英文:
Go's runtime library document out of date?
问题
所以，我正在使用GO解析一个POST请求。我想要的是POST请求的主体，所以我尝试了以下代码（在这个上下文中，r的类型是*http.Request）：
var body io.Reader
var d []byte
body = r.Body.Reader
body.Read(d)
然而，这导致了一个编译错误：
编译错误：<文件>：44：
r.Body.Reader未定义（类型io.ReadCloser没有字段或方法Reader）
奇怪。我本来以为它在文档中有定义...啊！在这里找到了。
现在，我对Go还比较新，但这听起来有点奇怪——我搞错了什么？
英文:
So, I'm working on parsing a POST using GO. What I want is the body of the post, so I try the following (r is of type *http.Request in this context):
var body io.Reader
var d []byte
body = r.Body.Reader
body.Read( d)
However, this results in a compilation error:
Compile error: <file>:44:
r.Body.Reader undefined (type io.ReadCloser has no field or method Reader)
Odd. I could have sworn that it was defined in the docs... Ah! here it is.
Now, I'm fairly new to Go, but this smells a little odd -- what have I screwed up?
答案1
得分: 6
从您的链接中，ReadCloser 的文档如下：
type ReadCloser interface {
Reader
Closer
}
这告诉您的是，ReadCloser 接口由 Reader 和 Closer 功能组成。它同时具备这两个功能。这意味着 ReadCloser 采用了这些接口定义。您并不是直接访问它们，它们不是实际的成员。
Reader 是：
type Reader interface {
Read(p []byte) (n int, err error)
}
所以这意味着您应该像这样访问 Read：
body = r.Body
body.Read(d)
英文:
From your link, the doc for a ReadCloser is:
type ReadCloser interface {
Reader
Closer
}
What this is telling you, is that a ReadCloser interface is composed of a Reader and a Closer functionality. It IS both. That means the ReadCloser takes on those interface definitions. They are not actually members, the way you are accessing them.
A Reader is:
type Reader interface {
Read(p []byte) (n int, err error)
}
So that means you should be accessing Read like this:
body = r.Body
body.Read(d)
答案2
得分: 0
在Go文档中定义接口的方式看起来像是一个“有一个”关系。实际上，它是一个“是一个”关系，所以以下代码实现了我想要的功能：
var d []byte
r.Body.Read(d)
英文:
The way interfaces are defined in Go documents, it looked like it was a "has-a" relationship. It's actually an "is-a" relationship, so the following code does what I want:
var d []byte
r.Body.Read(d)
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