EventSource demo

#!/usr/bin/env lua --[[ A server that responds with an infinite server-side-events format. https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#Event_stream_format Usage: lua examples/server_sent_events.lua [] ]] local port = arg[1] or 0 -- 0 means pick one at random local cqueues = require "cqueues" local http_server = require "http.server" local http_headers = require "http.headers" local myserver = assert(http_server.listen { host = "localhost"; port = port; onstream = function(myserver, stream) -- luacheck: ignore 212 -- Read in headers local req_headers = assert(stream:get_headers()) local req_method = req_headers:get ":method" -- Build response headers local res_headers = http_headers.new() if req_method ~= "GET" and req_method ~= "HEAD" then res_headers:upsert(":status", "405") assert(stream:write_headers(res_headers, true)) return end if req_headers:get ":path" == "/" then res_headers:append(":status", "200") res_headers:append("content-type", "text/html") -- Send headers to client; end the stream immediately if this was a HEAD request assert(stream:write_headers(res_headers, req_method == "HEAD")) if req_method ~= "HEAD" then assert(stream:write_chunk([[ EventSource demo

This page uses server-sent_events to show the live server time:

]], true)) end elseif req_headers:get ":path" == "/event-stream" then res_headers:append(":status", "200") res_headers:append("content-type", "text/event-stream") -- Send headers to client; end the stream immediately if this was a HEAD request assert(stream:write_headers(res_headers, req_method == "HEAD")) if req_method ~= "HEAD" then -- Start a loop that sends the current time to the client each second while true do local msg = string.format("data: The time is now %s.\n\n", os.date()) assert(stream:write_chunk(msg, false)) cqueues.sleep(1) -- yield the current thread for a second. end end else res_headers:append(":status", "404") assert(stream:write_headers(res_headers, true)) end end; onerror = function(myserver, context, op, err, errno) -- luacheck: ignore 212 local msg = op .. " on " .. tostring(context) .. " failed" if err then msg = msg .. ": " .. tostring(err) end assert(io.stderr:write(msg, "\n")) end; }) -- Manually call :listen() so that we are bound before calling :localname() assert(myserver:listen()) do local bound_port = select(3, myserver:localname()) assert(io.stderr:write(string.format("Now listening on port %d\nOpen http://localhost:%d/ in your browser\n", bound_port, bound_port))) end -- Start the main server loop assert(myserver:loop())