feat: create v2 for module support

v2/paste/paste.go

@@ -0,0 +1,188 @@
+package paste
+
+import (
+	"bufio"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"go.sour.is/paste/src/pkg/readutil"
+	"golang.org/x/sys/unix"
+	"sour.is/x/toolbox/log"
+)
+
+type Paste struct {
+	store string
+}
+
+func New(store string) (p *Paste, err error) {
+	p = &Paste{}
+	p.store = store
+
+	if !chkStore(p.store) {
+		err = fmt.Errorf("paste: store location [%s] does not exist or is not writable", p.store)
+		return
+	}
+	return
+}
+
+func chkStore(path string) bool {
+	file, err := os.Stat(path)
+
+	if err != nil && os.IsNotExist(err) {
+		err = os.MkdirAll(path, 0744)
+		if err != nil {
+			return false
+		}
+
+		file, err = os.Stat(path)
+	}
+
+	if err != nil {
+		return false
+	}
+
+	if !file.IsDir() {
+		return false
+	}
+
+	if unix.Access(path, unix.W_OK&unix.R_OK) != nil {
+		return false
+	}
+
+	return true
+}
+
+func chkFile(path string) bool {
+	file, err := os.Stat(path)
+	if err != nil {
+		return false
+	}
+
+	if file.IsDir() {
+		return false
+	}
+
+	if unix.Access(path, unix.W_OK&unix.R_OK) != nil {
+		return false
+	}
+
+	return true
+}
+
+func chkGone(path string) bool {
+	file, err := os.Stat(path)
+	if err != nil {
+		return true
+	}
+
+	if file.Size() == 0 {
+		return true
+	}
+
+	return false
+}
+
+func (p *Paste) Get(w io.Writer, id string) error {
+	fname := filepath.Join(p.store, id)
+
+	if !chkFile(fname) {
+		return ErrNotFound
+	}
+
+	if chkGone(fname) {
+		return ErrGone
+	}
+
+	f, err := os.Open(fname)
+	if err != nil {
+		return fmt.Errorf("%w: %w", ErrReadingContent, err)
+	}
+	defer f.Close()
+
+	pr := readutil.NewPreviewReader(f)
+
+	keep := true
+	scanner := bufio.NewScanner(pr)
+	for scanner.Scan() {
+		txt := scanner.Text()
+		log.Debug(txt)
+
+		// End of header found
+		if txt == "" {
+			break
+		}
+
+		if strings.HasPrefix(txt, "exp:") {
+			now := time.Now().Unix()
+			exp, err := strconv.ParseInt(strings.TrimSpace(strings.TrimPrefix(txt, "exp:")), 10, 64)
+			if err != nil {
+				return fmt.Errorf("%w: %w", ErrReadingContent, err)
+			}
+
+			log.Debugf("%d > %d", now, exp)
+			if now > exp {
+				deleteFile(fname)
+				return ErrGone
+			}
+		}
+
+		if strings.HasPrefix(txt, "burn:") {
+			burn := strings.TrimSpace(strings.TrimPrefix(txt, "burn:"))
+
+			if burn == "true" {
+				keep = false
+			}
+		}
+	}
+
+	_, _ = io.Copy(w, pr.Drain())
+
+	if !keep {
+		deleteFile(fname)
+	}
+
+	return nil
+}
+
+func (p *Paste) Set(r io.ReadCloser) (string, error) {
+	defer r.Close()
+
+	rdr := io.LimitReader(r, 1048576)
+
+	s256 := sha256.New()
+	tmp, _ := os.CreateTemp(p.store, "arch-")
+	defer os.Remove(tmp.Name())
+
+	m := io.MultiWriter(s256, tmp)
+	if _, err := io.Copy(m, rdr); err != nil {
+		return "", fmt.Errorf("%w: %w", ErrBadInput, err)
+	}
+	tmp.Close()
+
+	id := base64.RawURLEncoding.EncodeToString(s256.Sum(nil)[12:])
+	fname := filepath.Join(p.store, id)
+
+	_ = os.Rename(tmp.Name(), fname)
+
+	return id, nil
+}
+
+func deleteFile(path string) {
+	_ = ioutil.WriteFile(path, nil, 0644)
+}
+
+var (
+	ErrNotFound       = errors.New("not found")
+	ErrGone           = errors.New("gone")
+	ErrReadingContent = errors.New("reading content")
+	ErrBadInput       = errors.New("bad input")
+)