URL Encoding
URLs can only be sent over the Internet using the ASCII character-set.
Since URLs often contain characters outside the ASCII set, the URL has to be converted into a valid ASCII format.
URL encoding replaces unsafe ASCII characters with a “%” followed by two hexadecimal digits.
URLs cannot contain spaces. URL encoding normally replaces a space with a plus (+) sign or with %20.
掉坑是因为App内动态控制 url ,服务端返回的 url 带中文字符, NSString类提供了 stringByAddingPercentEscapesUsingEncoding: 方法.该方法能编码非 url 的字符,但对于类似 / & 的 reserved characters 没有做处理,也就是没有严格遵守 url 应该编码成 ASCII 字符的规范.
网上给的通用String的Category:
- (NSString *)urlencode {
NSMutableString *output = [NSMutableString string];
const unsigned char *source = (const unsigned char *)[self UTF8String];
int sourceLen = strlen((const char *)source);
for (int i = 0; i < sourceLen; ++i) {
const unsigned char thisChar = source[i];
if (thisChar == ' '){
[output appendString:@"+"];
} else if (thisChar == '.' || thisChar == '-' ||
thisChar == '_' || thisChar == '~' ||
(thisChar >= 'a' && thisChar <= 'z') ||
(thisChar >= 'A' && thisChar <= 'Z') ||
(thisChar >= '0' && thisChar <= '9')) {
[output appendFormat:@"%c", thisChar];
} else {
[output appendFormat:@"%%%02X", thisChar];
}
}
return output;
}