Xamarin forms: Epubreader: System.AggregateException: 'One or more errors occurred - xamarin.forms

Question

I am using epubreader (vers-one) NuGet package for parsing .epub files.
My Code:
string fileName = "SampleEPUB.epub";
var assembly = typeof(MainPage).GetTypeInfo().Assembly;
Stream stream = assembly.GetManifestResourceStream($"{assembly.GetName().Name}.{fileName}");
EpubBook epubBook = EpubReader.ReadBook(stream);
foreach (EpubNavigationItem chapter in epubBook.Navigation)
{
chapterDetails.Add(new ChapterDetails() { title = chapter.Title, htmlData = chapter.HtmlContentFile?.Content, subChapters = chapter.NestedItems });
}
For testing purposes, I have added the epub files on the project and parse the chapters like above. I need to change this implementation.
I am able to get the epub file links stored in our database. Now I need to parse the chapters of epub from the link. But when I use the link as the fileName in the above code I am getting the below exception:
System.AggregateException: 'One or more errors occurred. (Value cannot be null.Parameter name: stream)'
How can I solve this issue? One sample link is here. I have added a sample project here having .epub file links for the reference (epub file links are commented in the sample).

Answer 1

System.AggregateException: 'One or more errors occurred. (Value cannot be null.Parameter name: stream)'
The GetManifestResourceStream method is used to access the embedded file which should be placed in shared project for the Xamarin.Forms project. The code doesn't works for the file comes from a database. You could debug to get that the stream is null because the fileName doesn't exist in the project.
Stream stream = assembly.GetManifestResourceStream($"{assembly.GetName().Name}.{fileName}");
In your condition, it just needs to get the stream from the url. Try to use the following code to get the stream.
Stream stream;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse response = (HttpWebResponse)aRequest.GetResponse();
stream = response.GetResponseStream();