HTTP on Random Musings

Be wary of http/client.go

Sat, 25 Mar 2017 09:30:00 +0000

Recently, I found out an interesting problem in Go. The problem can be reduced to a simple client request to a HTTP server.

Suppose we have a HTTP server, which serves only one rooted path /foo/.

package main

import (
	"io"
	"log"
	"net/http"
	"net/http/httputil"
)

func handleFoo(w http.ResponseWriter, req *http.Request) {
	// request details
	dump, _ := httputil.DumpRequest(req, true)
	log.Println(string(dump))

	if auth := req.Header.Get("Authorization"); auth != "Bearer GoodToken" {
		http.Error(w, "401 Unauthorized", http.StatusUnauthorized)
		return
	}

	io.WriteString(w, "Hello World!")
}

func main() {
	http.HandleFunc("/foo/", handleFoo)
	log.Fatal(http.ListenAndServe(":12345", nil))
}

handleFoo simplily verifies that correct token is sent in the Authorization header. Otherwise, it returns 401 Unauthorized.

HTTP/2

Mon, 14 Mar 2016 08:53:00 +0000

What is HTTP/2 and Why

HTTP/1.1 has been serving most part of the Web since 1997. As websites get more and more sophisticated and resource intensive, it starts to show its limitations, e.g. one outstanding request per TCP connection. So its next-generation emerged: HTTP/2.

HTTP/2 FAQ does a great job explaining the background and specifications. Highly recommended. Here is an executive summary, HTTP/2:

is specifically designed to improve performance
is based on SPDY
is binary, instead of textual
is fully multiplexed, instead of ordered and blocking
can therefore use one connection for parallelism
uses header compression to reduce overhead
allows servers to push responses proactively into client caches
is backward-compatible, designed to be drop-in replacement for HTTP/1.1
is supported by most broswers over TLS

HttpWatch reported good performance improvement by using HTTP/2.

HTTP/2

Mon, 14 Mar 2016 08:53:00 +0000

What is HTTP/2 and Why

HTTP/2 FAQ does a great job explaining the background and specifications. Highly recommended. Here is an executive summary, HTTP/2:

is specifically designed to improve performance
is based on SPDY
is binary, instead of textual
is fully multiplexed, instead of ordered and blocking
can therefore use one connection for parallelism
uses header compression to reduce overhead
allows servers to push responses proactively into client caches
is backward-compatible, designed to be drop-in replacement for HTTP/1.1
is supported by most broswers over TLS

HttpWatch reported good performance improvement by using HTTP/2.