| .. _compat32_message: |
| |
| :mod:`email.message.Message`: Representing an email message using the :data:`~email.policy.compat32` API |
| -------------------------------------------------------------------------------------------------------- |
| |
| .. module:: email.message |
| :synopsis: The base class representing email messages in a fashion |
| backward compatible with python3.2 |
| |
| |
| The :class:`Message` class is very similar to the |
| :class:`~email.message.EmailMessage` class, without the methods added by that |
| class, and with the default behavior of certain other methods being slightly |
| different. We also document here some methods that, while supported by the |
| :class:`~email.message.EmailMessage` class, are not recommended unless you are |
| dealing with legacy code. |
| |
| The philosophy and structure of the two classes is otherwise the same. |
| |
| This document describes the behavior under the default (for :class:`Message`) |
| policy :attr:`~email.policy.Compat32`. If you are going to use another policy, |
| you should be using the :class:`~email.message.EmailMessage` class instead. |
| |
| An email message consists of *headers* and a *payload*. Headers must be |
| :rfc:`5233` style names and values, where the field name and value are |
| separated by a colon. The colon is not part of either the field name or the |
| field value. The payload may be a simple text message, or a binary object, or |
| a structured sequence of sub-messages each with their own set of headers and |
| their own payload. The latter type of payload is indicated by the message |
| having a MIME type such as :mimetype:`multipart/\*` or |
| :mimetype:`message/rfc822`. |
| |
| The conceptual model provided by a :class:`Message` object is that of an |
| ordered dictionary of headers with additional methods for accessing both |
| specialized information from the headers, for accessing the payload, for |
| generating a serialized version of the message, and for recursively walking |
| over the object tree. Note that duplicate headers are supported but special |
| methods must be used to access them. |
| |
| The :class:`Message` pseudo-dictionary is indexed by the header names, which |
| must be ASCII values. The values of the dictionary are strings that are |
| supposed to contain only ASCII characters; there is some special handling for |
| non-ASCII input, but it doesn't always produce the correct results. Headers |
| are stored and returned in case-preserving form, but field names are matched |
| case-insensitively. There may also be a single envelope header, also known as |
| the *Unix-From* header or the ``From_`` header. The *payload* is either a |
| string or bytes, in the case of simple message objects, or a list of |
| :class:`Message` objects, for MIME container documents (e.g. |
| :mimetype:`multipart/\*` and :mimetype:`message/rfc822`). |
| |
| Here are the methods of the :class:`Message` class: |
| |
| |
| .. class:: Message(policy=compat32) |
| |
| If *policy* is specified (it must be an instance of a :mod:`~email.policy` |
| class) use the rules it specifies to update and serialize the representation |
| of the message. If *policy* is not set, use the :class:`compat32 |
| <email.policy.Compat32>` policy, which maintains backward compatibility with |
| the Python 3.2 version of the email package. For more information see the |
| :mod:`~email.policy` documentation. |
| |
| .. versionchanged:: 3.3 The *policy* keyword argument was added. |
| |
| |
| .. method:: as_string(unixfrom=False, maxheaderlen=0, policy=None) |
| |
| Return the entire message flattened as a string. When optional *unixfrom* |
| is true, the envelope header is included in the returned string. |
| *unixfrom* defaults to ``False``. For backward compabitility reasons, |
| *maxheaderlen* defaults to ``0``, so if you want a different value you |
| must override it explicitly (the value specified for *max_line_length* in |
| the policy will be ignored by this method). The *policy* argument may be |
| used to override the default policy obtained from the message instance. |
| This can be used to control some of the formatting produced by the |
| method, since the specified *policy* will be passed to the ``Generator``. |
| |
| Flattening the message may trigger changes to the :class:`Message` if |
| defaults need to be filled in to complete the transformation to a string |
| (for example, MIME boundaries may be generated or modified). |
| |
| Note that this method is provided as a convenience and may not always |
| format the message the way you want. For example, by default it does |
| not do the mangling of lines that begin with ``From`` that is |
| required by the unix mbox format. For more flexibility, instantiate a |
| :class:`~email.generator.Generator` instance and use its |
| :meth:`~email.generator.Generator.flatten` method directly. For example:: |
| |
| from io import StringIO |
| from email.generator import Generator |
| fp = StringIO() |
| g = Generator(fp, mangle_from_=True, maxheaderlen=60) |
| g.flatten(msg) |
| text = fp.getvalue() |
| |
| If the message object contains binary data that is not encoded according |
| to RFC standards, the non-compliant data will be replaced by unicode |
| "unknown character" code points. (See also :meth:`.as_bytes` and |
| :class:`~email.generator.BytesGenerator`.) |
| |
| .. versionchanged:: 3.4 the *policy* keyword argument was added. |
| |
| |
| .. method:: __str__() |
| |
| Equivalent to :meth:`.as_string()`. Allows ``str(msg)`` to produce a |
| string containing the formatted message. |
| |
| |
| .. method:: as_bytes(unixfrom=False, policy=None) |
| |
| Return the entire message flattened as a bytes object. When optional |
| *unixfrom* is true, the envelope header is included in the returned |
| string. *unixfrom* defaults to ``False``. The *policy* argument may be |
| used to override the default policy obtained from the message instance. |
| This can be used to control some of the formatting produced by the |
| method, since the specified *policy* will be passed to the |
| ``BytesGenerator``. |
| |
| Flattening the message may trigger changes to the :class:`Message` if |
| defaults need to be filled in to complete the transformation to a string |
| (for example, MIME boundaries may be generated or modified). |
| |
| Note that this method is provided as a convenience and may not always |
| format the message the way you want. For example, by default it does |
| not do the mangling of lines that begin with ``From`` that is |
| required by the unix mbox format. For more flexibility, instantiate a |
| :class:`~email.generator.BytesGenerator` instance and use its |
| :meth:`~email.generator.BytesGenerator.flatten` method directly. |
| For example:: |
| |
| from io import BytesIO |
| from email.generator import BytesGenerator |
| fp = BytesIO() |
| g = BytesGenerator(fp, mangle_from_=True, maxheaderlen=60) |
| g.flatten(msg) |
| text = fp.getvalue() |
| |
| .. versionadded:: 3.4 |
| |
| |
| .. method:: __bytes__() |
| |
| Equivalent to :meth:`.as_bytes()`. Allows ``bytes(msg)`` to produce a |
| bytes object containing the formatted message. |
| |
| .. versionadded:: 3.4 |
| |
| |
| .. method:: is_multipart() |
| |
| Return ``True`` if the message's payload is a list of sub-\ |
| :class:`Message` objects, otherwise return ``False``. When |
| :meth:`is_multipart` returns ``False``, the payload should be a string |
| object (which might be a CTE encoded binary payload. (Note that |
| :meth:`is_multipart` returning ``True`` does not necessarily mean that |
| "msg.get_content_maintype() == 'multipart'" will return the ``True``. |
| For example, ``is_multipart`` will return ``True`` when the |
| :class:`Message` is of type ``message/rfc822``.) |
| |
| |
| .. method:: set_unixfrom(unixfrom) |
| |
| Set the message's envelope header to *unixfrom*, which should be a string. |
| |
| |
| .. method:: get_unixfrom() |
| |
| Return the message's envelope header. Defaults to ``None`` if the |
| envelope header was never set. |
| |
| |
| .. method:: attach(payload) |
| |
| Add the given *payload* to the current payload, which must be ``None`` or |
| a list of :class:`Message` objects before the call. After the call, the |
| payload will always be a list of :class:`Message` objects. If you want to |
| set the payload to a scalar object (e.g. a string), use |
| :meth:`set_payload` instead. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by :meth:`~email.message.EmailMessage.set_content` and the |
| related ``make`` and ``add`` methods. |
| |
| |
| .. method:: get_payload(i=None, decode=False) |
| |
| Return the current payload, which will be a list of |
| :class:`Message` objects when :meth:`is_multipart` is ``True``, or a |
| string when :meth:`is_multipart` is ``False``. If the payload is a list |
| and you mutate the list object, you modify the message's payload in place. |
| |
| With optional argument *i*, :meth:`get_payload` will return the *i*-th |
| element of the payload, counting from zero, if :meth:`is_multipart` is |
| ``True``. An :exc:`IndexError` will be raised if *i* is less than 0 or |
| greater than or equal to the number of items in the payload. If the |
| payload is a string (i.e. :meth:`is_multipart` is ``False``) and *i* is |
| given, a :exc:`TypeError` is raised. |
| |
| Optional *decode* is a flag indicating whether the payload should be |
| decoded or not, according to the :mailheader:`Content-Transfer-Encoding` |
| header. When ``True`` and the message is not a multipart, the payload will |
| be decoded if this header's value is ``quoted-printable`` or ``base64``. |
| If some other encoding is used, or :mailheader:`Content-Transfer-Encoding` |
| header is missing, the payload is |
| returned as-is (undecoded). In all cases the returned value is binary |
| data. If the message is a multipart and the *decode* flag is ``True``, |
| then ``None`` is returned. If the payload is base64 and it was not |
| perfectly formed (missing padding, characters outside the base64 |
| alphabet), then an appropriate defect will be added to the message's |
| defect property (:class:`~email.errors.InvalidBase64PaddingDefect` or |
| :class:`~email.errors.InvalidBase64CharactersDefect`, respectively). |
| |
| When *decode* is ``False`` (the default) the body is returned as a string |
| without decoding the :mailheader:`Content-Transfer-Encoding`. However, |
| for a :mailheader:`Content-Transfer-Encoding` of 8bit, an attempt is made |
| to decode the original bytes using the ``charset`` specified by the |
| :mailheader:`Content-Type` header, using the ``replace`` error handler. |
| If no ``charset`` is specified, or if the ``charset`` given is not |
| recognized by the email package, the body is decoded using the default |
| ASCII charset. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by :meth:`~email.message.EmailMessage.get_content` and |
| :meth:`~email.message.EmailMessage.iter_parts`. |
| |
| |
| .. method:: set_payload(payload, charset=None) |
| |
| Set the entire message object's payload to *payload*. It is the client's |
| responsibility to ensure the payload invariants. Optional *charset* sets |
| the message's default character set; see :meth:`set_charset` for details. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by :meth:`~email.message.EmailMessage.set_content`. |
| |
| |
| .. method:: set_charset(charset) |
| |
| Set the character set of the payload to *charset*, which can either be a |
| :class:`~email.charset.Charset` instance (see :mod:`email.charset`), a |
| string naming a character set, or ``None``. If it is a string, it will |
| be converted to a :class:`~email.charset.Charset` instance. If *charset* |
| is ``None``, the ``charset`` parameter will be removed from the |
| :mailheader:`Content-Type` header (the message will not be otherwise |
| modified). Anything else will generate a :exc:`TypeError`. |
| |
| If there is no existing :mailheader:`MIME-Version` header one will be |
| added. If there is no existing :mailheader:`Content-Type` header, one |
| will be added with a value of :mimetype:`text/plain`. Whether the |
| :mailheader:`Content-Type` header already exists or not, its ``charset`` |
| parameter will be set to *charset.output_charset*. If |
| *charset.input_charset* and *charset.output_charset* differ, the payload |
| will be re-encoded to the *output_charset*. If there is no existing |
| :mailheader:`Content-Transfer-Encoding` header, then the payload will be |
| transfer-encoded, if needed, using the specified |
| :class:`~email.charset.Charset`, and a header with the appropriate value |
| will be added. If a :mailheader:`Content-Transfer-Encoding` header |
| already exists, the payload is assumed to already be correctly encoded |
| using that :mailheader:`Content-Transfer-Encoding` and is not modified. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by the *charset* parameter of the |
| :meth:`email.emailmessage.EmailMessage.set_content` method. |
| |
| |
| .. method:: get_charset() |
| |
| Return the :class:`~email.charset.Charset` instance associated with the |
| message's payload. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class it always returns |
| ``None``. |
| |
| |
| The following methods implement a mapping-like interface for accessing the |
| message's :rfc:`2822` headers. Note that there are some semantic differences |
| between these methods and a normal mapping (i.e. dictionary) interface. For |
| example, in a dictionary there are no duplicate keys, but here there may be |
| duplicate message headers. Also, in dictionaries there is no guaranteed |
| order to the keys returned by :meth:`keys`, but in a :class:`Message` object, |
| headers are always returned in the order they appeared in the original |
| message, or were added to the message later. Any header deleted and then |
| re-added are always appended to the end of the header list. |
| |
| These semantic differences are intentional and are biased toward maximal |
| convenience. |
| |
| Note that in all cases, any envelope header present in the message is not |
| included in the mapping interface. |
| |
| In a model generated from bytes, any header values that (in contravention of |
| the RFCs) contain non-ASCII bytes will, when retrieved through this |
| interface, be represented as :class:`~email.header.Header` objects with |
| a charset of `unknown-8bit`. |
| |
| |
| .. method:: __len__() |
| |
| Return the total number of headers, including duplicates. |
| |
| |
| .. method:: __contains__(name) |
| |
| Return true if the message object has a field named *name*. Matching is |
| done case-insensitively and *name* should not include the trailing colon. |
| Used for the ``in`` operator, e.g.:: |
| |
| if 'message-id' in myMessage: |
| print('Message-ID:', myMessage['message-id']) |
| |
| |
| .. method:: __getitem__(name) |
| |
| Return the value of the named header field. *name* should not include the |
| colon field separator. If the header is missing, ``None`` is returned; a |
| :exc:`KeyError` is never raised. |
| |
| Note that if the named field appears more than once in the message's |
| headers, exactly which of those field values will be returned is |
| undefined. Use the :meth:`get_all` method to get the values of all the |
| extant named headers. |
| |
| |
| .. method:: __setitem__(name, val) |
| |
| Add a header to the message with field name *name* and value *val*. The |
| field is appended to the end of the message's existing fields. |
| |
| Note that this does *not* overwrite or delete any existing header with the same |
| name. If you want to ensure that the new header is the only one present in the |
| message with field name *name*, delete the field first, e.g.:: |
| |
| del msg['subject'] |
| msg['subject'] = 'Python roolz!' |
| |
| |
| .. method:: __delitem__(name) |
| |
| Delete all occurrences of the field with name *name* from the message's |
| headers. No exception is raised if the named field isn't present in the |
| headers. |
| |
| |
| .. method:: keys() |
| |
| Return a list of all the message's header field names. |
| |
| |
| .. method:: values() |
| |
| Return a list of all the message's field values. |
| |
| |
| .. method:: items() |
| |
| Return a list of 2-tuples containing all the message's field headers and |
| values. |
| |
| |
| .. method:: get(name, failobj=None) |
| |
| Return the value of the named header field. This is identical to |
| :meth:`__getitem__` except that optional *failobj* is returned if the |
| named header is missing (defaults to ``None``). |
| |
| Here are some additional useful methods: |
| |
| |
| .. method:: get_all(name, failobj=None) |
| |
| Return a list of all the values for the field named *name*. If there are |
| no such named headers in the message, *failobj* is returned (defaults to |
| ``None``). |
| |
| |
| .. method:: add_header(_name, _value, **_params) |
| |
| Extended header setting. This method is similar to :meth:`__setitem__` |
| except that additional header parameters can be provided as keyword |
| arguments. *_name* is the header field to add and *_value* is the |
| *primary* value for the header. |
| |
| For each item in the keyword argument dictionary *_params*, the key is |
| taken as the parameter name, with underscores converted to dashes (since |
| dashes are illegal in Python identifiers). Normally, the parameter will |
| be added as ``key="value"`` unless the value is ``None``, in which case |
| only the key will be added. If the value contains non-ASCII characters, |
| it can be specified as a three tuple in the format |
| ``(CHARSET, LANGUAGE, VALUE)``, where ``CHARSET`` is a string naming the |
| charset to be used to encode the value, ``LANGUAGE`` can usually be set |
| to ``None`` or the empty string (see :rfc:`2231` for other possibilities), |
| and ``VALUE`` is the string value containing non-ASCII code points. If |
| a three tuple is not passed and the value contains non-ASCII characters, |
| it is automatically encoded in :rfc:`2231` format using a ``CHARSET`` |
| of ``utf-8`` and a ``LANGUAGE`` of ``None``. |
| |
| Here's an example:: |
| |
| msg.add_header('Content-Disposition', 'attachment', filename='bud.gif') |
| |
| This will add a header that looks like :: |
| |
| Content-Disposition: attachment; filename="bud.gif" |
| |
| An example with non-ASCII characters:: |
| |
| msg.add_header('Content-Disposition', 'attachment', |
| filename=('iso-8859-1', '', 'Fußballer.ppt')) |
| |
| Which produces :: |
| |
| Content-Disposition: attachment; filename*="iso-8859-1''Fu%DFballer.ppt" |
| |
| |
| .. method:: replace_header(_name, _value) |
| |
| Replace a header. Replace the first header found in the message that |
| matches *_name*, retaining header order and field name case. If no |
| matching header was found, a :exc:`KeyError` is raised. |
| |
| |
| .. method:: get_content_type() |
| |
| Return the message's content type. The returned string is coerced to |
| lower case of the form :mimetype:`maintype/subtype`. If there was no |
| :mailheader:`Content-Type` header in the message the default type as given |
| by :meth:`get_default_type` will be returned. Since according to |
| :rfc:`2045`, messages always have a default type, :meth:`get_content_type` |
| will always return a value. |
| |
| :rfc:`2045` defines a message's default type to be :mimetype:`text/plain` |
| unless it appears inside a :mimetype:`multipart/digest` container, in |
| which case it would be :mimetype:`message/rfc822`. If the |
| :mailheader:`Content-Type` header has an invalid type specification, |
| :rfc:`2045` mandates that the default type be :mimetype:`text/plain`. |
| |
| |
| .. method:: get_content_maintype() |
| |
| Return the message's main content type. This is the :mimetype:`maintype` |
| part of the string returned by :meth:`get_content_type`. |
| |
| |
| .. method:: get_content_subtype() |
| |
| Return the message's sub-content type. This is the :mimetype:`subtype` |
| part of the string returned by :meth:`get_content_type`. |
| |
| |
| .. method:: get_default_type() |
| |
| Return the default content type. Most messages have a default content |
| type of :mimetype:`text/plain`, except for messages that are subparts of |
| :mimetype:`multipart/digest` containers. Such subparts have a default |
| content type of :mimetype:`message/rfc822`. |
| |
| |
| .. method:: set_default_type(ctype) |
| |
| Set the default content type. *ctype* should either be |
| :mimetype:`text/plain` or :mimetype:`message/rfc822`, although this is not |
| enforced. The default content type is not stored in the |
| :mailheader:`Content-Type` header. |
| |
| |
| .. method:: get_params(failobj=None, header='content-type', unquote=True) |
| |
| Return the message's :mailheader:`Content-Type` parameters, as a list. |
| The elements of the returned list are 2-tuples of key/value pairs, as |
| split on the ``'='`` sign. The left hand side of the ``'='`` is the key, |
| while the right hand side is the value. If there is no ``'='`` sign in |
| the parameter the value is the empty string, otherwise the value is as |
| described in :meth:`get_param` and is unquoted if optional *unquote* is |
| ``True`` (the default). |
| |
| Optional *failobj* is the object to return if there is no |
| :mailheader:`Content-Type` header. Optional *header* is the header to |
| search instead of :mailheader:`Content-Type`. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by the *params* property of the individual header objects |
| returned by the header access methods. |
| |
| |
| .. method:: get_param(param, failobj=None, header='content-type', unquote=True) |
| |
| Return the value of the :mailheader:`Content-Type` header's parameter |
| *param* as a string. If the message has no :mailheader:`Content-Type` |
| header or if there is no such parameter, then *failobj* is returned |
| (defaults to ``None``). |
| |
| Optional *header* if given, specifies the message header to use instead of |
| :mailheader:`Content-Type`. |
| |
| Parameter keys are always compared case insensitively. The return value |
| can either be a string, or a 3-tuple if the parameter was :rfc:`2231` |
| encoded. When it's a 3-tuple, the elements of the value are of the form |
| ``(CHARSET, LANGUAGE, VALUE)``. Note that both ``CHARSET`` and |
| ``LANGUAGE`` can be ``None``, in which case you should consider ``VALUE`` |
| to be encoded in the ``us-ascii`` charset. You can usually ignore |
| ``LANGUAGE``. |
| |
| If your application doesn't care whether the parameter was encoded as in |
| :rfc:`2231`, you can collapse the parameter value by calling |
| :func:`email.utils.collapse_rfc2231_value`, passing in the return value |
| from :meth:`get_param`. This will return a suitably decoded Unicode |
| string when the value is a tuple, or the original string unquoted if it |
| isn't. For example:: |
| |
| rawparam = msg.get_param('foo') |
| param = email.utils.collapse_rfc2231_value(rawparam) |
| |
| In any case, the parameter value (either the returned string, or the |
| ``VALUE`` item in the 3-tuple) is always unquoted, unless *unquote* is set |
| to ``False``. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by the *params* property of the individual header objects |
| returned by the header access methods. |
| |
| |
| .. method:: set_param(param, value, header='Content-Type', requote=True, \ |
| charset=None, language='', replace=False) |
| |
| Set a parameter in the :mailheader:`Content-Type` header. If the |
| parameter already exists in the header, its value will be replaced with |
| *value*. If the :mailheader:`Content-Type` header as not yet been defined |
| for this message, it will be set to :mimetype:`text/plain` and the new |
| parameter value will be appended as per :rfc:`2045`. |
| |
| Optional *header* specifies an alternative header to |
| :mailheader:`Content-Type`, and all parameters will be quoted as necessary |
| unless optional *requote* is ``False`` (the default is ``True``). |
| |
| If optional *charset* is specified, the parameter will be encoded |
| according to :rfc:`2231`. Optional *language* specifies the RFC 2231 |
| language, defaulting to the empty string. Both *charset* and *language* |
| should be strings. |
| |
| If *replace* is ``False`` (the default) the header is moved to the |
| end of the list of headers. If *replace* is ``True``, the header |
| will be updated in place. |
| |
| .. versionchanged:: 3.4 ``replace`` keyword was added. |
| |
| |
| .. method:: del_param(param, header='content-type', requote=True) |
| |
| Remove the given parameter completely from the :mailheader:`Content-Type` |
| header. The header will be re-written in place without the parameter or |
| its value. All values will be quoted as necessary unless *requote* is |
| ``False`` (the default is ``True``). Optional *header* specifies an |
| alternative to :mailheader:`Content-Type`. |
| |
| |
| .. method:: set_type(type, header='Content-Type', requote=True) |
| |
| Set the main type and subtype for the :mailheader:`Content-Type` |
| header. *type* must be a string in the form :mimetype:`maintype/subtype`, |
| otherwise a :exc:`ValueError` is raised. |
| |
| This method replaces the :mailheader:`Content-Type` header, keeping all |
| the parameters in place. If *requote* is ``False``, this leaves the |
| existing header's quoting as is, otherwise the parameters will be quoted |
| (the default). |
| |
| An alternative header can be specified in the *header* argument. When the |
| :mailheader:`Content-Type` header is set a :mailheader:`MIME-Version` |
| header is also added. |
| |
| This is a legacy method. On the |
| :class:`~email.emailmessage.EmailMessage` class its functionality is |
| replaced by the ``make_`` and ``add_`` methods. |
| |
| |
| .. method:: get_filename(failobj=None) |
| |
| Return the value of the ``filename`` parameter of the |
| :mailheader:`Content-Disposition` header of the message. If the header |
| does not have a ``filename`` parameter, this method falls back to looking |
| for the ``name`` parameter on the :mailheader:`Content-Type` header. If |
| neither is found, or the header is missing, then *failobj* is returned. |
| The returned string will always be unquoted as per |
| :func:`email.utils.unquote`. |
| |
| |
| .. method:: get_boundary(failobj=None) |
| |
| Return the value of the ``boundary`` parameter of the |
| :mailheader:`Content-Type` header of the message, or *failobj* if either |
| the header is missing, or has no ``boundary`` parameter. The returned |
| string will always be unquoted as per :func:`email.utils.unquote`. |
| |
| |
| .. method:: set_boundary(boundary) |
| |
| Set the ``boundary`` parameter of the :mailheader:`Content-Type` header to |
| *boundary*. :meth:`set_boundary` will always quote *boundary* if |
| necessary. A :exc:`~email.errors.HeaderParseError` is raised if the |
| message object has no :mailheader:`Content-Type` header. |
| |
| Note that using this method is subtly different than deleting the old |
| :mailheader:`Content-Type` header and adding a new one with the new |
| boundary via :meth:`add_header`, because :meth:`set_boundary` preserves |
| the order of the :mailheader:`Content-Type` header in the list of |
| headers. However, it does *not* preserve any continuation lines which may |
| have been present in the original :mailheader:`Content-Type` header. |
| |
| |
| .. method:: get_content_charset(failobj=None) |
| |
| Return the ``charset`` parameter of the :mailheader:`Content-Type` header, |
| coerced to lower case. If there is no :mailheader:`Content-Type` header, or if |
| that header has no ``charset`` parameter, *failobj* is returned. |
| |
| Note that this method differs from :meth:`get_charset` which returns the |
| :class:`~email.charset.Charset` instance for the default encoding of the message body. |
| |
| |
| .. method:: get_charsets(failobj=None) |
| |
| Return a list containing the character set names in the message. If the |
| message is a :mimetype:`multipart`, then the list will contain one element |
| for each subpart in the payload, otherwise, it will be a list of length 1. |
| |
| Each item in the list will be a string which is the value of the |
| ``charset`` parameter in the :mailheader:`Content-Type` header for the |
| represented subpart. However, if the subpart has no |
| :mailheader:`Content-Type` header, no ``charset`` parameter, or is not of |
| the :mimetype:`text` main MIME type, then that item in the returned list |
| will be *failobj*. |
| |
| |
| .. method:: get_content_disposition() |
| |
| Return the lowercased value (without parameters) of the message's |
| :mailheader:`Content-Disposition` header if it has one, or ``None``. The |
| possible values for this method are *inline*, *attachment* or ``None`` |
| if the message follows :rfc:`2183`. |
| |
| .. versionadded:: 3.5 |
| |
| .. method:: walk() |
| |
| The :meth:`walk` method is an all-purpose generator which can be used to |
| iterate over all the parts and subparts of a message object tree, in |
| depth-first traversal order. You will typically use :meth:`walk` as the |
| iterator in a ``for`` loop; each iteration returns the next subpart. |
| |
| Here's an example that prints the MIME type of every part of a multipart |
| message structure: |
| |
| .. testsetup:: |
| |
| >>> from email import message_from_binary_file |
| >>> with open('Lib/test/test_email/data/msg_16.txt', 'rb') as f: |
| ... msg = message_from_binary_file(f) |
| >>> from email.iterators import _structure |
| |
| .. doctest:: |
| |
| >>> for part in msg.walk(): |
| ... print(part.get_content_type()) |
| multipart/report |
| text/plain |
| message/delivery-status |
| text/plain |
| text/plain |
| message/rfc822 |
| text/plain |
| |
| ``walk`` iterates over the subparts of any part where |
| :meth:`is_multipart` returns ``True``, even though |
| ``msg.get_content_maintype() == 'multipart'`` may return ``False``. We |
| can see this in our example by making use of the ``_structure`` debug |
| helper function: |
| |
| .. doctest:: |
| |
| >>> for part in msg.walk(): |
| ... print(part.get_content_maintype() == 'multipart'), |
| ... part.is_multipart()) |
| True True |
| False False |
| False True |
| False False |
| False False |
| False True |
| False False |
| >>> _structure(msg) |
| multipart/report |
| text/plain |
| message/delivery-status |
| text/plain |
| text/plain |
| message/rfc822 |
| text/plain |
| |
| Here the ``message`` parts are not ``multiparts``, but they do contain |
| subparts. ``is_multipart()`` returns ``True`` and ``walk`` descends |
| into the subparts. |
| |
| |
| :class:`Message` objects can also optionally contain two instance attributes, |
| which can be used when generating the plain text of a MIME message. |
| |
| |
| .. attribute:: preamble |
| |
| The format of a MIME document allows for some text between the blank line |
| following the headers, and the first multipart boundary string. Normally, |
| this text is never visible in a MIME-aware mail reader because it falls |
| outside the standard MIME armor. However, when viewing the raw text of |
| the message, or when viewing the message in a non-MIME aware reader, this |
| text can become visible. |
| |
| The *preamble* attribute contains this leading extra-armor text for MIME |
| documents. When the :class:`~email.parser.Parser` discovers some text |
| after the headers but before the first boundary string, it assigns this |
| text to the message's *preamble* attribute. When the |
| :class:`~email.generator.Generator` is writing out the plain text |
| representation of a MIME message, and it finds the |
| message has a *preamble* attribute, it will write this text in the area |
| between the headers and the first boundary. See :mod:`email.parser` and |
| :mod:`email.generator` for details. |
| |
| Note that if the message object has no preamble, the *preamble* attribute |
| will be ``None``. |
| |
| |
| .. attribute:: epilogue |
| |
| The *epilogue* attribute acts the same way as the *preamble* attribute, |
| except that it contains text that appears between the last boundary and |
| the end of the message. |
| |
| You do not need to set the epilogue to the empty string in order for the |
| :class:`~email.generator.Generator` to print a newline at the end of the |
| file. |
| |
| |
| .. attribute:: defects |
| |
| The *defects* attribute contains a list of all the problems found when |
| parsing this message. See :mod:`email.errors` for a detailed description |
| of the possible parsing defects. |