#!/usr/bin/env lua
-- this software is licensed under the terms of the GNU affero public license
-- v3 or later. view LICENSE.txt for more information.
-- if you host your own instance, please change the email address in the about
-- page and clearly distinguish your instance from https://zzcxz.citrons.xyz.
local env = os.getenv
local f = io.open("/dev/urandom", 'r')
local e = f and f:read(1)
if f then f:close() end
math.randomseed(os.time() + string.byte(e))
local function url_encode(str)
return (str:gsub("([^A-Za-z0-9%_%.%-%~])", function(v)
return string.upper(string.format("%%%02x", string.byte(v)))
end))
end
local esc_sequences = {
["<"] = "<",
[">"] = ">",
['"'] = """
}
local function html_encode(x)
local escaped = tostring(x)
escaped = escaped:gsub("&", "&")
for char,esc in pairs(esc_sequences) do
escaped = string.gsub(escaped, char, esc)
end
return escaped
end
local function parse_qs(str)
local function decode(str, path)
local str = str
if not path then
str = str:gsub('+', ' ')
end
return (str:gsub("%%(%x%x)", function(c)
return string.char(tonumber(c, 16))
end))
end
local values = {}
for key,val in str:gmatch(string.format('([^%q=]+)(=*[^%q=]*)', '&', '&')) do
local key = decode(key)
local keys = {}
key = key:gsub('%[([^%]]*)%]', function(v)
-- extract keys between balanced brackets
if string.find(v, "^-?%d+$") then
v = tonumber(v)
else
v = decode(v)
end
table.insert(keys, v)
return "="
end)
key = key:gsub('=+.*$', "")
key = key:gsub('%s', "_") -- remove spaces in parameter name
val = val:gsub('^=+', "")
if not values[key] then
values[key] = {}
end
if #keys > 0 and type(values[key]) ~= 'table' then
values[key] = {}
elseif #keys == 0 and type(values[key]) == 'table' then
values[key] = decode(val)
end
local t = values[key]
for i,k in ipairs(keys) do
if type(t) ~= 'table' then
t = {}
end
if k == "" then
k = #t+1
end
if not t[k] then
t[k] = {}
end
if i == #keys then
t[k] = decode(val)
end
t = t[k]
end
end
return values
end
local function redirect(to)
return "", {
status = '303 see other',
headers = { location = to },
}
end
local function template(str)
return function (t)
return (str:gsub("$([A-Za-z][A-Za-z0-9]*)", function(v)
return t[v] or ""
end))
end
end
local base = template [[
zzcxz: $title
zzcxz
$content
]]
local not_found = function()
return
base {
title = "not found",
content = "the content requested was not found.",
}, { status = '404 not found' }
end
local function parse_directive(line, directives)
local directive, args = line:match "^#([A-Z]+)%s*(.-)\n?$"
if not directive then
return
elseif directive == "BACKLINK" then
local page, action = args:match "^(%w%w%w%w%w)%s+(.+)$"
if not page then return end
directives.backlinks = directives.backlinks or {}
table.insert(directives.backlinks, {page = page, action = action})
elseif directive == "DEADEND" then
directives.deadend = true
else
return
end
return true
end
local function convert_markup(m)
local result = {}
local directives = {}
local code_block = false
for line in (m..'\n'):gmatch "(.-)\n" do
line = html_encode(line)
if not code_block then
if line:match "^%s*$" then
goto continue
end
if line:sub(1,1) == '#' and
parse_directive(line, directives) then
goto continue
end
if line:sub(1,1) == ' ' then
table.insert(result, '
')
code_block = true
else
line = line:gsub("%[(.-)%]",
function(s)
return ('%s'):format(s)
end
)
table.insert(result, ('
%s
'):format(line))
end
end
if code_block then
if line:sub(1,1) == ' ' then
table.insert(result, line .. '\n')
else
table.insert(result, '
')
code_block = false
end
end
::continue::
end
if code_block then
table.insert(result, '')
code_block = false
end
return table.concat(result), directives
end
local function parse_page(s)
local page = {}
page.title = s:match "^(.-)\n"
page.actions = {}
local content = {}
for line in (s..'\n'):gmatch "(.-\n)" do
if line:sub(1,1) == '\t' then
table.insert(content, line:sub(2))
else
local target, action = line:match "^(%w%w%w%w%w):(.-)\n$"
if action then
table.insert(page.actions, {action = action, target = target})
end
end
end
page.content = table.concat(content)
return page
end
local function load_page(p, raw)
if not p:match("^%w%w%w%w%w$") then return nil end
local f, bee = io.open('content/'..p)
if not f then return nil end
local s = f:read "a"
f:close()
if not s then return nil end
if raw then return s end
return parse_page(s)
end
local function new_action(page, action, result)
local new_name = {}
for i=1,5 do
table.insert(new_name, string.char(string.byte 'a' + math.random(0,25)))
end
new_name = table.concat(new_name)
assert(not io.open('content/'..new_name, 'r'), "page already exists!")
local new = assert(io.open('content/'..new_name, 'w'))
local old = assert(io.open('content/'..page, 'a'))
action = action:gsub('\n', ' ')
assert(new:write(action..'\n'))
for line in (result..'\n'):gmatch "(.-\n)" do
assert(new:write('\t' .. line))
end
assert(old:write(('%s:%s\n'):format(new_name, action)))
local _, directives = convert_markup(result)
if directives.backlinks then
for _,d in ipairs(directives.backlinks) do
assert(new:write(('%s:%s\n'):format(d.page, d.action)))
end
end
new:close()
old:close()
return new_name
end
local map = {}
local page_template = template [[
$title
$content
$actions
]]
map["^/g/(%w%w%w%w%w)/?$"] = function(p)
local page = load_page(p)
if not page then return not_found() end
local _, directives = convert_markup(page.content)
if env "REQUEST_METHOD" ~= "POST" then
local actions = {}
for _,a in ipairs(page.actions) do
table.insert(actions,
('
]]):format(p, #page.actions == 0 and
"do something..." or "do something else...")
)
end
return base {
title = html_encode(page.title),
content = page_template {
title = html_encode(page.title),
content = convert_markup(page.content),
actions = table.concat(actions),
},
}
else
if directives.deadend then
return base {
title = "error",
content = "forbidden",
}, { status = '403 forbidden' }
end
local form = parse_qs(io.read "a")
form.wyd = form.wyd or "something"
form.happens = form.happens or "something"
if utf8.len(form.wyd) > 150 then form.wyd = "something" end
if utf8.len(form.happens) > 10000 then form.wyd = "something" end
local new = new_action(p, form.wyd, form.happens)
return redirect("/g/"..new)
end
end
local edit_template = template [[
$content
$preview
]]
local preview_template = template [[
$title
$content
]]
local submit_template = template [[
]]
map["^/g/(%w%w%w%w%w)/act$"] = function(p)
local page = load_page(p)
if not page then return not_found() end
local _, directives = convert_markup(page.content)
if directives.deadend then return not_found() end
if env "REQUEST_METHOD" ~= "POST" then
return base {
title = "do something new",
content = edit_template {
page = p,
content = convert_markup(page.content),
},
}
else
local form = parse_qs(io.read "a")
form.wyd = form.wyd or "something"
form.happens = form.happens or "something"
return base {
title = "do something new",
content = edit_template {
page = p,
content = convert_markup(page.content),
preview = preview_template {
title = html_encode(form.wyd),
content = convert_markup(form.happens),
},
title = html_encode(form.wyd),
editing = html_encode(form.happens),
submit = submit_template { page = p },
},
}
end
end
map["^/g/(%w%w%w%w%w)/raw$"] = function(p)
local page = load_page(p, true)
if not page then return not_found() end
return page, { content_type = 'text/plain' }
end
map["^/about/?$"] = function()
local f = assert(io.open("about.html", 'r'))
local h = assert(f:read 'a')
f:close()
return h
end
local function main()
if env "PATH_INFO" == "/" then
return redirect "/g/zzcxz"
end
for k,v in pairs(map) do
local m = {(env "PATH_INFO"):match(k)}
if m[1] then
return v(table.unpack(m))
end
end
return not_found()
end
local ok, content, resp = pcall(main)
if not ok or type(content) ~= 'string' then
io.stderr:write(content..'\n')
content = base {
title = "internal error",
content = "an internal error occurred."
}
resp = { status = '500 internal server error' }
end
resp = resp or {}
resp.content_type = resp.content_type or 'text/html'
resp.status = resp.status or '200 OK'
resp.headers = resp.headers or {}
resp.headers['content-type'] = resp.content_type
print(resp.status)
for k,v in pairs(resp.headers) do
print(("%s: %s"):format(k, v))
end
print ""
io.write(content)