英文:
The best way to get a string from a Writer
问题
我有一段代码，它使用内置的模板系统返回一个网页。它接受一个ResponseWriter，将生成的标记写入其中。现在，我想将生成的标记作为字符串获取，并在某些情况下将其放入数据库中。我将一个接受普通Writer而不是ResponseWriter的方法提取出来，现在正在尝试获取已写入的内容。啊哈 - 也许我需要一个Pipe，然后我可以使用bufio库中的ReadString方法获取字符串。但事实证明，从管道中出来的PipeReader与我需要的Reader（用于ReadString方法）不兼容。哇哦，大惊喜。所以我可以使用PipeReader读取字节数组，但感觉有点不对，因为有ReadString方法存在。
那么，最好的方法是什么？我应该继续使用Pipe并读取字节，还是有更好的方法我在手册中没有找到？
英文:
I have a piece of code that returns a web page using the built-in template system. It accepts a ResponseWriter to which the resulting markup is written. I now want to get to the markup as a string and put it in a database in some cases. I factored out a method that accepts a normal Writer instead of a ResponseWriter and am now trying to get to the written content. Aha - a Pipe may be what I need and then I can get the string with ReadString from the bufio library. But it turns out that the PipeReader coming out from the pipe is not compatible with Reader (that I would need for the ReadString method). W00t. Big surprise. So I could just read into byte[]s using the PipeReader but it feels a bit wrong when ReadString is there.
So what would be the best way to do it? Should I stick with the Pipe and read bytes or is there something better that I haven't found in the manual?
答案1
得分: 187
如果你的函数接受一个io.Writer，你可以传递一个*bytes.Buffer来捕获输出。
// import "bytes"
buf := new(bytes.Buffer)
f(buf)
buf.String() // 返回写入到它的字符串
如果它需要一个http.ResponseWriter，你可以使用一个*httptest.ResponseRecorder。响应记录器保存了可以发送到ResponseWriter的所有信息，但是body只是一个*bytes.Buffer。
// import "net/http/httptest"
r := httptest.NewRecorder()
f(r)
r.Body.String() // r.Body是一个*bytes.Buffer
英文:
If your function accepts an io.Writer, you can pass a *bytes.Buffer to capture the output.
// import "bytes"
buf := new(bytes.Buffer)
f(buf)
buf.String() // returns a string of what was written to it
If it requires an http.ResponseWriter, you can use a *httptest.ResponseRecorder. A response recorder holds all information that can be sent to a ResponseWriter, but the body is just a *bytes.Buffer.
// import "net/http/httptest"
r := httptest.NewRecorder()
f(r)
r.Body.String() // r.Body is a *bytes.Buffer
答案2
得分: -7
以下是翻译好的部分：
下面的代码可能是将Writer（或任何类型）转换为字符串的最简单方法
package main
import "fmt"
import "io"
import "reflect"
func main(){
var temp io.Writer
output := fmt.Sprint(temp)
fmt.Println(reflect.TypeOf(output))
}
输出：
string
英文:
The below code is possibly the simplest way to convert Writer (or any type) to string
package main
import "fmt"
import "io"
import "reflect"
func main(){
var temp io.Writer
output := fmt.Sprint(temp)
fmt.Println(reflect.TypeOf(output))
}
Output:
string
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论