Prototype of DirStore and some routes for working with buckets

store/store.go

@@ -0,0 +1,144 @@
+package store
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path"
+
+	"git.phc.dm.unipi.it/phc/storage/utils"
+)
+
+type Store interface {
+	// Create a new object by reading from the given io.Reader and returns its new id
+	Create(r io.Reader) (string, error)
+
+	// Read the object identified by "id" into the given io.Writer
+	Read(id string, w io.Writer) error
+
+	// Update the object identified by "id" by reading from the given io.Reader
+	Update(id string, r io.Reader) error
+
+	// Delete the object with the given id
+	Delete(id string) error
+}
+
+//
+// In Memory Byte Store
+//
+
+type memStore struct {
+	objects map[string][]byte
+}
+
+func NewMemStore() Store {
+	return &memStore{
+		objects: map[string][]byte{},
+	}
+}
+
+// Create a new object by reading from the given io.Reader and returns its new id
+func (m *memStore) Create(r io.Reader) (string, error) {
+	id := utils.GenerateRandomString(16)
+
+	data, err := io.ReadAll(r)
+	if err != nil {
+		return "", err
+	}
+
+	m.objects[id] = data
+	return id, nil
+}
+
+// Read the object identified by "id" into the given io.Writer
+func (m *memStore) Read(id string, w io.Writer) error {
+	data, found := m.objects[id]
+	if !found {
+		return fmt.Errorf("object with id %q not found", id)
+	}
+
+	if _, err := w.Write(data); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Update the object identified by "id" by reading from the given io.Reader
+func (m *memStore) Update(id string, r io.Reader) error {
+	data, err := io.ReadAll(r)
+	if err != nil {
+		return err
+	}
+
+	m.objects[id] = data
+	return nil
+}
+
+// Delete the object with the given id
+func (m *memStore) Delete(id string) error {
+	if _, found := m.objects[id]; !found {
+		return fmt.Errorf("object with id %q not found", id)
+	}
+
+	delete(m.objects, id)
+
+	return nil
+}
+
+//
+// Dir Store
+//
+
+type DirStore struct {
+	// BaseDir is the root folder of this Store
+	BaseDir string
+
+	// Prefix is the number of letters to use for the first layer of folders
+	Prefix int
+}
+
+func (d *DirStore) split(id string) (prefix, rest string) {
+	return id[:d.Prefix], id[d.Prefix:]
+}
+
+func (d *DirStore) Create(r io.Reader) (string, error) {
+	id := utils.GenerateRandomString(16)
+	prefix, rest := d.split(id)
+
+	os.MkdirAll(path.Join(d.BaseDir, prefix), os.ModePerm)
+
+	f, err := os.Create(path.Join(d.BaseDir, prefix, rest))
+	if err != nil {
+		return "", err
+	}
+
+	if _, err := io.Copy(f, r); err != nil {
+		return "", err
+	}
+
+	return id, nil
+}
+
+func (d *DirStore) Read(id string, w io.Writer) error {
+	prefix, rest := d.split(id)
+
+	f, err := os.Open(path.Join(d.BaseDir, prefix, rest))
+	if err != nil {
+		return err
+	}
+
+	if _, err := io.Copy(w, f); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (d *DirStore) Update(id string, r io.Reader) error {
+	panic("TODO: Not implemented")
+}
+
+func (d *DirStore) Delete(id string) error {
+	panic("TODO: Not implemented")
+}