gopher道場 #3-2

kadai3-2/po3rin/README.md

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+# Quick start
+
+you can exex test file server via below command
+
+```bash
+$ cd server
+$ go run main.go
+```
+
+exec splitt loader
+
+```bash
+$ cd loader
+$ go run main.go
+```
+
+##　反省
+まだキャンセルの実装ができていない。
+errgroupによるエラー処理を追加したが、全てのgorutineがちゃんととまているのかテストする術を調査中
+はじめてHeadメソッドを使ったので勉強になった。

kadai3-2/po3rin/loader/Gopkg.toml

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+# Gopkg.toml example
+#
+# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#   name = "github.com/x/y"
+#   version = "2.4.0"
+#
+# [prune]
+#   non-go = false
+#   go-tests = true
+#   unused-packages = true
+
+
+[prune]
+  go-tests = true
+  unused-packages = true

kadai3-2/po3rin/loader/length/length.go

@@ -0,0 +1,22 @@
+package length
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+)
+
+// Calc calcrate contents-length
+func Calc() int {
+	// get contents length
+	res, err := http.Head("http://localhost:8080/5mqx.cif")
+	if err != nil {
+		fmt.Println(err)
+	}
+	maps := res.Header
+	length, err := strconv.Atoi(maps["Content-Length"][0])
+	if err != nil {
+		fmt.Println(err)
+	}
+	return length
+}

kadai3-2/po3rin/loader/main.go

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+package main
+
+import (
+	"context"
+	"dojo2/kadai3-2/po3rin/loader/length"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+
+	"golang.org/x/sync/errgroup"
+)
+
+// var wg sync.WaitGroup
+
+func main() {
+	length := length.Calc()
+
+	// prepare val of split downloaf
+	limit := 10
+	leng := length / limit
+	diff := length % limit
+	body := make(map[int][]byte)
+
+	eg, ctx := errgroup.WithContext(context.Background())
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	// exec download file
+	for i := 0; i < limit; i++ {
+		i := i
+
+		// wg.Add(1)
+		min := leng * i
+		max := leng * (i + 1)
+
+		if i == limit-1 {
+			max += diff
+		}
+
+		eg.Go(func() error {
+			client := &http.Client{}
+			select {
+			case <-ctx.Done():
+				return errors.New("Error occurred")
+			default:
+				req, err := http.NewRequest("GET", "http://localhost:8080/5mqx.cif", nil)
+				if err != nil {
+					cancel()
+				}
+				rh := "bytes=" + strconv.Itoa(min) + "-" + strconv.Itoa(max-1)
+				req.Header.Add("Range", rh)
+				resp, err := client.Do(req)
+				if err != nil {
+					cancel()
+				}
+				defer resp.Body.Close()
+				reader, err := ioutil.ReadAll(resp.Body)
+				if err != err {
+					cancel()
+				}
+				body[i] = reader
+				return nil
+			}
+		})
+	}
+	if err := eg.Wait(); err != nil {
+		log.Fatal(err)
+	}
+
+	// create new file
+	buf := make([]byte, 0)
+	for i := 0; i < limit; i++ {
+		buf = append(buf, body[i]...)
+	}
+	file, err := os.Create(`../5mqx.cif`)
+	if err != nil {
+		fmt.Println(err)
+	}
+	defer file.Close()
+	file.Write(([]byte)(buf))
+}

kadai3-2/po3rin/server/main.go

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+package main
+
+import (
+	"log"
+	"net/http"
+)
+
+func main() {
+	http.Handle("/", http.FileServer(http.Dir("static")))
+	if err := http.ListenAndServe(":8080", nil); err != nil {
+		log.Fatal("ListenAndServe: ", err)
+	}
+}