feat(note/backlinks): added support for querying backlinks (#33)

* feat(link/backlinks): backlinks query

* feat(link/backlinks): register handler

* feat(note/backlinks): added backlink query and handler

cmd/main.go

@@ -37,6 +37,7 @@ func main() {
 	server.RegisterHandler("note/create", note.NewCreateNoteHandler(uow, tagService, noteRepo))
 	server.RegisterHandler("note/save", note.NewSaveNoteHandler(uow, noteRepo, tagService, noteService, linkService))
 	server.RegisterHandler("note/goto", note.NewGotoNoteHandler(noteRepo))
+	server.RegisterHandler("note/backlinks", note.NewGetBackLinksHandler(linkRepo, noteRepo))
 
 	server.RegisterHandler("completion/link", completion.NewCompleteLinkHandler(linkRepo))
 	server.RegisterHandler("completion/tag", completion.NewCompleteTagHandler(tagRepo))

core/dtos/backlink.go

@@ -0,0 +1,23 @@
+package dtos
+
+type Backlink struct {
+	ID    string `json:"id"`
+	Title string `json:"title"`
+	Slug  string `json:"slug"`
+	Path  string `json:"path"`
+	Raw   string `json:"raw"`
+	Line  int    `json:"line"`
+	Col   int    `json:"col"`
+}
+
+func NewBacklink(id, title, slug, path, raw string, col, line int) *Backlink {
+	return &Backlink{
+		ID:    id,
+		Title: title,
+		Slug:  slug,
+		Path:  path,
+		Raw:   raw,
+		Line:  line,
+		Col:   col,
+	}
+}

core/dtos/doc.go

@@ -0,0 +1,2 @@
+// Package dtos contains the data transfer objects used in the application.
+package dtos

core/handlers/note/get_backlinks_handler.go

@@ -0,0 +1,40 @@
+package note
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/KristianJBorgwarth/dendrite.daemon/persistence/repositories"
+)
+
+type getBacklinksCommand struct {
+	Path string `json:"path"`
+}
+
+type GetBackLinksHandler struct {
+	linkRepo repositories.ILinkRepository
+	noteRepo repositories.INoteRepository
+}
+
+func NewGetBackLinksHandler(lr repositories.ILinkRepository, nr repositories.INoteRepository) *GetBackLinksHandler {
+	return &GetBackLinksHandler{linkRepo: lr, noteRepo: nr}
+}
+
+func (h *GetBackLinksHandler) Handle(ctx context.Context, raw json.RawMessage) (any, error) {
+	var cmd getBacklinksCommand
+	if err := json.Unmarshal(raw, &cmd); err != nil {
+		return nil, err
+	}
+
+	note, err := h.noteRepo.GetByPath(ctx, cmd.Path)
+	if err != nil {
+		return nil, err
+	}
+
+	links, err := h.linkRepo.GetBacklinks(ctx, note.Slug())
+	if err != nil {
+		return nil, err
+	}
+
+	return links, nil
+}

persistence/repositories/link_repository.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"strings"
 
+	"github.com/KristianJBorgwarth/dendrite.daemon/core/dtos"
 	"github.com/KristianJBorgwarth/dendrite.daemon/core/models"
 	"github.com/KristianJBorgwarth/dendrite.daemon/persistence"
 )
@@ -14,6 +15,7 @@ type ILinkRepository interface {
 	GetByNoteID(ctx context.Context, dbContext persistence.IDbContext, fromNoteID string) ([]*models.Link, error)
 	GetBySlug(ctx context.Context, dbContext persistence.IDbContext, targetSlug string) ([]*models.Link, error)
 	Search(ctx context.Context, query string) ([]*models.Link, error)
+	GetBacklinks(ctx context.Context, slug string) ([]*dtos.Backlink, error)
 	Delete(ctx context.Context, dbContext persistence.IDbContext, fromNoteID string) error
 }
 
@@ -123,6 +125,32 @@ func (r *linkRepository) Search(ctx context.Context, query string) ([]*models.Li
 	return links, nil
 }
 
+func (r *linkRepository) GetBacklinks(ctx context.Context, slug string) ([]*dtos.Backlink, error) {
+	query := `
+	SELECT n.id, n.slug, n.title, n.path, l.raw, l.line, l.col
+	FROM link l
+	JOIN note n ON l.from_note_id = n.id
+	WHERE l.target_slug = ?`
+
+	rows, err := r.readDBContext.QueryContext(ctx, query, slug)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	backlinks := make([]*dtos.Backlink, 0)
+	for rows.Next() {
+		var noteID, noteSlug, noteTitle, notePath, raw string
+		var line, col int
+		if err := rows.Scan(&noteID, &noteSlug, &noteTitle, &notePath, &raw, &line, &col); err != nil {
+			return nil, err
+		}
+		backlinks = append(backlinks, dtos.NewBacklink(noteID, noteTitle, noteSlug, notePath, raw, line, col))
+	}
+
+	return backlinks, nil
+}
+
 func (r *linkRepository) Delete(ctx context.Context, dbContext persistence.IDbContext, fromNoteID string) error {
 	_, err := dbContext.ExecContext(ctx, "DELETE FROM link WHERE from_note_id = ?", fromNoteID)
 	return err

persistence/repositories/note_repository.go

@@ -14,6 +14,7 @@ type INoteRepository interface {
 	InsertRange(ctx context.Context, dbContext persistence.IDbContext, note []*models.Note) error
 	Update(ctx context.Context, dbContext persistence.IDbContext, noteID, path, title, slug string) error
 	GetBySlug(ctx context.Context, slug string) (*models.Note, error)
+	GetByPath(ctx context.Context, path string) (*models.Note, error)
 	GetNoteCount(ctx context.Context) (int, error)
 }
 
@@ -84,6 +85,22 @@ func (r *noteRepository) GetBySlug(ctx context.Context, slug string) (*models.No
 	return models.NewNote(id, path, title, slug, createdAt, updatedAt), nil
 }
 
+func (r *noteRepository) GetByPath(ctx context.Context, path string) (*models.Note, error) {
+	query := `SELECT id, title, path, slug, created_at, updated_at FROM note WHERE path = ?`
+	row := r.readDBContext.QueryRowContext(ctx, query, path)
+
+	var id, title, slug, createdAt, updatedAt string
+	err := row.Scan(&id, &title, &path, &slug, &createdAt, &updatedAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	
+	return models.NewNote(id, path, title, slug, createdAt, updatedAt), nil
+}
+
 func (r *noteRepository) GetNoteCount(ctx context.Context) (int, error) {
 	query := `SELECT COUNT(*) FROM note`
 	row := r.readDBContext.QueryRowContext(ctx, query)