Objective-C中的Mime编码的Word解析 [英] Mime Encoded-Word parsing in Objective-C

问题描述

OS X或iOS提供API来解析 MIME Encoded-Word ？这些可爱的字符串：

  =？iso-8859-1？Q？= A1Hola，_se = F1or！？= 
  

或者，是否有一个已知的开源库？

解决方案

我拿了@ NickolayO的 answer ，添加了基础64支持与 QSStrings ，并缩短代码使用 componentsSeparatedByString：和 stringByReplacingOccurrencesOfString：withString：。

我已将代码提供给 GitHub 。这是一个方便的代码片段：

  @implementation NSString（MimeEncodedWord）
 
  - （BOOL）isMimeEncodedWord 
 {
 return [self hasPrefix：@=？]&& [self hasSuffix：@？=]; 
} 
 
 +（NSString *）stringWithMimeEncodedWord：（NSString *）word 
 {//示例：=？iso-8859-1？Q？= A1Hola，_se = ！？= 
 NSArray * components = [word componentsSeparatedByString：@？]; 
 if（components.count< 5）return nil; 
 
 NSString * charset = [components objectAtIndex：1]; 
 NSStringEncoding encoding = CFStringConvertEncodingToNSStringEncoding（CFStringConvertIANACharSetNameToEncoding（（CFStringRef）charset））; // TODO：如果编码无效，会发生什么？ 
 
 NSString * encodingType = [components objectAtIndex：2]; 
 NSString * encodedText = [components objectAtIndex：3]; 
 if（[encodingType isEqualToString：@Q]）
 {// quoted-printable 
 encodedText = [encodedText stringByReplacingOccurrencesOfString：@_withString：@]; 
 encodedText = [encodedText stringByReplacingOccurrencesOfString：@=withString：@％]; 
 NSString * decoded = [encodedText stringByReplacingPercentEscapesUsingEncoding：encoding]; 
返回解码; 
} else if（[encodingType isEqualToString：@B]）
 {// base64 
 NSData * data = [QSStrings decodeBase64WithString：encodedText]; 
 NSString * decoded = [[NSString alloc] initWithData：data encoding：encoding]; 
返回解码; 
} else {
 NSLog（@％@不是有效的编码（必须是Q或B），encodingType）; 
 return nil; 
} 
} 
 
 @end 
  

Do OS X or iOS provide an API to parse MIME Encoded-Word? These lovely strings:

=?iso-8859-1?Q?=A1Hola,_se=F1or!?=

Alternatively, is there a known open-source library that does this?

解决方案

I took @NickolayO.'s answer, added base-64 support with QSStrings and shortened the code by using componentsSeparatedByString: and stringByReplacingOccurrencesOfString:withString:.

I've made the code available on GitHub. Here's a snippet for convenience:

@implementation NSString (MimeEncodedWord)

- (BOOL) isMimeEncodedWord
{
    return [self hasPrefix:@"=?"]  && [self hasSuffix:@"?="];
}

+ (NSString*) stringWithMimeEncodedWord:(NSString*)word
{ // Example: =?iso-8859-1?Q?=A1Hola,_se=F1or!?=
    NSArray *components = [word componentsSeparatedByString:@"?"];
    if (components.count < 5) return nil;

    NSString *charset = [components objectAtIndex:1];
    NSStringEncoding encoding = CFStringConvertEncodingToNSStringEncoding(CFStringConvertIANACharSetNameToEncoding((CFStringRef)charset)); // TODO: What happens if the encoding is invalid?

    NSString *encodingType = [components objectAtIndex:2];
    NSString *encodedText = [components objectAtIndex:3];
    if ([encodingType isEqualToString:@"Q"])
    { // quoted-printable
        encodedText = [encodedText stringByReplacingOccurrencesOfString:@"_" withString:@" "];
        encodedText = [encodedText stringByReplacingOccurrencesOfString:@"=" withString:@"%"];
        NSString *decoded = [encodedText stringByReplacingPercentEscapesUsingEncoding:encoding];
        return decoded;
    } else if ([encodingType isEqualToString:@"B"])
    { // base64
        NSData *data = [QSStrings decodeBase64WithString:encodedText];
        NSString *decoded = [[NSString alloc] initWithData:data encoding:encoding];
        return decoded;
    } else {
        NSLog(@"%@ is not a valid encoding (must be Q or B)", encodingType);
        return nil;
    }    
}

@end

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