This function will parse the header values given as argument into a
list of anonymous arrays containing key/value pairs. The function
knows how to deal with ``,'', ``;'' and ``='' as well as quoted values after
``=''. A list of space separated tokens are parsed as if they were
separated by ``;''.
If the @header_values passed as argument contains multiple values,
then they are treated as if they were a single value separated by
comma ``,''.
This means that this function is useful for parsing header fields that
follow this syntax (BNF as from the HTTP/1.1 specification, but we relax
the requirement for tokens).
headers = #header
header = (token | parameter) *( [";"] (token | parameter))
token = 1*<any CHAR except CTLs or separators>
separators = "(" | ")" | "<" | ">" | "@"
| "," | ";" | ":" | "\" | <">
| "/" | "[" | "]" | "?" | "="
| "{" | "}" | SP | HT
quoted-string = ( <"> *(qdtext | quoted-pair ) <"> )
qdtext = <any TEXT except <">>
quoted-pair = "\" CHAR
parameter = attribute "=" value
attribute = token
value = token | quoted-string
Each header is represented by an anonymous array of key/value
pairs. The keys will be all be forced to lower case.
The value for a simple token (not part of a parameter) is undef
.
Syntactically incorrect headers will not necessarily be parsed as you
would want.
This is easier to describe with some examples:
split_header_words('foo="bar"; port="80,81"; DISCARD, BAR=baz');
split_header_words('text/html; charset="iso-8859-1"');
split_header_words('Basic realm="\\"foo\\\\bar\\""');
will return
[foo=>'bar', port=>'80,81', discard=> undef], [bar=>'baz' ]
['text/html' => undef, charset => 'iso-8859-1']
[basic => undef, realm => "\"foo\\bar\""]
If you don't want the function to convert tokens and attribute keys to
lower case you can call it as _split_header_words
instead (with a
leading underscore).