HTTPD(8)                                                 HTTPD(8)

     NAME
          httpd, save, imagemap, man2html, webls - HTTP server

     SYNOPSIS
          ip/httpd/httpd [-a srvaddr] [-c cert [-C certchain]] [-d
          domain] [-n namespace] [-w webroot]

          ip/httpd/save [-b inbuf] [-d domain] [-r remoteip] [-w
          webroot] [-N netdir] method version uri [search]
          ip/httpd/imagemap ...
          ip/httpd/man2html ...
          ip/httpd/webls ...

     DESCRIPTION
          Httpd serves the webroot directory of the file system
          described by namespace (default /lib/namespace.httpd), using
          version 1.1 of the HTTP protocol.  It announces the service
          srvaddr (default tcp!*!http), and listens for incoming
          calls.  If an X.509 certificate is supplied with the -c
          option, then the service is instead tcp!*!https.  There
          should already be a factotum holding the corresponding pri-
          vate key.  If the specified certificate has been signed by a
          certificate authority, the -C option may be used to specify
          a file containing a chain of signed certificates.

          Httpd supports only the GET and HEAD methods of the HTTP
          protocol; some magic programs support POST as well.  Persis-
          tent connections are supported for HTTP/1.1 or later
          clients; all connections close after a magic command is exe-
          cuted.  The Content-type (default application/octet-stream)
          and Content-encoding (default binary) of a file are deter-
          mined by looking for suffixes of the file name in
          /sys/lib/mimetype.

        Redirection
          Each requested URI is looked up in a redirection table, read
          from /sys/lib/httpd.rewrite.  Fields are separated by spaces
          and tabs.  Anything following a `#' is ignored.  The first
          field of each line is a URI; the second a replacement path.
          If a prefix of the URI matches a redirection path, the URI
          is rewritten using the corresponding replacement path
          instead of the prefix, and a temporary redirect is sent to
          the HTTP client.  If the replacement path does not specify a
          server name, and the request has no explicit host, then
          domain is the host name used in the redirection.  The prefix
          can either be a domain root like http://system/ (which
          matches that URL only) or a path like /who/rob (which
          matches that path no matter what the requested server), but
          not both: http://system/who/rob will never match a request.
          If the first field ends in a slash, this is an exact match;

     HTTPD(8)                                                 HTTPD(8)

          otherwise it is a prefix match.  The first field is a lit-
          eral string, matched against each file prefix of each URL.
          The most specific, i.e., longest, pattern wins, and is
          applied once (there is no rescanning), except for the fol-
          lowing exceptions.  Httpd matches only the prefix and not
          subordinate pages if a replacement is prefixed with `>'.
          Httpd omits the unmatched part of the original URI from the
          rewritten URI if the replacement is prefixed with `*'.  This
          permits many-to-one mappings; for example, to send all ref-
          erences to an old subtree to a single error page.

          Httpd handles replacements prefixed with `@' internally,
          treating the request as if it were for the replacement
          (without the @) but not informing the client of the rewrit-
          ten name.  Replacement URLs prefixed with `=' generate a
          permanent redirection instead of a temporary one.  Httpd
          checks to see if this file has changed once every 50 new TCP
          connections.  HTTP 1.1 persistent connection implies many
          pages may come in one browser connection, so to kick-start
          httpd, try

               for(i in `{seq 50}) hget http://www.your-domain.com/ >/dev/null

        Access Control
          Before opening any file, httpd looks for a file in the same
          directory called .httplogin.  If the file exists, the direc-
          tory is considered locked and the client must specify a user
          name and password matching a pair in the file.  .httplogin
          contains a list of space or newline separated tokens, each
          possibly delimited by single quotes.  The first is a domain
          name presented to the HTTP client.  The rest are pairs of
          user name and password.  Thus, there can be many user
          name/password pairs valid for a directory.

        Auxiliaries (magic)
          If the requested URI begins with /magic/server/, httpd exe-
          cutes the file /bin/ip/httpd/server to finish servicing the
          request.  All the auxiliaries take the same arguments.
          Method and version are those received on the first line of
          the request.  Uri is the remaining portion of the requested
          URI.  Inbuf contains the rest of the bytes read by the
          server, and netdir is the network directory for the connec-
          tion.  There are routines for processing command arguments,
          parsing headers, etc. in the httpd library,
          /sys/src/cmd/ip/httpd/libhttpd.a.$O.  See httpd.h in that
          directory and existing magic commands for more details.

          Save writes a line to /usr/web/save/uri.data and returns the
          contents of /usr/web/save/uri.html.  Both files must be
          accessible for the request to succeed.  The saved line
          includes the current time and either the search string from
          a HEAD or GET or the first line of the body from a POST.  It

     HTTPD(8)                                                 HTTPD(8)

          is used to record form submissions.

          Imagemap processes an HTML imagemap query.  It looks up the
          point search in the image map file given by uri, and returns
          a redirection to the appropriate page.  The map file
          defaults to NCSA format.  Any entries after a line starting
          with the word #cern are interpreted in CERN format.

          Man2html converts man(6) format manual pages into html.  It
          includes some abilities to search the manuals.

          Webls produces directory listings on the fly, with output in
          the style of ls(1). /sys/lib/webls.allowed and
          /sys/lib/webls.denied contain regular expressions describing
          what parts of httpd's namespace may and may not be listed,
          respectively.  Webls.denied is first searched to see if
          access is by default denied.  If so webls.allowed is then
          searched to see if access is explicitly allowed.  Thus one
          can have very general expressions in the denied list (like
          .*), yet still allow exceptions.  If webls.denied does not
          exist or is unreadable, all accesses are assumed to be
          denied unless explicitly allowed in webls.allowed.

          Other sites will note that if neither webls.denied nor
          webls.allowed exist, any portion of httpd's namespace can be
          listed (however, webls will always endeavor to prevent list-
          ing of `.' and `..').  If webls.allowed exists but
          webls.denied does not, any directory to be listed must be
          described by a regular expression in webls.allowed.  Simi-
          larly, if webls.denied exists but webls.allowed does not,
          any directory to be listed must not be described by a regu-
          lar expression in webls.denied.  If both exist, a directory
          is listable if either it doesn't appear in webls.denied, or
          it appears in both webls.denied and webls.allowed.  In other
          words, webls.allowed overrides webls.denied.  If a listing
          for a directory is requested and access is denied, or
          another error occurs, a simple error page is returned.

     EXAMPLES
          These are all examples of how to use httpd.rewrite.

          A local redirection:
               /netlib/c++/idioms/index.html.Z /netlib/c++/idioms/index.html

          Redirection to another site:
               /netlib/lapack/lawns          =http://netlib.org/lapack/lawns
               http://inferno.bell-labs.com  =http://www.vitanuova.com

          Root directory for virtual host:
               http://www.ampl.com      /cm/cs/what/ampl

     FILES

     HTTPD(8)                                                 HTTPD(8)

          /sys/lib/mimetype       content type description file
          /lib/namespace.httpd    default namespace file for httpd
          /sys/lib/httpd.rewrite  redirection file
          /sys/lib/webls.allowed  regular expressions describing
                                  explicitly listable pathnames; over-
                                  rides webls.denied
          /sys/lib/webls.denied   regular expressions describing
                                  explicitly unlistable pathnames

     SOURCE
          /sys/src/cmd/ip/httpd

     SEE ALSO
          newns in auth(2), listen(8), rsa(8)