#include <x/headersimpl.H> #include <x/mime/structured_content_header.H> x::headersimpl<x::headersbase::lf_endl> headers; x::mime::structured_content_header content_disposition("attachment; x-source=file; filename=\"filename.txt\""); if (content_disposition == "attachment") { ... } // ... std::string name; std::string filename; x::mime::structured_content_header content_disposition("attachment") ("x-source", "file") .rfc2047("name", name, "UTF-8") .rfc2231("filename", filename, "UTF-8"); // ... x::mime::parameters_t::iterator b=content_disposition.parameters.begin(), e=content_disposition.parameters.begin(); while (b != e) { std::string name=b->first; x::mime::parameter_t parameter=b->second; std::string value=parameter.value; // ... } // ... content_disposition .append(headers, x::mime::structured_content_header::content_disposition);
x::mime::structured_content_header
represents a structured MIME header, like “Content-Type” or
“Content-Disposition”.
It consists of a value member, giving the primary
value of the header, with the header parameters kept in a
parameters_t parameters member,
which is a case-insensitive keyed
std::multimap.
x::mime::structured_content_header's
non-default constructor takes the entire value of the header, or just
its primary value, and breaks it down into
the value and the parameters.
Alternatively, various methods construct build the header, piece by piece,
using operator() and
rfc2231() methods. They return a
x::mime::structured_content_header &
for convenience.
operator() adds a simple, unformatted parameter,
by name and value.
rfc2047() encodes a parameter that may potentially
have non-Latin characters, using the method specified in
RFC 2047.
rfc2231() encodes a parameter that may potentially
have non-Latin characters, using the method specified in
RFC 2231.
Both
rfc2047() and
rfc2231() take the following additional parameters,
in addition to the parameter's name and value:
The value's character set.
An optional language specification, that defaults to “EN”.
rfc2231() also takes
an optional maximum targeted line width, that defaults to
76 characters.
The value does not get encoded if it does not have to be, in which case
the results are the same as with operator().
The value parameter's value gets encoded using the
RFC 2047 or 2231 method, if the value contains any
characters that
require encoding (which includes any non-Latin characters).
With rfc2231(), if the value
does not have any characters that require encoding, but
“name=value” is near, or exceeds, the targeted line with,
it gets encoded as multiple RFC 2231 parameter
fragments. Specifying the target line with as 0 results in the parameter
getting encoded only if it contains any characters that require it,
essentially setting an unlimited maximum targeted line with.
x::headersimpl<x::headersbase::lf_endl> headers; x::mime::structured_content_header hdr(headers, x::mime::structured_content_header::content_type); std::string type=hdr.mime_content_type(); std::string subtype=hdr.mime_content_subtype(); if (type == "text") { std::string charset=hdr.charset("iso-8859-1"); // ... } std::string name=hdr.decode_utf8("name", "iso-8859-1"); // ... hdr.append(headers, x::mime::structured_content_header::content_disposition)
Passing an x::headersimpl as the first parameter
to the constructor, and a name of a header for the second parameter,
constructs the x::mime::structured_content_header
from the value of the header with the given name.
The x::mime::structured_content_header gets
initialized with an empty string if the
x::headersimpl does not have this header.
The
x::mime::structured_content_header class includes
definitions of some common header names and parameters, like
x::mime::structured_content_header::content_type,
which is “Content-Type”.
Additional methods return values of most common parameters.
mime_content_type() and
mime_content_subtype() gives the MIME content
type and subtype. For “text” types,
charset() returns the value of the
charset parameter, its argument gives the default return
value if the header did not have a charset parameter.
decode_utf8() returns the value of an arbitrary
parameter, converted to the UTF-8 character set.
decode_utf8() understands character set encoding
methods specified in RFC 2047 and RFC 2231.
decode_utf8() 's parameter gives the default
character set when it is unspecified by the parameter's value, resulting
in the conversion of the parameter's value from the given character
set to UTF-8.