June 2021
Intermediate to advanced
290 pages
9h 21m
Chinese
Content preview from Node与Express开发（第2版）
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表单处理
｜
83
最后，把这些处理函数链进应用里（版本库的
ch08/meadowlark.js
）：
app.get('/newsletter-signup', handlers.newsletterSignup)
app.post('/newsletter-signup/process', handlers.newsletterSignupProcess)
app.get('/newsletter-signup/thank-you', handlers.newsletterSignupThankYou)
这些就是所有需要做的了。注意在处理函数里，我们重定向到了一个“感谢订阅”页，在里
面可以渲染一个视图。但要是那样做的话，访问者浏览器中的
URL
字段还是保持
/process
，
这会令人困惑。在这种情况下，让浏览器发出一个重定向请求就可以解决问题。
在这种情形中，你要使用
303
（或
302
）重定向而不是
301
重定向，这很重
要。
301
重定向是
“永久重定向”，意味着浏览器可能会缓存重定向的目标。
如果你使用了
301
重定向并且尝试再次提交这个表单
，浏览器就可以完全绕
过
/proce
ss
这个表单处理，直接进入
/thank-you
，因为它正确地理解了这个
重定向是永久的。另外，
303
重定向就相当于告诉浏览器
，“好的，你的请求
没问题，你可以从这里获取响应”，并且不要缓存重定向的目标。
对于大多数前端框架来说，更常见的是使用
fetch
API
（一会儿就会看到），把表单数据以
JSON
格式发送出去
。不过，理解浏览器默认如何处理表单提交仍然有好处 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.