refactor: dry conversion code

convert/convert.go

@@ -1,14 +1,9 @@
 package convert
 
-const (
-	MOBI_MIME = "application/x-mobipocket-ebook"
-	EPUB_MIME = "application/epub+zip"
-)
-
 type Converter interface {
 	// Whether or not the converter is available
 	// Usually based on the availability of the underlying tool
 	Available() bool
 	// Convert the input file to the output file
-	Convert(input string, output string) error
+	Convert(input string) (string, error)
 }

convert/kepub.go

@@ -1,29 +1,40 @@
 package convert
 
 import (
+	"fmt"
 	"os/exec"
+	"path/filepath"
+	"strings"
 	"sync"
 )
 
 type KepubConverter struct {
-	mutex sync.Mutex
+	mutex         sync.Mutex
+	available     bool
+	availableOnce sync.Once
 }
 
 func (kc *KepubConverter) Available() bool {
-	path, err := exec.LookPath("kepubify")
-	if err != nil {
-		return false
-	}
-	return path != ""
+	kc.availableOnce.Do(func() {
+		fmt.Println("TEST")
+		path, err := exec.LookPath("kepubify")
+		kc.available = err == nil && path != ""
+	})
+
+	return kc.available
 }
 
-func (kc *KepubConverter) Convert(input string, output string) error {
+func (kc *KepubConverter) Convert(input string) (string, error) {
 	kc.mutex.Lock()
 	defer kc.mutex.Unlock()
-	cmd := exec.Command("kepubify", "-v", "-u", "-o", output, input)
+
+	dir := filepath.Dir(input)
+	kepubFile := filepath.Join(dir, strings.Replace(filepath.Base(input), ".epub", ".kepub.epub", 1))
+
+	cmd := exec.Command("kepubify", "-v", "-u", "-o", kepubFile, input)
 	if err := cmd.Run(); err != nil {
-		return err
+		return "", err
 	}
 
-	return nil
+	return kepubFile, nil
 }

convert/mobi.go

@@ -5,34 +5,38 @@ import (
 	"fmt"
 	"os/exec"
 	"path/filepath"
+	"strings"
 	"sync"
 )
 
 type MobiConverter struct {
-	mutex sync.Mutex
+	mutex         sync.Mutex
+	available     bool
+	availableOnce sync.Once
 }
 
 func (mc *MobiConverter) Available() bool {
-	path, err := exec.LookPath("kindlegen")
-	if err != nil {
-		return false
-	}
-	return path != ""
+	mc.availableOnce.Do(func() {
+		path, err := exec.LookPath("kindlegen")
+		mc.available = err == nil && path != ""
+	})
+	return mc.available
 }
 
-func (mc *MobiConverter) Convert(input string, output string) error {
+func (mc *MobiConverter) Convert(input string) (string, error) {
 	mc.mutex.Lock()
 	defer mc.mutex.Unlock()
 
 	// KindleGen doesn't allow the input file to be in a different directory
 	// So set the working directory to the input file.
 	outDir, _ := filepath.Abs(filepath.Dir(input))
+	mobiFile := filepath.Join(outDir, strings.Replace(filepath.Base(input), ".epub", ".mobi", 1))
 
 	// And remove the directory from file paths
 	cmd := exec.Command("kindlegen",
 		filepath.Base(input),
 		"-dont_append_source", "-c1", "-o",
-		filepath.Base(output),
+		filepath.Base(mobiFile),
 	)
 	cmd.Dir = outDir
 
@@ -45,13 +49,13 @@ func (mc *MobiConverter) Convert(input string, output string) error {
 		if exiterr, ok := err.(*exec.ExitError); ok {
 			if exiterr.ExitCode() != 1 {
 				fmt.Println(fmt.Sprint(err) + ": " + out.String() + ":" + stderr.String())
-				return err
+				return "", err
 			}
 		} else {
 			fmt.Println(fmt.Sprint(err) + ": " + out.String() + ":" + stderr.String())
-			return err
+			return "", err
 		}
 	}
 
-	return nil
+	return mobiFile, nil
 }