From 3dc24130247597153c0c54156448d48a260b4a07 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Fri, 28 Jul 2023 15:06:57 -0400 Subject: [PATCH] helloserver: add basic hello world web server We want to revive golang.org/x/example as a test case for an experiment with a 'gonew' command. This CL adds a basic "hello, world" web server as golang.org/x/example/helloserver. Change-Id: Icf76c756f7b256285d4c5e6a33655996597eb2da Reviewed-on: https://go-review.googlesource.com/c/example/+/513997 Auto-Submit: Russ Cox TryBot-Result: Gopher Robot Run-TryBot: Russ Cox Reviewed-by: Cameron Balahan --- helloserver/go.mod | 4 +++ helloserver/server.go | 75 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 79 insertions(+) create mode 100644 helloserver/go.mod create mode 100644 helloserver/server.go diff --git a/helloserver/go.mod b/helloserver/go.mod new file mode 100644 index 0000000..1de477a --- /dev/null +++ b/helloserver/go.mod @@ -0,0 +1,4 @@ +module golang.org/x/example/helloserver + +go 1.19 + diff --git a/helloserver/server.go b/helloserver/server.go new file mode 100644 index 0000000..425386a --- /dev/null +++ b/helloserver/server.go @@ -0,0 +1,75 @@ +// Copyright 2023 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Hello is a simple hello, world demonstration web server. +// +// It serves version information on /version and answers +// any other request like /name by saying "Hello, name!". +// +// See golang.org/x/example/outyet for a more sophisticated server. +package main + +import ( + "flag" + "fmt" + "html" + "log" + "net/http" + "os" + "runtime/debug" + "strings" +) + +func usage() { + fmt.Fprintf(os.Stderr, "usage: helloserver [options]\n") + flag.PrintDefaults() + os.Exit(2) +} + +var ( + greeting = flag.String("g", "Hello", "Greet with `greeting`") + addr = flag.String("addr", "localhost:8080", "address to serve") +) + +func main() { + // Parse flags. + flag.Usage = usage + flag.Parse() + + // Parse and validate arguments (none). + args := flag.Args() + if len(args) != 0 { + usage() + } + + // Register handlers. + // All requests not otherwise mapped with go to greet. + // /version is mapped specifically to version. + http.HandleFunc("/", greet) + http.HandleFunc("/version", version) + + log.Printf("serving http://%s\n", *addr) + log.Fatal(http.ListenAndServe(*addr, nil)) +} + +func version(w http.ResponseWriter, r *http.Request) { + info, ok := debug.ReadBuildInfo() + if !ok { + http.Error(w, "no build information available", 500) + return + } + + fmt.Fprintf(w, "\n
\n")
+	fmt.Fprintf(w, "%s\n", html.EscapeString(info.String()))
+}
+
+func greet(w http.ResponseWriter, r *http.Request) {
+	name := strings.Trim(r.URL.Path, "/")
+	if name == "" {
+		name = "Gopher"
+	}
+
+	fmt.Fprintf(w, "\n")
+	fmt.Fprintf(w, "Hello, %s!\n", html.EscapeString(name))
+}