iOS URL转码

Posted 2023-01-19 长沙火山

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最近开发一个相册的功能，测试人员反馈部分图片加载不出来，但是安卓却可以正常显示。第一反应应该就是图片的URL有问题，于是断点调试将图片的URL打印出来，果不其然发现图片URL里面含有中文。于是在网上搜索了一下，发现有两种解决方案，下面将这两种方法对比一下。

//图片url
http://10.10.10.10:8080/file/download?token=xxx&path=/home/47825309/素材库/（壁纸）素材库更新50000张壁纸/1280及以下高清壁纸/7_4c14478879c1b.jpg&type=1

一、方法一：逐个字符判断转码

//处理特殊字符
- (NSString *)isChinese:(NSString *)str 
   NSString *newString = str;
   //遍历字符串中的字符
   for(int i=0; i< [str length];i++)
       int a = [str characterAtIndex:i];
       //汉字的处理
       if( a > 0x4e00 && a < 0x9fff)
       
           NSString *oldString = [str substringWithRange:NSMakeRange(i, 1)];
           NSString *string = [oldString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
           newString = [newString stringByReplacingOccurrencesOfString:oldString withString:string];
       
       //空格处理
       if ([newString containsString:@" "]) 
           newString = [newString stringByReplacingOccurrencesOfString:@" " withString:@"%20"];
       
   
   return newString;

转码后的结果：

http://10.10.10.10:8080/file/download?token=xxx&path=/home/47825309/%E7%B4%A0%E6%9D%90%E5%BA%93/（%E5%A3%81%E7%BA%B8）%E7%B4%A0%E6%9D%90%E5%BA%93%E6%9B%B4%E6%96%B050000%E5%BC%A0%E5%A3%81%E7%BA%B8/1280%E5%8F%8A%E4%BB%A5%E4%B8%8B%E9%AB%98%E6%B8%85%E5%A3%81%E7%BA%B8/7_4c14478879c1b.jpg&type=1

这种方法只会对url中的中文进行转码，如果url里含有特殊符号比如括号，就不会转码。所以如果url中含有特殊符号，这种方法就不适用了。

二、方法二：统一转码

NSString *testUlr13 = [str stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@"?!@#$^%*+,:;'\\"`<>()[]/\\\\| "] invertedSet]];

转码后的结果：

http%3A%2F%2F10.10.10.10%3A8080%2Ffile%2Fdownload%3Ftoken=xxx&path=%2Fhome%2F47825309%2F%E7%B4%A0%E6%9D%90%E5%BA%93%2F%EF%BC%88%E5%A3%81%E7%BA%B8%EF%BC%89%E7%B4%A0%E6%9D%90%E5%BA%93%E6%9B%B4%E6%96%B050000%E5%BC%A0%E5%A3%81%E7%BA%B8%2F1280%E5%8F%8A%E4%BB%A5%E4%B8%8B%E9%AB%98%E6%B8%85%E5%A3%81%E7%BA%B8%2F7_4c14478879c1b.jpg&type=1

这种方式将url中所有的字符都转码了，包括http的冒号和双斜杠，这种方式肯定不可取。很明显我们只需要对后面的参数进行转码，改进后的方法：

//处理特殊字符
- (NSString *)isSpecialStr:(NSString *)str 
   NSString *newString = str;
    if ([newString containsString:@"&path="]) 
        NSArray *paths = [newString componentsSeparatedByString:@"&path="];
        NSString *pathString1 = paths.firstObject;
        NSString *pathString2 = paths.lastObject;
        pathString2 = [pathString2 stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@"?!@#$^&%*+,:;='\\"`<>()[]/\\\\| "] invertedSet]];
        newString = [NSString stringWithFormat:@"%@&path=%@",pathString1,pathString2];
    
    NSLog(@"路径:%@", newString);
   return newString;

转码后的结果：

http://10.10.10.10:8080/file/download?token=xxx&path=%2Fhome%2F47825309%2F%E7%B4%A0%E6%9D%90%E5%BA%93%2F%EF%BC%88%E5%A3%81%E7%BA%B8%EF%BC%89%E7%B4%A0%E6%9D%90%E5%BA%93%E6%9B%B4%E6%96%B050000%E5%BC%A0%E5%A3%81%E7%BA%B8%2F1280%E5%8F%8A%E4%BB%A5%E4%B8%8B%E9%AB%98%E6%B8%85%E5%A3%81%E7%BA%B8%2F7_4c14478879c1b.jpg&type=1

本来以为这样就解决了，但是图片还是加载不了，于是让安卓的同学将这个url转码之后，结果是这样的：

http://10.10.10.10:8080/file/download?token=xxx&path=%2Fhome%2F47825309%2F%E7%B4%A0%E6%9D%90%E5%BA%93%2F%EF%BC%88%E5%A3%81%E7%BA%B8%EF%BC%89%E7%B4%A0%E6%9D%90%E5%BA%93%E6%9B%B4%E6%96%B050000%E5%BC%A0%E5%A3%81%E7%BA%B8%2F1280%E5%8F%8A%E4%BB%A5%E4%B8%8B%E9%AB%98%E6%B8%85%E5%A3%81%E7%BA%B8%2F7_4c14478879c1b.jpg%26type%3D1

经过对比发现，安卓的转码中，没有对 & 和 = 这两个特殊字符进行转码。

删除这两个特殊字符，就和安卓的转码一致了：

//处理特殊字符
- (NSString *)isSpecialStr:(NSString *)str 
   NSString *newString = str;
    if ([newString containsString:@"&path="]) 
        NSArray *paths = [newString componentsSeparatedByString:@"&path="];
        NSString *pathString1 = paths.firstObject;
        NSString *pathString2 = paths.lastObject;
       pathString2 = [pathString2 stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@"?!@#$^%*+,:;'\\"`<>()[]/\\\\| "] invertedSet]]; //去掉了 & 和 = 这两个字符串
        newString = [NSString stringWithFormat:@"%@&path=%@",pathString1,pathString2];
    
    NSLog(@"路径:%@", newString);
   return newString;

三、NSCharacterSet对象

@interface NSCharacterSet (NSURLUtilities)
// 预定义字符集用于六个URL组件和子组件，它们允许百分比编码。 
- (nullable NSString *)stringByAddingPercentEncodingWithAllowedCharacters:(NSCharacterSet *)allowedCharacters

// 包含URL用户子组件中允许的字符的字符集
@property (class, readonly, copy) NSCharacterSet *URLUserAllowedCharacterSet API_AVAILABLE(macos(10.9), ios(7.0), watchos(2.0), tvos(9.0));

// 包含URL密码子组件中允许的字符的字符集
@property (class, readonly, copy) NSCharacterSet *URLPasswordAllowedCharacterSet API_AVAILABLE(macos(10.9), ios(7.0), watchos(2.0), tvos(9.0));

// 包含URL的主机子组件中允许的字符的字符集
@property (class, readonly, copy) NSCharacterSet *URLHostAllowedCharacterSet API_AVAILABLE(macos(10.9), ios(7.0), watchos(2.0), tvos(9.0));

// 返回一个包含字符的字符集允许URL的路径组件。字符“;”是一种合法的路径,但是建议最好是percent-encoded兼容NSURL(-stringByAddingPercentEncodingWithAllowedCharacters:percent-encode任何‘;’字符如果你通过URLPathAllowedCharacterSet)
@property (class, readonly, copy) NSCharacterSet *URLPathAllowedCharacterSet API_AVAILABLE(macos(10.9), ios(7.0), watchos(2.0), tvos(9.0));

// 包含URL查询组件中允许的字符的字符集
@property (class, readonly, copy) NSCharacterSet *URLQueryAllowedCharacterSet API_AVAILABLE(macos(10.9), ios(7.0), watchos(2.0), tvos(9.0));

// 包含URL片段组件中允许的字符的字符集
@property (class, readonly, copy) NSCharacterSet *URLFragmentAllowedCharacterSet API_AVAILABLE(macos(10.9), ios(7.0), watchos(2.0), tvos(9.0));

@end

编码字符范围
URLFragmentAllowedCharacterSet  "#%<>[\\]^`|
URLHostAllowedCharacterSet      "#%/<>?@\\^`|
URLPasswordAllowedCharacterSet  "#%/:<>?@[\\]^`|
URLPathAllowedCharacterSet      "#%;<>?[\\]^`|
URLQueryAllowedCharacterSet     "#%<>[\\]^`|
URLUserAllowedCharacterSet      "#%/:<>?@[\\]^`