HTTPD(8) HTTPD(8)
NAME
httpd, mirror, save, imagemap, man2html, webls - HTTP server
SYNOPSIS
ip/httpd/httpd [-a srvaddr] [-c cert] [-d domain] [-n
namespace] [-w webroot]
ip/httpd/mirror [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri [search]
ip/httpd/save [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri [search]
ip/httpd/imagemap [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri
ip/httpd/man2html [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri [search]
ip/httpd/notas [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri [search]
ip/httpd/group [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri [search]
ip/httpd/webls [-b inbuf] [-d domain] [-r remoteip] [-w
webroot] [-N netdir] method version uri [search]
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.
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.
Each requested URI is looked up in a redirection table, read
from /sys/lib/httpd.rewrite. If a prefix of the URI matches
a redirection path, the URI is rewritten using a replacement
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path, and a 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. Httpd handles replacements pre-
fixed with @ internally, treating the request as if it were
for the replacement (without the @) but not informing the
client of the rewritten name.
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 machine 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.
If the requested URI begins with /magic/server/, httpd exe-
cutes the file /bin/ip/httpd/server to finish servicing the
request. 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 con-
nection. There are routines for processing command argu-
ments, 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.
Mirror is a trivial server that just returns the method,
URI, any search, the headers, and the message body sent by
the client.
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
is used to record form submissions.
Imagemap processes an HTML imagemap query. It looks up a
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.
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Notas gives access to student grades after searching for the
student NIF in a grade listing. Listings are kept under
/usr/prof/notas Each listing is made of two files, one with
the grades, and one with the student information (see an
existing one as an example).
Group implements web discussion groups. Each group is kept
at a directory under /usr/web/groups and has one file per
article. Replies are stored within the article file. The
program uses templates to generate the index, the view-
article, and the post-article pages. See an existing group
for an example. The directory must contain an append-only,
writeable by all, INDEX file, used to record existing arti-
cles.
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.
FILES
/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 explic-
itly listable pathnames; overrides
webls.denied
/sys/lib/webls.denied regular expressions describing
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explicitly unlistable pathnames
SOURCE
/sys/src/cmd/ip/httpd
SEE ALSO
newns in auth(2), listen(8), x509(8)
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