From f7d72adfb594980b0442c0fa7b5586e6248f96ac Mon Sep 17 00:00:00 2001 From: Brian Picciano Date: Fri, 6 May 2022 17:22:17 -0600 Subject: Implement post.Store --- srv/src/post/date.go | 59 +++++++ srv/src/post/post.go | 39 +---- srv/src/post/store.go | 403 +++++++++++++++++++++++++++++++++++++++++++++ srv/src/post/store_test.go | 248 ++++++++++++++++++++++++++++ 4 files changed, 711 insertions(+), 38 deletions(-) create mode 100644 srv/src/post/date.go create mode 100644 srv/src/post/store_test.go (limited to 'srv/src/post') diff --git a/srv/src/post/date.go b/srv/src/post/date.go new file mode 100644 index 0000000..34fe109 --- /dev/null +++ b/srv/src/post/date.go @@ -0,0 +1,59 @@ +package post + +import ( + "database/sql/driver" + "fmt" + "time" +) + +// Date represents a calendar date with no timezone information attached. +type Date struct { + Year int + Month time.Month + Day int +} + +// DateFromTime converts a Time into a Date, truncating all non-date +// information. +func DateFromTime(t time.Time) Date { + t = t.UTC() + return Date{ + Year: t.Year(), + Month: t.Month(), + Day: t.Day(), + } +} + +// ToTime converts a Date into a Time. The returned time will be UTC midnight of +// the Date. +func (d *Date) ToTime() time.Time { + return time.Date(d.Year, d.Month, d.Day, 0, 0, 0, 0, time.UTC) +} + +// Scan implements the sql.Scanner interface. +func (d *Date) Scan(src interface{}) error { + + if src == nil { + *d = Date{} + return nil + } + + ts, ok := src.(int64) + + if !ok { + return fmt.Errorf("cannot scan value %#v into Date", src) + } + + *d = DateFromTime(time.Unix(ts, 0)) + return nil +} + +// Value implements the driver.Valuer interface. +func (d Date) Value() (driver.Value, error) { + + if d == (Date{}) { + return nil, nil + } + + return d.ToTime().Unix(), nil +} diff --git a/srv/src/post/post.go b/srv/src/post/post.go index 54555c3..7803c82 100644 --- a/srv/src/post/post.go +++ b/srv/src/post/post.go @@ -2,30 +2,10 @@ package post import ( - "fmt" - "path" "regexp" "strings" - "time" ) -// Date represents a calendar date with no timezone information attached. -type Date struct { - Year int - Month time.Month - Day int -} - -// DateFromTime converts a Time into a Date, truncating all non-date -// information. -func DateFromTime(t time.Time) Date { - return Date{ - Year: t.Year(), - Month: t.Month(), - Day: t.Day(), - } -} - var titleCleanRegexp = regexp.MustCompile(`[^a-z ]`) // NewID generates a (hopefully) unique ID based on the given title. @@ -43,22 +23,5 @@ type Post struct { Description string Tags []string Series string - - PublishedAt Date - LastUpdatedAt Date - - Body string -} - -// URL returns the relative URL of the Post. -func (p Post) URL() string { - return path.Join( - fmt.Sprintf( - "%d/%0d/%0d", - p.PublishedAt.Year, - p.PublishedAt.Month, - p.PublishedAt.Day, - ), - p.ID+".html", - ) + Body string } diff --git a/srv/src/post/store.go b/srv/src/post/store.go index 235520f..2898315 100644 --- a/srv/src/post/store.go +++ b/srv/src/post/store.go @@ -1 +1,404 @@ package post + +import ( + "database/sql" + "errors" + "fmt" + "path" + "strings" + + _ "github.com/mattn/go-sqlite3" + migrate "github.com/rubenv/sql-migrate" + "github.com/tilinna/clock" +) + +var ( + // ErrNotFound is used to indicate a Post could not be found in the + // database. + ErrNotFound = errors.New("not found") +) + +// StoredPost is a Post which has been stored in a Store, and has been given +// some extra fields as a result. +type StoredPost struct { + Post + + PublishedAt Date + LastUpdatedAt Date +} + +// URL returns the relative URL of the StoredPost. +func (p StoredPost) URL() string { + return path.Join( + fmt.Sprintf( + "%d/%0d/%0d", + p.PublishedAt.Year, + p.PublishedAt.Month, + p.PublishedAt.Day, + ), + p.ID+".html", + ) +} + +// Store is used for storing posts to a persistent storage. +type Store interface { + + // Set sets the Post data into the storage, keyed by the Post's ID. It + // overwrites a previous Post with the same ID, if there was one. + Set(Post) error + + // Get returns count StoredPosts, sorted time descending, offset by the given page + // number. The returned boolean indicates if there are more pages or not. + Get(page, count int) ([]StoredPost, bool, error) + + // GetByID will return the StoredPost with the given ID, or ErrNotFound. + GetByID(id string) (StoredPost, error) + + // GetBySeries returns all StoredPosts with the given series, sorted time + // ascending, or empty slice. + GetBySeries(series string) ([]StoredPost, error) + + // GetByTag returns all StoredPosts with the given tag, sorted time + // ascending, or empty slice. + GetByTag(tag string) ([]StoredPost, error) + + // Delete will delete the StoredPost with the given ID. + Delete(id string) error + + Close() error +} + +var migrations = []*migrate.Migration{ + &migrate.Migration{ + Id: "1", + Up: []string{ + `CREATE TABLE posts ( + id TEXT NOT NULL PRIMARY KEY, + title TEXT NOT NULL, + description TEXT NOT NULL, + series TEXT, + + published_at INTEGER NOT NULL, + last_updated_at INTEGER, + + body TEXT NOT NULL + )`, + `CREATE TABLE post_tags ( + post_id TEXT NOT NULL, + tag TEXT NOT NULL, + UNIQUE(post_id, tag) + )`, + }, + Down: []string{ + "DROP TABLE post_tags", + "DROP TABLE posts", + }, + }, +} + +// Params are parameters used to initialize a new Store. All fields are required +// unless otherwise noted. +type StoreParams struct { + + // Path to the file the database will be stored at. + DBFilePath string + + Clock clock.Clock +} + +type store struct { + params StoreParams + db *sql.DB +} + +// NewStore initializes a new Store using a sqlite3 database at the given file +// path. +func NewStore(params StoreParams) (Store, error) { + + db, err := sql.Open("sqlite3", params.DBFilePath) + if err != nil { + return nil, fmt.Errorf("opening sqlite file: %w", err) + } + + migrations := &migrate.MemoryMigrationSource{Migrations: migrations} + + if _, err := migrate.Exec(db, "sqlite3", migrations, migrate.Up); err != nil { + return nil, fmt.Errorf("running migrations: %w", err) + } + + return &store{ + params: params, + db: db, + }, nil +} + +func (s *store) Close() error { + return s.db.Close() +} + +// if the callback returns an error then the transaction is aborted +func (s *store) withTx(cb func(*sql.Tx) error) error { + + tx, err := s.db.Begin() + + if err != nil { + return fmt.Errorf("starting transaction: %w", err) + } + + if err := cb(tx); err != nil { + + if rollbackErr := tx.Rollback(); rollbackErr != nil { + return fmt.Errorf( + "rolling back transaction: %w (original error: %v)", + rollbackErr, err, + ) + } + + return fmt.Errorf("performing transaction: %w (rolled back)", err) + } + + if err := tx.Commit(); err != nil { + return fmt.Errorf("committing transaction: %w", err) + } + + return nil +} + +func (s *store) Set(post Post) error { + return s.withTx(func(tx *sql.Tx) error { + currentDate := DateFromTime(s.params.Clock.Now()) + + _, err := tx.Exec( + `INSERT INTO posts ( + id, title, description, series, published_at, body + ) + VALUES + (?, ?, ?, ?, ?, ?) + ON CONFLICT (id) DO UPDATE SET + title=excluded.title, + description=excluded.description, + series=excluded.series, + last_updated_at=?, + body=excluded.body`, + post.ID, + post.Title, + post.Description, + &sql.NullString{String: post.Series, Valid: post.Series != ""}, + currentDate, + post.Body, + currentDate, + ) + + if err != nil { + return fmt.Errorf("inserting into posts: %w", err) + } + + // this is a bit of a hack, but it allows us to update the tagset without + // doing a diff. + _, err = tx.Exec(`DELETE FROM post_tags WHERE post_id = ?`, post.ID) + + if err != nil { + return fmt.Errorf("clearning post tags: %w", err) + } + + for _, tag := range post.Tags { + + _, err = tx.Exec( + `INSERT INTO post_tags (post_id, tag) VALUES (?, ?) + ON CONFLICT DO NOTHING`, + post.ID, + tag, + ) + + if err != nil { + return fmt.Errorf("inserting tag %q: %w", tag, err) + } + } + + return nil + }) +} + +func (s *store) get( + querier interface { + Query(string, ...interface{}) (*sql.Rows, error) + }, + limit, offset int, + where string, whereArgs ...interface{}, +) ( + []StoredPost, error, +) { + + query := `SELECT + p.id, p.title, p.description, p.series, pt.tag, + p.published_at, p.last_updated_at, + p.body + FROM posts p + LEFT JOIN post_tags pt ON (p.id = pt.post_id) + ` + where + ` + ORDER BY p.published_at ASC, p.title ASC` + + if limit > 0 { + query += fmt.Sprintf(" LIMIT %d", limit) + } + + if offset > 0 { + query += fmt.Sprintf(" OFFSET %d", offset) + } + + rows, err := querier.Query(query, whereArgs...) + + if err != nil { + return nil, fmt.Errorf("selecting: %w", err) + } + + var posts []StoredPost + + for rows.Next() { + + var ( + post StoredPost + series, tag sql.NullString + ) + + err := rows.Scan( + &post.ID, &post.Title, &post.Description, &series, &tag, + &post.PublishedAt, &post.LastUpdatedAt, + &post.Body, + ) + + if err != nil { + return nil, fmt.Errorf("scanning row: %w", err) + } + + if tag.Valid { + + if l := len(posts); l > 0 && posts[l-1].ID == post.ID { + posts[l-1].Tags = append(posts[l-1].Tags, tag.String) + continue + } + + post.Tags = append(post.Tags, tag.String) + } + + post.Series = series.String + + posts = append(posts, post) + } + + if err := rows.Close(); err != nil { + return nil, fmt.Errorf("closing row iterator: %w", err) + } + + return posts, nil +} + +func (s *store) Get(page, count int) ([]StoredPost, bool, error) { + + posts, err := s.get(s.db, count+1, page*count, ``) + + if err != nil { + return nil, false, fmt.Errorf("querying posts: %w", err) + } + + var hasMore bool + + if len(posts) > count { + hasMore = true + posts = posts[:count] + } + + return posts, hasMore, nil +} + +func (s *store) GetByID(id string) (StoredPost, error) { + + posts, err := s.get(s.db, 0, 0, `WHERE p.id=?`, id) + + if err != nil { + return StoredPost{}, fmt.Errorf("querying posts: %w", err) + } + + if len(posts) == 0 { + return StoredPost{}, ErrNotFound + } + + if len(posts) > 1 { + panic(fmt.Sprintf("got back multiple posts querying id %q: %+v", id, posts)) + } + + return posts[0], nil +} + +func (s *store) GetBySeries(series string) ([]StoredPost, error) { + return s.get(s.db, 0, 0, `WHERE p.series=?`, series) +} + +func (s *store) GetByTag(tag string) ([]StoredPost, error) { + + var posts []StoredPost + + err := s.withTx(func(tx *sql.Tx) error { + + rows, err := tx.Query(`SELECT post_id FROM post_tags WHERE tag = ?`, tag) + + if err != nil { + return fmt.Errorf("querying post_tags by tag: %w", err) + } + + var ( + placeholders []string + whereArgs []interface{} + ) + + for rows.Next() { + + var id string + + if err := rows.Scan(&id); err != nil { + rows.Close() + return fmt.Errorf("scanning id: %w", err) + } + + whereArgs = append(whereArgs, id) + placeholders = append(placeholders, "?") + } + + if err := rows.Close(); err != nil { + return fmt.Errorf("closing row iterator: %w", err) + } + + where := fmt.Sprintf("WHERE p.id IN (%s)", strings.Join(placeholders, ",")) + + if posts, err = s.get(tx, 0, 0, where, whereArgs...); err != nil { + return fmt.Errorf("querying for ids %+v: %w", whereArgs, err) + } + + return nil + }) + + return posts, err +} + +func (s *store) Delete(id string) error { + + tx, err := s.db.Begin() + + if err != nil { + return fmt.Errorf("starting transaction: %w", err) + } + + if _, err := tx.Exec(`DELETE FROM post_tags WHERE post_id = ?`, id); err != nil { + return fmt.Errorf("deleting from post_tags: %w", err) + } + + if _, err := tx.Exec(`DELETE FROM posts WHERE id = ?`, id); err != nil { + return fmt.Errorf("deleting from posts: %w", err) + } + + if err := tx.Commit(); err != nil { + return fmt.Errorf("committing transaction: %w", err) + } + + return nil +} diff --git a/srv/src/post/store_test.go b/srv/src/post/store_test.go new file mode 100644 index 0000000..1890511 --- /dev/null +++ b/srv/src/post/store_test.go @@ -0,0 +1,248 @@ +package post + +import ( + "io/ioutil" + "os" + "sort" + "strconv" + "testing" + "time" + + "github.com/stretchr/testify/assert" + "github.com/tilinna/clock" +) + +func testPost(i int) Post { + istr := strconv.Itoa(i) + return Post{ + ID: istr, + Title: istr, + Description: istr, + Body: istr, + } +} + +type storeTestHarness struct { + clock *clock.Mock + store Store +} + +func newStoreTestHarness(t *testing.T) storeTestHarness { + + clock := clock.NewMock(time.Now().Truncate(1 * time.Hour)) + + tmpFile, err := ioutil.TempFile(os.TempDir(), "mediocre-blog-post-store-test-") + if err != nil { + t.Fatal("Cannot create temporary file", err) + } + tmpFilePath := tmpFile.Name() + tmpFile.Close() + + t.Logf("using temporary sqlite file at %q", tmpFilePath) + + t.Cleanup(func() { + if err := os.Remove(tmpFilePath); err != nil { + panic(err) + } + }) + + store, err := NewStore(StoreParams{ + DBFilePath: tmpFilePath, + Clock: clock, + }) + assert.NoError(t, err) + + t.Cleanup(func() { + assert.NoError(t, store.Close()) + }) + + return storeTestHarness{ + clock: clock, + store: store, + } +} + +func (h *storeTestHarness) testStoredPost(i int) StoredPost { + post := testPost(i) + return StoredPost{ + Post: post, + PublishedAt: DateFromTime(h.clock.Now()), + } +} + +func TestStore(t *testing.T) { + + assertPostEqual := func(t *testing.T, exp, got StoredPost) { + t.Helper() + sort.Strings(exp.Tags) + sort.Strings(got.Tags) + assert.Equal(t, exp, got) + } + + assertPostsEqual := func(t *testing.T, exp, got []StoredPost) { + t.Helper() + + if !assert.Len(t, got, len(exp), "exp:%+v\ngot: %+v", exp, got) { + return + } + + for i := range exp { + assertPostEqual(t, exp[i], got[i]) + } + } + + t.Run("not_found", func(t *testing.T) { + h := newStoreTestHarness(t) + + _, err := h.store.GetByID("foo") + assert.ErrorIs(t, err, ErrNotFound) + }) + + t.Run("set_get_delete", func(t *testing.T) { + h := newStoreTestHarness(t) + + nowDate := DateFromTime(h.clock.Now()) + + post := testPost(0) + post.Tags = []string{"foo", "bar"} + + assert.NoError(t, h.store.Set(post)) + + gotPost, err := h.store.GetByID(post.ID) + assert.NoError(t, err) + + assertPostEqual(t, StoredPost{ + Post: post, + PublishedAt: nowDate, + }, gotPost) + + // we will now try updating the post on a different day, and ensure it + // updates properly + + h.clock.Add(24 * time.Hour) + newNowDate := DateFromTime(h.clock.Now()) + + post.Title = "something else" + post.Series = "whatever" + post.Body = "anything" + post.Tags = []string{"bar", "baz"} + + assert.NoError(t, h.store.Set(post)) + + gotPost, err = h.store.GetByID(post.ID) + assert.NoError(t, err) + + assertPostEqual(t, StoredPost{ + Post: post, + PublishedAt: nowDate, + LastUpdatedAt: newNowDate, + }, gotPost) + + // delete the post, it should go away + assert.NoError(t, h.store.Delete(post.ID)) + + _, err = h.store.GetByID(post.ID) + assert.ErrorIs(t, err, ErrNotFound) + }) + + t.Run("get", func(t *testing.T) { + h := newStoreTestHarness(t) + + posts := []StoredPost{ + h.testStoredPost(0), + h.testStoredPost(1), + h.testStoredPost(2), + h.testStoredPost(3), + } + + for _, post := range posts { + assert.NoError(t, h.store.Set(post.Post)) + } + + gotPosts, hasMore, err := h.store.Get(0, 2) + assert.NoError(t, err) + assert.True(t, hasMore) + assertPostsEqual(t, posts[:2], gotPosts) + + gotPosts, hasMore, err = h.store.Get(1, 2) + assert.NoError(t, err) + assert.False(t, hasMore) + assertPostsEqual(t, posts[2:4], gotPosts) + + posts = append(posts, h.testStoredPost(4)) + assert.NoError(t, h.store.Set(posts[4].Post)) + + gotPosts, hasMore, err = h.store.Get(1, 2) + assert.NoError(t, err) + assert.True(t, hasMore) + assertPostsEqual(t, posts[2:4], gotPosts) + + gotPosts, hasMore, err = h.store.Get(2, 2) + assert.NoError(t, err) + assert.False(t, hasMore) + assertPostsEqual(t, posts[4:], gotPosts) + }) + + t.Run("get_by_series", func(t *testing.T) { + h := newStoreTestHarness(t) + + posts := []StoredPost{ + h.testStoredPost(0), + h.testStoredPost(1), + h.testStoredPost(2), + h.testStoredPost(3), + } + + posts[0].Series = "foo" + posts[1].Series = "bar" + posts[2].Series = "bar" + + for _, post := range posts { + assert.NoError(t, h.store.Set(post.Post)) + } + + fooPosts, err := h.store.GetBySeries("foo") + assert.NoError(t, err) + assertPostsEqual(t, posts[:1], fooPosts) + + barPosts, err := h.store.GetBySeries("bar") + assert.NoError(t, err) + assertPostsEqual(t, posts[1:3], barPosts) + + bazPosts, err := h.store.GetBySeries("baz") + assert.NoError(t, err) + assert.Empty(t, bazPosts) + }) + + t.Run("get_by_tag", func(t *testing.T) { + + h := newStoreTestHarness(t) + + posts := []StoredPost{ + h.testStoredPost(0), + h.testStoredPost(1), + h.testStoredPost(2), + h.testStoredPost(3), + } + + posts[0].Tags = []string{"foo"} + posts[1].Tags = []string{"foo", "bar"} + posts[2].Tags = []string{"bar"} + + for _, post := range posts { + assert.NoError(t, h.store.Set(post.Post)) + } + + fooPosts, err := h.store.GetByTag("foo") + assert.NoError(t, err) + assertPostsEqual(t, posts[:2], fooPosts) + + barPosts, err := h.store.GetByTag("bar") + assert.NoError(t, err) + assertPostsEqual(t, posts[1:3], barPosts) + + bazPosts, err := h.store.GetByTag("baz") + assert.NoError(t, err) + assert.Empty(t, bazPosts) + }) +} -- cgit v1.2.3