c# - OpenXml Excel: throw error in any word after mail address

Question

I read Excel files using OpenXml. all work fine but if the spreadsheet contains one cell that has an address mail and after it a space and another word, such as:

[email protected] abc

It throws an exception immediately at the opening of the spreadsheet:

var _doc = SpreadsheetDocument.Open(_filePath, false); 

exception:

DocumentFormat.OpenXml.Packaging.OpenXmlPackageException
Additional information:
Invalid Hyperlink: Malformed URI is embedded as a hyperlink in the document.

Answer 1

There is an open issue on the OpenXml forum related to this problem: Malformed Hyperlink causes exception

In the post they talk about encountering this issue with a malformed "mailto:" hyperlink within a Word document.

They propose a work-around here: Workaround for malformed hyperlink exception

The workaround is essentially a small console application which locates the invalid URL and replaces it with a hard-coded value; here is the code snippet from their sample that does the replacement; you could augment this code to attempt to correct the passed brokenUri:

private static Uri FixUri(string brokenUri)
{
    return new Uri("http://broken-link/");
}

The problem I had was actually with an Excel document (like you) and it had to do with a malformed http URL; I was pleasantly surprised to find that their code worked just fine with my Excel file.

Here is the entire work-around source code, just in case one of these links goes away in the future:

 void Main(string[] args)
    {
        var fileName = @"C:empcorrupt.xlsx";
        var newFileName = @"c:empFixed.xlsx";
        var newFileInfo = new FileInfo(newFileName);

        if (newFileInfo.Exists)
            newFileInfo.Delete();

        File.Copy(fileName, newFileName);

        WordprocessingDocument wDoc;
        try
        {
            using (wDoc = WordprocessingDocument.Open(newFileName, true))
            {
                ProcessDocument(wDoc);
            }
        }
        catch (OpenXmlPackageException e)
        {
            e.Dump();
            if (e.ToString().Contains("The specified package is not valid."))
            {
                using (FileStream fs = new FileStream(newFileName, FileMode.OpenOrCreate, FileAccess.ReadWrite))
                {
                    UriFixer.FixInvalidUri(fs, brokenUri => FixUri(brokenUri));
                }               
            }
        }
    }

    private static Uri FixUri(string brokenUri)
    {
        brokenUri.Dump();
        return new Uri("http://broken-link/");
    }

    private static void ProcessDocument(WordprocessingDocument wDoc)
    {
        var elementCount = wDoc.MainDocumentPart.Document.Descendants().Count();
        Console.WriteLine(elementCount);
    }
}

public static class UriFixer
{
    public static void FixInvalidUri(Stream fs, Func<string, Uri> invalidUriHandler)
    {
        XNamespace relNs = "http://schemas.openxmlformats.org/package/2006/relationships";
        using (ZipArchive za = new ZipArchive(fs, ZipArchiveMode.Update))
        {
            foreach (var entry in za.Entries.ToList())
            {
                if (!entry.Name.EndsWith(".rels"))
                    continue;
                bool replaceEntry = false;
                XDocument entryXDoc = null;
                using (var entryStream = entry.Open())
                {
                    try
                    {
                        entryXDoc = XDocument.Load(entryStream);
                        if (entryXDoc.Root != null && entryXDoc.Root.Name.Namespace == relNs)
                        {
                            var urisToCheck = entryXDoc
                                .Descendants(relNs + "Relationship")
                                .Where(r => r.Attribute("TargetMode") != null && (string)r.Attribute("TargetMode") == "External");
                            foreach (var rel in urisToCheck)
                            {
                                var target = (string)rel.Attribute("Target");
                                if (target != null)
                                {
                                    try
                                    {
                                        Uri uri = new Uri(target);
                                    }
                                    catch (UriFormatException)
                                    {
                                        Uri newUri = invalidUriHandler(target);
                                        rel.Attribute("Target").Value = newUri.ToString();
                                        replaceEntry = true;
                                    }
                                }
                            }
                        }
                    }
                    catch (XmlException)
                    {
                        continue;
                    }
                }
                if (replaceEntry)
                {
                    var fullName = entry.FullName;
                    entry.Delete();
                    var newEntry = za.CreateEntry(fullName);
                    using (StreamWriter writer = new StreamWriter(newEntry.Open()))
                    using (XmlWriter xmlWriter = XmlWriter.Create(writer))
                    {
                        entryXDoc.WriteTo(xmlWriter);
                    }
                }
            }
        }
    }