在Go中模拟HTTPS响应

Question

我正在尝试为一个向Web服务发出请求的包编写测试.我遇到的问题可能是由于我对TLS缺乏了解.

目前我的测试看起来像这样:

func TestSimple() {
    server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Content-Type", "application/json")
        w.WriteHeader(200)
        fmt.Fprintf(w, `{ "fake" : "json data here" }`)
    }))
    transport := &http.Transport{
        Proxy: func(req *http.Request) (*url.URL, error) {
            return url.Parse(server.URL)
        },
    }
    // Client is the type in my package that makes requests
    client := Client{
        c: http.Client{Transport: transport},
    }

    client.DoRequest() // ...
}

我的包有一个包变量(我希望它是一个常量..),用于查询的Web服务的基地址.这是一个https URL.我上面创建的测试服务器是纯HTTP,没有TLS.

默认情况下,我的测试失败并显示错误"tls:第一条记录看起来不像TLS握手".

为了使其工作,我的测试在进行查询之前将包变量更改为普通的http URL而不是https.

有没有办法解决？我可以将包变量设为常量(https),并设置http.Transport"降级"为未加密的HTTP,还是使用httptest.NewTLSServer()？

(当我尝试使用时,NewTLSServer()我从127.0.0.1:45678获取"http:TLS握手错误:tls:收到长度超过20037的记录")

Answer 1

大多数行为都net/http可以被嘲笑,扩展或改变.虽然http.Client是实现HTTP客户端语义的具体类型,但是它的所有字段都是导出的并且可以自定义.

Client.Transport特别是,可以替换该字段以使客户端执行任何操作,从使用自定义协议(例如ftp://或file://)到直接连接到本地处理程序(不生成HTTP协议字节或通过网络发送任何内容) ).

客户端的功能,例如http.Get,所有利用导出的http.DefaultClient,其利用这些方便的功能不包变量(你可以修改的),所以码不,例如,必须改变到呼叫上的自定义客户端变量的方法.请注意,虽然在公共库中修改全局行为是不合理的,但在应用程序和测试(包括库测试)中这样做非常有用.

http://play.golang.org/p/afljO086iB包含一个自定义http.RoundTripper,它重写请求URL以便它将被路由到本地托管httptest.Server,另一个示例直接将请求传递给http.Handler一个自定义http.ResponseWriter实现,为了创造一个http.Response.第二种方法不像第一种方法那样勤奋(它没有填充响应值中的许多字段)但效率更高,并且应该足够兼容以与大多数处理程序和客户端调用程序一起使用.

以上链接的代码也包含在下面:

package main

import (
    "fmt"
    "io"
    "log"
    "net/http"
    "net/http/httptest"
    "net/url"
    "os"
    "path"
    "strings"
)

func Handler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "hello %s\n", path.Base(r.URL.Path))
}

func main() {
    s := httptest.NewServer(http.HandlerFunc(Handler))
    u, err := url.Parse(s.URL)
    if err != nil {
        log.Fatalln("failed to parse httptest.Server URL:", err)
    }
    http.DefaultClient.Transport = RewriteTransport{URL: u}
    resp, err := http.Get("https://google.com/path-one")
    if err != nil {
        log.Fatalln("failed to send first request:", err)
    }
    fmt.Println("[First Response]")
    resp.Write(os.Stdout)

    fmt.Print("\n", strings.Repeat("-", 80), "\n\n")

    http.DefaultClient.Transport = HandlerTransport{http.HandlerFunc(Handler)}
    resp, err = http.Get("https://google.com/path-two")
    if err != nil {
        log.Fatalln("failed to send second request:", err)
    }
    fmt.Println("[Second Response]")
    resp.Write(os.Stdout)
}

// RewriteTransport is an http.RoundTripper that rewrites requests
// using the provided URL's Scheme and Host, and its Path as a prefix.
// The Opaque field is untouched.
// If Transport is nil, http.DefaultTransport is used
type RewriteTransport struct {
    Transport http.RoundTripper
    URL       *url.URL
}

func (t RewriteTransport) RoundTrip(req *http.Request) (*http.Response, error) {
    // note that url.URL.ResolveReference doesn't work here
    // since t.u is an absolute url
    req.URL.Scheme = t.URL.Scheme
    req.URL.Host = t.URL.Host
    req.URL.Path = path.Join(t.URL.Path, req.URL.Path)
    rt := t.Transport
    if rt == nil {
        rt = http.DefaultTransport
    }
    return rt.RoundTrip(req)
}

type HandlerTransport struct{ h http.Handler }

func (t HandlerTransport) RoundTrip(req *http.Request) (*http.Response, error) {
    r, w := io.Pipe()
    resp := &http.Response{
        Proto:      "HTTP/1.1",
        ProtoMajor: 1,
        ProtoMinor: 1,
        Header:     make(http.Header),
        Body:       r,
        Request:    req,
    }
    ready := make(chan struct{})
    prw := &pipeResponseWriter{r, w, resp, ready}
    go func() {
        defer w.Close()
        t.h.ServeHTTP(prw, req)
    }()
    <-ready
    return resp, nil
}

type pipeResponseWriter struct {
    r     *io.PipeReader
    w     *io.PipeWriter
    resp  *http.Response
    ready chan<- struct{}
}

func (w *pipeResponseWriter) Header() http.Header {
    return w.resp.Header
}

func (w *pipeResponseWriter) Write(p []byte) (int, error) {
    if w.ready != nil {
        w.WriteHeader(http.StatusOK)
    }
    return w.w.Write(p)
}

func (w *pipeResponseWriter) WriteHeader(status int) {
    if w.ready == nil {
        // already called
        return
    }
    w.resp.StatusCode = status
    w.resp.Status = fmt.Sprintf("%d %s", status, http.StatusText(status))
    close(w.ready)
    w.ready = nil
}