added unixy extension

xurfer/ext/unixy/main.lua

@@ -0,0 +1,111 @@
+-- The unixy extension allows proxying api-functions through cli apps.
+-- Why? 
+-- Sometimes the host OS already has cli-apps which can make up for missing lua functionality.
+-- The unixy extension is written in such way that it does not block the mainloop too much.
+-- Instead it checks whether the PID still exists at a certain interval-seconds (dtmax)
+--
+-- example of proxying an api-function to a cli app (curl):
+--
+--    api.protocol.http.request = unixy.proxyCLI( 
+--      function(url,opts, cb) return string.format( "curl -v -s %s", url ) end,
+--      function( stdout, stderr, retcode, url, opts, cb) 
+--        local status = 200
+--        if retcode ~= 0 then status = retcode end
+--        cb( retcode, stdout, {string = stderr}) -- todo: parse string into key/values
+--      end
+--    )
+--
+--    api.protocol.http.request( "https://2wa.isvery.ninja", {}, function(status,data,headers)
+--      print_r(status)
+--      print_r(headers)
+--      print_r(data)
+--    end)
+--
+local api = ...
+local ecs = api.ecs
+
+if table.unpack == nil then 
+  table.unpack = unpack
+end
+
+local unixy 
+unixy = {
+  name      = "unixy",
+  enabled   = true,
+  jobs      = {},
+  dtmax     = 1,
+  dt        = 0,
+
+  init = function() 
+  end,
+
+  proxyCLI = function( cmdfunc, callback )
+    return function(...)
+      return unixy.addjob( cmdfunc, callback, ...)
+    end
+  end,
+
+  update = function(dt)
+    unixy.dt = unixy.dt + dt
+    if unixy.dt > unixy.dtmax then
+      unixy.dt = 0
+      if #unixy.jobs > 0 then
+        unixy.check_jobs()
+      end
+    end
+  end,
+
+  addjob = function( cmdgen, callback, ...)
+    local stdout_file = os.tmpname()
+    local stderr_file = os.tmpname()
+    local pid_file    = os.tmpname()
+
+    -- Run curl in the background (&) + Save curl's PID ($!) to a file 
+    local cmd = cmdgen( ... )
+    cmd = string.format( cmd .. " 1> %s 2> %s & echo $! > %s", stdout_file, stderr_file, pid_file)
+    os.execute(cmd)
+
+    -- Read the PID that was generated
+    local f = io.open(pid_file, "r")
+    local pid = f:read("*a"):gsub("%s+", "")
+    f:close()
+    os.remove(pid_file) -- clean up pid file immediately
+
+    table.insert(unixy.jobs, {
+      pid = pid,
+      args = {...},
+      stdout_file = stdout_file,
+      stderr_file = stderr_file,
+      callback = callback
+    })
+    trace("[unixy] start job with pid " .. pid .. " => 1> " .. stdout_file .. " 2> " .. stderr_file)
+    print_r(unixy.jobs)
+  end,
+
+  check_jobs = function()
+    for i = #unixy.jobs, 1, -1 do
+      local job = unixy.jobs[i]
+      -- 'kill -0' doesn't kill the process, it just checks if it exists.
+      local retcode = os.execute("ps -p " .. job.pid .. " > /dev/null")
+      if retcode ~= 0 then
+        -- Process finished! Read stdout & stderr
+        local f = io.open(job.stdout_file, "r")
+        local stdout = f:read("*a")
+        f:close()
+        f = io.open(job.stderr_file, "r")
+        local stderr = f:read("*a")
+        f:close()
+        -- Clean up 
+        os.remove(job.stdout_file)
+        os.remove(job.stderr_file)
+        job.callback(stdout, stderr, retcode, unpack(job.args) )
+        table.remove(unixy.jobs, i)
+      else
+        io.write(".")
+        io.flush()
+      end
+    end
+  end,
+}
+
+return unixy