Add ./bin/dummy_server.go

Author: hioki-daichi

kadai3-2/hioki-daichi/bin/dummy_server.go

@@ -0,0 +1,93 @@
+//usr/bin/env go run $0 $@ ; exit
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"math/rand"
+	"net/http"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func main() {
+	rand.Seed(time.Now().UnixNano())
+
+	flg := flag.NewFlagSet("test", flag.ExitOnError)
+
+	port := flg.Int("port", 8080, "Port on which the dummy server listens.")
+	failureRate := flg.Int("failure-rate", 0, "Probability to return InternalServerError.")
+	maxDelay := flg.Duration("max-delay", time.Second, "Maximum time delay randomly applied from receiving a request until returning a response.")
+
+	flg.Parse(os.Args[1:])
+
+	fmt.Print(`--------------------------------------------------------------------------------
+# Endpoint
+
+  GET /foo.png // Get a gopher image
+
+# Command-line options**
+
+`)
+	flg.PrintDefaults()
+	fmt.Println("--------------------------------------------------------------------------------")
+
+	contents := func() string {
+		b, err := ioutil.ReadFile("./downloading/testdata/foo.png")
+		if err != nil {
+			panic(err)
+		}
+		return string(b)
+	}()
+
+	handler := func(w http.ResponseWriter, req *http.Request) {
+		if req.Method != "HEAD" {
+			time.Sleep(time.Duration(rand.Intn(int(*maxDelay))))
+		}
+
+		w.Header().Set("Accept-Ranges", "bytes")
+
+		var body string
+		var statusCode int
+		if req.Method == "GET" && rand.Intn(100) < *failureRate {
+			body = "Internal Server Error"
+			statusCode = http.StatusInternalServerError
+		} else {
+			body = func(req *http.Request) string {
+				rangeHeader := req.Header.Get("Range") // e.g. "bytes=0-99"
+				if rangeHeader == "" {
+					return contents
+				}
+				c := strings.Split(strings.Split(rangeHeader, "=")[1], "-")
+				min, _ := strconv.Atoi(c[0])
+				max, _ := strconv.Atoi(c[1])
+				return contents[min : max+1]
+			}(req)
+			statusCode = http.StatusPartialContent
+		}
+
+		w.Header().Set("Content-Length", fmt.Sprintf("%d", len(body)))
+		w.WriteHeader(statusCode)
+		fmt.Fprint(w, body)
+
+		log.Printf("%s %s %d %s\n", req.Method, req.RequestURI, statusCode, req.Header.Get("Range"))
+	}
+
+	http.HandleFunc("/foo.png", handler)
+
+	if *failureRate > 0 {
+		log.Printf("Server starting with a failure rate of %d%% on http://localhost:%d\n", *failureRate, *port)
+	} else {
+		log.Printf("Server starting on http://localhost:%d\n", *port)
+	}
+
+	err := http.ListenAndServe(fmt.Sprintf(":%d", *port), nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+}