Epub parsing too strict?

[ne0rrmatrix]

Hello. I have been developing a new ebook reader and I have an issue with missing files in some of epubs. I have not been able to configure the Reader options to ignore this. If anyone knows how I can ignore errors and handle them myself?
Example error on attempting to open some ebooks:

 Incorrect EPUB 2 NCX: content source "OEBPS/part0000.xhtml" not found in EPUB manifest.

If I switch to a different library to parse epubs I can open and read this book. I simply want to ignore the error as I have code to handle the null response for the missing files.

[ne0rrmatrix]

I have tried:

EpubBook book;

try
{
	book = VersOne.Epub.EpubReader.ReadBook(path, EpubReaderOptionsPreset.IGNORE_ALL_ERRORS);
}
catch (Exception ex)
{
	logger.Error($"Error opening ebook: {ex.Message}");
	return null;
}

I have tried this also:

EpubReaderOptions options = new();
options.Epub2NcxReaderOptions.IgnoreMissingContentForNavigationPoints = true;
options.BookCoverReaderOptions.Epub2MetadataIgnoreMissingManifestItem = true;
options.XmlReaderOptions.SkipXmlHeaders = true;
options.SpineReaderOptions.IgnoreMissingManifestItems = true;
options.PackageReaderOptions.IgnoreMissingToc = true;
options.PackageReaderOptions.SkipInvalidManifestItems = true;
options.ContentReaderOptions.ContentFileMissing += (sender, e) =>
{
	e.SuppressException = true;
};
EpubBook book;

try
{
	book = VersOne.Epub.EpubReader.ReadBook(path, options);
}
catch (Exception ex)
{
	logger.Error($"Error opening ebook: {ex.Message}");
	return null;
}

[ne0rrmatrix]

I figured out a solution:

try
{
	book = VersOne.Epub.EpubReader.OpenBook(path, EpubReaderOptionsPreset.IGNORE_ALL_ERRORS);
}
catch (Exception ex)
{
	logger.Error($"Error opening ebook: {ex.Message}");
	return null;
}

I guess if I want to ignore errors I need to use OpenBook and not ReadBook.

[vers-one]

This error:

 Incorrect EPUB 2 NCX: content source "OEBPS/part0000.xhtml" not found in EPUB manifest.

means that the table of contents (NCX) is referencing the OEBPS/part0000.xhtml file which is not present inside the EPUB file. EpubReader.ReadBook attempts to read all referenced content files into the memory, which is helpful if you can't keep the original EPUB file open. EpubReader.OpenBook does not read content files until it they are explicitly requested. Using EpubReader.OpenBook will not throw any exceptions in this case, but if the user tries to navigate to that file from the table of contents, they will get a similar exception due to the missing content file.

[ne0rrmatrix]

Thank you for the explanation. Most of the libraries functions are pretty self explanatory. You have made excellent naming choices for classes and methods! I am very impressed with this library btw. I switched to it just recently from a different library. I am developing an open source ebook reader as a project for fun.

[vers-one]

Forgot to mention, EpubReaderOptionsPreset.IGNORE_ALL_ERRORS option is a work in progress (tracked in #95). It's not fully implemented yet.