---
- 4.3
- 5.3
- '[1] node.js'
---
- 13.4
- 14.4
- '[2] node.js in brief: Server-side Javascript Built on Google’s V8 Evented, non-blocking I/O. Similar to EventMachine or Twisted. CommonJS module system. 8000 lines of C/C++, 2000 lines of Javascript, 14 contributors.'
---
- 43.0
- 44
- '[3] I/O needs to be done differently.'
---
- 72.0
- 73
- '[4] Many web applications have code like this:'
---
- 95.7
- 96.7
- '[5] In many cases, just waiting for the response.'
---
- 127.2
- 128.2
- '[6] I/O latency L1: 3 cycles L2: 14 cycles RAM: 250 cycles DISK: 41,000,000 cycles NETWORK: 240,000,000 cycles'
---
- 166.4
- 167.4
- '[7] Better software can multitask. Other threads of execution can run while waiting.'
---
- 183.5
- 184.5
- '[8] Is that the best that can be done? A look at Apache and NGINX.'
---
- 203.5
- 204.5
- '[9] Apache vs NGINX'
---
- 243.5
- 244.5
- '[10] Apache vs NGINX'
---
- 307.5
- 308.5
- '[11] Apache vs NGINX'
---
- 322.7
- 323.7
- '[12] Context switching is not free Execution stacks take up memory For massive concurrency, cannot use an OS thread for each connection.'
---
- 391.7
- 392.7
- '[13] Green threads or coroutines can improve the situation dramatically BUT there is still machinery involved to create the illusion of holding execution on I/O.'
---
- 438.0
- 439
- '[14] Threaded concurrency is a leaky abstraction.'
---
- 460.4
- 461.4
- '[15] Code like this'
---
- 496.0
- 497
- '[16] But a line of code like this'
---
- 535.1
- 536.1
- '[17] db.query("select..", function (result) { // use result });'
---
- 547.8
- 548.8
- '[18] So why isn’t everyone using event loops, callbacks, and non-blocking I/O? For reasons both cultural and infrastructural.'
---
- 574.9
- 575.9
- '[19] Cultural Bias'
---
- 609.8
- 610.8
- '[20] Cultural Bias'
---
- 640.9
- 641.9
- '[21] Missing Infrastructure'
---
- 672.4
- 673.4
- '[22] Missing Infrastructure'
---
- 725.1
- 726.1
- '[23] Too Much Infrastructure'
---
- 779.3
- 780.3
- '[24] Too Much Infrastructure'
---
- 796.1
- 797.1
- '[25] Javascript designed specifically to be used with an event loop: Anonymous functions, closures. Only one callback at a time. I/O through DOM event callbacks.'
---
- 832.2
- 833.2
- '[26] The culture of Javascript is already geared towards evented programming.'
---
- 857.9
- 858.9
- '[27] This is the node.js project: To provide a purely evented, non-blocking infrastructure to script highly concurrent programs.'
---
- 888.2
- 889.2
- '[28] Design Goals'
---
- 926.4
- 927.4
- '[29] Design Goals'
---
- 982.7
- 983.7
- '[30] Design Goals'
---
- 1007.0
- 1008
- '[31] Design Goals'
---
- 1041.6
- 1042.6
- '[32] Design Goals'
---
- 1080.6
- 1081.6
- '[33] Usage and Examples'
---
- 1087.0
- 1088
- '[34] Download, configure, compile, and make install it.'
---
- 1107.7
- 1108.7
- '[35] 1 2 3 4 5 6'
---
- 1152.0
- 1153
- '[36] 1 2 3 4 5 6'
---
- 1168.3
- 1169.3
- '[37] % node hello_world.js hello'
---
- 1182.5
- 1183.5
- '[38] Change the “hello world” program to loop forever, but print an exit message when the user kills it. We will use the special object process and the "SIGINT" signal.'
---
- 1212.2
- 1213.2
- '[39] 1 2 3 4 5 6 7 8 9 10 11'
---
- 1263.2
- 1264.2
- '[40] process.addListener("SIGINT", ...);'
---
- 1291.2
- 1292.2
- '[41] Also:'
---
- 1302.4
- 1303.4
- '[42] Like process, many other objects in Node emit events.'
---
- 1318.2
- 1319.2
- '[43] A TCP server emits a "connection" event each time someone connects. An HTTP upload emits a "body" event on each packet.'
---
- 1345.4
- 1346.4
- '[44] All objects which emit events are are instances of process.EventEmitter.'
---
- 1354.8
- 1355.8
- '[45] Write a program which: starts a TCP server on port 8000 send the peer a message close the connection'
---
- 1373.7
- 1374.7
- '[46] 1 2 3 4 5 6 7 8 9 10'
---
- 1404.8
- 1405.8
- '[47] % node server.js & [1] 9120 % telnet localhost 8000 Trying 127.0.0.1... Connected to localhost. Escape character is ’ˆ]’. hello! Connection closed by foreign host. %'
---
- 1425.4
- 1426.4
- '[48] The "connection" listener can be provided as the first argument to tcp.createServer(), so the program can be simplified:'
---
- 1440.9
- 1441.9
- '[49] 1 2 3 4 5'
---
- 1447.0
- 1448
- '[50] File I/O is non-blocking too. (Something typically hard to do.)'
---
- 1471.1
- 1472.1
- '[51] As an example, a program that outputs the last time /etc/passwd was modified:'
---
- 1517.0
- 1518
- '[52] A promise is a kind of EventEmitter which emits either "success" or "error". (But not both.) All file operations return a promise.'
---
- 1563.0
- 1564
- '[53] promise.addCallback(cb)'
---
- 1572.2
- 1573.2
- '[54] Simple HTTP Server:'
---
- 1666.8
- 1667.8
- '[55] % node http_server.js & [4] 27355 % curl -i http://localhost:8000/ HTTP/1.1 200 OK Content-Type: text/plain Connection: keep-alive Transfer-Encoding: chunked Hello World %'
---
- 1680.0
- 1681
- '[56] Streaming HTTP Server:'
---
- 1759.1
- 1760.1
- '[57] % node http_server2.js & [4] 27355 % curl http://localhost:8000/ Hello'
---
- 1773.8
- 1774.8
- '[58] 1 2 3 4 5'
---
- 1815.5
- 1816.5
- '[59] But Node never forces buffering'
---
- 1857.9
- 1858.9
- '[60] 1 2 3 4 5 6 7 8 9 10 11 12 13'
---
- 1918.0
- 1919
- '[61] Demo / Experiment'
---
- 2330.2
- 2331.2
- '[62] Internal Design'
---
- 2336.4
- 2337.4
- '[63] V8 (Google) libev event loop library (Marc Lehmann) libeio thread pool library (Marc Lehmann) http-parser a ragel HTTP parser (Me) evcom stream socket library on top of libev (Me) udns non-blocking DNS resolver (Michael Tokarev)'
---
- 2385.4
- 2386.4
- '[64] Blocking (or possibly blocking) system calls are executed in the thread pool. Signal handlers and thread pool callbacks are marshaled back into the main thread via a pipe.'
---
- 2466.4
- 2467.4
- '[65] % node myscript.js < hugefile.txt'
---
- 2526.8
- 2527.8
- '[66] Solution: Start a pipe, and a “pumping thread”. Pump data from blocking fd into pipe. Main thread can poll for data on the pipe.'
---
- 2564.7
- 2565.7
- '[67] Future'
---
- 2639.0
- 2640
- '[68] Future'
---
- 2675.1
- 2676.1
- '[69] Questions...?'