servlets - 如何根据 Racket Web servlet 中的路径显示不同的内容？

Question

我正在尝试按照简单网络应用程序的球拍指南上的教程进行操作，但无法获得一个基本的基本内容。

如何让 servlet 根据请求 URL 提供不同的内容？尽管经过我的努力，即使是巨大的博客示例也是一个大文件，并且在我背后使用巨大的 get 查询字符串处理所有内容。如何根据 URL 做任何事情？defpageClojure 的 Noir 框架将这个基本功能放在了主页的前面（

Answer 1

The URL is part of the request structure that the servlet receives as an argument. You can get the URL by calling request-uri, then you can look at it to do whatever you want. The request also includes the HTTP method, headers, and so on.

But that's pretty low-level. A better solution is to use dispatch-rules to define a mapping from URL patterns to handler functions. Here's an example from the docs:

(define-values (blog-dispatch blog-url)
  (dispatch-rules
   [("") list-posts]
   [("posts" (string-arg)) review-post]
   [("archive" (integer-arg) (integer-arg)) review-archive]
   [else list-posts]))

Make your main servlet handler blog-dispatch. The URL http://yoursite.com/ will be handled by calling (list-posts req), where req is the request structure. The URL http://yoursite.com/posts/a-funny-story will be handled by calling (review-post req "a-funny-story"). And so on.