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lua-scripting: Revised examples for Lua 5.0. And other updates.

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Use admonishment elements, especially WARNING for insecure temporary files.
Don't say anything about enabling system functions.
Linuxgames.com no longer uses <CENTER>.
AppWatch.com was shut down on 2001-08-31.

[ From commit e27a3c3f58 in ELinks
  0.12.GIT.  --KON ]
This commit is contained in:
Kalle Olavi Niemitalo 2007-04-19 00:14:13 +03:00 committed by Kalle Olavi Niemitalo
parent b1f1e9911b
commit c69ee15963
1 changed files with 72 additions and 69 deletions
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139
doc/lua-scripting.txt
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@ -146,7 +146,7 @@ goto_url_hook (url, current_url)::
that ELinks should follow, or `nil` to cancel the operation. that ELinks should follow, or `nil` to cancel the operation.
follow_url_hook (url):: follow_url_hook (url)::
This hook is passed the URL that Links is about to follow. It should This hook is passed the URL that ELinks is about to follow. It should
return a string (the URL modified or unmodified), or `nil` to stop return a string (the URL modified or unmodified), or `nil` to stop
ELinks following the URL ELinks following the URL
@ -173,7 +173,7 @@ lua_console_hook (string)::
`someprogram`. `someprogram`.
- `return "eval", "somefunction(1+2)"` will attempt to call the Lua - `return "eval", "somefunction(1+2)"` will attempt to call the Lua
function `somefunction` with an argument, 3. function `somefunction` with an argument, 3.
- `return "goto_url", "http://www.bogus.com"` will ask Links to visit - `return "goto_url", "http://www.bogus.com"` will ask ELinks to visit
the URL "http://www.bogus.com". the URL "http://www.bogus.com".
- `return nil` will do nothing. - `return nil` will do nothing.
@ -188,7 +188,7 @@ Functions
As well as providing hooks, ELinks provides some functions in addition to the As well as providing hooks, ELinks provides some functions in addition to the
standard Lua functions. standard Lua functions.
Note: The standard Lua function `os.setlocale` affects ELinks' idea of NOTE: The standard Lua function `os.setlocale` affects ELinks' idea of
the system locale, which ELinks uses for the "System" charset, for the the system locale, which ELinks uses for the "System" charset, for the
"System" language, and for formatting dates. This may however have to "System" language, and for formatting dates. This may however have to
be changed in a future version of ELinks, in order to properly support be changed in a future version of ELinks, in order to properly support
@ -219,21 +219,28 @@ current_document_formatted ([width])::
pipe_read (command):: pipe_read (command)::
Executes `command` and reads in all the data from stdout, until there Executes `command` and reads in all the data from stdout, until there
is no more. This is a hack, because for some reason the standard Lua is no more. This is a hack, because for some reason the standard Lua
function `read` seems to crash ELinks when used in pipe-reading mode. function `file:read` seems to crash ELinks when used in pipe-reading
mode.
execute (string):: execute (string)::
Executes shell commands `string` without waiting for it to exit. Beware Executes shell commands `string` without waiting for it to exit. Beware
that you must not read or write to stdin and stdout. And unlike the that you must not read or write to stdin and stdout. And unlike the
standard Lua function of the same name, the return value is standard Lua function `os.execute`, the return value is meaningless.
meaningless.
tmpname ():: tmpname ()::
Returns a unique name for a temporary file, or `nil` if no Returns a unique name for a temporary file, or `nil` if no
such name is available. The returned string includes the such name is available. The returned string includes the
directory name. This function does not create the file and directory name. Unlike the standard Lua function
does not guarantee exclusive access to it: the caller must `os.tmpname`, this one generates ELinks-related names
handle the possibility that another process creates the file (currently with "elinks" at the beginning of the name).
and begins using it while this function is returning. +
WARNING: The `tmpname` function does not create the file and does not
guarantee exclusive access to it: the caller must handle the
possibility that another process creates the file and begins
using it while this function is returning. Failing to do this
may expose you to symlink attacks by other users. To avoid
the risk, use `io.tmpfile` instead; unfortunately, it does not
tell you the name of the file.
bind_key (keymap, keystroke, function):: bind_key (keymap, keystroke, function)::
Currently, `keymap` must be the string `"main"`. Keystroke is a Currently, `keymap` must be the string `"main"`. Keystroke is a
@ -329,49 +336,48 @@ dialog box, and it will convert them to the URL I actually want to visit. As
a bonus, it allows me perform some searches on sites like Google without a bonus, it allows me perform some searches on sites like Google without
loading up the front page first. loading up the front page first.
TIP: The ``URI rewriting'' feature of ELinks handles many of the same
tasks as the Lua hook shown here, and you can conveniently configure
it via the option manager. It is not quite as versatile, though.
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
function match (prefix, url) function match (prefix, url)
return strsub (url, 1, strlen (prefix)) == prefix return string.sub (url, 1, string.len (prefix)) == prefix
end end
function strip (str) function strip (str)
return gsub (str, "^%s*(.-)%s*$", "%1") return string.gsub (str, "^%s*(.-)%s*$", "%1")
end end
function plusify (str) function plusify (str)
return gsub (str, "%s", "+") return string.gsub (str, "%s", "+")
end end
function goto_url_hook (url, current_url) function goto_url_hook (url, current_url)
-- Google search (e.g. ,gg unix browsers). -- Google search (e.g. ,gg unix browsers).
if match (",gg", url) then if match (",gg", url) then
url = plusify (strip (strsub (url, 4))) url = plusify (strip (string.sub (url, 4)))
return "http://www.google.com/search?q="..url.."&btnG=Google+Search" return "http://www.google.com/search?q="..url.."&btnG=Google+Search"
-- Freshmeat search. -- Freshmeat search.
elseif match (",fm", url) then elseif match (",fm", url) then
url = plusify (strip (strsub (url, 4))) url = plusify (strip (string.sub (url, 4)))
return "http://www.freshmeat.net/search/?q="..url return "http://www.freshmeat.net/search/?q="..url
-- Appwatch search (e.g. ,aw lynx).
elseif match (",aw", url) then
url = plusify (strip (strsub (url, 4)))
return "http://www.appwatch.com/Linux/Users/find?q="..url
-- Dictionary.com search (e.g. ,dict congenial). -- Dictionary.com search (e.g. ,dict congenial).
elseif match (",dict", url) then elseif match (",dict", url) then
url = plusify (strip (strsub (url, 6))) url = plusify (strip (string.sub (url, 6)))
return "http://www.dictionary.com/cgi-bin/dict.pl?db=%2A&term="..url return "http://www.dictionary.com/cgi-bin/dict.pl?db=%2A&term="..url
-- RPM search (e.g. ,rpm links). -- RPM search (e.g. ,rpm links).
elseif match (",rpm", url) then elseif match (",rpm", url) then
url = plusify (strip (strsub (url, 5))) url = plusify (strip (string.sub (url, 5)))
return "http://www.rpmfind.net/linux/rpm2html/search.php?query=" return "http://www.rpmfind.net/linux/rpm2html/search.php?query="
..url.."&submit=Search+..." ..url.."&submit=Search+..."
-- Netcraft.com search (e.g. ,whatis www.google.com). -- Netcraft.com search (e.g. ,whatis www.google.com).
elseif match (",whatis", url) then elseif match (",whatis", url) then
url = plusify (strip (strsub (url, 8))) url = plusify (strip (string.sub (url, 8)))
return "http://uptime.netcraft.com/up/graph/?host="..url return "http://uptime.netcraft.com/up/graph/?host="..url
-- LinuxToday home page. -- LinuxToday home page.
@ -380,7 +386,7 @@ function goto_url_hook (url, current_url)
-- Weather forecast for Melbourne, Australia. -- Weather forecast for Melbourne, Australia.
elseif match (",forecast", url) then elseif match (",forecast", url) then
return "http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDF02V00.txt" return "http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDV10450.txt"
-- Unmatched -- Unmatched
else else
@ -389,9 +395,6 @@ function goto_url_hook (url, current_url)
end end
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
(Note that this was noticably enhanced and rewritten in the ELinks standart
hooks.)
Expanding ~ (tilde) Expanding ~ (tilde)
^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^
@ -402,21 +405,16 @@ and `~user/zappo`, like in the shell
and other Unix programs. and other Unix programs.
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
-- Home directory: If you do not enable system functions, you will need
-- to set the following to your home directory.
home_dir = (getenv and getenv ("HOME")) or "/home/MYSELF"
function goto_url_hook (url, current_url) function goto_url_hook (url, current_url)
. .
. .
-- Expand ~ to home directories. -- Expand ~ to home directories.
elseif match ("~", url) then elseif match ("~", url) then
if strsub(url, 2, 2) == "/" then -- ~/foo if string.sub(url, 2, 2) == "/" then -- ~/foo
return home_dir..strsub(url, 2) return os.getenv ("HOME")..string.sub(url, 2)
else -- ~foo/bar else -- ~foo/bar
return "/home/"..strsub(url, 2) return "/home/"..string.sub(url, 2)
end end
. .
@ -436,16 +434,16 @@ use ELinks Lua support to manipulate the HTML before it reaches the parser.
linuxtoday.com linuxtoday.com
++++++++++++++ ++++++++++++++
Note: This recipe is out of date. NOTE: This recipe is out of date for the web site.
Linux Today has two problems when viewed in ELinks: the useless columns on the Linux Today has two problems when viewed in ELinks: the useless columns on the
left and the right and all the text appears in cyan. Here is a quick recipe left and the right and all the text appears in cyan. Here is a quick recipe
to fix that: to fix that:
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
-- Plain strfind (no metacharacters) -- Plain string.find (no metacharacters)
function sstrfind (s, pattern) function sstrfind (s, pattern)
return strfind (s, pattern, 1, 1) return string.find (s, pattern, 1, true)
end end
function pre_format_html_hook (url, html) function pre_format_html_hook (url, html)
@ -453,15 +451,15 @@ function pre_format_html_hook (url, html)
-- and change the font colour to white. -- and change the font colour to white.
if sstrfind (url, "linuxtoday.com") then if sstrfind (url, "linuxtoday.com") then
if sstrfind (url, "news_story") then if sstrfind (url, "news_story") then
html = gsub (html, '<TABLE CELLSPACING="0".-</TABLE>', '', 1) html = string.gsub (html, '<TABLE CELLSPACING="0".-</TABLE>', '', 1)
html = gsub (html, '<TR BGCOLOR="#FFF.-</TR></TABLE>', '', 1) html = string.gsub (html, '<TR BGCOLOR="#FFF.-</TR></TABLE>', '', 1)
else else
html = gsub (html, 'WIDTH="120">\n<TR.+</TABLE></TD>', '>', 1) html = string.gsub (html, 'WIDTH="120">\n<TR.+</TABLE></TD>', '>', 1)
end end
html = gsub (html, '<A HREF="http://www.internet.com.-</A>', '') html = string.gsub (html, '<A HREF="http://www.internet.com.-</A>', '')
html = gsub (html, "<IFRAME.-</IFRAME>", "") html = string.gsub (html, "<IFRAME.-</IFRAME>", "")
-- emphasis in text is lost -- emphasis in text is lost
return gsub (html, 'text="#002244"', 'text="#001133"', 1) return string.gsub (html, 'text="#002244"', 'text="#001133"', 1)
end end
return nil return nil
@ -471,6 +469,8 @@ end
linuxgames.com linuxgames.com
++++++++++++++ ++++++++++++++
NOTE: This recipe is out of date for the web site.
Here is a simpler example, for link:http://www.linuxgames.com/[]. Here is a simpler example, for link:http://www.linuxgames.com/[].
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
@ -478,8 +478,8 @@ function pre_format_html_hook (url, html)
. .
. .
elseif strfind (url, "linuxgames.com", 1, 1) then elseif string.find (url, "linuxgames.com", 1, true) then
return gsub (html, "<CENTER>.-</center>", "", 1) return string.gsub (html, "<CENTER>.-</center>", "", 1)
. .
. .
@ -489,25 +489,27 @@ function pre_format_html_hook (url, html)
Reading gzipped files Reading gzipped files
^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^
Note: ELinks already supports gzipped files natively. NOTE: ELinks already supports gzipped files natively.
Sometimes documents come gzipped in order to save space, but then you need to Sometimes documents come gzipped in order to save space, but then you need to
uncompress them to read them with ELinks. Here is a recipe to handle gzipped uncompress them to read them with ELinks. Here is a recipe to handle gzipped
files on a Unix system. files on a Unix system.
------------------------------------------------------------------------------- WARNING: This recipe opens a temporary file insecurely.
-- This script requires system functions.
-------------------------------------------------------------------------------
function pre_format_html_hook (url, html) function pre_format_html_hook (url, html)
. .
. .
-- Handle gzip'd files within reasonable size. -- Handle gzip'd files within reasonable size.
if strfind (url, "%.gz$") and strlen (html) < 65536 then if string.find (url, "%.gz$") and string.len (html) < 65536 then
local tmp = tmpname () local name = tmpname ()
writeto (tmp) write (html) writeto () local file = io.open (name, "wb")
html = pipe_read ("(gzip -dc "..tmp.." || cat "..tmp..") 2>/dev/null") file:write (html)
remove (tmp) file:close ()
html = pipe_read ("(gzip -dc "..name.." || cat "..name..") 2>/dev/null")
os.remove (name)
return html return html
end end
@ -530,25 +532,27 @@ using `lpr' or `enscript'. Type `lpr()` or `enscript()` in the Lua Console to
run them. (In the `hooks.lua`, I have also made it so you can just type `lpr` run them. (In the `hooks.lua`, I have also made it so you can just type `lpr`
or `enscript`.) or `enscript`.)
------------------------------------------------------------------------------- NOTE: The `io.popen` function is not available on all platforms.
-- This script requires system functions.
function catto (output) -------------------------------------------------------------------------------
writeto (output) function pipe_formatted_to (program)
write (current_document_formatted (79)) local lp, errmsg = io.popen (program, "w")
writeto () if lp == nil then
error (errmsg)
else
lp:write (current_document_formatted (79))
lp:close ()
end
end end
-- Send the current document to `lpr'. -- Send the current document to `lpr'.
function lpr () function lpr ()
-- You must compile Lua with `popen' support for pipes to work. pipe_formatted_to ("lpr")
-- See `config' in the Lua distribution.
catto ("|lpr")
end end
-- Send the current document to `enscript'. -- Send the current document to `enscript'.
function enscript () function enscript ()
catto ("|enscript -fCourier8") pipe_formatted_to ("enscript -fCourier8")
end end
------------------------------------------------------------------------------- -------------------------------------------------------------------------------
@ -560,9 +564,9 @@ If you come across a brain-dead web page that is totally unreadable with
ELinks, you'd probably want to open it with a graphical browser. The ELinks, you'd probably want to open it with a graphical browser. The
following function opens the current document in Netscape. following function opens the current document in Netscape.
------------------------------------------------------------------------------- TIP: You can also use the built-in ``URI passing'' feature for this.
-- This function requires `execute', a system function.
-------------------------------------------------------------------------------
-- When starting Netscape: Set to `nil' if you do not want -- When starting Netscape: Set to `nil' if you do not want
-- to open a new window for each document. -- to open a new window for each document.
netscape_new_window = 1 netscape_new_window = 1
@ -580,13 +584,12 @@ Alternative bookmark system
^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^
Many people would like to have a bookmark system with categories (note that Many people would like to have a bookmark system with categories (note that
ELinks already supports that, marketing name Hiearchical bookmarks), and also ELinks already supports that, marketing name Hierarchical bookmarks), and also
to be able to view them and search for them in an HTML page. I have written to be able to view them and search for them in an HTML page. I have written
an alternative bookmark system (for ELinks), which some people may like better an alternative bookmark system (for ELinks), which some people may like better
than the standard bookmark system. than the standard bookmark system.
More ideas More ideas
^^^^^^^^^^ ^^^^^^^^^^