init(searchEngine: OpenSearchEngine, userAgent: String) {
+        self.searchEngine = searchEngine
+        self.userAgent = userAgent
+    }
+
+    func query(_ query: String, callback: @escaping (_ response: [String]?, _ error: NSError?) -> Void) {
+        let url = searchEngine.suggestURLForQuery(query)
+        if url == nil {
+            let error = NSError(domain: SearchSuggestClientErrorDomain, code: SearchSuggestClientErrorInvalidEngine, userInfo: nil)
+            callback(nil, error)
+            return
+        }
+
+        request = alamofire.request(url!)
+            .validate(statusCode: 200..<300)
+            .responseJSON { response in
+                if let error = response.result.error {
+                    callback(nil, error as NSError?)
+                    return
+                }
+
+                // The response will be of the following format:
+                //    ["foobar",["foobar","foobar2000 mac","foobar skins",...]]
+                // That is, an array of at least two elements: the search term and an array of suggestions.
+                let array = response.result.value as? NSArray
+                if array?.count ?? 0 < 2 {
+                    let error = NSError(domain: SearchSuggestClientErrorDomain, code: SearchSuggestClientErrorInvalidResponse, userInfo: nil)
+                    callback(nil, error)
+                    return
+                }
+
+                let suggestions = array?[1] as? [String]
+                if suggestions == nil {
+                    let error = NSError(domain: SearchSuggestClientErrorDomain, code: SearchSuggestClientErrorInvalidResponse, userInfo: nil)
+                    callback(nil, error)
+                    return
+                }
+
+                callback(suggestions!, nil)
+        }
+
+    }
+
+    func cancelPendingRequest() {
+        request?.cancel()
+    }
+}