svg-templater/pkg/svg/storage.go

package svg

import (
	"errors"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"golang.org/x/image/font/sfnt"
)

type SvgStorage interface {
	Create(id string, svg io.Reader) (string, error)
	Get(id string) (io.ReadCloser, error)
	AddFont(reader io.Reader, format string) error
	GetFonts() ([]string, error)
	GetFontsDir() (string, error)
	CreatePublic(data io.Reader, filetype string) (string, error)
	GetPublic(path string) (io.ReadCloser, error)
	GetPublicDir() http.Dir
}

var _ SvgStorage = FileSvgStorage{}
var TempDir string = ""

type FileSvgStorage struct {
	basepath, publicSubPath, fontssubpath string
}

func NewFileStorage(path, publicSubPath, fontssubpath string) *FileSvgStorage {
	err := os.MkdirAll(path, 0755)
	if err != nil {
		panic(err)
	}
	err = os.MkdirAll(filepath.Join(path, fontssubpath), 0755)
	if err != nil {
		panic(err)
	}
	log.Println("Initialized file storage handler")
	return &FileSvgStorage{path, publicSubPath, fontssubpath}
}

func (f FileSvgStorage) Create(id string, svg io.Reader) (string, error) {
	file, err := os.Create(filepath.Join(f.basepath, id+".svg"))

	if err != nil {
		return "", err
	}
	defer file.Close()

	_, err = io.Copy(file, svg)
	if err != nil {
		return "", err
	}

	log.Println("Created File: ", file.Name())
	return file.Name(), nil
}

func (f FileSvgStorage) Get(id string) (io.ReadCloser, error) {
	file, err := os.Open(filepath.Join(f.basepath, id+".svg"))
	if err != nil {
		return nil, err
	}
	return file, nil
}

func (f FileSvgStorage) CreatePublic(data io.Reader, filetype string) (string, error) {
	path := filepath.Join(f.basepath, f.publicSubPath)
	if err := os.MkdirAll(path, 0755); err != nil {
		return "", err
	}

	file, err := os.CreateTemp(path, "*."+filetype)
	if err != nil {
		return "", err
	}
	defer file.Close()
	_, err = io.Copy(file, data)
	if err != nil {
		return "", err
	}

	return strings.TrimPrefix(file.Name(), path), nil
}

func (f FileSvgStorage) GetPublic(path string) (io.ReadCloser, error) {
	file, err := os.Open(filepath.Join(f.basepath, f.publicSubPath, path))
	if err != nil {
		return nil, err
	}
	return file, nil
}

func (f FileSvgStorage) GetPublicDir() http.Dir {
	return http.Dir(filepath.Join(f.basepath, f.publicSubPath))
}

func CreateTemp(data io.Reader, filetype string) (string, error) {
	file, err := os.CreateTemp(TempDir, "*."+filetype)
	if err != nil {
		return "", err
	}
	defer file.Close()
	_, err = io.Copy(file, data)
	if err != nil {
		return "", err
	}

	return file.Name(), nil
}

func (f FileSvgStorage) AddFont(fontreader io.Reader, format string) error {
	if format != "ttf" && format != "otf" {
		return errors.New("Format not supported")
	}
	file, err := os.CreateTemp(filepath.Join(f.basepath, f.fontssubpath), "*."+format)
	if err != nil {
		return err
	}
	defer file.Close()
	log.Printf("Writing %s font to %s\n", format, file.Name())
	_, err = io.Copy(file, fontreader)
	if err != nil {
		return err
	}
	return nil
}

func (f FileSvgStorage) GetFonts() ([]string, error) {
	path := filepath.Join(f.basepath, f.fontssubpath)
	entries, err := os.ReadDir(path)
	if err != nil {
		return nil, err
	}
	fonts := make([]string, len(entries))
	for i, entry := range entries {
		if entry.IsDir() {
			continue
		}
		if strings.HasSuffix(entry.Name(), ".ttf") || strings.HasSuffix(entry.Name(), ".otf") {
			fontblob, err := os.ReadFile(filepath.Join(path, entry.Name()))
			if err != nil {
				return nil, err
			}
			fontname, err := getFontName(fontblob)
			if err != nil {
				return nil, err
			}
			fonts[i] = fontname
		}
	}
	log.Printf("Got fonts \n%s\n", strings.Join(fonts, "\n"))
	return fonts, nil
}

func (f FileSvgStorage) GetFontsDir() (string, error) {
	return filepath.Join(f.basepath, f.fontssubpath), nil
}

func getFontName(svgblob []byte) (string, error) {
	font, err := sfnt.Parse(svgblob)
	if err != nil {
		return "", err
	}
	name, err := font.Name(nil, sfnt.NameIDFull)
	if err != nil {
		return "", err
	}
	return name, nil
}