The emails we've been looking at so far have been only simple text. Modern email usage often demands fancier formatted emails.
We can control the content type of an email using the Content-Type header. This is very similar to the content type header used by HTTP, which we covered in Chapter 7, Building a Simple Web Server.
If the content type header is missing, a content type of text/plain is assumed by default. Therefore, the Content-Type header in the following email is redundant:
From: Alice Doe <alice@example.net>
To: Bob Doe <bob@example.com>
Subject: Re: The Cake
Date: Fri, 03 May 2019 02:31:20 +0000
Content-Type: text/plain
Hi Bob,
Do NOT forget to bring the cake!
Best,
Alice
If you want formatting support in your email, which is common today, you should use a text/html content type. In the following email, HTML is used to add emphasis:
From: Alice...
