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HtmlHelper attributes and embedded images content type #98

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HtmlHelper attributes and embedded images content type #98

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76c6aa1
HtmlHelper EmbedImage method overload - generic attributes
Dec 5, 2014
d46a63c
Remote embedded image content type from response header
Dec 5, 2014
712b400
EmailViewResult format enforcing support
Dec 5, 2014
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100 changes: 51 additions & 49 deletions src/Postal/EmailViewResult.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,107 +18,109 @@ public class EmailViewResult : ViewResult
IEmailViewRenderer Renderer { get; set; }
IEmailParser Parser { get; set; }
Email Email { get; set; }
string Format { get; set; }

/// <summary>
/// Creates a new <see cref="EmailViewResult"/>.
/// </summary>
public EmailViewResult(Email email, IEmailViewRenderer renderer, IEmailParser parser)
public EmailViewResult( Email email, IEmailViewRenderer renderer, IEmailParser parser, string format = null )
{
Email = email;
Renderer = renderer ?? new EmailViewRenderer(ViewEngineCollection);
Parser = parser ?? new EmailParser(Renderer);
Renderer = renderer ?? new EmailViewRenderer( ViewEngineCollection );
Parser = parser ?? new EmailParser( Renderer );
Format = format;
}

/// <summary>
/// Creates a new <see cref="EmailViewResult"/>.
/// </summary>
public EmailViewResult(Email email)
: this(email, null, null)
public EmailViewResult( Email email, string format = null )
: this( email, null, null, format )
{
}

/// <summary>
/// When called by the action invoker, renders the view to the response.
/// </summary>
public override void ExecuteResult(ControllerContext context)
public override void ExecuteResult( ControllerContext context )
{
var httpContext = context.RequestContext.HttpContext;
var query = httpContext.Request.QueryString;
var format = query["format"];
var contentType = ExecuteResult(context.HttpContext.Response.Output, format);
var format = Format ?? query["format"];
var contentType = ExecuteResult( context.HttpContext.Response.Output, format );
httpContext.Response.ContentType = contentType;
}

/// <summary>
/// Writes the email preview in the given format.
/// </summary>
/// <returns>The content type for the HTTP response.</returns>
public string ExecuteResult(TextWriter writer, string format = null)
public string ExecuteResult( TextWriter writer, string format = null )
{
var result = Renderer.Render(Email);
var mailMessage = Parser.Parse(result, Email);
var result = Renderer.Render( Email );
var mailMessage = Parser.Parse( result, Email );

// no special requests; render what's in the template
if (string.IsNullOrEmpty(format))
if (string.IsNullOrEmpty( format ))
{
if (!mailMessage.IsBodyHtml)
{
writer.Write(result);
writer.Write( result );
return TextContentType;
}

var template = Extract(result);
template.Write(writer);
var template = Extract( result );
template.Write( writer );
return HtmlContentType;
}

// Check if alternative
var alternativeContentType = CheckAlternativeViews(writer, mailMessage, format);
var alternativeContentType = CheckAlternativeViews( writer, mailMessage, format );

if (!string.IsNullOrEmpty(alternativeContentType))
if (!string.IsNullOrEmpty( alternativeContentType ))
return alternativeContentType;

if (format == "text")
{
if(mailMessage.IsBodyHtml)
throw new NotSupportedException("No text view available for this email");
if (mailMessage.IsBodyHtml)
throw new NotSupportedException( "No text view available for this email" );

writer.Write(result);
writer.Write( result );
return TextContentType;
}

if (format == "html")
{
if (!mailMessage.IsBodyHtml)
throw new NotSupportedException("No html view available for this email");
throw new NotSupportedException( "No html view available for this email" );

var template = Extract(result);
template.Write(writer);
var template = Extract( result );
template.Write( writer );
return HtmlContentType;
}

throw new NotSupportedException(string.Format("Unsupported format {0}", format));
throw new NotSupportedException( string.Format( "Unsupported format {0}", format ) );
}

static string CheckAlternativeViews(TextWriter writer, MailMessage mailMessage, string format)
static string CheckAlternativeViews( TextWriter writer, MailMessage mailMessage, string format )
{
var contentType = format == "html"
? HtmlContentType
: TextContentType;

// check for alternative view
var view = mailMessage.AlternateViews.FirstOrDefault(v => v.ContentType.MediaType == contentType);
var view = mailMessage.AlternateViews.FirstOrDefault( v => v.ContentType.MediaType == contentType );

if (view == null)
return null;

string content;
using (var reader = new StreamReader(view.ContentStream))
using (var reader = new StreamReader( view.ContentStream ))
content = reader.ReadToEnd();

content = ReplaceLinkedImagesWithEmbeddedImages(view, content);
content = ReplaceLinkedImagesWithEmbeddedImages( view, content );

writer.Write(content);
writer.Write( content );
return contentType;
}

Expand All @@ -127,46 +129,46 @@ class TemplateParts
readonly string header;
readonly string body;

public TemplateParts(string header, string body)
public TemplateParts( string header, string body )
{
this.header = header;
this.body = body;
}

public void Write(TextWriter writer)
public void Write( TextWriter writer )
{
writer.WriteLine("<!--");
writer.WriteLine(header);
writer.WriteLine("-->");
writer.WriteLine(body);
writer.WriteLine( "<!--" );
writer.WriteLine( header );
writer.WriteLine( "-->" );
writer.WriteLine( body );
}
}

static TemplateParts Extract(string template)
static TemplateParts Extract( string template )
{
var headerBuilder = new StringBuilder();

using (var reader = new StringReader(template))
using (var reader = new StringReader( template ))
{
// try to read until we passed headers
var line = reader.ReadLine();

while (line != null)
{
if (string.IsNullOrEmpty(line))
if (string.IsNullOrEmpty( line ))
{
return new TemplateParts(headerBuilder.ToString(), reader.ReadToEnd());
return new TemplateParts( headerBuilder.ToString(), reader.ReadToEnd() );
}

headerBuilder.AppendLine(line);
headerBuilder.AppendLine( line );
line = reader.ReadLine();
}
}

return null;
}

internal static string ReplaceLinkedImagesWithEmbeddedImages(AlternateView view, string content)
internal static string ReplaceLinkedImagesWithEmbeddedImages( AlternateView view, string content )
{
var resources = view.LinkedResources;

Expand All @@ -176,27 +178,27 @@ internal static string ReplaceLinkedImagesWithEmbeddedImages(AlternateView view,
foreach (var resource in resources)
{
var find = "src=\"cid:" + resource.ContentId + "\"";
var imageData = ComposeImageData(resource);
content = content.Replace(find, "src=\"" + imageData + "\"");
var imageData = ComposeImageData( resource );
content = content.Replace( find, "src=\"" + imageData + "\"" );
}

return content;
}

static string ComposeImageData(LinkedResource resource)
static string ComposeImageData( LinkedResource resource )
{
var contentType = resource.ContentType.MediaType;
var bytes = ReadFully(resource.ContentStream);
return string.Format("data:{0};base64,{1}",
var bytes = ReadFully( resource.ContentStream );
return string.Format( "data:{0};base64,{1}",
contentType,
Convert.ToBase64String(bytes));
Convert.ToBase64String( bytes ) );
}

static byte[] ReadFully(Stream input)
static byte[] ReadFully( Stream input )
{
using (var ms = new MemoryStream())
{
input.CopyTo(ms);
input.CopyTo( ms );
return ms.ToArray();
}
}
Expand Down
40 changes: 31 additions & 9 deletions src/Postal/HtmlExtensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,23 +16,45 @@ public static class HtmlExtensions
/// <param name="imagePathOrUrl">An image file path or URL. A file path can be relative to the web application root directory.</param>
/// <param name="alt">The content for the &lt;img alt&gt; attribute.</param>
/// <returns>An HTML &lt;img&gt; tag.</returns>
public static IHtmlString EmbedImage(this HtmlHelper html, string imagePathOrUrl, string alt = "")
[Obsolete( "Use second method overload" )]
public static IHtmlString EmbedImage( this HtmlHelper html, string imagePathOrUrl, string alt = "" )
{
if (string.IsNullOrWhiteSpace(imagePathOrUrl)) throw new ArgumentException("Path or URL required", "imagePathOrUrl");
return EmbedImage( html, imagePathOrUrl, new { alt = alt } );
}

/// <summary>
/// Embeds the given image into the email and returns an HTML &lt;img&gt; tag referencing the image.
/// </summary>
/// <param name="html">The <see cref="HtmlHelper"/>.</param>
/// <param name="imagePathOrUrl">An image file path or URL. A file path can be relative to the web application root directory.</param>
/// <param name="htmlAttributes">An object that contains the HTML attributes to set for the element.</param>
/// <returns>An HTML &lt;img&gt; tag.</returns>
public static IHtmlString EmbedImage( this HtmlHelper html, string imagePathOrUrl, object htmlAttributes = null )
{
if (string.IsNullOrWhiteSpace( imagePathOrUrl )) throw new ArgumentException( "Path or URL required", "imagePathOrUrl" );

if (IsFileName(imagePathOrUrl))
if (IsFileName( imagePathOrUrl ))
{
imagePathOrUrl = html.ViewContext.HttpContext.Server.MapPath(imagePathOrUrl);
imagePathOrUrl = html.ViewContext.HttpContext.Server.MapPath( imagePathOrUrl );
}
var imageEmbedder = (ImageEmbedder)html.ViewData[ImageEmbedder.ViewDataKey];
var resource = imageEmbedder.ReferenceImage(imagePathOrUrl);
return new HtmlString(string.Format("<img src=\"cid:{0}\" alt=\"{1}\"/>", resource.ContentId, html.AttributeEncode(alt)));
var resource = imageEmbedder.ReferenceImage( imagePathOrUrl );

var img = new TagBuilder( "img" );

if (htmlAttributes is string) // method overload back compatibility
img.MergeAttribute( "alt", (string)htmlAttributes );
else
img.MergeAttributes( HtmlHelper.AnonymousObjectToHtmlAttributes( htmlAttributes ) );

img.MergeAttribute( "src", String.Format( "cid:{0}", resource.ContentId ), true );
return new MvcHtmlString( img.ToString( TagRenderMode.SelfClosing ) );
}

static bool IsFileName(string pathOrUrl)
static bool IsFileName( string pathOrUrl )
{
return !(pathOrUrl.StartsWith("http:", StringComparison.OrdinalIgnoreCase)
|| pathOrUrl.StartsWith("https:", StringComparison.OrdinalIgnoreCase));
return !(pathOrUrl.StartsWith( "http:", StringComparison.OrdinalIgnoreCase )
|| pathOrUrl.StartsWith( "https:", StringComparison.OrdinalIgnoreCase ));
}
}
}
12 changes: 11 additions & 1 deletion src/Postal/ImageEmbedder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,17 @@ public static LinkedResource CreateLinkedResource(string imagePathOrUrl)
{
var client = new WebClient();
var bytes = client.DownloadData(imagePathOrUrl);
return new LinkedResource(new MemoryStream(bytes));

// get content type from response
string contentType = client.ResponseHeaders[HttpResponseHeader.ContentType];
if (!String.IsNullOrWhiteSpace( contentType ))
{
return new LinkedResource( new MemoryStream( bytes ), new ContentType( contentType ) );
}
else
{
return new LinkedResource( new MemoryStream( bytes ));
}
}
else
{
Expand Down