用 CocoaHttpServer 实现 https 服务

继承 HTTPConnection 类：

@interface MyHTTPConnection : HTTPConnection

在 HTTPConnection 子类中，实现 - (BOOL)isSecureServer 方法并返回 YES，表示支持 https。

制作一个 SSL 自签名证书，安装到钥匙串，然后导出为 .p12 文件，记住导出密码。

制作证书时需要注意 /CN 参数必须指定主机名，比如 /CN 参数指定为 127.0.0.1，则访问时只能用 https://127.0.0.1，而不能用 https://localhost 替代。

实现 sslIdentityAndCertificates 方法：

- (NSArray *)sslIdentityAndCertificates
{
    SecIdentityRef identityRef = NULL;
    SecCertificateRef certificateRef = NULL;
    SecTrustRef trustRef = NULL;

    NSString *thePath = [[NSBundle mainBundle] pathForResource:@"127.0.0.1" ofType:@"p12"];
    NSData *PKCS12Data = [[NSData alloc] initWithContentsOfFile:thePath];
    CFDataRef inPKCS12Data = (__bridge CFDataRef)PKCS12Data;
    CFStringRef password = CFSTR("你导出 .p12 的密码");
    const void *keys[] = { kSecImportExportPassphrase };
    const void *values[] = { password };
    CFDictionaryRef optionsDictionary = CFDictionaryCreate(NULL, keys, values, 1, NULL, NULL);
    CFArrayRef items = CFArrayCreate(NULL, 0, 0, NULL);

    OSStatus securityError = errSecSuccess;
    securityError =  SecPKCS12Import(inPKCS12Data, optionsDictionary, &items);
    if (securityError == 0) {
        CFDictionaryRef myIdentityAndTrust = CFArrayGetValueAtIndex (items, 0);
        const void *tempIdentity = NULL;
        tempIdentity = CFDictionaryGetValue (myIdentityAndTrust, kSecImportItemIdentity);
        identityRef = (SecIdentityRef)tempIdentity;
        const void *tempTrust = NULL;
        tempTrust = CFDictionaryGetValue (myIdentityAndTrust, kSecImportItemTrust);
        trustRef = (SecTrustRef)tempTrust;
    } else {
        NSLog(@"Failed with error code %d",(int)securityError);
        return nil;
    }

    SecIdentityCopyCertificate(identityRef, &certificateRef);
    NSArray *result = [[NSArray alloc] initWithObjects:(__bridge id)identityRef, (__bridge id)certificateRef, nil];

    return result;
}

复制 HTTPConnetion.m 中的 startConnection 方法和 startReadingRequest 方法代码。
找到 startConnection 方法中如下语句：

[settings setObject:(NSString *)kCFStreamSocketSecurityLevelNegotiatedSSL                            forKey:(NSString *)kCFStreamSSLLevel]

替换为：

[settings setObject:[NSNumber numberWithInteger:2] forKey:GCDAsyncSocketSSLProtocolVersionMin];
[settings setObject:[NSNumber numberWithInteger:2] forKey:GCDAsyncSocketSSLProtocolVersionMax];

在启动 HTTPServer （调用 startServer ）之前，使用 setConnectionClass 方法将 HTTPConnecdtion 替换为 MyHTTPConnection：

[httpServer setConnectionClass:[MyHTTPConnection class]];