Fix crash in eidFromURL when arg has no querystr (#25)

Fixes #24

Author: bmilekic

Source/OptableSDK.swift

@@ -385,24 +385,25 @@ public class OptableSDK: NSObject {
     //
     @objc
     public func eidFromURL(_ urlString: String) -> String {
-        let url = URL(string: urlString)
-        let urlc = URLComponents(url: url!, resolvingAgainstBaseURL: false)
+        guard let url = URL(string: urlString) else { return "" }
+        guard let urlc = URLComponents(url: url, resolvingAgainstBaseURL: false) else { return "" }
+        guard let urlqis = urlc.queryItems else { return "" }
 
         // Look for an oeid parameter in the urlString:
         var oeid = ""
-        for qi: URLQueryItem in (urlc?.queryItems)! {
-            if qi.value == nil {
+        for qi: URLQueryItem in urlqis {
+            guard let val = qi.value else {
                 continue
             }
             if qi.name.lowercased() == "oeid" {
-                oeid = qi.value!
+                oeid = val
                 break
             }
         }
 
         // Check that oeid looks like a valid SHA256:
         let range = NSRange(location: 0, length: oeid.utf16.count)
-        let regex = try! NSRegularExpression(pattern: "[a-f0-9]{64}", options: .caseInsensitive)
+        guard let regex = try? NSRegularExpression(pattern: "[a-f0-9]{64}", options: .caseInsensitive) else { return "" }
         if (oeid.count != 64) || (regex.firstMatch(in: oeid, options: [], range: range) == nil) {
             return ""
         }

Tests/OptableSDKTests.swift

@@ -71,13 +71,27 @@ class OptableSDKTests: XCTestCase {
         XCTAssertEqual(expected, sdk.eidFromURL(url))
     }
 
-    func test_eidFromURL_returnsEmptyWhenOeidAbsent() throws {
+    func test_eidFromURL_returnsEmptyWhenArgEmpty() throws {
+        let url = ""
+        let expected = ""
+
+        XCTAssertEqual(expected, sdk.eidFromURL(url))
+    }
+
+    func test_eidFromURL_returnsEmptyWhenOeidAbsentFromQuerystring() throws {
         let url = "http://some.domain.com/some/path?some=query&something=else"
         let expected = ""
 
         XCTAssertEqual(expected, sdk.eidFromURL(url))
     }
 
+    func test_eidFromURL_returnsEmptyWhenQuerystringAbsent() throws {
+        let url = "http://some.domain.com/some/path"
+        let expected = ""
+
+        XCTAssertEqual(expected, sdk.eidFromURL(url))
+    }
+
     func test_eidFromURL_expectsSHA256() throws {
         let url = "http://some.domain.com/some/path?some=query&something=else&oeid=AAAAAAAa665a45920422f9d417e4867efdc4fb8a04a1f3fff1fa07e998e86f7f7a27ae3&foo=bar&baz"
         let expected = ""