diff options
author | Brian Picciano <mediocregopher@gmail.com> | 2023-04-15 21:07:16 +0200 |
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committer | Brian Picciano <mediocregopher@gmail.com> | 2023-04-15 21:07:16 +0200 |
commit | 7872296b838f4d1b26c6a0a01d79d27fe5ab44cc (patch) | |
tree | 9487f5abb93d88ab3b52700d2b3002b7dda373d6 /src/post/asset/asset.go | |
parent | 68f3215df6e2e4f345076dd5b20b9bf5867353cf (diff) |
Move asset store into its own package
Diffstat (limited to 'src/post/asset/asset.go')
-rw-r--r-- | src/post/asset/asset.go | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/src/post/asset/asset.go b/src/post/asset/asset.go new file mode 100644 index 0000000..d20b347 --- /dev/null +++ b/src/post/asset/asset.go @@ -0,0 +1,116 @@ +package asset + +import ( + "bytes" + "database/sql" + "errors" + "fmt" + "io" + + "github.com/mediocregopher/blog.mediocregopher.com/srv/post" +) + +var ( + // ErrNotFound is used to indicate an Asset could not be found in the + // Store. + ErrNotFound = errors.New("asset not found") +) + +// Store implements the storage and retrieval of binary assets, which are +// intended to be used by posts (e.g. images). +type Store 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 + // ErrNotFound. + Get(id string, into io.Writer) error + + // Delete's the body stored for the id, if any. + Delete(id string) error + + // List returns all ids which are currently stored. + List() ([]string, error) +} + +type store struct { + db *post.SQLDB +} + +// NewStore initializes a new Store using an existing SQLDB. +func NewStore(db *post.SQLDB) Store { + return &store{ + db: db, + } +} + +func (s *store) 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 *store) 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 ErrNotFound + } 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 *store) Delete(id string) error { + _, err := s.db.Exec(`DELETE FROM assets WHERE id = ?`, id) + return err +} + +func (s *store) List() ([]string, error) { + + rows, err := s.db.Query(`SELECT id FROM assets ORDER BY id ASC`) + + if err != nil { + return nil, fmt.Errorf("querying: %w", err) + } + + defer rows.Close() + + var ids []string + + for rows.Next() { + + var id string + if err := rows.Scan(&id); err != nil { + return nil, fmt.Errorf("scanning row: %w", err) + } + + ids = append(ids, id) + } + + return ids, nil +} |