// Get the image from the filesystem if it exists or download from network
private Observable<Page> getOrDownloadImage(final Page page, Download download) {
// If the image URL is empty, do nothing
if (page.getImageUrl() == null) return Observable.just(page);
String filename = getImageFilename(page);
File imagePath = new File(download.directory, filename);
// If the image is already downloaded, do nothing. Otherwise download from network
Observable<Page> pageObservable =
isImageDownloaded(imagePath)
? Observable.just(page)
: downloadImage(page, download.source, download.directory, filename);
return pageObservable
// When the image is ready, set image path, progress (just in case) and status
.doOnNext(
p -> {
page.setImagePath(imagePath.getAbsolutePath());
page.setProgress(100);
download.downloadedImages++;
page.setStatus(Page.READY);
})
// Mark this page as error and allow to download the remaining
.onErrorResumeNext(
e -> {
page.setProgress(0);
page.setStatus(Page.ERROR);
return Observable.just(page);
});
}
// Public method to get the image from the filesystem. It does NOT provide any way to download the
// image
public Observable<Page> getDownloadedImage(final Page page, File chapterDir) {
if (page.getImageUrl() == null) {
page.setStatus(Page.ERROR);
return Observable.just(page);
}
File imagePath = new File(chapterDir, getImageFilename(page));
// When the image is ready, set image path, progress (just in case) and status
if (isImageDownloaded(imagePath)) {
page.setImagePath(imagePath.getAbsolutePath());
page.setProgress(100);
page.setStatus(Page.READY);
} else {
page.setStatus(Page.ERROR);
}
return Observable.just(page);
}
// Get the filename for an image given the page
private String getImageFilename(Page page) {
String url = page.getImageUrl();
return url.substring(url.lastIndexOf("/") + 1, url.length());
}