147 lines
4.2 KiB
Go
147 lines
4.2 KiB
Go
// request
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package repositories
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import (
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"bytes"
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"crypto/rand"
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"database/sql"
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"html/template"
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"math/big"
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"net/smtp"
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"sprechstundentool/models"
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)
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type RequestRepo struct {
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db *sql.DB
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officeHourRepo models.OfficeHourRepository
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}
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func NewRequestRepo(db *sql.DB, officeHourRepo models.OfficeHourRepository) *RequestRepo {
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return &RequestRepo{
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db: db,
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officeHourRepo: officeHourRepo,
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}
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}
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func (r *RequestRepo) FindBySecret(secret string) (models.Request, error) {
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// This query is not safe against timing sidechannel attacks – I don't care.
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row := r.db.QueryRow("SELECT * FROM request WHERE secret=?", secret)
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var request models.Request
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var officeHourId int
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err := row.Scan(&request.Id, &officeHourId, &request.Action, &request.Secret)
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if err != nil {
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return models.Request{}, err
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}
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request.OfficeHour, err = r.officeHourRepo.FindById(officeHourId)
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return request, err
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}
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func (r *RequestRepo) FindByOfficeHour(officeHour models.OfficeHour) ([]models.Request, error) {
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rows, err := r.db.Query("SELECT * FROM request WHERE officeHour=?", officeHour.Id)
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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var requests []models.Request
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for rows.Next() {
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var request models.Request
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var officeHourId int
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if err := rows.Scan(&request.Id, &officeHourId, &request.Action, &request.Secret); err != nil {
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return requests, err
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}
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request.OfficeHour, err = r.officeHourRepo.FindById(officeHourId)
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if err != nil {
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return requests, err
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}
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requests = append(requests, request)
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}
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return requests, nil
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}
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func (r *RequestRepo) Add(officeHour models.OfficeHour, action int) (int, error) {
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existents, err := r.FindByOfficeHour(officeHour)
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if err != nil && err != sql.ErrNoRows {
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return 0, err
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}
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/* Resend confirmation mail if identical request exists,
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* but don't insert new request into database.
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*/
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for _, request := range existents {
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if request.Action == action { // already covered by selection && request.OfficeHour == officeHour {
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return request.Id, sendConfirmationMail(request)
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}
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}
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secret, err := r.newSecret()
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if err != nil {
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return 0, err
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}
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request := models.Request{0, officeHour, action, secret}
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_, err = r.db.Exec("INSERT INTO `request` (officeHour, action, secret) VALUES (?,?,?)", officeHour.Id, action, secret)
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if err != nil {
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return 0, err
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}
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request, err = r.FindBySecret(secret)
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if err != nil {
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return request.Id, err
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}
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return request.Id, sendConfirmationMail(request)
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}
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func (r *RequestRepo) Execute(request models.Request) error {
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var err error
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switch request.Action {
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case models.RequestActivate:
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_, err = r.db.Exec("UPDATE officeHour SET active=true WHERE id=?", request.OfficeHour.Id)
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r.db.Exec("DELETE FROM request WHERE id=?", request.Id)
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case models.RequestDelete:
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_, err = r.db.Exec("DELETE FROM officeHour WHERE id=?", request.OfficeHour.Id)
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r.db.Exec("DELETE FROM request WHERE id=?", request.Id)
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default:
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r.db.Exec("DELETE FROM request WHERE id=?", request.Id)
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}
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return err
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}
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func (r *RequestRepo) newSecret() (string, error) {
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secret := randomString(models.SecretLength)
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_, err := r.FindBySecret(secret)
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if err != nil && err != sql.ErrNoRows {
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return "", err
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}
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// find unused secret
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for err != sql.ErrNoRows {
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secret = randomString(models.SecretLength)
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_, err = r.FindBySecret(secret)
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}
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return secret, nil
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}
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func sendConfirmationMail(request models.Request) error {
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to := []string{request.OfficeHour.Tutor.Email}
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tmpl, err := template.New("confirmationMail").Funcs(template.FuncMap{"DayName": models.DayName}).ParseFiles("templates/confirmationMail")
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var message bytes.Buffer
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err = tmpl.Execute(&message, request)
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if err != nil {
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return err
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}
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err = smtp.SendMail("192.168.0.24:25", nil, "Mathebau Sprechstunden <sprechstunden@mathebau.de>", to, message.Bytes())
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return err
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}
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func randomString(n int) string {
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// []byte would be faster and also work, but []rune keeps working for UTF8 characters
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// if someone would like them.
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var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
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s := make([]rune, n)
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for i := range s {
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position, _ := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
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s[i] = letters[position.Int64()]
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}
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return string(s)
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}
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