一个大的猫窝,voidcat

- (NSString *)addURLParameter:(NSString *)parameterName withValue:(NSString *)parameterValue {
    // 获取 URL 的 query 部分
    NSString *query = nil;
    NSRange queryRange = [self rangeOfString:@"?" options:NSLiteralSearch];
    // 标记是否在原URL中发现了?
    BOOL isExistQuestionMark = queryRange.location != NSNotFound;
    if (isExistQuestionMark) {
        query = [self substringFromIndex:NSMaxRange(queryRange)];
    }
    
    //保存目前处理过的参数
    NSMutableDictionary *params = [NSMutableDictionary dictionary];
    if(query){
        NSArray *queryComponents = [query componentsSeparatedByString:@"&"];
        for(NSString *param in queryComponents){
            NSArray *keyValue = [param componentsSeparatedByString:@"="];
            if(keyValue.count > 0){
                [params setValue:keyValue.count==2?keyValue[1]:@"" forKey:keyValue[0]];
            }
        }
    }
    
    // 将新参数加入到目前处理过的参数中, 如果参数名存在则替换旧的值
    [params setValue:parameterValue forKey:parameterName];
    
    // 根据目前处理过的参数，重新生成查询的query
    NSMutableString *newQuery = [NSMutableString string];
    [params enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        if([newQuery length] == 0){
            [newQuery appendFormat:@"%@=%@", key,obj];
        }else{
            [newQuery appendFormat:@"&%@=%@", key,obj];
        }
    }];
    return isExistQuestionMark?[self stringByReplacingOccurrencesOfString:query withString:newQuery]:[NSString stringWithFormat:@"%@?%@",self,newQuery];
}