23

我正在尝试实现一个使用 RestKit 的 iOS 应用程序。到目前为止,在我看到的所有示例中,都使用以下代码来创建 URL:

NSURL *baseURL = [NSURL URLWithString:@"https://api.service.com/v1"];
NSURL *relativeURL = [NSURL URLWithString:@"/files/search" relativeToURL:baseURL];

但随后[relativeURL absoluteString]会返回https://api.service.com/files/search

所以我尝试了几个例子:

NSURL *baseURL1 = [NSURL URLWithString:@"https://api.service.com/v1/"];
NSURL *baseURL2 = [NSURL URLWithString:@"https://api.service.com/v1"];
NSURL *baseURL3 = [NSURL URLWithString:@"/v1" relativeToURL:[NSURL URLWithString:@"https://api.service.com"]];

NSURL *relativeURL1 = [NSURL URLWithString:@"/files/search" relativeToURL:baseURL1];
NSURL *relativeURL2 = [NSURL URLWithString:@"/files/search" relativeToURL:baseURL2];
NSURL *relativeURL3 = [NSURL URLWithString:@"/files/search" relativeToURL:baseURL3];
NSURL *relativeURL4 = [NSURL URLWithString:@"files/search" relativeToURL:baseURL1];
NSURL *relativeURL5 = [NSURL URLWithString:@"files/search" relativeToURL:baseURL2];
NSURL *relativeURL6 = [NSURL URLWithString:@"files/search" relativeToURL:baseURL3];

NSLog(@"1: %@", [relativeURL1 absoluteString]);
NSLog(@"2: %@", [relativeURL2 absoluteString]);
NSLog(@"3: %@", [relativeURL3 absoluteString]);
NSLog(@"4: %@", [relativeURL4 absoluteString]);
NSLog(@"5: %@", [relativeURL5 absoluteString]);
NSLog(@"6: %@", [relativeURL6 absoluteString]);

这是输出:

1: https://api.service.com/files/search
2: https://api.service.com/files/search
3: https://api.service.com/files/search
4: https://api.service.com/v1/files/search
5: https://api.service.com/files/search
6: https://api.service.com/files/search

所以返回我想要的唯一示例是#4。谁能解释为什么?

4

3 回答 3

51

我阅读了[RFC1808],它定义了解析相对 URL 的规范算法

2个问题:

  1. 相对 url 可能不以 / 开头,或者它被认为是绝对的:

     Step 4: If the embedded URL path is preceded by a slash "/", the
        path is not relative and we skip to Step 7."
    
  2. 当基本 url 以非斜杠结尾时。从最后一个斜杠开始的所有内容都被跳过

     Step 6: The last segment of the base URL's path (anything
        following the rightmost slash "/", or the entire path if no
        slash is present) is removed and the embedded URL's path is
        appended in its place.  The following operations are
        then applied, in order, to the new path:"
    

这样就可以解释了。baseURL 需要以 / 结尾,并且相对 url 不应以 / 开头

于 2013-05-16T08:32:28.280 回答
9

你在这里有两个问题:

首先,字符串/files/search绝对路径,因为它以斜杠开头。针对任何现有 URL 解析它将忽略现有路径。

其次,https://api.service.com/v1没有尾部斜杠来表示它是一个目录。任何针对它解析的字符串将始终忽略该v1部分。

总而言之,您需要一个相对路径 - files/search- 和目录基础 URL -的组合https://api.service.com/v1/

于 2013-05-16T08:50:37.203 回答
0

另一个例子:

//it's right
NSURL *url = [NSURL URLWithString:@"getValidNumber" relativeToURL:[NSURL URLWithString:@"http://dns.test.com:22009/service/"]]; 

//error
NSURL *url = [NSURL URLWithString:@"getValidNumber" relativeToURL:[NSURL URLWithString:@"dns.test.com:22009/service/"]]; 

//error
NSURL *url = [NSURL URLWithString:@"/getValidNumber" relativeToURL:[NSURL URLWithString:@"http://dns.test.com:22009/service"]];

` 'http://' 是使用此方法所必需的。

于 2016-01-13T09:05:16.317 回答