1 files changed, 175 insertions, 0 deletions
diff --git a/cmd/dlgbook/main.go b/cmd/dlgbook/main.go
new file mode 100644
index 0000000..3aa8015
--- /dev/null
+++ b/cmd/dlgbook/main.go
@@ -0,0 +1,175 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"path"
+	"strings"
+	"unicode"
+)
+
+const usage = `Usage: dlgbook bookid [-a author] [-y year] [-t title] [savedir]
+
+Downloads all pages from a Google Book, using the getgbook
+tool, extracting the date, author name and title from
+Google Books (unless given as arguments to dlgbook), and
+saves them into a directory named YEAR_AUTHORSURNAME_Title 
+`
+
+// formatAuthors formats a list of authors by just selecting
+// the first one listed, and returning the uppercased final
+// name.
+func formatAuthors(authors []string) string {
+	if len(authors) == 0 {
+		return ""
+	}
+
+	s := authors[0]
+
+	parts := strings.Fields(s)
+	if len(parts) > 1 {
+		s = parts[len(parts)-1]
+	}
+
+	s = strings.ToUpper(s)
+
+	return s
+}
+
+// mapTitle is a function for strings.Map to strip out
+// unwanted characters from the title.
+func mapTitle(r rune) rune {
+	if !unicode.IsLetter(r) {
+		return -1
+	}
+	return r
+}
+
+// formatTitle formats a title to our preferences, notably
+// by stripping spaces and punctuation characters.
+func formatTitle(title string) string {
+	return strings.Map(mapTitle, title)
+}
+
+// getMetadata queries Google Books for metadata we care about
+// and returns it formatted as we need it.
+func getMetadata(id string) (string, string, string, error) {
+	var author, title, year string
+	url := fmt.Sprintf("https://www.googleapis.com/books/v1/volumes/%s", id)
+
+	// designed to be unmarshalled by encoding/json's Unmarshal()
+	type bookInfo struct {
+		VolumeInfo struct {
+			Title string
+			Authors []string
+			PublishedDate string
+		}
+	}
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return author, title, year, fmt.Errorf("Error downloading metadata %s: %v", url, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return author, title, year, fmt.Errorf("Error downloading metadata %s: %v", url, err)
+	}
+
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return author, title, year, fmt.Errorf("Error reading metadata %s: %v", url, err)
+	}
+
+	v := bookInfo{}
+	err = json.Unmarshal(b, &v)
+	if err != nil {
+		return author, title, year, fmt.Errorf("Error parsing metadata %s: %v", url, err)
+	}
+
+	author = formatAuthors(v.VolumeInfo.Authors)
+	title = formatTitle(v.VolumeInfo.Title)
+	year = v.VolumeInfo.PublishedDate
+
+	return author, title, year, nil
+}
+
+func main() {
+	author := flag.String("author", "", "Set author, rather than autodetecting")
+	title := flag.String("title", "", "Set title, rather than autodetecting")
+	year := flag.String("year", "", "Set year, rather than autodetecting")
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), usage)
+		flag.PrintDefaults()
+	}
+	flag.Parse()
+
+	if flag.NArg() < 1 {
+		flag.Usage()
+		return
+	}
+	bookid := flag.Arg(0)
+
+	if *author == "" || *title == "" || *year == "" {
+		a, t, y, err := getMetadata(bookid)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if *author == "" {
+			*author = a
+		}
+		if *title == "" {
+			*title = t
+		}
+		if *year == "" {
+			*year = y
+		}
+	}
+
+	dir := fmt.Sprintf("%s_%s_%s", *year, *author, *title)
+	err := os.MkdirAll(dir, 0755)
+	if err != nil {
+		log.Fatalf("Couldn't create directory %s: %v", dir, err)
+	}
+	cmd := exec.Command("getgbook", bookid)
+	cmd.Dir = dir
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err = cmd.Run()
+	if err != nil {
+		log.Fatalf("Error running getgbook %s: %v", bookid, err)
+	}
+
+	// getgbook downloads into bookid directory, so move files out of
+	// there directly into dir
+	tmpdir := path.Join(dir, bookid)
+	f, err := os.Open(tmpdir)
+	if err != nil {
+		log.Fatalf("Failed to open %s to move files: %v", tmpdir, err)
+	}
+	files, err := f.Readdir(0)
+	if err != nil {
+		log.Fatalf("Failed to readdir %s to move files: %v", tmpdir, err)
+	}
+	for _, v := range files {
+		orig := path.Join(tmpdir, v.Name())
+		new := path.Join(dir, v.Name())
+		err = os.Rename(orig, new)
+		if err != nil {
+			log.Fatalf("Failed to move %s to %s: %v", orig, new, err)
+		}
+	}
+
+	err = os.Remove(tmpdir)
+	if err != nil {
+		log.Fatalf("Failed to remove temporary directory %s: %v", tmpdir, err)
+	}
+
+	fmt.Printf("Successfully download to %s\n", dir)
+}