在Go中添加默认的HTTP标头

Question

我正在Go中迈出第一步，并且想使用REST API。服务器要求使用承载令牌来授权每个请求。

如何将此标头添加到客户端，以便每个请求都使用此令牌？

import "net/http"

const accessToken = "MY_DEMO_TOKEN"

func main() {
    customHeader := http.Header{}
    customHeader.Add("Authorization: Bearer %s", accessToken)
    client := &http.Client{
        Timeout: time.Second*10,
    }
}

Answer 1

您可以装饰客户的运输工具。例如：

package main

import "net/http"

func main() {
        client := http.DefaultClient

        rt := WithHeader(client.Transport)
        rt.Set("Authorization", "Bearer <token>")
        client.Transport = rt

        client.Get("http://example.com")
}

type withHeader struct {
        http.Header
        rt http.RoundTripper
}

func WithHeader(rt http.RoundTripper) withHeader {
        if rt == nil {
                rt = http.DefaultTransport
        }

        return withHeader{Header: make(http.Header), rt: rt}
}

func (h withHeader) RoundTrip(req *http.Request) (*http.Response, error) {
        for k, v := range h.Header {
                req.Header[k] = v
        }

        return h.rt.RoundTrip(req)
}

对于授权令牌的特定目的，您可能对golang.org/x/oauth2软件包感兴趣，该软件包本质上是相同的，但是还支持自动令牌更新：

package main

import (
        "context"

        "golang.org/x/oauth2"
)

func main() {
        ctx := context.Background()
        client := oauth2.NewClient(ctx, oauth2.StaticTokenSource(&oauth2.Token{
                AccessToken: "<your token>",
                TokenType:   "Bearer",
        }))

        client.Get("http://example.com")
}

Answer 2

您可以围绕 http.RoundTripper 编写一个装饰器并将其传递给客户端。但实际上我最终会得到一个助手，按照阿德里安的建议为每个查询准备请求。

package main

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

const accessToken = "MY_DEMO_TOKEN"

type MyRoundTripper struct {
    r http.RoundTripper
}

func (mrt MyRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
    r.Header.Add("Authorization", "Bearer: "+accessToken)
    return mrt.r.RoundTrip(r)
}

func main() {
    client := &http.Client{
        Timeout:   time.Second * 10,
        Transport: MyRoundTripper{r: http.DefaultTransport},
    }

    fmt.Println(client.Get("http://google.com/"))
}