Add: first commit

+package main
+
+import (
+	"encoding/json"
+	"io/ioutil"
+)
+
+type Config struct {
+	Server   ConfigServer   `json:"server"`
+	Database ConfigDatabase `json:"database"`
+}
+
+type ConfigServer struct {
+	LocalMode bool `json:"local_mode"`
+	Port      int  `json:"port"`
+}
+
+type ConfigDatabase struct {
+	Host     string `json:"host"`
+	Port     int    `json:"port"`
+	User     string `json:"user"`
+	Password string `json:"password"`
+	Schema   string `json:"schema"`
+}
+
+func LoadConfig(filePath string) (*Config, error) {
+	cfg := &Config{}
+
+	dataBytes, err := ioutil.ReadFile(filePath)
+	if err != nil {
+		return cfg, err
+	}
+
+	json.Unmarshal(dataBytes, cfg)
+
+	return cfg, nil
+}

+package endpoints
+
+import (
+	"classroom/functions"
+	"classroom/models"
+	"database/sql"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/julienschmidt/httprouter"
+)
+
+// GET /timetables/<file_id>/<sheet_id>/cell
+func (e *Endpoints) CellGet(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
+	// Get user email
+	var email string
+	if _email, ok := r.Header["X-User-Email"]; ok {
+		email = _email[0]
+	} else {
+		functions.ResponseError(w, 401, "X-User-Email 헤더를 보내세요.")
+		return
+	}
+
+	// Get Path Parameters
+	fileID := ps.ByName("file_id")
+	sheetID := ps.ByName("sheet_id")
+
+	// Get Query Parameters
+	qp := r.URL.Query()
+	var cellColumn string
+	var cellStart int
+	var cellEnd int
+	var err error
+
+	if _cellColumn, ok := qp["column"]; ok {
+		cellColumn = strings.ToUpper(_cellColumn[0])
+	} else {
+		functions.ResponseError(w, 400, "column 파라미터를 보내세요.")
+		return
+	}
+
+	if _cellStart, ok := qp["start"]; ok {
+		cellStart, err = strconv.Atoi(_cellStart[0])
+		if err != nil {
+			functions.ResponseError(w, 400, "start 파라미터를 보내세요.")
+			return
+		}
+	}
+	if _cellEnd, ok := qp["end"]; ok {
+		cellEnd, err = strconv.Atoi(_cellEnd[0])
+		if err != nil {
+			functions.ResponseError(w, 400, "end 파라미터를 보내세요.")
+			return
+		}
+	}
+
+	// Check Permission
+	var _timetable, _email string
+	timetable := fmt.Sprintf("%s,%s", fileID, sheetID)
+	row := e.DB.QueryRow(`
+		SELECT a.timetable_id, u.email
+		FROM allowlist AS a, users AS u
+		WHERE a.timetable_id=?
+			AND a.user_id=u.id;
+	`, timetable)
+	if err := row.Scan(&_timetable, &_email); err != nil {
+		if err == sql.ErrNoRows {
+			functions.ResponseError(w, 404, "존재하지 않은 timetable.")
+			return
+		}
+	}
+	if _email != email {
+		functions.ResponseError(w, 403, "timetable 접근 권한 부족")
+		return
+	}
+
+	// Result Resp
+	resp := models.CellGetResponse{}
+	resp.Cells = []models.CellItem{}
+
+	// Querying
+	rows, err := e.DB.Query(`
+		SELECT u.email, u.id, t.cell_column, t.cell_start, t.cell_end, t.lecture, t.professor, t.transaction_id, t.created_at, t.capacity
+		FROM transactions AS t, users AS u
+		WHERE t.user_id=u.id
+			AND u.email=?
+			AND t.transaction_type=1
+			AND t.timetable_id=?
+			AND t.cell_column=?;`, email, timetable, cellColumn)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			resp.CellsCount = 0
+			functions.ResponseOK(w, "success", resp)
+			return
+		}
+		functions.ResponseError(w, 500, err.Error())
+		return
+	}
+	defer rows.Close()
+
+	cells := []models.CellTransactionModel{}
+	for rows.Next() {
+		temp := models.CellTransactionModel{}
+		err := rows.Scan(&temp.UserEmail, &temp.UserID, &temp.CellColumn, &temp.CellStart, &temp.CellEnd, &temp.Lecture, &temp.Professor, &temp.TransactionID, &temp.CreatedAt, &temp.Capacity)
+		if err != nil {
+			continue
+		}
+		cells = append(cells, temp)
+	}
+
+	// Compare
+	for i := cellStart; i <= cellEnd; i++ {
+		isInRange := false
+		for _, cell := range cells {
+			if functions.InRange(i, cell.CellStart, cell.CellEnd) {
+				temp := models.CellItem{}
+				temp.Cell = fmt.Sprintf("%s%d", cellColumn, i)
+				temp.IsReserved = true
+				temp.UserEmail = cell.UserEmail
+				temp.UserID = cell.UserID
+				temp.Lecture = cell.Lecture
+				temp.Professor = cell.Professor
+				temp.TransactionID = cell.TransactionID
+				temp.CreatedAt = functions.ToKST(cell.CreatedAt)
+				temp.Capacity = cell.Capacity
+
+				resp.Cells = append(resp.Cells, temp)
+				isInRange = true
+				break
+			}
+		}
+
+		if !isInRange {
+			temp := models.CellItem{}
+			temp.Cell = fmt.Sprintf("%s%d", cellColumn, i)
+			temp.IsReserved = false
+
+			resp.Cells = append(resp.Cells, temp)
+		}
+	}
+
+	// Struct for response
+	resp.CellsCount = len(resp.Cells)
+
+	functions.ResponseOK(w, "success", resp)
+}

+package endpoints
+
+import (
+	"database/sql"
+)
+
+type Endpoints struct {
+	DB *sql.DB
+}

+module classroom/endpoints
+
+go 1.14
+
+require (
+	classroom/functions v0.0.0
+	github.com/julienschmidt/httprouter v1.3.0
+)
+
+replace classroom/functions v0.0.0 => ../functions

+github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=
+github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=

+package endpoints
+
+import (
+	"classroom/functions"
+	"classroom/models"
+	"net/http"
+
+	"github.com/julienschmidt/httprouter"
+)
+
+// GET /
+func (e *Endpoints) IndexGet(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+	w.Header().Set("Content-Type", "application/json")
+
+	// Struct for response
+	resp := models.IndexResponse{}
+	resp.WelcomeMessage = "Hello, Kyung Hee!"
+
+	// Response with JSON
+	functions.ResponseOK(w, "success", resp)
+}

+package endpoints
+
+import (
+	"classroom/functions"
+	"classroom/models"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+
+	"github.com/julienschmidt/httprouter"
+)
+
+// POST /timetables/<file_id>/<sheet_id>/reservation
+func (e *Endpoints) ReservationPost(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
+	// Get user email
+	var email string
+	if _email, ok := r.Header["X-User-Email"]; ok {
+		email = _email[0]
+	} else {
+		functions.ResponseError(w, 401, "X-User-Email 헤더를 보내세요.")
+		return
+	}
+
+	// Get Path Parameters
+	fileID := ps.ByName("file_id")
+	sheetID := ps.ByName("sheet_id")
+
+	// Check Permission
+	var _timetable, _email string
+	var userID int
+	timetable := fmt.Sprintf("%s,%s", fileID, sheetID)
+	row := e.DB.QueryRow(`
+		SELECT a.timetable_id, u.email, u.id
+		FROM allowlist AS a, users AS u
+		WHERE a.timetable_id=?
+			AND a.user_id=u.id;
+	`, timetable)
+	if err := row.Scan(&_timetable, &_email, &userID); err != nil {
+		if err == sql.ErrNoRows {
+			functions.ResponseError(w, 404, "존재하지 않는 timetable")
+			return
+		}
+		functions.ResponseError(w, 500, "예기치 못한 에러 발생 : "+err.Error())
+		return
+	}
+	if _email != email {
+		functions.ResponseError(w, 403, "timetable 접근 권한 부족")
+		return
+	}
+
+	// Parse Request Data
+	type reqDataStruct struct {
+		Column    *string `json:"column"`
+		Start     *int    `json:"start"`
+		End       *int    `json:"end"`
+		Lecture   *string `json:"lecture"`
+		Professor *string `json:"professor"`
+		Capacity  *int    `json:"capacity"`
+	}
+	var reqData reqDataStruct
+	if strings.Contains(r.Header.Get("Content-Type"), "application/json") {
+		body, err := ioutil.ReadAll(r.Body)
+		if err != nil {
+			functions.ResponseError(w, 500, err.Error())
+		}
+		json.Unmarshal(body, &reqData)
+	} else {
+		functions.ResponseError(w, 400, "JSON 형식만 가능합니다.")
+		return
+	}
+	if reqData.Column == nil || reqData.Start == nil || reqData.End == nil ||
+		reqData.Lecture == nil || reqData.Professor == nil || reqData.Capacity == nil {
+		functions.ResponseError(w, 400, "파라미터를 전부 보내주세요.")
+		return
+	}
+
+	// Querying (Cell Validation Check)
+	isPossible := true
+	rows, err := e.DB.Query(`
+		SELECT cell_start, cell_end
+		FROM transactions
+		WHERE transaction_type=1
+			AND cell_column=?;
+	`, *(reqData.Column))
+	if err == sql.ErrNoRows {
+		isPossible = true
+	}
+	defer rows.Close()
+
+loopCheckingValidation:
+	for rows.Next() {
+		var _start, _end int
+		err = rows.Scan(&_start, &_end)
+		if err != nil {
+			continue
+		}
+		for i := *(reqData.Start); i <= *(reqData.End); i++ {
+			if functions.InRange(i, _start, _end) {
+				isPossible = false
+				break loopCheckingValidation
+			}
+		}
+	}
+
+	if !isPossible {
+		functions.ResponseError(w, 500, "해당 셀 범위에 예약이 존재합니다.")
+		return
+	}
+
+	// Result Resp
+	resp := models.ReservationPostResponse{}
+
+	// Querying (Making a Transaction)
+	res, err := e.DB.Exec(`
+		INSERT INTO transactions (transaction_type, user_id, timetable_id, lecture, capacity, cell_column, cell_start, cell_end, professor)
+		VALUES (1, ?, ?, ?, ?, ?, ?, ?, ?);
+		`, userID, timetable, *(reqData.Lecture), *(reqData.Capacity), *(reqData.Column), *(reqData.Start), *(reqData.End), *(reqData.Professor))
+	if err != nil {
+		functions.ResponseError(w, 500, err.Error())
+		return
+	}
+
+	resp.TransactionID, err = res.LastInsertId()
+	if err != nil {
+		functions.ResponseError(w, 500, err.Error())
+		return
+	}
+
+	resp.IsSuccess = true
+	resp.CellColumn = *(reqData.Column)
+	resp.CellStart = *(reqData.Start)
+	resp.CellEnd = *(reqData.End)
+	resp.Lecture = *(reqData.Lecture)
+	resp.Professor = *(reqData.Professor)
+
+	functions.ResponseOK(w, "success", resp)
+}
+
+// DELETE /timetables/<file_id>/<sheet_id>/reservation/<reservation_id>
+func (e *Endpoints) ReservationDelete(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
+	// Get user email
+	var email string
+	if _email, ok := r.Header["X-User-Email"]; ok {
+		email = _email[0]
+	} else {
+		functions.ResponseError(w, 401, "X-User-Email 헤더를 보내세요.")
+		return
+	}
+
+	// Get Path Parameters
+	fileID := ps.ByName("file_id")
+	sheetID := ps.ByName("sheet_id")
+	reservationID := ps.ByName("reservation_id")
+
+	// Check Timetable Permission
+	var _timetable, _email string
+	var userID int
+	timetable := fmt.Sprintf("%s,%s", fileID, sheetID)
+	row := e.DB.QueryRow(`
+		SELECT a.timetable_id, u.email, u.id
+		FROM allowlist AS a, users AS u
+		WHERE a.timetable_id=?
+			AND a.user_id=u.id;
+	`, timetable)
+	if err := row.Scan(&_timetable, &_email, &userID); err != nil {
+		if err == sql.ErrNoRows {
+			functions.ResponseError(w, 404, "존재하지 않는 timetable")
+			return
+		}
+		functions.ResponseError(w, 500, "예기치 못한 에러 발생 : "+err.Error())
+		return
+	}
+	if _email != email {
+		functions.ResponseError(w, 403, "timetable 접근 권한 부족")
+		return
+	}
+
+	// Check Transaction Permission
+	var _transactionType int64
+	row = e.DB.QueryRow(`
+		SELECT u.email, t.transaction_type
+		FROM transactions AS t, users AS u
+		WHERE t.user_id=u.id
+			AND t.transaction_id=?;
+	`, reservationID)
+	err := row.Scan(&_email, &_transactionType)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			functions.ResponseError(w, 404, "존재하지 않는 예약")
+			return
+		}
+		functions.ResponseError(w, 500, "예기치 못한 에러 발생 : "+err.Error())
+		return
+	}
+	if _email != email {
+		functions.ResponseError(w, 403, "예약 접근 권한 부족")
+		return
+	}
+	if _transactionType == 0 {
+		functions.ResponseError(w, 500, "이미 취소된 예약")
+		return
+	}
+
+	// Querying
+	res, err := e.DB.Exec(`
+		UPDATE transactions SET transaction_type=0 WHERE transaction_id=?
+	`, reservationID)
+	if err != nil {
+		functions.ResponseError(w, 500, err.Error())
+		return
+	}
+	if affected, _ := res.RowsAffected(); affected != 1 {
+		functions.ResponseError(w, 500, "예기치 못한 에러 발생. (RowsAffected != 1)")
+		return
+	}
+
+	functions.ResponseOK(w, "success", nil)
+}

+package functions
+
+// InRange returns if the target is in the `range (start, end)
+func InRange(target, start, end int) bool {
+	return (start <= target) && (target <= end)
+}

+module classroom/functions
+
+go 1.14

+package functions
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+
+	"classroom/models"
+)
+
+// ResponseOK make 200 response.
+func ResponseOK(w http.ResponseWriter, msg string, data interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
+	w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
+	w.WriteHeader(200)
+	json.NewEncoder(w).Encode(&models.Response{
+		Status:  200,
+		Message: msg,
+		Data:    data,
+	})
+}
+
+// ResponseError make error response.
+func ResponseError(w http.ResponseWriter, errorCode int, errorMsg string) {
+	log.Println("[Error] :", errorCode, errorMsg)
+
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
+	w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
+	w.WriteHeader(errorCode)
+	json.NewEncoder(w).Encode(&models.Response{
+		Status:  errorCode,
+		Message: errorMsg,
+		Data:    nil,
+	})
+}

+package functions
+
+import (
+	"time"
+)
+
+func ToKST(utc string) string {
+	t, _ := time.Parse(time.RFC3339, utc)
+	t = t.Add(9 * time.Hour)
+	return t.Format("2006-01-02 15:04:05")
+}

+module classroom
+
+go 1.14
+
+require (
+	github.com/go-sql-driver/mysql v1.5.0
+	github.com/julienschmidt/httprouter v1.3.0
+	github.com/rs/cors v1.7.0
+
+	classroom/endpoints v0.0.0
+	classroom/models v0.0.0
+	classroom/functions v0.0.0
+)
+
+replace (
+	classroom/endpoints v0.0.0 => ./endpoints
+	classroom/models v0.0.0 => ./models
+	classroom/functions v0.0.0 => ./functions
+)
\ No newline at end of file

+github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
+github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=
+github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=
+github.com/rs/cors v1.7.0 h1:+88SsELBHx5r+hZ8TCkggzSstaWNbDvThkVK8H6f9ik=
+github.com/rs/cors v1.7.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=

+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+
+	"classroom/endpoints"
+	"classroom/functions"
+
+	_ "github.com/go-sql-driver/mysql"
+	"github.com/julienschmidt/httprouter"
+	"github.com/rs/cors"
+)
+
+var logger *log.Logger
+
+type HostSwitch map[string]http.Handler
+
+func (hs HostSwitch) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if handler := hs[r.Host]; handler != nil {
+		ip := r.RemoteAddr
+		log.Println("[Req]", r.Method, r.URL, ip)
+		handler.ServeHTTP(w, r)
+	} else {
+		functions.ResponseError(w, 403, "Forbidden hostname : "+r.Host)
+	}
+}
+
+func main() {
+	// Logger
+	logger = log.New(os.Stdout, "LOG ", log.LstdFlags)
+
+	// Config
+	cfg, err := LoadConfig("config.json")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// DB Setting
+	if !(cfg.Server.LocalMode) {
+		time.Sleep(time.Second * 10)
+	}
+	dbStr := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?allowNativePasswords=true&parseTime=true",
+		cfg.Database.User,
+		cfg.Database.Password,
+		cfg.Database.Host,
+		cfg.Database.Port,
+		cfg.Database.Schema)
+	db, err := sql.Open("mysql", dbStr)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+	ep := endpoints.Endpoints{DB: db}
+
+	// Router Setting
+	router := httprouter.New()
+	router.GET("/api", ep.IndexGet)
+	router.GET("/api/timetables/:file_id/:sheet_id/cell", ep.CellGet)
+	router.POST("/api/timetables/:file_id/:sheet_id/reservation", ep.ReservationPost)
+	router.DELETE("/api/timetables/:file_id/:sheet_id/reservation/:reservation_id", ep.ReservationDelete)
+
+	// Local Mode
+	portStr := strconv.Itoa(cfg.Server.Port)
+	if cfg.Server.LocalMode {
+		handler := cors.AllowAll().Handler(router)
+
+		// Start Server in Local Mode
+		log.Println("[Local Mode] Starting HTTP API Server on port", portStr)
+		log.Fatal(http.ListenAndServe(":"+portStr, handler))
+
+	} else { // Release Mode
+		handler := cors.AllowAll().Handler(router)
+		hs := make(HostSwitch)
+		hs["web-api"] = handler
+
+		// Start Server
+		log.Println("[Release Mode] Starting HTTP API Server on port", portStr)
+		log.Fatal(http.ListenAndServe(":"+portStr, hs))
+	}
+}

+package models
+
+type CellTransactionModel struct {
+	TransactionID int
+	UserID        int
+	UserEmail     string
+	Lecture       string
+	CellColumn    string
+	CellStart     int
+	CellEnd       int
+	Professor     string
+	CreatedAt     string
+	Capacity      int
+}
+
+type CellGetResponse struct {
+	Cells      []CellItem `json:"cells"`
+	CellsCount int        `json:"cells_count"`
+}
+
+type CellItem struct {
+	Cell          string `json:"cell"`
+	IsReserved    bool   `json:"is_reserved"`
+	UserEmail     string `json:"user_email"`
+	UserID        int    `json:"user_id"`
+	Lecture       string `json:"lecture"`
+	Professor     string `json:"professor"`
+	Capacity      int    `json:"capacity"`
+	TransactionID int    `json:"transaction_id"`
+	CreatedAt     string `json:"created_at"`
+}

+module classroom/models
+
+go 1.14

+package models
+
+type IndexResponse struct {
+	WelcomeMessage string `json:"welcome_message"`
+}

+package models
+
+type ReservationPostResponse struct {
+	IsSuccess     bool   `json:"is_success"`
+	TransactionID int64  `json:"transaction_id"`
+	CellColumn    string `json:"cell_column"`
+	CellStart     int    `json:"cell_start"`
+	CellEnd       int    `json:"cell_end"`
+	Lecture       string `json:"lecture"`
+	Professor     string `json:"professor"`
+}

+package models
+
+type Response struct {
+	Status  int         `json:"status"`
+	Message string      `json:"message"`
+	Data    interface{} `json:"data"`
+}