func deletePost(app *App, w http.ResponseWriter, r *http.Request) error {
vars := mux.Vars(r)
friendlyID := vars["post"]
editToken := r.FormValue("token")
var ownerID int64
var u *User
accessToken := r.Header.Get("Authorization")
if accessToken == "" && editToken == "" {
u = getUserSession(app, r)
if u == nil {
return ErrNoAccessToken
}
}
var res sql.Result
var t *sql.Tx
var err error
var collID sql.NullInt64
var coll *Collection
var pp *PublicPost
if editToken != "" {
// TODO: SELECT owner_id, as well, and return appropriate error if NULL instead of running two queries
var dummy int64
err = app.db.QueryRow("SELECT 1 FROM posts WHERE id = ?", friendlyID).Scan(&dummy)
switch {
case err == sql.ErrNoRows:
return impart.HTTPError{http.StatusNotFound, "Post not found."}
}
err = app.db.QueryRow("SELECT 1 FROM posts WHERE id = ? AND owner_id IS NULL", friendlyID).Scan(&dummy)
switch {
case err == sql.ErrNoRows:
// Post already has an owner. This could provide a bad experience
// for the user, but it's more important to ensure data isn't lost
// unexpectedly. So prevent deletion via token.
return impart.HTTPError{http.StatusConflict, "This post belongs to some user (hopefully yours). Please log in and delete it from that user's account."}
}
res, err = app.db.Exec("DELETE FROM posts WHERE id = ? AND modify_token = ? AND owner_id IS NULL", friendlyID, editToken)
} else if accessToken != "" || u != nil {
// Caller provided some way to authenticate; assume caller expects the
// post to be deleted based on a specific post owner, thus we should
// return corresponding errors.
if accessToken != "" {
ownerID = app.db.GetUserID(accessToken)
if ownerID == -1 {
return ErrBadAccessToken
}
} else {
ownerID = u.ID
}
// TODO: don't make two queries
var realOwnerID sql.NullInt64
err = app.db.QueryRow("SELECT collection_id, owner_id FROM posts WHERE id = ?", friendlyID).Scan(&collID, &realOwnerID)
if err != nil {
return err
}
if !collID.Valid {
// There's no collection; simply delete the post
res, err = app.db.Exec("DELETE FROM posts WHERE id = ? AND owner_id = ?", friendlyID, ownerID)
} else {
// Post belongs to a collection; do any additional clean up