[iiifdownloader] Split out NoPgNums downloading to its own function

1 files changed, 84 insertions, 76 deletions

diff --git a/cmd/iiifdownloader/main.go b/cmd/iiifdownloader/main.go
index 3572dae..9dfc067 100644
--- a/cmd/iiifdownloader/main.go
+++ b/cmd/iiifdownloader/main.go
@@ -59,6 +59,88 @@ func parseMets(url string) ([]string, error) {
 	return urls, nil
 }
 
+// dlNoPgNums downloads all pages, starting from zero, until either
+// a 404 is returned, or identical files are returned for two subsequent
+// pages (the latter being the behaviour of BNF's server).
+func dlNoPgNums(bookdir, pgurlStart, pgurlEnd, pgurlAltStart, pgurlAltEnd string) error {
+	pgnum := 0
+	for {
+		pgnum++
+
+		fmt.Printf("Downloading page %d\n", pgnum)
+
+		fn := path.Join(bookdir, fmt.Sprintf("%04d.jpg", pgnum))
+		_, err := os.Stat(fn)
+		if err == nil || os.IsExist(err) {
+			fmt.Printf("Skipping already present page %d\n", pgnum)
+			continue
+		}
+
+		u := fmt.Sprintf("%s%d%s", pgurlStart, pgnum, pgurlEnd)
+		resp, err := http.Get(u)
+		if err != nil {
+			return fmt.Errorf("Error downloading page %d, %s: %v\n", pgnum, u, err)
+		}
+		defer resp.Body.Close()
+		switch {
+		case resp.StatusCode == http.StatusNotFound:
+			fmt.Printf("Got 404, assuming end of pages, for page %d, %s\n", pgnum, u)
+			return nil
+		case resp.StatusCode != http.StatusOK:
+			fmt.Printf("Error downloading page %d, %s: HTTP Code %s\n", pgnum, u, resp.Status)
+
+			if pgurlAltStart == "" && pgurlAltEnd == "" {
+				return fmt.Errorf("No alternative URL to try, book failed (or ended, hopefully)")
+			}
+
+			fmt.Printf("Trying to redownload page %d at lower quality\n", pgnum)
+			u = fmt.Sprintf("%s%d%s", pgurlAltStart, pgnum, pgurlAltEnd)
+			resp, err = http.Get(u)
+			if err != nil {
+				return fmt.Errorf("Error downloading page %d, %s: %v\n", pgnum, u, err)
+			}
+			defer resp.Body.Close()
+
+			if resp.StatusCode != http.StatusOK {
+				return fmt.Errorf("Error downloading page %d, %s: HTTP Code %s\n", pgnum, u, resp.Status)
+			}
+		}
+
+		f, err := os.Create(fn)
+		defer f.Close()
+		if err != nil {
+			return fmt.Errorf("Error creating file %s: %v\n", fn, err)
+		}
+		_, err = io.Copy(f, resp.Body)
+		if err != nil {
+			return fmt.Errorf("Error writing file %s: %v\n", fn, err)
+		}
+
+		// Close once finished with, as defer won't trigger until the end of the function
+		resp.Body.Close()
+		f.Close()
+
+		// Check that the last two downloaded files aren't identical, as this
+		// can happen when there are no more pages to download.
+		if pgnum == 1 {
+			continue
+		}
+		fn2 := path.Join(bookdir, fmt.Sprintf("%04d.jpg", pgnum-1))
+		identical, err := filesAreIdentical(fn, fn2)
+		if err != nil {
+			return fmt.Errorf("Error checking for files being identical: %v\n", err)
+		}
+		if identical {
+			fmt.Println("Last 2 pages were identical, looks like it's the end of the book")
+			err = os.Remove(fn)
+			if err != nil {
+				return fmt.Errorf("Error removing dupilicate page %d: %v", fn, err)
+			}
+			return nil
+		}
+	}
+}
+
 func main() {
 	flag.Usage = func() {
 		fmt.Fprintf(flag.CommandLine.Output(), usage)
@@ -110,6 +192,7 @@ func main() {
 			log.Fatalln("Failed to extract BNF book ID from URL")
 		}
 		bookid := f[0]
+		bookdir = bookid
 		metsurl := "https://daten.digitale-sammlungen.de/~db/mets/" + bookid + "_mets.xml"
 
 		pgUrls, err = parseMets(metsurl)
@@ -128,81 +211,6 @@ func main() {
 	if len(pgUrls) > 0 {
 		fmt.Printf("I'll do something proper with these urls: %v\n", pgUrls)
 	} else if noPgNums {
-		pgnum := 0
-		for {
-			pgnum++
-
-			fmt.Printf("Downloading page %d\n", pgnum)
-
-			fn := path.Join(bookdir, fmt.Sprintf("%04d.jpg", pgnum))
-			_, err = os.Stat(fn)
-			if err == nil || os.IsExist(err) {
-				fmt.Printf("Skipping already present page %d\n", pgnum)
-				continue
-			}
-
-			u := fmt.Sprintf("%s%d%s", pgurlStart, pgnum, pgurlEnd)
-			resp, err := http.Get(u)
-			if err != nil {
-				log.Fatalf("Error downloading page %d, %s: %v\n", pgnum, u, err)
-			}
-			defer resp.Body.Close()
-			switch {
-			case resp.StatusCode == http.StatusNotFound:
-				fmt.Printf("Got 404, assuming end of pages, for page %d, %s\n", pgnum, u)
-				return
-			case resp.StatusCode != http.StatusOK:
-				fmt.Printf("Error downloading page %d, %s: HTTP Code %s\n", pgnum, u, resp.Status)
-
-				if pgurlAltStart == "" && pgurlAltEnd == "" {
-					log.Fatalln("No alternative URL to try, book failed (or ended, hopefully)")
-				}
-
-				fmt.Printf("Trying to redownload page %d at lower quality\n", pgnum)
-				u = fmt.Sprintf("%s%d%s", pgurlAltStart, pgnum, pgurlAltEnd)
-				resp, err = http.Get(u)
-				if err != nil {
-					log.Fatalf("Error downloading page %d, %s: %v\n", pgnum, u, err)
-				}
-				defer resp.Body.Close()
-
-				if resp.StatusCode != http.StatusOK {
-					log.Fatalf("Error downloading page %d, %s: HTTP Code %s\n", pgnum, u, resp.Status)
-				}
-			}
-
-			f, err := os.Create(fn)
-			defer f.Close()
-			if err != nil {
-				log.Fatalf("Error creating file %s: %v\n", fn, err)
-			}
-			_, err = io.Copy(f, resp.Body)
-			if err != nil {
-				log.Fatalf("Error writing file %s: %v\n", fn, err)
-			}
-
-			// Close once finished with, as defer won't trigger until the end of the function
-			resp.Body.Close()
-			f.Close()
-
-			// Check that the last two downloaded files aren't identical, as this
-			// can happen when there are no more pages to download.
-			if pgnum == 1 {
-				continue
-			}
-			fn2 := path.Join(bookdir, fmt.Sprintf("%04d.jpg", pgnum-1))
-			identical, err := filesAreIdentical(fn, fn2)
-			if err != nil {
-				log.Fatalf("Error checking for files being identical: %v\n", err)
-			}
-			if identical {
-				fmt.Println("Last 2 pages were identical, looks like it's the end of the book")
-				err = os.Remove(fn)
-				if err != nil {
-					log.Fatalf("Error removing dupilicate page %d: %v", fn, err)
-				}
-				return
-			}
-		}
+		dlNoPgNums(bookdir, pgurlStart, pgurlEnd, pgurlAltStart, pgurlAltEnd)
 	}
 }