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email — An email and MIME handling package
Source code: Lib/email/__init__.py
The email
package is a library for managing email messages. It is specifically not designed to do any sending of email messages to SMTP (RFC 2821 ), NNTP, or other servers; those are functions of modules such as smtplib
and nntplib
. The email
package attempts to be as RFC-compliant as possible, supporting RFC 5233 and RFC 6532 , as well as such MIME-related RFCs as RFC 2045 , RFC 2046 , RFC 2047 , RFC 2183 , and RFC 2231 .
The overall structure of the email package can be divided into three major components, plus a fourth component that controls the behavior of the other components.
The central component of the package is an “object model” that represents email messages. An application interacts with the package primarily through the object model interface defined in the message
sub-module. The application can use this API to ask questions about an existing email, to construct a new email, or to add or remove email subcomponents that themselves use the same object model interface. That is, following the nature of email messages and their MIME subcomponents, the email object model is a tree structure of objects that all provide the EmailMessage
API.
The other two major components of the package are the parser
and the generator
. The parser takes the serialized version of an email message (a stream of bytes) and converts it into a tree of EmailMessage
objects. The generator takes an EmailMessage
and turns it back into a serialized byte stream. (The parser and generator also handle streams of text characters, but this usage is discouraged as it is too easy to end up with messages that are not valid in one way or another.)
The control component is the policy
module. Every EmailMessage
, every generator
, and every parser
has an associated policy
object that controls its behavior. Usually an application only needs to specify the policy when an EmailMessage
is created, either by directly instantiating an EmailMessage
to create a new email, or by parsing an input stream using a parser
. But the policy can be changed when the message is serialized using a generator
. This allows, for example, a generic email message to be parsed from disk, but to serialize it using standard SMTP settings when sending it to an email server.
The email package does its best to hide the details of the various governing RFCs from the application. Conceptually the application should be able to treat the email message as a structured tree of unicode text and binary attachments, without having to worry about how these are represented when serialized. In practice, however, it is often necessary to be aware of at least some of the rules governing MIME messages and their structure, specifically the names and nature of the MIME “content types” and how they identify multipart documents. For the most part this knowledge should only be required for more complex applications, and even then it should only be the high level structure in question, and not the details of how those structures are represented. Since MIME content types are used widely in modern internet software (not just email), this will be a familiar concept to many programmers.
The following sections describe the functionality of the email
package. We start with the message
object model, which is the primary interface an application will use, and follow that with the parser
and generator
components. Then we cover the policy
controls, which completes the treatment of the main components of the library.
The next three sections cover the exceptions the package may raise and the defects (non-compliance with the RFCs) that the parser
may detect. Then we cover the headerregistry
and the contentmanager
sub-components, which provide tools for doing more detailed manipulation of headers and payloads, respectively. Both of these components contain features relevant to consuming and producing non-trivial messages, but also document their extensibility APIs, which will be of interest to advanced applications.
Following those is a set of examples of using the fundamental parts of the APIs covered in the preceding sections.
The foregoing represent the modern (unicode friendly) API of the email package. The remaining sections, starting with the Message
class, cover the legacy compat32
API that deals much more directly with the details of how email messages are represented. The compat32
API does not hide the details of the RFCs from the application, but for applications that need to operate at that level, they can be useful tools. This documentation is also relevant for applications that are still using the compat32
API for backward compatibility reasons.
Changed in version 3.6: Docs reorganized and rewritten to promote the new EmailMessage
/EmailPolicy
API.
Contents of the email
package documentation:
email.message
: Representing an email messageemail.parser
: Parsing email messagesemail.generator
: Generating MIME documentsemail.policy
: Policy Objectsemail.errors
: Exception and Defect classesemail.headerregistry
: Custom Header Objectsemail.contentmanager
: Managing MIME Contentemail
: Examples
Legacy API:
email.message.Message
: Representing an email message using thecompat32
APIemail.mime
: Creating email and MIME objects from scratchemail.header
: Internationalized headersemail.charset
: Representing character setsemail.encoders
: Encodersemail.utils
: Miscellaneous utilitiesemail.iterators
: Iterators
See also
-
Module
smtplib
-
SMTP (Simple Mail Transport Protocol) client
-
Module
poplib
-
POP (Post Office Protocol) client
-
Module
imaplib
-
IMAP (Internet Message Access Protocol) client
-
Module
nntplib
-
NNTP (Net News Transport Protocol) client
-
Module
mailbox
-
Tools for creating, reading, and managing collections of messages on disk using a variety standard formats.
-
Module
smtpd
-
SMTP server framework (primarily useful for testing)