如何从此请求获取POST值？

Question

I have the following code:

package main

import (
    "bytes"
    "fmt"
    "net/http"
)

func main() {

    var jsonStr = []byte(`{"title":"Buy cheese and bread for breakfast."}`)
    req, err := http.NewRequest("POST", "/", bytes.NewBuffer(jsonStr))
    if err != nil {
        panic(err)
    }
    req.Header.Set("X-Custom-Header", "myvalue")
    req.Header.Set("Content-Type", "application/json")

    req.ParseForm()
    fmt.Printf("%v:%v", "title", req.Form.Get("title"))
}

I am unable to extract the "title" param and not sure why.

Answer 1

As noted in the GoDoc for the http.Request.ParseForm method, the type of the body must be application/x-www-form-urlencoded, not JSON like your current example:

For other HTTP methods, or when the Content-Type is not application/x-www-form-urlencoded, the request Body is not read, and r.PostForm is initialized to a non-nil, empty value.

Here is an updated example of your code using a form body, which gives the intended result: https://play.golang.org/p/Zrw05T2Zb5Z

If you want to extract values from a JSON body, that can be done using a method such as json.Unmarshal, however a JSON body doesn't represent a form.