tests(all): improve tests, refactor(api): saving books

metadata/metadata.go

@@ -3,27 +3,47 @@ package metadata
 import (
 	"errors"
 	"fmt"
+	"io"
 	"path/filepath"
 
 	"github.com/gabriel-vasile/mimetype"
+	"reichard.io/antholume/utils"
 )
 
+type MetadataHandler func(string) (*MetadataInfo, error)
+
+type DocumentType string
+
+const (
+	TYPE_EPUB DocumentType = ".epub"
+)
+
+var extensionHandlerMap = map[DocumentType]MetadataHandler{
+	TYPE_EPUB: getEPUBMetadata,
+}
+
 type Source int
 
 const (
-	GBOOK Source = iota
-	OLIB
+	SOURCE_GBOOK Source = iota
+	SOURCE_OLIB
 )
 
 type MetadataInfo struct {
-	ID          *string
+	ID         *string
+	MD5        *string
+	PartialMD5 *string
+	WordCount  *int64
+
 	Title       *string
 	Author      *string
 	Description *string
 	ISBN10      *string
 	ISBN13      *string
+	Type        DocumentType
 }
 
+// Downloads the Google Books cover file and saves it to the provided directory.
 func CacheCover(gbid string, coverDir string, documentID string, overwrite bool) (*string, error) {
 	// Get Filepath
 	coverFile := "." + filepath.Clean(fmt.Sprintf("/%s.jpg", documentID))
@@ -39,11 +59,12 @@ func CacheCover(gbid string, coverDir string, documentID string, overwrite bool)
 	return &coverFile, nil
 }
 
+// Searches source for metadata based on the provided information.
 func SearchMetadata(s Source, metadataSearch MetadataInfo) ([]MetadataInfo, error) {
 	switch s {
-	case GBOOK:
+	case SOURCE_GBOOK:
 		return getGBooksMetadata(metadataSearch)
-	case OLIB:
+	case SOURCE_OLIB:
 		return nil, errors.New("Not implemented")
 	default:
 		return nil, errors.New("Not implemented")
@@ -51,32 +72,112 @@ func SearchMetadata(s Source, metadataSearch MetadataInfo) ([]MetadataInfo, erro
 	}
 }
 
-func GetWordCount(filepath string) (int64, error) {
-	fileMime, err := mimetype.DetectFile(filepath)
-	if err != nil {
-		return 0, err
-	}
-
-	if fileExtension := fileMime.Extension(); fileExtension == ".epub" {
-		totalWords, err := countEPUBWords(filepath)
-		if err != nil {
-			return 0, err
-		}
-		return totalWords, nil
-	} else {
-		return 0, errors.New("Invalid Extension")
-	}
-}
-
-func GetMetadata(filepath string) (*MetadataInfo, error) {
+// Returns the word count of the provided filepath. An error will be returned
+// if the file is not supported.
+func GetWordCount(filepath string) (*int64, error) {
 	fileMime, err := mimetype.DetectFile(filepath)
 	if err != nil {
 		return nil, err
 	}
 
 	if fileExtension := fileMime.Extension(); fileExtension == ".epub" {
-		return getEPUBMetadata(filepath)
+		totalWords, err := countEPUBWords(filepath)
+		if err != nil {
+			return nil, err
+		}
+		return &totalWords, nil
 	} else {
-		return nil, errors.New("Invalid Extension")
+		return nil, fmt.Errorf("Invalid extension")
 	}
 }
+
+// Returns embedded metadata of the provided file. An error will be returned if
+// the file is not supported.
+func GetMetadata(filepath string) (*MetadataInfo, error) {
+	// Detect Extension Type
+	fileMime, err := mimetype.DetectFile(filepath)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get Extension Type Metadata Handler
+	fileExtension := fileMime.Extension()
+	handler, ok := extensionHandlerMap[DocumentType(fileExtension)]
+	if !ok {
+		return nil, fmt.Errorf("invalid extension %s", fileExtension)
+	}
+
+	// Acquire Metadata
+	metadataInfo, err := handler(filepath)
+
+	// Calculate MD5 & Partial MD5
+	partialMD5, err := utils.CalculatePartialMD5(filepath)
+	if err != nil {
+		return nil, fmt.Errorf("unable to calculate partial MD5")
+	}
+
+	// Calculate Actual MD5
+	MD5, err := utils.CalculateMD5(filepath)
+	if err != nil {
+		return nil, fmt.Errorf("unable to calculate MD5")
+	}
+
+	// Calculate Word Count
+	wordCount, err := GetWordCount(filepath)
+	if err != nil {
+		return nil, fmt.Errorf("unable to calculate word count")
+	}
+
+	metadataInfo.WordCount = wordCount
+	metadataInfo.PartialMD5 = partialMD5
+	metadataInfo.MD5 = MD5
+
+	return metadataInfo, nil
+}
+
+// Returns the extension of the provided filepath (e.g. ".epub"). An error
+// will be returned if the file is not supported.
+func GetDocumentType(filepath string) (*DocumentType, error) {
+	// Detect Extension Type
+	fileMime, err := mimetype.DetectFile(filepath)
+	if err != nil {
+		return nil, err
+	}
+
+	// Detect
+	fileExtension := fileMime.Extension()
+	docType, ok := ParseDocumentType(fileExtension)
+	if !ok {
+		return nil, fmt.Errorf("filetype not supported")
+	}
+
+	return &docType, nil
+}
+
+// Returns the extension of the provided file reader (e.g. ".epub"). An error
+// will be returned if the file is not supported.
+func GetDocumentTypeReader(r io.Reader) (*DocumentType, error) {
+	// Detect Extension Type
+	fileMime, err := mimetype.DetectReader(r)
+	if err != nil {
+		return nil, err
+	}
+
+	// Detect
+	fileExtension := fileMime.Extension()
+	docType, ok := ParseDocumentType(fileExtension)
+	if !ok {
+		return nil, fmt.Errorf("filetype not supported")
+	}
+
+	return &docType, nil
+}
+
+// Given a filetype string, attempt to resolve a DocumentType
+func ParseDocumentType(input string) (DocumentType, bool) {
+	validTypes := map[string]DocumentType{
+		string(TYPE_EPUB): TYPE_EPUB,
+	}
+	found, ok := validTypes[input]
+	return found, ok
+}