azure-functions-cli(nodejs) で text/html がエラーになるので proxy 書いた

fuck-the-azure-proxy.go

package main

import (
	"io"
	"net/http"
	"strings"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		res, err := Proxy(r)
		if err != nil {
			http.Error(w, err.Error(), 400)
			return
		}
		defer res.Body.Close()
		if strings.HasPrefix(res.Header.Get("Content-Type"), "text") {
			res.Header.Set("Content-Type", "text/html")
		}
		for key := range res.Header {
			val := res.Header.Get(key)
			w.Header().Set(key, val)
		}
		w.WriteHeader(res.StatusCode)
		io.Copy(w, res.Body)
	})

	http.ListenAndServe(":17071", nil)
}

// Proxy ...
func Proxy(r *http.Request) (*http.Response, error) {
	req, err := http.NewRequest(r.Method, "http://localhost:7071"+r.URL.Path, r.Body)
	if err != nil {
		return nil, err
	}
	for key := range r.Header {
		val := r.Header.Get(key)
		req.Header.Set(key, val)
	}
	client := &http.Client{}
	return client.Do(req)
}