add Host header manually (#10)

main.go

@@ -1,42 +1,45 @@
 package main
 
 import (
-    "fmt"
-    "log"
-    "net/http"
-    "sort"
-    "flag"
-    "strings"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"sort"
+	"strings"
 )
 
 var Name = flag.String("name", "example", "name of instance")
 
 func headers(w http.ResponseWriter, req *http.Request) {
-    log.Println("Hello! There's a request incoming!")
-    log.Printf("%v %v %v %v", req.RemoteAddr, req.URL, req.Host, req.Header)
-    sortedKeys := make([]string, 0, len(req.Header))
-
-    fmt.Fprintf(w, "Instance name: %s\n", *Name)
-    for name, _ := range req.Header {
-        sortedKeys = append(sortedKeys, name)
-    }
-    sort.Strings(sortedKeys)
-    for _, v := range sortedKeys {
-        fmt.Fprintf(w, "%v: %v\n", v, req.Header[v])
-    }
+	log.Println("Hello! There's a request incoming!")
+	log.Printf("%v %v %v %v", req.RemoteAddr, req.URL, req.Host, req.Header)
+
+	// For incoming requests, the Host header is promoted to the
+	// Request.Host field and removed from the Header map.
+	req.Header.Set("host", req.Host)
+	sortedKeys := make([]string, 0, len(req.Header))
+
+	fmt.Fprintf(w, "Instance name: %s\n", *Name)
+	for name, _ := range req.Header {
+		sortedKeys = append(sortedKeys, name)
+	}
+	sort.Strings(sortedKeys)
+	for _, v := range sortedKeys {
+		fmt.Fprintf(w, "%v: %v\n", v, req.Header[v])
+	}
 }
 
-
 func main() {
-    http.HandleFunc("/", headers)
+	http.HandleFunc("/", headers)
 
-    var host = flag.String("host", "", "host to run on")
-    var port = flag.String("port", "8080", "port to run on")
+	var host = flag.String("host", "", "host to run on")
+	var port = flag.String("port", "8080", "port to run on")
 
-    flag.Parse()
+	flag.Parse()
 
-    var address = strings.Join([]string{*host, *port}, ":")
+	var address = strings.Join([]string{*host, *port}, ":")
 
-    log.Printf("Starting instance %s server at %s", *Name, address)
-    http.ListenAndServe(address, nil)
+	log.Printf("Starting instance %s server at %s", *Name, address)
+	http.ListenAndServe(address, nil)
 }

test.sh

@@ -22,7 +22,8 @@ RESULT=$(curl -H 'User-Agent:' -H 'Header1: header1' -H 'Header2: header2' local
 WANT='Instance name: example
 Accept: [*/*]
 Header1: [header1]
-Header2: [header2]'
+Header2: [header2]
+Host: [localhost:9001]'
 
 printf "===\nResult:\n===\n$RESULT\n"; printf "Want:\n===\n$WANT\n";