Render email messages as HTML, PDF, PNG, and JPEG files Leave feedback

GroupDocs.Viewer for Node.js via Java allows you to render your email messages in HTML, PDF, PNG, and JPEG formats. You do not need to use third-party email clients to view the contents of email files within your Node.js application (web or desktop).

To start with the GroupDocs.Viewer API, create a Viewer class instance. Pass an email message you want to view to the class constructor. You can load the message from a file or stream. Call one of the Viewer.view method overloads to convert the loaded message to HTML, PDF, or image format. These methods allow you to render the entire message or specific pages.

View email files online View demos and examples on GitHub

GroupDocs.Viewer supports the following email file formats:

• Email Message (.EML)
• Apple Mail Message (.EMLX)
• Email Mailbox File (.MBOX)
• Outlook Message Item File (.MSG)
• vCard (Virtual Contact) File (.VCF, .VCARD)

Create an HtmlViewOptions class instance and pass it to the Viewer.view method to convert an email message to HTML. The HtmlViewOptions class properties allow you to control the conversion process. For instance, you can embed all external resources in the generated HTML file, minify the output file, and exclude specific fonts. Refer to the following documentation section for details: Rendering to HTML.

To embed an email message in an HTML page, call the HtmlViewOptions.forEmbeddedResources method and specify the output file name.

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Create an HTML file for the letter.
const viewOptions = groupdocs.viewer.HtmlViewOptions.forEmbeddedResources("output.html")
viewer.view(viewOptions)

The following image demonstrates the result:

To save an email message to a separate folder, call the HtmlViewOptions.forExternalResources method and pass the following parameters:

• The output file path format
• The path format for the folder with external resources
• The resource URL format

import com.groupdocs.viewer.Viewer;
import com.groupdocs.viewer.options.HtmlViewOptions;
// ...

try (Viewer viewer = new Viewer("sample.eml")) {
    // Specify the HTML file name and location of external resources.
    // {0} is replaced with the resource name in the output file name.
    HtmlViewOptions viewOptions = HtmlViewOptions.forExternalResources("output.html", "output/resource_{0}", "output/resource_{0}");
    viewer.view(viewOptions);
}

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Specify the HTML file name and location of external resources.
// {0} is replaced with the resource name in the output file name.
const viewOptions = groupdocs.viewer.HtmlViewOptions.forExternalResources("output.html", "output/resource_{0}", "output/resource_{0}")
viewer.view(viewOptions)

The result is shown below. External resources are placed in a separate folder.

Create a PdfViewOptions class instance and pass it to the Viewer.view method to convert an email message to PDF. The PdfViewOptions class properties allow you to control the conversion process. For instance, you can protect the output PDF file, reorder its pages, and specify the quality of document images. Refer to the following documentation section for details: Rendering to PDF.

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Create a PDF file for the letter.
const viewOptions = groupdocs.viewer.PdfViewOptions("output.pdf")
viewer.view(viewOptions)

The following image demonstrates the result:

Create a PngViewOptions class instance and pass it to the Viewer.view method to convert an email message to PNG. Use the PngViewOptions.setHeight and PngViewOptions.setWidth methods to specify the output image size in pixels.

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Create a PNG image for the letter.
const viewOptions = groupdocs.viewer.PngViewOptions("output.png")
// Set width and height.
viewOptions.setWidth(950)
viewOptions.setHeight(550)
viewer.view(viewOptions)

The following image demonstrates the result:

Create a JpgViewOptions class instance and pass it to the Viewer.view method to convert an email message to JPEG. Use the JpgViewOptions.setHeight and JpgViewOptions.setWidth methods to specify the output image size in pixels.

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Create a JPG image for the letter.
const viewOptions = groupdocs.viewer.JpgViewOptions("output.jpg")
// Set width and height.
viewOptions.setWidth(950)
viewOptions.setHeight(550)
viewer.view(viewOptions)

GroupDocs.Viewer supports the EmailOptions class that allows you to specify different options for rendering email messages. To access these options, use the setEmailOptions method for one of the following classes (depending on the output file format):

• HtmlViewOptions
• PdfViewOptions
• PngViewOptions
• JpgViewOptions

GroupDocs.Viewer allows you to specify page size for the output file when you convert an email message to HTML, PDF, or image format. Use the EmailOptions.setPageSize method to select one of the predefined page sizes (LETTER, LEDGER, A0, A1, A2, A3, or A4) (see the PageSize enumeration).

The following example specifies page size for the output PDF file:

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Create a PDF file for the letter.
const viewOptions = groupdocs.viewer.PdfViewOptions("output.pdf")
viewOptions.getEmailOptions().setPageSize(groupdocs.viewer.PageSize.LETTER)
viewer.view(viewOptions)

GroupDocs.Viewer allows you to change how standard fields (such as From, To, Subject, and so on) are displayed in the email message header.

Use the EmailOptions.setFieldTextMap method to specify custom field labels. Static fields of the Field class allow you to access default email header fields, as shown in the example below.

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Specify custom field labels.
const field = groupdocs.viewer.Field
const map = {}
map[field.FROM] = "Sender"
map[field.TO] = "Receiver"
map[field.SENT] = "Date"
map[field.SUBJECT] = "Email subject"
// Create an HTML file.
const viewOptions = groupdocs.viewer.HtmlViewOptions.forEmbeddedResources("output.html")
viewOptions.getEmailOptions().setFieldTextMap(map)
viewer.view(viewOptions)

The following image illustrates the result:

When rendering email messages, GroupDocs.Viewer formats date and time information in the message header based on the system’s date and time settings. If you want to change the default date and time format or specify the time zone offset, use the following methods:

• EmailOptions.setDateTimeFormat—Allows you to define a custom date and time format. See the following topics for details:
  • Standard date and time format strings
  • Custom date and time format strings
• EmailOptions.setTimeZoneOffset—Specifies the hours and minutes offset from UTC. The offset is displayed with a leading sign. A plus sign (+) indicates time ahead of UTC, and a minus sign (-) indicates time behind UTC.

const java = require('java')
const timeOffset = java.import("java.util.TimeZone").getTimeZone("GMT+1")

const viewer = new groupdocs.viewer.Viewer("sample.eml")
// Create an HTML file
const viewOptions = groupdocs.viewer.HtmlViewOptions.forEmbeddedResources("output.html")
// Apply a custom format to the date in the email message header.
viewOptions.getEmailOptions().setDateTimeFormat("MM d yyyy HH:mm tt zzz");
// Specify the time zone offset. 
viewOptions.getEmailOptions().setTimeZoneOffset(timeOffset)

viewer.view(viewOptions)

The following image illustrates the result: