比较两个 NSURL 或一个 NSURL 和一个 NSString 的可靠方法?

问题描述

我最近在比较两个 NSURL 并将一个 NSURL 与一个 NSString(这是一个 URL 地址)进行比较时遇到了一个问题，情况是我从某个地方得到一个 NSURLRequest，我可能知道也可能不知道它指向的 URL 地址，我有一个 URL NSString，比如http://m.google.com"，现在我需要检查该 NSURLRequest 中的 URL 是否与我的 URL 字符串相同:

I recently had a problem when comparing two NSURLs and compare one NSURL with an NSString(which is a URL address), the situation is I got an NSURLRequest from somewhere, I may or may not know the URL address it points to, and I have an URL NSString, say "http://m.google.com", now I need to check if the URL in that NSURLRequest is the same as the URL string I had:

[[request.URL.absoluteString lowercaseString] isEqualToString: [self.myAddress lowercaseString]];

这返回 NO，因为 absoluteString 给了我http://m.google.com/"，而我的字符串是http://m.google.com"，没有斜杠结束，即使我使用

this returns NO as the absoluteString gives me "http://m.google.com/" whereas my string is "http://m.google.com" without a slash in the end, even if I create the NSURLRequest using

[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://m.google.com"]]

absoluteString 仍然给我http://m.google.com/"，我想知道有没有可靠的方法来比较 NSURL 或一个 NSURL 和一个 NSString?

it still gives me "http://m.google.com/" for absoluteString, I wonder is there any reliable way to compare to NSURL or one NSURL and one NSString?

1. 检查一个是否包含"另一个，但这并不可靠，因为http://m.google.com/blabla"包含http://m.google.com".

1. check if one 'contains' another, but this is not reliable as 'http://m.google.com/blabla' contains 'http://m.google.com'.

将 NSString 转换为 NSURL 并使用 isEqual 方法比较两个 NSURL，希望 NSURL 的 isEqual 实现可以解决?

convert the NSString to NSURL and use the isEqual method to compare two NSURL and hopefully NSURL's implementation of isEqual can figure it out?

基于第 2 步，但使用 standardizedURL 将每个 NSURL 转换为标准 URL?

based on step 2, but convert each NSURL to a standard URL using standardizedURL?

非常感谢！

推荐答案

如果你只关心尾部斜线的歧义，你可以通过知道 NSURL 路径修剪尾部斜线来快速省去这个问题.

If you care only about the trailing slash ambiguity, you can dispense with this question quickly by knowing that NSURL path trims the trailing slash.

但我喜欢在 NSURL 上实现一些基于标准的等价的类别方法的想法(在这种情况下，等价"可能比等价更好).

But I like the idea of a category method on NSURL that implements some standards-based equivalence ("equivalence" is probably a better term than equality in this case).

@RobNapier 引用了一个相关问题，该问题的答案很好，指向 RFC2616.url 语法的另一个相关标准是 RFC1808.

@RobNapier refers to a related question with a good answer that points to RFC2616. Another relevant standard for url syntax is RFC1808.

困难的部分是确定我们所说的等价是什么意思，例如，不同的查询或片段(锚链接)呢?对于这些歧义，下面的代码在允许方面犯了错误......

The tough part is deciding what we mean by equivalence, for example, what about differing queries or fragments (anchor links)? The code below errs on the side of permissiveness for most of these ambiguities...

// in NSURL+uriEquivalence.m

- (BOOL)isEquivalent:(NSURL *)aURL {

    if ([self isEqual:aURL]) return YES;
    if ([[self scheme] caseInsensitiveCompare:[aURL scheme]] != NSOrderedSame) return NO;
    if ([[self host] caseInsensitiveCompare:[aURL host]] != NSOrderedSame) return NO;

    // NSURL path is smart about trimming trailing slashes
    // note case-sensitivty here
    if ([[self path] compare:[aURL path]] != NSOrderedSame) return NO;

    // at this point, we've established that the urls are equivalent according to the rfc
    // insofar as scheme, host, and paths match

    // according to rfc2616, port's can weakly match if one is missing and the
    // other is default for the scheme, but for now, let's insist on an explicit match
    if ([self port] || [aURL port]) {
        if (![[self port] isEqual:[aURL port]]) return NO;
        if (![[self query] isEqual:[aURL query]]) return NO;
    }

    // for things like user/pw, fragment, etc., seems sensible to be
    // permissive about these.
    return YES;
}

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