Golang：带有 JSON 负载的 http.NewRequest POST 返回错误 500

我正在开发一个 API 库。有一个API端点（POST），当您发出curl命令时，它是：

curl -H "X-API-TOKEN: API-TOKEN" 'http://interest-graph.getprismatic.com/text/topic' \
  --data "title=Clojure" \
  --data "body=Clojure is a dynamic programming language that targets the Java Virtual Machine (and the CLR, and JavaScript). It is designed to be a general-purpose language, combining the approachability and interactive development of a scripting language with an efficient and robust infrastructure for multithreaded programming.Clojure is a compiled language - it compiles directly to JVM bytecode, yet remains completely dynamic. Every feature supported by Clojure is supported at runtime."

我正在尝试使用 http.NewRequest 执行上述命令：

   var jsonReq = []byte(`{"title": "Clojure", "body": "Clojure is a dynamic programming language that targets the Java Virtual Machine 
        (and the CLR, and JavaScript). It is designed to be a general-purpose language, 
        combining the approachability and interactive development of a 
        scripting language with an efficient and robust infrastructure for multithreaded programming.
        Clojure is a compiled language - it compiles directly to JVM bytecode, 
        yet remains completely dynamic. Every feature supported by Clojure is supported at runtime."}`)

    buf := new(bytes.Buffer)

    err := json.NewEncoder(buf).Encode(jsonReq)
    if err != nil {
        fmt.Println(err)
    }

    u := "http://interest-graph.getprismatic.com/text/topic"
    ApiToken := "API-TOKEN"
    req, err := http.NewRequest("POST", u, buf)
    req.Header.Set("Content-Type", "application/json")
    req.Header.Set("X-API-TOKEN", ApiToken)

    if err != nil {
        log.Fatal(err)
    }
    c := http.DefaultClient
    resp, err := c.Do(req)
    if err != nil {
        log.Fatal(err)
    }

    defer resp.Body.Close()

    r, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(string(r))

不确定我这样做是否正确，因为我不断收到错误 500。知道我做错了什么吗？

正确的代码：

package main

import (
    "bytes"
    "fmt"
    "io/ioutil"
    "log"
    "net/http"
    "net/url"
)

func main() {

    u := "http://interest-graph.getprismatic.com/text/topic"
    ApiToken := "API-CODE"

    data := url.Values{}
    data.Set("title", "Clojure")
    data.Set("body", `Clojure is a dynamic programming language that targets the Java Virtual Machine 
        (and the CLR, and JavaScript). It is designed to be a general-purpose language, 
        combining the approachability and interactive development of a 
        scripting language with an efficient and robust infrastructure for multithreaded programming.
        Clojure is a compiled language - it compiles directly to JVM bytecode, 
        yet remains completely dynamic. Every feature supported by Clojure is supported at runtime.`)

    b := bytes.NewBufferString(data.Encode())

    req, err := http.NewRequest("POST", u, b)
    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
    req.Header.Set("X-API-TOKEN", ApiToken)

    if err != nil {
        log.Fatal(err)
    }
    c := http.DefaultClient
    resp, err := c.Do(req)
    if err != nil {
        log.Fatal(err)
    }

    defer resp.Body.Close()

    r, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(string(r))

}