77 lines
3.1 KiB
TeX
77 lines
3.1 KiB
TeX
\chapter{Parsing and Processing URLs}\label{cha:url}
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%
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This modules contains procedures to parse and unparse HTTP 1.1 Request-URIs.
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\section{HTTP URLs}
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\defun{parse-uri} {uri-string } {host port path query} \label{proc:parse-uri}
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\begin{desc}
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Parses an HTTP 1.1 Request-URI \var{uri\=string} into its four fields.
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The fields returned are \emph{not} decoded.
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If \var{uri\=string} is not an http URL but an abs\_path
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the \var{host}, \var{port}
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and \var{query} portions are not specified, they are \sharpf.
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Otherwise, \var{host}, \var{port}, and \var{query} are
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strings. \var{path} is a non-empty string list---the path split
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at slashes.
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\end{desc}
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This parser does not absolutely conform to RFC 2616 in allowing
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a fragment-suffix. Furthermore only http URLs, not absolute URIs in general are
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recognized (see source for further explanation).
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\defun{make-http-url}{server path search frag-id}{http-url}
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\defunx{http-url?}{thing}{boolean}
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\defunx{http-url-server}{http-url}{server}
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\defunx{http-url-path}{http-url}{list}
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\defunx{http-url-search}{http-url}{string-or-\sharpf}
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\defunx{http-url-frag-ment-identifier}{http-url}{string-or-\sharpf}
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%
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\begin{desc}
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\ex{Make-http-url} creates a new \ex{httpd-url} record.
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\var{Server} is a record, containing the initial part of the address
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(like \ex{anonymous@clark.lcs.mit.edu:80}). \var{Path} contains the
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URL's URI path ( a list). These elements are in raw, unescaped
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format. To convert them back to a string, use
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\ex{(uri-path->uri (map escape-uri pathlist))}. \var{Search}
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and \var{frag-id} are the last two parts of the URL. (See
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Chapter~\ref{cha:uri} about parts of an URI.)
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\ex{Http-url?} is the predicate for HTTP URL values, and
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\ex{http-url-server}, \ex{http-url-path}, \ex{http-url-search} and
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\ex{http-url-fragment-identifier} are the corresponding selectors.
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\end{desc}
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\defun{parse-http-url}{path search frag-id}{http-url}
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\begin{defundescx}{http-url->string}{http-url}{string}
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This constructs an HTTP URL record from a URI path (a list of path
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components), a search, and a frag-id component.
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\ex{Http-url->string} just does the inverse job. It converts an
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HTTP URL record into a string.
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\end{defundescx}
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%
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Note: The URI parser \ex{parse-uri} maps a string to four parts:
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\var{scheme}, \var{path}, \var{search} and \var{frag-id} (see
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Section~\ref{proc:parse-uri} for details). If \var{scheme} is
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\ex{http}, then the other three parts can be passed to
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\ex{parse-http-url}, which parses them into a \ex{http-url} record.
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All strings come back from the URI parser encoded. \var{Search} and
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\var{frag-id} are left that way; this parser decodes the path
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elements. The first two list elements of the path indicating the
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leading double-slash are omitted.
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The following procedure combines the jobs of \ex{parse-uri} and
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\ex{parse-http-url}:
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\defun{parse-http-url-string}{string}{http-url}
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\begin{desc}
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This parses an HTTP URL and returns the corresponding URL value; it
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calls \ex{fatal-syntax-error} if the URL string doesn't have an
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\ex{http} scheme.
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\end{desc}
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%%% Local Variables:
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%%% mode: latex
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%%% TeX-master: "man"
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%%% End:
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