iOS中的url編碼問題

NSString 的 stringByAddingPercentEscapesUsingEncoding 可以對 url 參數進行編碼，但是有點小問題，不會對所有需要編碼的字符都編碼。我們可以通過CFStringRef 的CFURLCreateStringByAddingPercentEscapes 函數來封裝這個功能。代碼如下：

- (NSString *)encodeToPercentEscapeString: (NSString *) input
{
    // Encode all the reserved characters, per RFC 3986
    // (<http://www.ietf.org/rfc/rfc3986.txt>)
    NSString *outputStr = (NSString *) 
    CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                            (CFStringRef)input,
                                            NULL,
                                            (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                            kCFStringEncodingUTF8);
    return outputStr;
}

- (NSString *)decodeFromPercentEscapeString: (NSString *) input
{
    NSMutableString *outputStr = [NSMutableString stringWithString:input];
    [outputStr replaceOccurrencesOfString:@"+"
                               withString:@" "
                                  options:NSLiteralSearch
                                    range:NSMakeRange(0, [outputStr length])];

    return [outputStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}

測試代碼：

    NSString * testUrl = @"http://search.google.com?keywords=($# it's {a*123})00!*'();:@&=+$,/?%#[]";
    NSLog(@"original: %@", testUrl);

    NSString * encodeStr = [self encodeToPercentEscapeString:testUrl];
    NSLog(@"encoded: %@", encodeStr);
    
    NSString * encodeStr2 = [testUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSLog(@"encoded2:%@", encodeStr2);
    
    NSString * decodeStr = [self decodeFromPercentEscapeString:encodeStr];
    NSLog(@"decoded: %@", decodeStr);

結果如下：

    >> original: http://search.google.com?keywords=($# it's {a*123})00!*'();:@&=+$,/?%#[]
    >> encoded:  http%3A%2F%2Fsearch.google.com%3Fkeywords%3D%28%24%23%20it%27s%20%7Ba%2A123%7D%2900%21%2A%27%28%29%3B%3A%40%26%3D%2B%24%2C%2F%3F%25%23%5B%5D
    >> encoded2: http://search.google.com?keywords=($%23%20it's%20%7Ba*123%7D)00!*'();:@&=+$,/?%25%23%5B%5D
    >> decoded:  http://search.google.com?keywords=($# it's {a*123})00!*'();:@&=+$,/?%#[]

 

另一個URL編碼&解碼的例子：

NSString* string1 = @"https://www.cloudsafe.com/文件夾";

NSString* string2 = [string1 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSString* string3 = [string2 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSString* string4 = [string2 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSString* string5 = [string3 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSString* string6 = [string4 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSString* string7 = [string5 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

 

輸出結果：

 

string1:https://www.cloudsafe.com/文件夾

string2:https://www.cloudsafe.com/%E6%96%87%E4%BB%B6%E5%A4%B9

string3:https://www.cloudsafe.com/%25E6%2596%2587%25E4%25BB%25B6%25E5%25A4%25B9

string4:https://www.cloudsafe.com/文件夾

string5:https://www.cloudsafe.com/%E6%96%87%E4%BB%B6%E5%A4%B9

string6:https://www.cloudsafe.com/文件夾

string7:https://www.cloudsafe.com/文件夾