Category: Go

### previous, nextを書いていく
app.go

	var start, end, previous, next int
	
	// p はcurrentのint
	previous = p - 1
	next = p + 1

	return c.Render(content, previous, next)

html

    <nav class="pagination" role="navigation" aria-label="pagination">
      <a href="/paging?page={{.previous}}" class="pagination-previous">Previous</a>
      <a href="/paging?page={{.next}}" class="pagination-next">Next page</a>
    </nav>

ただし、previousとnextは、currentが最初もしくは最後のページの場合、非表示にする
app.go

	current = p
	previous = p - 1
	next = p + 1

    <nav class="pagination" role="navigation" aria-label="pagination">
      {{if ne .current 1}}
      <a href="/paging?page={{.previous}}" class="pagination-previous is-left">Previous</a>
      {{end}}
      <a href="/paging?page={{.next}}" class="pagination-next is-right">Next page</a>
    </nav>

うわああああああああああ、条件分岐が永遠増えていく…

これは次行こう

1. まずgetパラメータでpageの値を取得する
string型での取得

	var page int
	var s string=c.Params.Get("page")
	page, _ = strconv.Atoi(s)
	fmt.Println(page)

http://192.168.34.10:9000/paging?page=1
-> 1

2. ページのスタートと終わりの値を計算
例えば、1ページ5つの値のみを表示するとする場合、l(limit)=5として、startとendの値を求めます。

	var l int = 5
	var start, end int
	start = (p - 1) * l
	end = start + l
	fmt.Println(start)
	fmt.Println(end)

http://192.168.34.10:9000/paging?page=2
2 // 2ページ目
5 // start
10 // end

3. 配列からスライス(要素を取り出す)

	text := [15][2]string{
		{"1","content"},
		{"2","content"},
		{"3","content"},
		{"4","content"},
		{"5","content"},
		{"6","content"},
		{"7","content"},
		{"8","content"},
		{"9","content"},
		{"10","content"},
		{"11","content"},
		{"12","content"},
		{"13","content"},
		{"14","content"},
		{"15","content"},
	}
	fmt.Println(text[start:end])

http://192.168.34.10:9000/paging?page=2
-> [[6 content] [7 content] [8 content] [9 content] [10 content]]

4.全部をつなげて、templeteに出力

func (c App) Paging() revel.Result {

	var p int
	var s string=c.Params.Get("page")
	p, _ = strconv.Atoi(s)
	fmt.Println(p)

	var l int = 5
	var start, end int
	start = (p - 1) * l
	end = start + l
	fmt.Println(start)
	fmt.Println(end)

	text := [15][2]string{
		{"1","content"},
		{"2","content"},
		{"3","content"},
		{"4","content"},
		{"5","content"},
		{"6","content"},
		{"7","content"},
		{"8","content"},
		{"9","content"},
		{"10","content"},
		{"11","content"},
		{"12","content"},
		{"13","content"},
		{"14","content"},
		{"15","content"},

	}
	fmt.Println(text[start:end])
	content := text[start:end]
	return c.Render(content)
}

html側

    <h1>paging</h1>
    <ul>
    {{range .content}}
    <li>{{ index . 0 }} {{.}}</li>
    {{end}}
    </ul>

問題は、view側のページネーションのbuttonをどう実装するか…
0から作るの大変だな..

app.go

func (c App) Paging() revel.Result {

	text := [3][2]string{
		{"20211113","2021/11/13"},
		{"20211112","2021/11/12"},
		{"20211111","2021/11/11"},
	}
	fmt.Println(text)
	fmt.Println(text[0][1])
	return c.Render(text)
}

views
L indexを使う

    <ul>
    {{range .text}}
    <li>{{ index . 0 }} {{.}}</li>
    {{end}}
    </ul>

ウヒョーーーーーー

.[0] で表示できないので、かなり時間がかかりました。

まずHTMLとroutingを作ります。

    <button type=“button” onclick="location.href='/test/download'">download</button>

GET		/test 				  App.Test
GET     /test/download		  App.Download

続いてaws-sdk-goをget
$ go get -u github.com/aws/aws-sdk-go

最後にcontroller
app.go
L ファイルのリターンはc.RenderFileName(“${file_path}”, revel.Attachment)

import (
	"github.com/revel/revel"
	"os"
	"log"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
)
func (c App) Download() revel.Result {


	creds := credentials.NewStaticCredentials("${AWS_ACCESS_KEY_ID}","${AWS_SECRET_ACCESS_KEY}","")
	sess := session.Must(session.NewSession(&aws.Config{
		Credentials: creds,
		Region: aws.String("ap-northeast-1"),
	}))

	f, err := os.Create("public/tmp/sample.json")
	if err != nil {
		log.Fatal(err)
	}

	bucketName := "${bucketName}"
	objectKey := "${file}"

	downloader := s3manager.NewDownloader(sess)
	n, err := downloader.Download(f, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key: aws.String(objectKey),
	})

	if err != nil {
		log.Fatal(err)
	}
	log.Printf("DownloadedSize: %d byte", n)


	return c.RenderFileName("public/tmp/sample.json", revel.Attachment)
}

動作テスト

OKOK, これで議事録機能はできたかな
ファイルパスのところを、/public/tmp/sample.json って書いてハマってしまったorz
さあ続いてKVS

app.go

import (
	"github.com/revel/revel"
	"app/app/models"
	"fmt"
	_ "image/jpeg"
	"io/ioutil"
	"os"
	"net/smtp"
	"crypto/rand"
	"errors"
)

func (c App) Rand() revel.Result {

	random, _ := MakeRandomStr(8)
	fmt.Println(random)
	return c.Render()
}

func MakeRandomStr(digit uint32)(string, error){
	const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

	b := make([]byte, digit)
	if _, err := rand.Read(b); err != nil {
		return "", errors.New("unexpected error...")
	}

	var result string
	for _, v := range b {
		result += string(letters[int(v)%len(letters)])
	}
	return result, nil
}

dJdJvsWf

OK, これでPasswordを作成する

gmailのsmtpで送信する場合と書き方はほぼ同じ

func (c App) Mail() revel.Result {

	name := "hpscript"
	email := "test@hpscript.com"
	comments := "桜木町の夜景は良いですね"

	auth := smtp.PlainAuth (
		"",
		"hogehoge", // Mailtrap Username
		"fugafuga", // Mailtrap Password
		"smtp.mailtrap.io",
	)

	msg := []byte("From: info@hpscript.com\r\n" +
		"To: " +email + "\r\n" +
		"Subject: SMTPテスト\r\n" +
		"\r\n" +
		"名前: " + name + "\r\n" +
		"メールアドレス" + email + "\r\n" +
		"問い合わせ内容: " + comments + "\r\n")

	err := smtp.SendMail(
		"smtp.mailtrap.io:25",
		auth,
		"info@hpscrpt.com",
		[]string{email}, // 宛先
		msg,
	)

	if err != nil {
		fmt.Println(err)
	}
	return c.Render()
}

OKOK