dev001hajipro/main.go

## main.go
package main

import (
	"context"
	"html/template"
	"io"
	"net/http"

	"encoding/csv"
	"strings"

	"google.golang.org/appengine"
	"google.golang.org/appengine/blobstore"
	"google.golang.org/appengine/log"
)

func serveError(ctx context.Context, w http.ResponseWriter, err error) {
	w.WriteHeader(http.StatusInternalServerError)
	w.Header().Set("Content-Type", "text/plain")
	io.WriteString(w, "Internal Server Error")
	log.Errorf(ctx, "%v", err)
}

var rootTemplate = template.Must(template.New("root").Parse(rootTemplateHTML))

const rootTemplateHTML = `
<html><body>
<form action="{{.}}" method="POST" enctype="multipart/form-data">
Upload CSV File: <input type="file" name="file"><br>
<input type="submit" name="submit" value="Submit">
</form></body></html>
`

func handleRoot(w http.ResponseWriter, r *http.Request) {
	ctx := appengine.NewContext(r)
	uploadURL, err := blobstore.UploadURL(ctx, "/upload", nil)
	if err != nil {
		serveError(ctx, w, err)
		return
	}
	w.Header().Set("Content-Type", "text/html")
	err = rootTemplate.Execute(w, uploadURL)
	if err != nil {
		log.Errorf(ctx, "%v", err)
	}
}

func handleServe(w http.ResponseWriter, r *http.Request) {

	c := appengine.NewContext(r)
	bkey := appengine.BlobKey(r.FormValue("blobKey"))

	w.Header().Set("Content-Type", "text/plain")

	// Blobを取得
	out := blobstore.NewReader(c, bkey)

	// csv解析
	data := csv.NewReader(out)
	// csv全出力
	cols, err := data.Read()
	// 最初の読み込みでエラーが出るなら、Blobは存在しないってよ
	if err != nil {
		http.Error(w, "blob file doesn't exist", http.StatusNotFound)
		return
	}
	for err == nil {
		w.Write([]byte(strings.Join(cols, ",")))
		cols, err = data.Read()
	}

}

func handleUpload(w http.ResponseWriter, r *http.Request) {
	ctx := appengine.NewContext(r)
	blobs, _, err := blobstore.ParseUpload(r)
	if err != nil {
		serveError(ctx, w, err)
		return
	}
	file := blobs["file"]
	if len(file) == 0 {
		log.Errorf(ctx, "no file uploaded")
		http.Redirect(w, r, "/", http.StatusFound)
		return
	}

	http.Redirect(w, r, "/serve/?blobKey="+string(file[0].BlobKey), http.StatusFound)
}

func main() {
	http.HandleFunc("/", handleRoot)
	http.HandleFunc("/serve/", handleServe)
	http.HandleFunc("/upload", handleUpload)

	appengine.Main()
}
	package main

	import (
	"context"
	"html/template"
	"io"
	"net/http"

	"encoding/csv"
	"strings"

	"google.golang.org/appengine"
	"google.golang.org/appengine/blobstore"
	"google.golang.org/appengine/log"
	)

	func serveError(ctx context.Context, w http.ResponseWriter, err error) {
	w.WriteHeader(http.StatusInternalServerError)
	w.Header().Set("Content-Type", "text/plain")
	io.WriteString(w, "Internal Server Error")
	log.Errorf(ctx, "%v", err)
	}

	var rootTemplate = template.Must(template.New("root").Parse(rootTemplateHTML))

	const rootTemplateHTML = `
	<html><body>
	<form action="{{.}}" method="POST" enctype="multipart/form-data">
	Upload CSV File: <input type="file" name="file"><br>
	<input type="submit" name="submit" value="Submit">
	</form></body></html>
	`

	func handleRoot(w http.ResponseWriter, r *http.Request) {
	ctx := appengine.NewContext(r)
	uploadURL, err := blobstore.UploadURL(ctx, "/upload", nil)
	if err != nil {
	serveError(ctx, w, err)
	return
	}
	w.Header().Set("Content-Type", "text/html")
	err = rootTemplate.Execute(w, uploadURL)
	if err != nil {
	log.Errorf(ctx, "%v", err)
	}
	}

	func handleServe(w http.ResponseWriter, r *http.Request) {

	c := appengine.NewContext(r)
	bkey := appengine.BlobKey(r.FormValue("blobKey"))

	w.Header().Set("Content-Type", "text/plain")

	// Blobを取得
	out := blobstore.NewReader(c, bkey)

	// csv解析
	data := csv.NewReader(out)
	// csv全出力
	cols, err := data.Read()
	// 最初の読み込みでエラーが出るなら、Blobは存在しないってよ
	if err != nil {
	http.Error(w, "blob file doesn't exist", http.StatusNotFound)
	return
	}
	for err == nil {
	w.Write([]byte(strings.Join(cols, ",")))
	cols, err = data.Read()
	}

	}

	func handleUpload(w http.ResponseWriter, r *http.Request) {
	ctx := appengine.NewContext(r)
	blobs, _, err := blobstore.ParseUpload(r)
	if err != nil {
	serveError(ctx, w, err)
	return
	}
	file := blobs["file"]
	if len(file) == 0 {
	log.Errorf(ctx, "no file uploaded")
	http.Redirect(w, r, "/", http.StatusFound)
	return
	}

	http.Redirect(w, r, "/serve/?blobKey="+string(file[0].BlobKey), http.StatusFound)
	}

	func main() {
	http.HandleFunc("/", handleRoot)
	http.HandleFunc("/serve/", handleServe)
	http.HandleFunc("/upload", handleUpload)

	appengine.Main()
	}