Cookies

Cookies in Selenium manage session data, authentication tokens, and user preferences across browser sessions.

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Core Cookie Operations

1. Adding Cookies

// Add single cookie
Cookie cookie = new Cookie("sessionId", "abc123");
driver.manage().addCookie(cookie);

// Add multiple cookies
Cookie userCookie = new Cookie("user", "testuser");
Cookie themeCookie = new Cookie("theme", "dark");
driver.manage().addCookies(userCookie, themeCookie);

Requirements: Page must be loaded (driver.get("https://example.com")) before adding cookies.

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2. Reading Cookies

// Get single cookie by name
Cookie sessionCookie = driver.manage().getCookieNamed("sessionId");
String sessionValue = sessionCookie.getValue();  // "abc123"

// Get ALL cookies
Set<Cookie> allCookies = driver.manage().getCookies();
System.out.println("Total cookies: " + allCookies.size());

// Iterate and print
for (Cookie cookie : allCookies) {
    System.out.println(cookie.getName() + " = " + cookie.getValue());
}

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3. Deleting Cookies

// Delete specific cookie
driver.manage().deleteCookieNamed("sessionId");

// Delete cookie by object reference
driver.manage().deleteCookie(sessionCookie);

// Delete ALL cookies
driver.manage().deleteAllCookies();

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4. Cookie Properties (Cookie Class Methods)

Cookie cookie = new Cookie("test", "value");
cookie.getName();      // "test"
cookie.getValue();     // "value"
cookie.getDomain();    // "example.com"
cookie.getPath();      // "/"
cookie.getExpiry();    // Expiry Date
cookie.isSecure();     // false
cookie.isHttpOnly();   // false

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Complete Cookie Lifecycle Example

@Test
public void completeCookieTest() {
    driver.get("https://example.com");
    
    // 1. ADD cookies
    driver.manage().addCookie(new Cookie("username", "testuser"));
    driver.manage().addCookie(new Cookie("sessionToken", "xyz789", 
                                        ".example.com", "/", 3600)); // domain, path, maxAge
    
    // 2. READ cookies
    Set<Cookie> cookies = driver.manage().getCookies();
    assertEquals(2, cookies.size());
    
    // 3. MODIFY - delete and re-add
    driver.manage().deleteCookieNamed("username");
    driver.manage().addCookie(new Cookie("username", "admin"));
    
    // 4. Verify
    Cookie newUserCookie = driver.manage().getCookieNamed("username");
    assertEquals("admin", newUserCookie.getValue());
    
    // 5. CLEANUP
    driver.manage().deleteAllCookies();
}

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Advanced Cookie Features

Cookie with Full Parameters

// Complete Cookie constructor: name, value, domain, path, expiry, secure, httpOnly
Date expiryDate = new Date(System.currentTimeMillis() + 3600000); // 1 hour
Cookie authCookie = new Cookie("auth", "token123", 
                              "example.com", "/secure", 
                              expiryDate, true, true);
driver.manage().addCookie(authCookie);

Persistent Cookies (Save/Load Across Sessions)

// SAVE cookies to file
Set<Cookie> cookies = driver.manage().getCookies();
String cookiesJson = new Gson().toJson(cookies);
Files.write(Paths.get("cookies.json"), cookiesJson.getBytes());

// LOAD cookies in new session
driver.get("https://example.com"); // Must navigate first
Type cookiesType = new TypeToken<Set<Cookie>>(){}.getType();
Set<Cookie> savedCookies = new Gson().fromJson(cookiesJson, cookiesType);
for (Cookie cookie : savedCookies) {
    driver.manage().addCookie(cookie);
}
driver.navigate().refresh(); // Refresh to apply cookies

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Cookie Management Utility Class

public class CookieManager {
    public static void addAuthCookie(WebDriver driver, String token) {
        driver.manage().addCookie(new Cookie("authToken", token, 
                                            ".example.com", "/", 
                                            true, true));
    }
    
    public static String getSessionId(WebDriver driver) {
        Cookie session = driver.manage().getCookieNamed("sessionId");
        return session != null ? session.getValue() : null;
    }
    
    public static void clearAll(WebDriver driver) {
        driver.manage().deleteAllCookies();
    }
}

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Common Cookie Scenarios

Scenario	Code
Bypass login	Add session cookies before navigation
Test cookie-based auth	Add/delete cookies, verify redirects
Persistent sessions	Save/load cookies between test runs
Domain/path testing	Set specific domain/path in Cookie constructor

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Cookie vs LocalStorage/SessionStorage

Storage	Selenium Method	Persistence
Cookies	driver.manage().addCookie()	Browser session + expiry
LocalStorage	((JavascriptExecutor)driver).executeScript("localStorage.setItem('key','value');")	Persistent
SessionStorage	((JavascriptExecutor)driver).executeScript("sessionStorage.setItem('key','value');")	Tab session

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Best Practices

1. Always navigate first: driver.get(url) before addCookie()
2. Use proper domain: Include leading dot for subdomains (.example.com)
3. Set realistic expiry: Use maxAge or expiry Date
4. Secure & HttpOnly: Set true for production-like testing
5. Cleanup: deleteAllCookies() in @AfterMethod
6. Save sessions: Serialize cookies for login bypass in test suites

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Quick Reference Table

Action	Method
Add cookie	driver.manage().addCookie(cookie)
Get all	driver.manage().getCookies()
Get one	driver.manage().getCookieNamed("name")
Delete one	driver.manage().deleteCookieNamed("name")
Delete all	driver.manage().deleteAllCookies()