NSURL为null,而NSString在Objective-C中正确 [英] NSURL is null while NSString is correct in Objective-C
问题描述
我有一个包含URL的NSString
,当我用NSString
分配NSURL
时,NSURL输出(空).这是因为url中有一些非法字符,如果不对包含URL的NSString
进行编码,则NSURL
无法读取.
I have an NSString
containing a url and when I allocate NSURL
with the NSString
, NSURL outputs (null). It's because there are some illegal characters in the url, which NSURL
can't read without encoding the NSString
containing the url.
NSString *u = [incomingUrlString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url = [NSURL URLWithString:u];
NSLog(@"INCOMINGURLSTRING: %@" , u);
NSLog(@"URL: %@" , url);
输出为:
INCOMINGURLSTRING: /url/path/fileName_blå.pdf
URL: (null)
incomingUrlString包含挪威字母å",我认为这是NSURL
为(空)的原因
incomingUrlString contains the Norwegian letter "å", which I think is the reason for the NSURL
being (null)
我也尝试过:
NSString *trimmedString = [file stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
NSString *encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)trimmedString, NULL, (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ", kCFStringEncodingUTF8);
NSLog(@"TRIMMEDSTRING: %@" , trimmedString);
NSLog(@"ENCODEDSTRING: %@" , [encodedString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]);
NSURL *url = [NSURL URLWithString:encodedString];
NSLog(@"URL: %@" , url);
这里的输出是:
TRIMMEDSTRING: /url/path/fileName_blå.pdf
ENCODEDSTRING: /url/path/fileName_blå.pdf
URL: %2Furl%2FPath%2FfileName_bl%C3%A5.pdf
我的目标是将URL加载到UIWebView
中.它适用于除此URL以外的所有其他传入URL,除了文件名外,它们看起来都相同.这是唯一包含非法字符的人.但是我必须找到一种编码方法,因为将来会出现更多包含æ",ø"或å"的文件.
My goal is to load the URL into a UIWebView
. It works for all the other incoming urls except for this one, they all look the same except for the filename. This is the only one containg an illegal character. But I have to find a way to encode this, because there will be more files containg either "æ", "ø" or "å" in the future.
我知道根据url标准,输出看起来不正确,这是我故意这样做的.出于安全原因,我无法使用 http://blah blah显示正确的网址.
I know the output does not look correct according to url standards, which I did on purpose. I can't show the correct url with http://blah blah because of security reasons.
任何人都可以帮忙吗?
推荐答案
您用于对字符串中的字符进行百分比编码的方法也会转义合法的URL字符.如果您要编码URL参数,这将是适当的,在这种情况下,尽管最好使用stringByAddingPercentEscapesUsingEncoding:
,因为它会保留URL结构中的字符(':','/'等),这会更好.完整:
The method you're using for percent-encoding the characters in the string also escapes legal URL characters. This would be appropriate if you were encoding a URL parameter, in this case though it would be better to simply use stringByAddingPercentEscapesUsingEncoding:
because it leaves the characters that are part of the URL's structure (':', '/', etc.) intact:
NSString *u = @"http://example/path/fileName_blå.pdf";
u = [u stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url = [NSURL URLWithString:u];
NSLog(@"%@", url); // http://example.com/path/fileName_bl%C3%A5.pdf
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