aboutsummaryrefslogtreecommitdiff
path: root/public/simple-server-sent-events-based-pubsub-server.html
diff options
context:
space:
mode:
authorMitja Felicijan <mitja.felicijan@gmail.com>2023-10-31 18:02:35 +0100
committerMitja Felicijan <mitja.felicijan@gmail.com>2023-10-31 18:02:35 +0100
commitcc492b31774be0f98ae9152d0f272324c415e4d8 (patch)
tree54814afa8ce1f81785edfe95b62bac2c0e811b43 /public/simple-server-sent-events-based-pubsub-server.html
parentfd3a6a3730d4078f6be4239a9c24c9747ef9d555 (diff)
downloadmitjafelicijan.com-cc492b31774be0f98ae9152d0f272324c415e4d8.tar.gz
Theme update
Diffstat (limited to 'public/simple-server-sent-events-based-pubsub-server.html')
-rwxr-xr-xpublic/simple-server-sent-events-based-pubsub-server.html8
1 files changed, 4 insertions, 4 deletions
diff --git a/public/simple-server-sent-events-based-pubsub-server.html b/public/simple-server-sent-events-based-pubsub-server.html
index 9115ab1..93853b1 100755
--- a/public/simple-server-sent-events-based-pubsub-server.html
+++ b/public/simple-server-sent-events-based-pubsub-server.html
@@ -1,4 +1,4 @@
1<!doctype html><html lang=en-us><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=generator content="JBMAFP - github.com/mitjafelicijan/jbmafp"><link href="data:image/x-icon;base64,AAABAAEAEBAAAAEAIABoBAAAFgAAACgAAAAQAAAAIAAAAAEAIAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAL69vf8AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAv76+/8LBwQkAAAAAAAAAAAAAAAC+vb3/AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAL+9vf/Bv78JAAAAAAAAAAAAAAAAu7q6/wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAC7ubr/vr29CAAAAAAAAAAAy8nJAZ6foP8AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAnqGj/6GipAoAAAAAHLjU/xcXHf/BwsL/I8XY/yPK3v8XGiD/IbjL/yPF2f8XGiD/Fxkf/yLF2f8gnK3/Fxog/62ztv8fwNf/FRcd/x271v8mz93/GRsi/xkXHf8p097/GiIp/xobIv8p0t3/KdPe/xocIv8fYmr/KNPe/xoZH/8aHCL/J87c/xy81/8VFxz/IsPZ/8zS0/8XGiD/Ir/R/yPH2/8XGiD/Fxkf/yPH2/8dd4T/GBog/yPJ3f8jyNr/uru9/xcUGv8cudb/EhITDKi5vRKlvMP/RUpOERwcHRAdOj4QHTk8EBwdHRAdNTgQHTo/EBwcHRAcHB0QSGduEKW4vf+koqQfHzg+EBqz0ewSFRv7EyMr/xq51vsTERb7ExUb+xq41fsau9j7ExUb+xiPp/sZudb7ExUb+xMVG/sZuNX/GKvI/BIUGfMdvdn/IrfL/xcaIP8n1eb/J9Dh/xkcIf8ZGR7/J8/f/xxCSv8ZGyH/J9Dg/ybQ4P8ZHCL/FSQs/yPK3/8UExj/GE1b/ybS5P8ZGB7/Ghwj/ynW5P8p2Ob/Ghwi/yWrtv8p1eH/Ghwi/xocIv8p1uT/J8XT/xkcIv8m1un/Hb7d/xUYH/8hzOr/HtHu/xcaIf8XGB//I8vi/xgxOv8XGSD/I8rg/yPK4P8XGiD/GUFL/yPP6f8SERj/Fhkh/x3A4f8AAAAAJ2f9/ydr//8mZPH/AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlYu38J2v//ydo/f8AAAAAAAAAAAd8/fkFqf//Iob8sAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMY39awWr//8FfP3/AAAAAAAAAAAFm/7/SfD//wR+/f8AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAOB/f9B7v//BaX+/wAAAAAAAAAAQ878SAyZ/v9n1v4KAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADu9v8DDJb+/z3N/XgAAAAA3/sAAN/7AADf+wAA3/sAAAAAAAAAAAAAAAAAAN/7AAAAAAAAAAAAAAAAAAAAAAAAj/EAAI/5AACP8QAA3/sAAA==" rel=icon type=image/x-icon><title>Simple Server-Sent Events based PubSub Server</title><meta name=description content="Before we continue ."><meta name=author content="Mitja Felicijan"><link rel=alternate type=application/rss+xml title="Mitja Felicijan's posts" href=https://mitjafelicijan.com/index.xml><link rel=alternate type=application/rss+xml title="Mitja Felicijan's notes" href=https://mitjafelicijan.com/notes.xml><style>:root{--border-color:gainsboro;--border-size:2px;--link-color:blue;--bg-color:#eee}*::selection{background:var(--link-color);color:#fff}*::-moz-selection{background:var(--link-color);color:#fff}*::-webkit-selection{background:var(--link-color);color:#fff}body{padding:2.5rem;max-width:1900px;background:#fff;font-family:sans-serif;line-height:1.35rem;font-size:16px}hr{border:0;border-bottom:var(--border-size)solid var(--border-color);margin-block-start:1.5rem}a{color:var(--link-color);text-decoration:none}h1,h2,h3{line-height:initial}h1{font-size:xx-large}footer{margin-block-start:2rem}cap{text-transform:capitalize}blockquote{font-style:italic}table{max-width:100%;border:var(--border-size)solid var(--border-color);border-collapse:separate;border-spacing:0}table thead tr th{border-bottom:var(--border-size)solid var(--border-color);text-align:left}table th,table td{padding:.5em .8em}ul.list li{padding:.2em 0}ul{line-height:1.35em}pre{text-wrap:nowrap;overflow-x:auto;padding:0 1em;border:var(--border-size)solid var(--border-color)}code{padding:0 3px;font-size:14px;border:0;background:var(--bg-color)}pre code{line-height:1.3em;background:#fff}pre,code,pre *,code *{font-family:monospace}figure{margin-inline-start:0;margin-inline-end:0}figcaption{width:800px;max-width:100%;text-align:center}figcaption p{margin:.3em 0 1.5em;font-style:italic}img,video,audio{width:800px;max-width:100%;border:var(--border-size)solid var(--border-color);padding:.5em}header nav{display:flex;gap:.9rem}article iframe{margin:0!important}audio::-webkit-media-controls-enclosure{border-radius:0}@media only screen and (max-width:600px){body{padding:.5em;word-wrap:break-word}header nav{gap:.7rem}header nav .hob{display:none}a{word-wrap:break-word}}</style><header><nav class=main itemscope itemtype=http://schema.org/SiteNavigationElement role=toolbar><a href=/>Home</a> 1<!doctype html><html lang=en-us><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=generator content="JBMAFP - github.com/mitjafelicijan/jbmafp"><link href="data:image/x-icon;base64,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" rel=icon type=image/x-icon><title>Simple Server-Sent Events based PubSub Server</title><meta name=description content="Before we continue ."><meta name=author content="Mitja Felicijan"><link rel=alternate type=application/rss+xml title="Mitja Felicijan's posts" href=https://mitjafelicijan.com/index.xml><link rel=alternate type=application/rss+xml title="Mitja Felicijan's notes" href=https://mitjafelicijan.com/notes.xml><style>:root{--border-color:gainsboro;--border-size:2px;--link-color:blue;--bg-color:#eee}*::selection{background:var(--link-color);color:#fff}*::-moz-selection{background:var(--link-color);color:#fff}*::-webkit-selection{background:var(--link-color);color:#fff}body{padding:2.5rem;max-width:1900px;background:#fff;font-family:sans-serif;line-height:1.35rem;font-size:16px}hr{border:0;border-bottom:var(--border-size)solid var(--border-color);margin-block-start:1.5rem}a{color:var(--link-color);text-decoration:none}h1,h2,h3{line-height:initial}h1{font-size:xx-large}footer{margin-block-start:2rem}cap{text-transform:capitalize}blockquote{font-style:italic}table{max-width:100%;border:var(--border-size)solid var(--border-color);border-collapse:separate;border-spacing:0}table thead tr th{border-bottom:var(--border-size)solid var(--border-color);text-align:left}table th,table td{padding:.5em .8em}ul.list li{padding:.2em 0}ul{line-height:1.35em}pre{text-wrap:nowrap;overflow-x:auto;padding:0 1em;border:var(--border-size)solid var(--border-color)}code{padding:0 3px;font-size:14px;border:0;background:var(--bg-color)}pre code{line-height:1.3em;background:#fff}pre,code,pre *,code *{font-family:monospace}figure{margin-inline-start:0;margin-inline-end:0}figcaption{width:800px;max-width:100%;text-align:center}figcaption p{margin:.3em 0 1.5em;font-style:italic}img,video,audio{width:800px;max-width:100%;border:var(--border-size)solid var(--border-color);padding:.5em}header nav{display:flex;gap:.9rem}article iframe{margin:0!important}audio::-webkit-media-controls-enclosure{border-radius:0}@media only screen and (max-width:600px){body{padding:.5em;word-wrap:break-word}header nav{gap:.7rem}header nav .hob{display:none}a{word-wrap:break-word}}</style><header><nav class=main itemscope itemtype=http://schema.org/SiteNavigationElement role=navigation aria-label="Main navigation"><a href=/>Home</a>
2<a href=/#posts>Posts</a> 2<a href=/#posts>Posts</a>
3<a href=/#notes>Notes</a> 3<a href=/#notes>Notes</a>
4<a href=/#sideprojects class=hob>Side Projects</a> 4<a href=/#sideprojects class=hob>Side Projects</a>
@@ -22,7 +22,7 @@ Events</a>
22to all the subscribers.</ul><h2 id=how-exactly-does-the-pubsub-model-work>How exactly does the pub/sub model work?</h2><p>The easiest way to explain this is with diagram bellow. Basic function is 22to all the subscribers.</ul><h2 id=how-exactly-does-the-pubsub-model-work>How exactly does the pub/sub model work?</h2><p>The easiest way to explain this is with diagram bellow. Basic function is
23simple. We have subscribers that receive messages, and we have publishers that 23simple. We have subscribers that receive messages, and we have publishers that
24create and post messages. Similar model is also well know pattern that works on 24create and post messages. Similar model is also well know pattern that works on
25a premise of consumers and producers, and they take similar roles.<figure><img loading="lazy" src=/posts/simple-pubsub-server/pubsub-overview.png alt="How PubSub works"></figure><p><strong>These are some naive characteristics we want to achieve:</strong><ul><li>producer is publishing messages to subscribe topic,<li>consumer is receiving messages from subscribed topic,<li>servers is also known as Broker,<li>broker does not store messages or tracks success,<li>broker uses 25a premise of consumers and producers, and they take similar roles.<figure><img src=/posts/simple-pubsub-server/pubsub-overview.png alt="How PubSub works"></figure><p><strong>These are some naive characteristics we want to achieve:</strong><ul><li>producer is publishing messages to subscribe topic,<li>consumer is receiving messages from subscribed topic,<li>servers is also known as Broker,<li>broker does not store messages or tracks success,<li>broker uses
26<a href=https://en.wikipedia.org/wiki/FIFO_(computing_and_electronics)>FIFO</a> method 26<a href=https://en.wikipedia.org/wiki/FIFO_(computing_and_electronics)>FIFO</a> method
27for delivering messages,<li>if consumer wants to receive messages from a topic, producer and consumer 27for delivering messages,<li>if consumer wants to receive messages from a topic, producer and consumer
28topics must match,<li>consumer can subscribe to multiple topics,<li>producer can publish to multiple topics,<li>each message has a messageId.</ul><p><strong>Known drawbacks:</strong><ul><li>messages will not be stored in a persistent queue or unreceived messages like 28topics must match,<li>consumer can subscribe to multiple topics,<li>producer can publish to multiple topics,<li>each message has a messageId.</ul><p><strong>Known drawbacks:</strong><ul><li>messages will not be stored in a persistent queue or unreceived messages like
@@ -32,7 +32,7 @@ Events</a>
32opens a long-running connection between the client and the server so make sure 32opens a long-running connection between the client and the server so make sure
33if your setup is load balanced that the load balancer in this case can have 33if your setup is load balanced that the load balancer in this case can have
34long opened connection,<li>no system moderation due to the dynamic nature of creating queues.</ul><h2 id=server-sent-events>Server-Sent Events</h2><p>Read more about it on <a href=https://html.spec.whatwg.org/multipage/server-sent-events.html>official specification 34long opened connection,<li>no system moderation due to the dynamic nature of creating queues.</ul><h2 id=server-sent-events>Server-Sent Events</h2><p>Read more about it on <a href=https://html.spec.whatwg.org/multipage/server-sent-events.html>official specification
35page</a>.<h3 id=current-browser-support>Current browser support</h3><figure><img loading="lazy" src=/posts/simple-pubsub-server/caniuse.png alt="Browser support"></figure><p>Check 35page</a>.<h3 id=current-browser-support>Current browser support</h3><figure><img src=/posts/simple-pubsub-server/caniuse.png alt="Browser support"></figure><p>Check
36<a href="https://caniuse.com/#feat=eventsource">https://caniuse.com/#feat=eventsource</a> 36<a href="https://caniuse.com/#feat=eventsource">https://caniuse.com/#feat=eventsource</a>
37for latest information about browser support.<h3 id=known-issues>Known issues</h3><ul><li>Firefox 52 and below do not support EventSource in web/shared workers<li>In Firefox prior to version 36 server-sent events do not reconnect 37for latest information about browser support.<h3 id=known-issues>Known issues</h3><ul><li>Firefox 52 and below do not support EventSource in web/shared workers<li>In Firefox prior to version 36 server-sent events do not reconnect
38automatically in case of a connection interrupt (bug)<li>Reportedly, CORS in EventSource is currently supported in Firefox 10+, Opera 38automatically in case of a connection interrupt (bug)<li>Reportedly, CORS in EventSource is currently supported in Firefox 10+, Opera
@@ -55,7 +55,7 @@ server that triggers browser to threat response as a EventStream.<p>Headers resp
55Events</a> 55Events</a>
56which is quite nice and available from Developer Tools under Network tab.<blockquote><p>You can debug only client side events that get received and not the server 56which is quite nice and available from Developer Tools under Network tab.<blockquote><p>You can debug only client side events that get received and not the server
57ones. For debugging server events add <code>console.log</code> to <code>server.js</code> code and 57ones. For debugging server events add <code>console.log</code> to <code>server.js</code> code and
58print out events.</blockquote><figure><img loading="lazy" src=/posts/simple-pubsub-server/chrome-debugging.png alt="Google Chrome Developer Tools EventStream"></figure><h2 id=server-implementation>Server implementation</h2><p>For the sake of this example we will use <a href=https://nodejs.org/en/>Node.js</a> with 58print out events.</blockquote><figure><img src=/posts/simple-pubsub-server/chrome-debugging.png alt="Google Chrome Developer Tools EventStream"></figure><h2 id=server-implementation>Server implementation</h2><p>For the sake of this example we will use <a href=https://nodejs.org/en/>Node.js</a> with
59<a href=https://expressjs.com>Express</a> as our router since this is the easiest way to 59<a href=https://expressjs.com>Express</a> as our router since this is the easiest way to
60get started and we will use already written SSE library for node 60get started and we will use already written SSE library for node
61<a href=https://www.npmjs.com/package/sse-pubsub>sse-pubsub</a> so we don't reinvent the 61<a href=https://www.npmjs.com/package/sse-pubsub>sse-pubsub</a> so we don't reinvent the
generated by cgit v1.2.3 (git 2.46.0) at 2026-04-30 22:45:50 +0000