public static async Task <Epub3NavDocument> ReadEpub3NavDocumentAsync(ZipArchive epubArchive, string contentDirectoryPath, EpubPackage package)
{
Epub3NavDocument result = new Epub3NavDocument();
EpubManifestItem navManifestItem =
package.Manifest.FirstOrDefault(item => item.Properties != null && item.Properties.Contains(ManifestProperty.NAV));
if (navManifestItem == null)
{
if (package.EpubVersion == EpubVersion.EPUB_2)
{
return(null);
}
else
{
throw new Exception("EPUB parsing error: NAV item not found in EPUB manifest.");
}
}
string navFileEntryPath = ZipPathUtils.Combine(contentDirectoryPath, navManifestItem.Href);
ZipArchiveEntry navFileEntry = epubArchive.GetEntry(navFileEntryPath);
if (navFileEntry == null)
{
throw new Exception($"EPUB parsing error: navigation file {navFileEntryPath} not found in archive.");
}
if (navFileEntry.Length > Int32.MaxValue)
{
throw new Exception($"EPUB parsing error: navigation file {navFileEntryPath} is larger than 2 Gb.");
}
XDocument navDocument;
using (Stream containerStream = navFileEntry.Open())
{
navDocument = await XmlUtils.LoadDocumentAsync(containerStream).ConfigureAwait(false);
}
XNamespace xhtmlNamespace = navDocument.Root.Name.Namespace;
XElement htmlNode = navDocument.Element(xhtmlNamespace + "html");
if (htmlNode == null)
{
throw new Exception("EPUB parsing error: navigation file does not contain html element.");
}
XElement bodyNode = htmlNode.Element(xhtmlNamespace + "body");
if (bodyNode == null)
{
throw new Exception("EPUB parsing error: navigation file does not contain body element.");
}
result.Navs = new List <Epub3Nav>();
string folder = ZipPathUtils.GetDirectoryPath(navManifestItem.Href);
foreach (XElement navNode in bodyNode.Elements(xhtmlNamespace + "nav"))
{
Epub3Nav epub3Nav = ReadEpub3Nav(navNode);
AdjustRelativePath(epub3Nav.Ol, folder);
result.Navs.Add(epub3Nav);
}
return(result);
}
private static Epub3Nav ReadEpub3Nav(XElement navNode)
{
Epub3Nav epub3Nav = new Epub3Nav();
foreach (XAttribute navNodeAttribute in navNode.Attributes())
{
string attributeValue = navNodeAttribute.Value;
switch (navNodeAttribute.GetLowerCaseLocalName())
{
case "type":
epub3Nav.Type = StructuralSemanticsPropertyParser.Parse(attributeValue);
break;
case "hidden":
epub3Nav.IsHidden = true;
break;
}
}
foreach (XElement navChildNode in navNode.Elements())
{
switch (navChildNode.GetLowerCaseLocalName())
{
case "h1":
case "h2":
case "h3":
case "h4":
case "h5":
case "h6":
epub3Nav.Head = navChildNode.Value.Trim();
break;
case "ol":
Epub3NavOl epub3NavOl = ReadEpub3NavOl(navChildNode);
epub3Nav.Ol = epub3NavOl;
break;
}
}
return(epub3Nav);
}
private static List <EpubNavigationItemRef> GetNavigationItems(EpubBookRef bookRef, Epub3Nav epub3Nav)
{
List <EpubNavigationItemRef> result;
if (epub3Nav != null)
{
if (epub3Nav.Head != null)
{
result = new List <EpubNavigationItemRef>();
EpubNavigationItemRef navigationItemRef = EpubNavigationItemRef.CreateAsHeader();
navigationItemRef.Title = epub3Nav.Head;
navigationItemRef.NestedItems = GetNavigationItems(bookRef, epub3Nav.Ol);
result.Add(navigationItemRef);
}
else
{
result = GetNavigationItems(bookRef, epub3Nav.Ol);
}
}
else
{
result = new List <EpubNavigationItemRef>();
}
return(result);
}