IOS 如何使用 nsscanner 类找到完整的 RSS 提要链接 [英] IOS How to find full rss feed link with nsscanner class

问题描述

我正在从基于 rss 提要的项目中获取数据.通过在 google 上搜索，我发现通常在 HTML 源中以这种格式找到 RSS 链接.

I am working on fetching data from rss feed based project.From searching on google i found that generally RSS link found in this format in source of HTML.

<link rel="alternate" type="application/rss+xml" title="RSS Feed" href="http://feeds.abcnews.com/abcnews/topstories" />

因此，我必须使用 nsscanner 类从 HTML 源中查找 RSS 提要的链接.但我不知道正确的模式，我必须设置 scanUpToString: 和 haracterSetWithCharactersInString: 等.所以，请帮助我如何找到 RSS 提要的完整链接.

so, I have to use nsscanner class to find the link of RSS feed from HTML source. but i don't know proper pattern and which i have to set scanUpToString: and haracterSetWithCharactersInString: or etc. So, please help me how to i find the full link of RSS feed.

这是我的尝试:

- (void)viewDidLoad {
NSString *googleString = @"http://abcnews.go.com/";
NSURL *googleURL = [NSURL URLWithString:googleString];
NSError *error;
NSString *googlePage = [NSString stringWithContentsOfURL:googleURL encoding:NSASCIIStringEncoding
                                                   error:&error];

NSLog(@"%@",[self yourStringArrayWithHTMLSourceString:googlePage]);//will return NSMutableArray
}

-(NSMutableArray *)yourStringArrayWithHTMLSourceString:(NSString *)html
{
NSString *from = @"<a href=\"";
NSString *to = @"</a>";
NSMutableArray *array = [[NSMutableArray alloc]init];

NSScanner* scanner = [NSScanner scannerWithString:html];

[scanner scanUpToString:@"<link" intoString:nil];
if (![scanner isAtEnd]) {
    NSString *url = nil;

    [scanner scanUpToString:@"RSS Feed" intoString:nil];
    NSCharacterSet *charset = [NSCharacterSet characterSetWithCharactersInString:@"/>"];
    [scanner scanUpToCharactersFromSet:charset intoString:nil];
    [scanner scanCharactersFromSet:charset intoString:nil];
    [scanner scanUpToCharactersFromSet:charset intoString:&url];
    NSLog(@"%@",url);
    // "url" now contains the URL of the img
 }

return array;
}

目前我只能找到此代码的链接.

currently i am able find only link with this code .

输出:

但完整链接是:-

http://feeds.abcnews.com/abcnews/topstories

推荐答案

使用link"而不是此参考文献中的a"标签.

Use "link" instead of "a" tags from this reference.

参考:ios中提取href url并丢弃其余锚标记的正则表达式

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