package main import ( "database/sql" "errors" "fmt" "net/http" "strconv" "github.com/go-chi/chi/v5" ) func (db *database) shortenPath(p string) (string, error) { if p == "" { return "", errors.New("empty path") } idi, err, _ := db.sp.Do(p, func() (interface{}, error) { id := db.getShortPathID(p) if id == -1 { _, err := db.exec("insert or ignore into shortpath (path) values (@path)", sql.Named("path", p)) if err != nil { return nil, err } id = db.getShortPathID(p) } return id, nil }) if err != nil { return "", err } id := idi.(int) if id == -1 { return "", errors.New("failed to retrieve short path for " + p) } return fmt.Sprintf("/s/%x", id), nil } func (db *database) getShortPathID(p string) (id int) { if p == "" { return -1 } if idi, ok := db.spc.Load(p); ok { return idi.(int) } row, err := db.queryRow("select id from shortpath where path = @path", sql.Named("path", p)) if err != nil { return -1 } err = row.Scan(&id) if err != nil { return -1 } db.spc.Store(p, id) return id } func (a *goBlog) redirectToLongPath(rw http.ResponseWriter, r *http.Request) { id, err := strconv.ParseInt(chi.URLParam(r, "id"), 16, 64) if err != nil { a.serve404(rw, r) return } row, err := a.db.queryRow("select path from shortpath where id = @id", sql.Named("id", id)) if err != nil { a.serve404(rw, r) return } var path string err = row.Scan(&path) if err != nil { a.serve404(rw, r) return } http.Redirect(rw, r, path, http.StatusMovedPermanently) }