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Add shared memory hit counter example to redbean

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Justine Tunney 2022-10-08 08:39:13 -07:00
parent 38e3ab57a6
commit 8aca94f951
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GPG key ID: BE714B4575D6E328
6 changed files with 114 additions and 29 deletions
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78
tool/net/demo/.init.lua
View file

@ -20,35 +20,73 @@ db:exec[[
INSERT INTO test (content) VALUES ('Hello Sqlite3');
]]
-- shared memory hit counter
SHM_LOCK = 0 -- index zero (first eight bytes) will hold mutex
SHM_JSON = 8 -- store json payload starting at the index eight
shm = unix.mapshared(65520)
function Lock()
local ok, old = shm:cmpxchg(SHM_LOCK, 0, 1)
if not ok then
if old == 1 then
old = shm:xchg(SHM_LOCK, 2)
end
while old > 0 do
shm:wait(SHM_LOCK, 2)
old = shm:xchg(SHM_LOCK, 2)
end
end
end
function Unlock()
old = shm:fetch_add(SHM_LOCK, -1)
if old == 2 then
shm:store(SHM_LOCK, 0)
shm:wake(SHM_LOCK, 1)
end
end
function OnServerListen(fd, ip, port)
unix.setsockopt(fd, unix.SOL_TCP, unix.TCP_SAVE_SYN, true)
return false
unix.setsockopt(fd, unix.SOL_TCP, unix.TCP_SAVE_SYN, true)
return false
end
function OnClientConnection(ip, port, serverip, serverport)
syn, synerr = unix.getsockopt(GetClientFd(), unix.SOL_TCP, unix.TCP_SAVED_SYN)
syn, synerr = unix.getsockopt(GetClientFd(), unix.SOL_TCP, unix.TCP_SAVED_SYN)
end
function UpdateHitCounter()
local s, t, k
Lock()
s = shm:read(SHM_JSON)
if s == '' then s = '{}' end
t = DecodeJson(s)
k = GetPath()
if not t[k] then t[k] = 0 end
t[k] = t[k] + 1
shm:write(SHM_JSON, EncodeJson(t))
Unlock()
end
-- this intercepts all requests if it's defined
function OnHttpRequest()
if GetHeader('User-Agent') then
Log(kLogInfo, "client is running %s and reports %s" % {
finger.GetSynFingerOs(finger.FingerSyn(syn)),
VisualizeControlCodes(GetHeader('User-Agent'))})
end
if HasParam('magic') then
Write('<p>\r\n')
Write('OnHttpRequest() has intercepted your request<br>\r\n')
Write('because you specified the magic parameter\r\n')
Write('<pre>\r\n')
Write(EscapeHtml(LoadAsset('/.init.lua')))
Write('</pre>\r\n')
else
Route() -- this asks redbean to do the default thing
end
SetHeader('Server', 'redbean!')
UpdateHitCounter()
if GetHeader('User-Agent') then
Log(kLogInfo, "client is running %s and reports %s" % {
finger.GetSynFingerOs(finger.FingerSyn(syn)),
VisualizeControlCodes(GetHeader('User-Agent'))})
end
if HasParam('magic') then
Write('<p>\r\n')
Write('OnHttpRequest() has intercepted your request<br>\r\n')
Write('because you specified the magic parameter\r\n')
Write('<pre>\r\n')
Write(EscapeHtml(LoadAsset('/.init.lua')))
Write('</pre>\r\n')
else
Route() -- this asks redbean to do the default thing
end
SetHeader('Server', 'redbean!')
end
function Adder(x, y)
return x + y
return x + y
end

35
tool/net/demo/hitcounter.lua Normal file
View file

@ -0,0 +1,35 @@
Write([[<!doctype html>
<title>redbean mapshared demo</title>
<style>
body { padding: 1em; }
h1 a { color: inherit; text-decoration: none; }
h1 img { border: none; vertical-align: middle; }
input { margin: 1em; padding: .5em; }
pre { margin-left: 2em; }
p { word-break: break-word; max-width: 650px; }
dt { font-weight: bold; }
dd { margin-top: 1em; margin-bottom: 1em; }
.hdr { text-indent: -1em; padding-left: 1em; }
</style>
<h1>
<a href="/"><img src="/redbean.png"></a>
<a href="fetch.lua">redbean mapshared demo</a>
</h1>
<p>
This page displays a <code>unix.mapshared()</code> hit counter of
the <code>GetPath()</code>.
</p>
<dl>
]])
Lock()
s = shm:read(SHM_JSON)
if s == '' then s = '{}' end
t = DecodeJson(s)
Unlock()
for k,v in pairs(t) do
Write('<dt>%s<dd>%d\n' % {EscapeHtml(k), v})
end
Write('</dl>')