Managed C++/CLI - Convert email to HTML¶

#include "stdafx.h"

using namespace System;
using namespace System::Text;
using namespace System::Text::RegularExpressions;
using namespace System::Collections;
using namespace System::IO;
using namespace EAGetMail; //add EAGetMail namespace

String^ _FormatHtmlTag(String ^src)
{
    src = src->Replace(">", ">");
    src = src->Replace("<", "&lt;");
    return src;
}

// We generate a html + attachment folder for every email, once the html is create,
// next time we don't need to parse the email again.
void _GenerateHtmlForEmail(String ^emlFile, String ^htmlFile, String ^attachmentFolder)
{
    Mail ^oMail = gcnew Mail("TryIt");
    oMail->Load(emlFile, false);

    if (oMail->IsEncrypted)
    {
        try
        {
            // This email is encrypted, we decrypt it by user default certificate.
            // you can also use specified certificate like this
            // Certificate ^oCert = gcnew Certificate();
            // oCert->Load("c:\\test.pfx", "pfxpassword",
            //      Certificate::CertificateKeyLocation::CRYPT_USER_KEYSET);
            // oMail = oMail->Decrypt( oCert );
            oMail = oMail->Decrypt(nullptr);
        }
        catch (Exception ^ep)
        {
            Console::WriteLine(ep->Message);
            oMail->Load(emlFile, false);
        }
    }

    if (oMail->IsSigned)
    {
        try
        {
            // This email is digital signed.
            EAGetMail::Certificate ^cert = oMail->VerifySignature();
            Console::WriteLine("This email contains a valid digital signature.");

            // You can add the certificate to your certificate storage like this
            // cert->AddToStore(
            // Certificate::CertificateStoreLocation::CERT_SYSTEM_STORE_CURRENT_USER,
            //      "addressbook" );
            // then you can use send the encrypted email back to this sender.
        }
        catch (Exception ^ep)
        {
            Console::WriteLine(ep->Message);
        }
    }

    // Decode winmail.dat (TNEF) and RTF body (convert RTF to HTML) automatically
    oMail->DecodeTNEF();

    String ^html = oMail->HtmlBody;
    StringBuilder ^hdr = gcnew StringBuilder();

    hdr->Append("<font face=\"Courier New,Arial\" size=2>");
    hdr->Append(String::Format("<b>From:</b> {0}<br>",
        _FormatHtmlTag(oMail->From->ToString())));

    array<MailAddress^>^  addrs = oMail->To;
    int count = addrs->Length;
    if (count > 0)
    {
        hdr->Append("<b>To:</b> ");
        for (int i = 0; i < count; i++)
        {
            hdr->Append(_FormatHtmlTag(addrs[i]->ToString()));
            if (i < count - 1)
            {
                hdr->Append(";");
            }
        }
        hdr->Append("<br>");
    }

    addrs = oMail->Cc;

    count = addrs->Length;
    if (count > 0)
    {
        hdr->Append("<b>Cc:</b> ");
        for (int i = 0; i < count; i++)
        {
            hdr->Append(_FormatHtmlTag(addrs[i]->ToString()));
            if (i < count - 1)
            {
                hdr->Append(";");
            }
        }
        hdr->Append("<br>");
    }

    hdr->Append(String::Format("<b>Subject:</b>{0}<br>\r\n",
        _FormatHtmlTag(oMail->Subject)));

    array<Attachment^>^ atts = oMail->Attachments;
    count = atts->Length;
    if (count > 0)
    {
        if (!Directory::Exists(attachmentFolder))
            Directory::CreateDirectory(attachmentFolder);

        hdr->Append("<b>Attachments:</b>");
        for (int i = 0; i < count; i++)
        {
            Attachment ^att = atts[i];

            String ^attname = String::Format("{0}\\{1}", attachmentFolder, att->Name);
            att->SaveAs(attname, true);
            hdr->Append(String::Format("<a href=\"{0}\" target=\"_blank\">{1}</a> ",
                attname, att->Name));
            String^ simage = "image/";
            if (att->ContentID->Length > 0)
            {
                // Show embedded image.
                html = html->Replace(String::Format("cid:{0}", att->ContentID), attname);
            }
            else if (String::Compare(att->ContentType, 0,
                "image/", 0, simage->Length, true) == 0)
            {
                // show attached image.
                html = String::Concat(html,
                    String::Format("<hr><img src=\"{0}\">", attname));
            }
        }
    }

    Regex ^reg = gcnew Regex("(<meta[^>]*charset[ \t]*=[ \t\"]*)([^<> \r\n\"]*)",
        (RegexOptions)(RegexOptions::Multiline | RegexOptions::IgnoreCase));
    html = reg->Replace(html, "$1utf-8");
    if (!reg->IsMatch(html))
    {
        hdr->Insert(0,
            "<meta HTTP-EQUIV=\"Content-Type\" Content=\"text-html; charset=utf-8\">");
    }

    html = html->Insert(0, "<hr>");
    html = html->Insert(0, hdr->ToString());

    FileStream ^fs = gcnew FileStream(htmlFile,
        FileMode::Create, FileAccess::Write, FileShare::None);

    array<unsigned char>^ data = System::Text::UTF8Encoding::UTF8->GetBytes(html);
    fs->Write(data, 0, data->Length);
    fs->Close();
}

void ConvertMailToHtml(String ^fileName)
{
    try
    {
        int pos = fileName->LastIndexOf(".");
        String ^attachmentFolder = fileName->Substring(0, pos);
        String ^htmlFile = fileName->Substring(0, pos) + ".htm";

        if (!File::Exists(htmlFile))
        {
            // We haven't generate the html for this email, generate it now.
            _GenerateHtmlForEmail(fileName, htmlFile, attachmentFolder);
        }

        Console::WriteLine("Please open {0} to browse your email",
            htmlFile);
    }
    catch (Exception ^ep)
    {
        Console::WriteLine(ep->Message);
    }
}

int main(array<System::String ^> ^args)
{
    //convert specified email file to HTML
    ConvertMailToHtml("c:\\my folder\\test.eml");

    return 0;
}