验证没有方案的 URL [英] Validate URL without scheme

问题描述

Swift 5、Xcode 10、iOS 12

我的代码使用 UIApplication.shared.canOpenURL 来验证 URL，不幸的是，如果没有例如http://".

示例:

print(UIApplication.shared.canOpenURL(URL(string: "stackoverflow.com")!))//false打印(UIApplication.shared.canOpenURL(URL(字符串:http://stackoverflow.com")！))//true打印(UIApplication.shared.canOpenURL(URL(字符串:129.0.0.1")！))//假打印(UIApplication.shared.canOpenURL(URL(string: "ftp://129.0.0.1")!))//true

我知道 schemes (iOS9+) 并且我知道如果字符串尚未以http://"开头，我可以添加前缀，然后检查这个新字符串，但我仍然想知道:

问题:如何添加没有方案"方案，以便像stackoverflow.com"这样的有效 URL 也返回 true(这是否可能?)?

解决方案

不可能给 URL 添加一个有效的方案，因为没有人知道哪个前缀会添加到哪个 URL.您可以在 regex 的帮助下验证 URL.

我搜索并修改了正则表达式.

扩展字符串{func isValidUrl() ->布尔{让正则表达式 = "((http|https|ftp)://)?((\\w)*|([0-9]*)|([-|_])*)+([\\.|/]((\\w)*|([0-9]*)|([-|_])*))+"let predicate = NSPredicate(格式: "SELF MATCHES %@", regex)return predicate.evaluate(with: self)}}

我使用以下网址对其进行了测试:

print("http://stackoverflow.com".isValidUrl())打印(stackoverflow.com".isValidUrl())打印("ftp://127.0.0.1".isValidUrl())打印(www.google.com".isValidUrl())打印(127.0.0.1".isValidUrl())打印(127".isValidUrl())打印(你好".isValidUrl())

<块引用>

输出

真真的真的真的真的错误的错误的

注意: 100% 正则表达式无法验证 email 和 url

Swift 5, Xcode 10, iOS 12

My code uses UIApplication.shared.canOpenURL to validate URLs, which unfortunately fails without e.g. "http://".

Example:

print(UIApplication.shared.canOpenURL(URL(string: "stackoverflow.com")!)) //false
print(UIApplication.shared.canOpenURL(URL(string: "http://stackoverflow.com")!)) //true
print(UIApplication.shared.canOpenURL(URL(string: "129.0.0.1")!)) //false
print(UIApplication.shared.canOpenURL(URL(string: "ftp://129.0.0.1")!)) //true

I'm aware of the change with schemes (iOS9+) and I know that I can just add a prefix like "http://" if the String doesn't start with it already, then check this new String but I'm still wondering:

Question: How do I add a "there's no scheme" scheme, so valid URLs like "stackoverflow.com" return true too (is this even possible?)?

解决方案

It's not possible to add a valid scheme to URL because no one knows which prefix will be add to which URL. You can just validate a URL with the help of regex.

I searched and modified the regex.

extension String { 
    func isValidUrl() -> Bool { 
        let regex = "((http|https|ftp)://)?((\\w)*|([0-9]*)|([-|_])*)+([\\.|/]((\\w)*|([0-9]*)|([-|_])*))+" 
        let predicate = NSPredicate(format: "SELF MATCHES %@", regex) 
        return predicate.evaluate(with: self) 
    } 
}

I tested it with below urls:

print("http://stackoverflow.com".isValidUrl()) 
print("stackoverflow.com".isValidUrl()) 
print("ftp://127.0.0.1".isValidUrl()) 
print("www.google.com".isValidUrl()) 
print("127.0.0.1".isValidUrl()) 
print("127".isValidUrl()) 
print("hello".isValidUrl())

Output

true 
true 
true 
true 
true 
false 
false

Note: 100% regex is not possible to validate the email and url

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