From 3088c9d76ca2c88996bb794b17e87cd1d5e76064 Mon Sep 17 00:00:00 2001 From: Brian Picciano Date: Sat, 7 May 2022 18:07:27 -0600 Subject: Implement AssetStore interface --- srv/src/post/asset.go | 86 ++++++++++++++++++++++++++++++++++++++++++++++ srv/src/post/asset_test.go | 67 ++++++++++++++++++++++++++++++++++++ 2 files changed, 153 insertions(+) create mode 100644 srv/src/post/asset.go create mode 100644 srv/src/post/asset_test.go (limited to 'srv/src/post') diff --git a/srv/src/post/asset.go b/srv/src/post/asset.go new file mode 100644 index 0000000..3e6ae28 --- /dev/null +++ b/srv/src/post/asset.go @@ -0,0 +1,86 @@ +package post + +import ( + "bytes" + "database/sql" + "errors" + "fmt" + "io" +) + +var ( + // ErrAssetNotFound is used to indicate an Asset could not be found in the + // AssetStore. + ErrAssetNotFound = errors.New("asset not found") +) + +// AssetStore implements the storage and retrieval of binary assets, which are +// intended to be used by posts (e.g. images). +type AssetStore interface { + + // Set sets the id to the contents of the given io.Reader. + Set(id string, from io.Reader) error + + // Get writes the id's body to the given io.Writer, or returns + // ErrAssetNotFound. + Get(id string, into io.Writer) error + + // Delete's the body stored for the id, if any. + Delete(id string) error +} + +type assetStore struct { + db *sql.DB +} + +// NewAssetStore initializes a new AssetStore using an existing SQLDB. +func NewAssetStore(db *SQLDB) AssetStore { + return &assetStore{ + db: db.db, + } +} + +func (s *assetStore) Set(id string, from io.Reader) error { + + body, err := io.ReadAll(from) + if err != nil { + return fmt.Errorf("reading body fully into memory: %w", err) + } + + _, err = s.db.Exec( + `INSERT INTO assets (id, body) + VALUES (?, ?) + ON CONFLICT (id) DO UPDATE SET body=excluded.body`, + id, body, + ) + + if err != nil { + return fmt.Errorf("inserting into assets: %w", err) + } + + return nil +} + +func (s *assetStore) Get(id string, into io.Writer) error { + + var body []byte + + err := s.db.QueryRow(`SELECT body FROM assets WHERE id = ?`, id).Scan(&body) + + if errors.Is(err, sql.ErrNoRows) { + return ErrAssetNotFound + } else if err != nil { + return fmt.Errorf("selecting from assets: %w", err) + } + + if _, err := io.Copy(into, bytes.NewReader(body)); err != nil { + return fmt.Errorf("writing body to io.Writer: %w", err) + } + + return nil +} + +func (s *assetStore) Delete(id string) error { + _, err := s.db.Exec(`DELETE FROM assets WHERE id = ?`, id) + return err +} diff --git a/srv/src/post/asset_test.go b/srv/src/post/asset_test.go new file mode 100644 index 0000000..4b88000 --- /dev/null +++ b/srv/src/post/asset_test.go @@ -0,0 +1,67 @@ +package post + +import ( + "bytes" + "io" + "testing" + + "github.com/stretchr/testify/assert" +) + +type assetTestHarness struct { + store AssetStore +} + +func newAssetTestHarness(t *testing.T) assetTestHarness { + + db := NewInMemSQLDB() + t.Cleanup(func() { db.Close() }) + + store := NewAssetStore(db) + + return assetTestHarness{ + store: store, + } +} + +func (h *assetTestHarness) assertGet(t *testing.T, exp, id string) { + t.Helper() + buf := new(bytes.Buffer) + err := h.store.Get(id, buf) + assert.NoError(t, err) + assert.Equal(t, exp, buf.String()) +} + +func (h *assetTestHarness) assertNotFound(t *testing.T, id string) { + t.Helper() + err := h.store.Get(id, io.Discard) + assert.ErrorIs(t, ErrAssetNotFound, err) +} + +func TestAssetStore(t *testing.T) { + + h := newAssetTestHarness(t) + + h.assertNotFound(t, "foo") + h.assertNotFound(t, "bar") + + err := h.store.Set("foo", bytes.NewBufferString("FOO")) + assert.NoError(t, err) + + h.assertGet(t, "FOO", "foo") + h.assertNotFound(t, "bar") + + err = h.store.Set("foo", bytes.NewBufferString("FOOFOO")) + assert.NoError(t, err) + + h.assertGet(t, "FOOFOO", "foo") + h.assertNotFound(t, "bar") + + assert.NoError(t, h.store.Delete("foo")) + h.assertNotFound(t, "foo") + h.assertNotFound(t, "bar") + + assert.NoError(t, h.store.Delete("bar")) + h.assertNotFound(t, "foo") + h.assertNotFound(t, "bar") +} -- cgit v1.2.3