Double quoted cookie values are supported now. (#460)

Motivation:

In according to RFC 6265 a cookie value may be placed between double quotes.

Modifications:

HTTPClient.Cookie ignores now the double quotes at the beginning and the ending of a cookie value.
New unit test is added to check it.

Result:

Quoted cookie values are parsed properly now.

Author: fundaev

Diff for: Sources/AsyncHTTPClient/HTTPClient+HTTPCookie.swift

@@ -59,7 +59,7 @@ extension HTTPClient {
             }
 
             self.name = nameAndValue[0]
-            self.value = nameAndValue[1]
+            self.value = nameAndValue[1].omittingQuotes()
 
             guard !self.name.isEmpty else {
                 return nil
@@ -153,6 +153,19 @@ extension HTTPClient {
     }
 }
 
+private extension String {
+    func omittingQuotes() -> String {
+        let dquote = "\""
+        if !hasPrefix(dquote) || !hasSuffix(dquote) {
+            return self
+        }
+
+        let begin = index(after: startIndex)
+        let end = index(before: endIndex)
+        return String(self[begin..<end])
+    }
+}
+
 extension HTTPClient.Response {
     /// List of HTTP cookies returned by the server.
     public var cookies: [HTTPClient.Cookie] {

Diff for: Tests/AsyncHTTPClientTests/HTTPClientCookieTests+XCTest.swift

@@ -31,6 +31,7 @@ extension HTTPClientCookieTests {
             ("testCookieInit", testCookieInit),
             ("testMalformedCookies", testMalformedCookies),
             ("testCookieExpiresDateParsing", testCookieExpiresDateParsing),
+            ("testQuotedCookies", testQuotedCookies),
         ]
     }
 }

Diff for: Tests/AsyncHTTPClientTests/HTTPClientCookieTests.swift

@@ -93,4 +93,16 @@ class HTTPClientCookieTests: XCTestCase {
         c = HTTPClient.Cookie(header: "key=value; eXpIRes=Sun Nov  6 08:49:37 1994;", defaultDomain: "example.org")!
         XCTAssertEqual(Date(timeIntervalSince1970: 784_111_777), c.expires)
     }
+
+    func testQuotedCookies() {
+        var c = HTTPClient.Cookie(header: "key=\"value\"", defaultDomain: "example.org")!
+        XCTAssertEqual("value", c.value)
+
+        c = HTTPClient.Cookie(header: "key=\"value\"; Path=/path", defaultDomain: "example.org")!
+        XCTAssertEqual("value", c.value)
+        XCTAssertEqual("/path", c.path)
+
+        c = HTTPClient.Cookie(header: "key=\"\"", defaultDomain: "example.org")!
+        XCTAssertEqual("", c.value)
+    }
 }