ios - NSURL URLWithString :relativeToURL: is clipping relative url

Question

我正在尝试实现一个使用 RestKit 的 iOS 应用程序。到目前为止，在我见过的所有示例中，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];

但是 [relativeURL absoluteString] 将返回 https://api.service.com/files/search。

所以我试了几个例子:

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。谁能解释一下为什么？

Answer 1

我读了[RFC1808]它定义了解析相对 URL 的规范算法

2 个问题:

1. 相对 URL 不能以/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，相对 url 不应以/

开头