factor/library/httpd/cont-responder.factor

376 lines
13 KiB
Factor

! Copyright (C) 2004 Chris Double.
!
! Redistribution and use in source and binary forms, with or without
! modification, are permitted provided that the following conditions are met:
!
! 1. Redistributions of source code must retain the above copyright notice,
! this list of conditions and the following disclaimer.
!
! 2. Redistributions in binary form must reproduce the above copyright notice,
! this list of conditions and the following disclaimer in the documentation
! and/or other materials provided with the distribution.
!
! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
IN: cont-responder
USING: http httpd math random namespaces io
lists strings kernel html hashtables
parser generic sequences ;
#! Used inside the session state of responders to indicate whether the
#! next request should use the post-refresh-get pattern. It is set to
#! true after each request.
SYMBOL: post-refresh-get?
: expiry-timeout ( -- timeout-seconds )
#! Number of seconds to timeout continuations in
#! continuation table. This value will need to be
#! tuned. I leave it at 24 hours but it can be
#! higher/lower as needed. Default to 15 minutes for
#! testing.
900 ;
: get-random-id ( -- id )
#! Generate a random id to use for continuation URL's
[ 32 [ 0 9 random-int CHAR: 0 + , ] times ] "" make
string>number 36 >base ;
#! Name of variable holding the table of continuations.
SYMBOL: table
: continuation-table ( -- <namespace> )
#! Return the global table of continuations
table get ;
: reset-continuation-table ( -- )
#! Create the initial global table
{{ }} clone table set ;
#! Tuple for holding data related to a continuation.
TUPLE: item expire? quot id time-added ;
: continuation-item ( expire? quot id -- <item> )
#! A continuation item is the actual item stored
#! in the continuation table. It contains the id,
#! quotation/continuation, time added, etc. If
#! expire? is true then the continuation will
#! be expired after a certain amount of time.
millis <item> ;
: seconds>millis ( seconds -- millis )
#! Convert a number of seconds to milliseconds
1000 * ;
: expired? ( timeout-seconds <item> -- bool )
#! Return true if the continuation item is expirable
#! and has expired (ie. was added to the table more than
#! timeout milliseconds ago).
[ item-time-added swap seconds>millis + millis - 0 < ] keep item-expire? and ;
: continuation-items ( -- alist )
#! Return an alist of all continuation items in the continuation
#! table with the car as the id and the cdr as the item.
continuation-table hash>alist ;
: expire-continuations ( timeout-seconds -- )
#! Expire all continuations in the continuation table
#! if they are 'timeout-seconds' old (ie. were added
#! more than 'timeout-seconds' ago.
continuation-items [
uncons pick swap expired? [
continuation-table remove-hash
] [
drop
] ifte
] each drop ;
: expirable ( quot -- t quot )
#! Set the stack up for a register-continuation call
#! so that the given quotation is registered that it can
#! be expired.
t swap ;
: permanent ( quot -- f quot )
#! Set the stack up for a register-continuation call
#! so that the given quotation is never expired after
#! registration.
f swap ;
: register-continuation ( expire? quot -- id )
#! Store a continuation in the table and associate it with
#! a random id. That continuation will be expired after
#! a certain period of time if 'expire?' is true.
get-random-id -rot pick continuation-item over continuation-table set-hash ;
: register-continuation* ( expire? quots -- id )
#! Like register-continuation but registers a quotation
#! that will call all quotations in the list, in the order given.
concat register-continuation ;
: get-continuation-item ( id -- <item> )
#! Get the continuation item associated with the id.
continuation-table hash ;
: id>url ( id -- string )
#! Convert the continuation id to an URL suitable for
#! embedding in an HREF or other HTML.
url-encode "?id=" swap append ;
DEFER: show-final
DEFER: show
: expired-page-handler ( alist -- )
#! Display a page has expired message.
#! TODO: Need to handle this better to enable
#! returning back to root continuation.
drop
[
<html>
<body>
<p> "This page has expired." write </p>
</body>
</html>
] show-final ;
: get-registered-continuation ( id -- cont )
#! Return the continuation or quotation
#! associated with the given id.
#! TODO: handle expired pages better.
expiry-timeout expire-continuations
get-continuation-item [
item-quot
] [
[ expired-page-handler ]
] ifte* ;
: resume-continuation ( value id -- )
#! Call the continuation associated with the given id,
#! with 'value' on the top of the stack.
get-registered-continuation call ;
#! Name of the variable holding the continuation used to exit
#! back to the httpd responder, returning any generated HTML.
SYMBOL: exit-cc
: exit-continuation ( -- exit )
#! Get the current exit continuation
exit-cc get ;
: call-exit-continuation ( value -- )
#! Call the exit continuation, passing it the given value on the
#! top of the stack.
exit-cc get call ;
: with-exit-continuation ( quot -- )
#! Call the quotation with the variable exit-cc bound such that when
#! the exit continuation is called, computation will resume from the
#! end of this 'with-exit-continuation' call, with the value passed
#! to the exit continuation on the top of the stack.
[ exit-cc set call f call-exit-continuation ] callcc1 nip ;
#! Name of variable holding the 'callback' continuation, used for
#! returning back to previous 'show' calls.
SYMBOL: callback-cc
: store-callback-cc ( -- )
#! Store the current continuation in the variable 'callback-cc'
#! so it can be returned to later by callbacks. Note that it
#! recalls itself when the continuation is called to ensure that
#! it resets its value back to the most recent show call.
[ ( 0 -- )
[ ( 0 1 -- )
callback-cc set ( 0 -- )
call
] callcc1 ( 0 [ ] == )
nip
call
store-callback-cc
] callcc0 ;
: forward-to-url ( url -- )
#! When executed inside a 'show' call, this will force a
#! HTTP 302 to occur to instruct the browser to forward to
#! the request URL.
[
"HTTP/1.1 302 Document Moved\nLocation: " % %
"\nContent-Length: 0\nContent-Type: text/plain\n\n" %
] "" make call-exit-continuation ;
: redirect-to-here ( -- )
#! Force a redirect to the client browser so that the browser
#! goes to the current point in the code. This forces an URL
#! change on the browser so that refreshing that URL will
#! immediately run from this code point. This prevents the
#! "this request will issue a POST" warning from the browser
#! and prevents re-running the previous POST logic. This is
#! known as the 'post-refresh-get' pattern.
post-refresh-get? get [
[
expirable register-continuation
id>url forward-to-url
] callcc1 drop
] [
t post-refresh-get? set
] ifte ;
: show ( quot -- namespace )
#! Call the quotation with the URL associated with the current
#! continuation. Return the HTML string generated by that code
#! to the exit continuation. When the URL is later referenced then
#! computation will resume from this 'show' call with a namespace on
#! the stack containing any query or post parameters.
#! NOTE: On return from 'show' the stack is exactly the same as
#! initial entry with 'quot' popped off an <namespace> put on. Even
#! if the quotation consumes items on the stack.
store-callback-cc redirect-to-here
[
expirable register-continuation id>url swap
\ serving-html swons string-out call-exit-continuation
] callcc1
nip ;
: show-final ( quot -- namespace )
#! Similar to 'show', except the quotation does not receive the URL
#! to resume computation following 'show-final'. No continuation is
#! stored for this resumption. As a result, 'show-final' is for use
#! when a page is to be displayed with no further action to occur. Its
#! use is an optimisation to save having to generate and save a continuation
#! in that special case.
store-callback-cc redirect-to-here
\ serving-html swons string-out call-exit-continuation ;
#! Name of variable for holding initial continuation id that starts
#! the responder.
SYMBOL: root-continuation
: id-or-root ( -- id )
#! Return the continuation id for the current requested continuation
#! or the root continuation if no id is supplied.
"id" "query" get assoc [ root-continuation get ] unless* ;
: cont-get/post-responder ( id-or-f -- )
#! httpd responder that retrieves a continuation and calls it.
#! The continuation id must be in a query parameter called 'id'.
#! If it does not exist the root continuation is called. If
#! no root continuation exists the expired continuation handler
#! should be called.
drop [
"response" get alist>hash
id-or-root [
resume-continuation
] [
expired-page-handler
] ifte*
] with-exit-continuation [ write flush ] when* ;
: callback-quot ( quot -- quot )
#! Convert the given quotation so it works as a callback
#! by returning a quotation that will pass the original
#! quotation to the callback continuation.
[ , callback-cc get , \ call , ] [ ] make ;
: quot-href ( text quot -- )
#! Write to standard output an HTML HREF where the href,
#! when referenced, will call the quotation and then return
#! back to the most recent 'show' call (via the callback-cc).
#! The text of the link will be the 'text' argument on the
#! stack.
<a href= callback-quot expirable register-continuation id>url a> write </a> ;
: init-session-namespace ( -- )
#! Setup the initial session namespace. Currently this only
#! sets the redirect flag so that the initial request of the
#! responder will not do a post-refresh-get style redirect.
#! This prevents the initial request to a responder from redirecting
#! to an URL with a continuation id. This word must be run from
#! within the session namespace.
f post-refresh-get? set ;
: install-cont-responder ( name quot -- )
#! Install a cont-responder with the given name
#! that will initially run the given quotation.
#!
#! Convert the quotation so it is run within a session namespace
#! and that namespace is initialized first.
\ init-session-namespace swons [ , \ with-scope , ] [ ] make
[
[ cont-get/post-responder ] "get" set
[ cont-get/post-responder ] "post" set
swap "responder" set
reset-continuation-table
permanent register-continuation root-continuation set
] make-responder ;
: responder-items ( name -- items )
#! Return the table of continuation items for a given responder.
#! Useful for debugging.
responders get hash [ continuation-table ] bind ;
: simple-page ( title quot -- )
#! Call the quotation, with all output going to the
#! body of an html page with the given title.
<html>
<head> <title> swap write </title> </head>
<body> call </body>
</html> ;
: styled-page ( title stylesheet-quot quot -- )
#! Call the quotation, with all output going to the
#! body of an html page with the given title. stylesheet-quot
#! is called to generate the required stylesheet.
<html>
<head>
<title> rot write </title>
swap call
</head>
<body> call </body>
</html> ;
: paragraph ( str -- )
#! Output the string as an html paragraph
<p> write </p> ;
: show-message-page ( message -- )
#! Display the message in an HTML page with an OK button.
[
"Press OK to Continue" [
swap paragraph
<a href= a> "OK" write </a>
] simple-page
] show 2drop ;
: vertical-layout ( list -- )
#! Given a list of HTML components, arrange them vertically.
<table>
[ <tr> <td> call </td> </tr> ] each
</table> ;
: horizontal-layout ( list -- )
#! Given a list of HTML components, arrange them horizontally.
<table>
<tr valign= "top" tr> [ <td> call </td> ] each </tr>
</table> ;
: button ( label -- )
#! Output an HTML submit button with the given label.
<input type= "submit" value= input/> ;
: with-simple-html-output ( quot -- )
#! Run the quotation inside an HTML stream wrapped
#! around stdio.
<pre>
stdio get <html-stream> [
call
] with-stream
</pre> ;