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Deno Deploy Demo: a multi-datacenter chat, client+server in 23 lines of TS

186 points by ondras 5y ago

deleted 5y ago
[deleted]
vnglst 5y ago
Nice, I like how short and simple it is. The title seems to imply it runs on multiple datacenters. How does it sync messages between those?
- jitl 5y ago
  I believe the BroadcastChannel implements the server-side distributed messaging.
  - paulgb 5y ago
    Neat, it’s a server-side implementation of the browser API for tab-to-tab communication. https://deno.com/deploy/docs/runtime-broadcast-channel/ https://deno.com/deploy/docs/runtime-broadcast-channel/
  - rhizome 5y ago
    class BroadcastChannel return `system('ircd')` end Only three lines! :D
- ondras 5y ago
  Right, as jitl suggested. The BroadcastChannel is used to allow cross-datacenter messaging. So every script instance has its own set of clients and forwards incoming client messages to other script/datacenter instances. I suppose this is not limited to multiple datacenters, but to multiple script instances in one datacenter as well.
- schemescape 5y ago
  I was also wondering how this worked, and the following Deno Deploy documentation explains it: https://deno.com/deploy/docs/runtime-broadcast-channel/#broadcastchannel https://deno.com/deploy/docs/runtime-broadcast-channel/#broa...
deleted 5y ago
[deleted]
vnglst 5y ago
What I really like about this is that you open the dependency in a web browser and see the human readable source code. No transpiling! https://deno.land/std/http/server.ts https://deno.land/std/http/server.ts
- judge2020 5y ago
  This is generally already possible with webpack, but many/most websites i've looked at have source maps turned off. Maybe the extra compile time is too much, or they just want to disincentivize client-side reverse engineering.
  - tehlike 5y ago
    It's the latter.
honkycat 5y ago
Deno is such a nice little scripting tool. I've been using it for devops glue and scripts lately. Native typescript, easy-as-pie dependency management. its great!
- IshKebab 5y ago
  I agree - also rock solid IDE support helps. It's really lightyears ahead of any other scripting options (Bash, Python, etc.)
- andyfleming 5y ago
  Do you have any libraries you use often with scripts or mostly just deno built-ins?
- 29athrowaway 5y ago
  Personally I do not like the fact that it puts too much trust into DNS. DNS wasn't created with security in mind, so to say Deno is secure because it uses a permissions system while relying directly into DNS for imports to me sounds weird.
  - IshKebab 5y ago
    It uses https. Are you not satisfied that that is reasonably secure?
  - simonw 5y ago
    It's not just DNS, thankfully - deno.land has a TLS certificate too, which I think means that DNS exploits wouldn't succeed in causing clients to install untrusted packages.
  - koprulusector 5y ago
    How is this any different than any other package management system? If you npm or pip install a package and import it, you’re still relying on DNS to resolve pypi or npmjs. But with deno, if you’ve just accidentally installed some malicious squatters’ package that mimics the one you meant to use, at least you’ve got less exposure because the malicious code won’t necessarily have blanket permissions to make network calls, read files, etc. virtually any other language/package management system cannot say the same. deno will download and cache the dependencies you import, they’re right in the project folder vs buried in a sea of node_modules. It’s super convenient to look at and inspect, if there’s any doubt or idle curiosity.
ranger_danger 5y ago
what is TS?
- ondras 5y ago
  TypeScript...
  - ranger_danger 5y ago
    what, I'm just supposed to know that?
    - orf 5y ago
      I think it's not unobvious if you open the link
      - capableweb 5y ago
        To be fair, there is absolutely zero information about what technology is being used on the page the submission links to. Clicking the top-left icon brings you to "https://dash.deno.com/projects https://dash.deno.com/projects" which then forces you to login, still not giving any indication on what this thing is about or even written in. I can see how you can get confused, even if I wasn't as I'm around the JS community.
    - Mikeb85 5y ago
      When discussing Deno, yes.
    - agumonkey 5y ago
      Nothing is to be known by everybody. But it's surprising that you don't associate typescript with deno. Unless you didn't know about deno in the first place. Just saying because TS had some kind of popularity these days.
amadeuspagel 5y ago
Here's a version that resets the input field when you hit enter: https://dash.deno.com/playground/careful-toad-72 https://dash.deno.com/playground/careful-toad-72
mwcampbell 5y ago
Has anyone written a comparison of Deno Deploy and Cloudflare Workers yet?
- babelfish 5y ago
  Deno: 28 datacenters Workers: 200+ datacenters
  - Soremwar 5y ago
    Not that simple of a comparison since "data centers" mean a different thing in both cases
  - capableweb 5y ago
    Deno: written by a guy who regrets his previous attempt at writing a programming environment CloudFlare: global, huge company who regrets they don't already route 100% of internet traffic Edit: I should add, I commend both efforts, both probably improve the world more than they hurt it, just injecting a bit of humor.
1_player 5y ago
There's few things as fun as a multiplayer notepad that wasn't intended to be an actual chat, before it's invaded by bots and spammers. Congrats on the fella that tried to paste an ascii art version of Pepe the Frog.
- ushakov 5y ago
  yes, it was me all along https://imgur.com/a/aEHjQcp https://imgur.com/a/aEHjQcp update: the original version was too spammy, i have changed it so that pepe only responds to greetings or when you type "pepe" update 2: i have throttled pepe so it only comes back after minute of cooldown
- ushakov 5y ago
  code for pepe is now available: https://gist.github.com/mishushakov/eb281f8edbb7e2bd2e6580de193d87f4 https://gist.github.com/mishushakov/eb281f8edbb7e2bd2e6580de...
  - Lucasoato 5y ago
    Thanks for posting pepe, my friend
divan 5y ago
Related: https://news.ycombinator.com/item?id=12477190 https://news.ycombinator.com/item?id=12477190
simonw 5y ago
This is such a neat demo. I wrote up an annotated version of the code while I was figuring out exactly how it worked. https://til.simonwillison.net/deno/annotated-deno-deploy-demo https://til.simonwillison.net/deno/annotated-deno-deploy-dem...
- mceachen 5y ago
  Thanks for sharing! I expect the demo works with or without the await on the listen promise because the listen code runs regardless (and prevents main from exiting).
- tomcam 5y ago
  Fantastic, thanks.
zcbenz 5y ago
I'm a bit confused when people say "native TypeScript" and "no transpiling" about Deno, does Deno now execute TypeScript without translating it to JavaScript first?
- koprulusector 5y ago
  It always did. That’s been a core feature / benefit from day 1.
  - bryanrasmussen 5y ago
    so question - normally the thing I like about Node.js is not much context switching and ability to rerun code between backend and frontend. I can get the same thing with TS if I compile in both backend and frontend - if in Deno I don't compile and in the frontend I do are there any weird gotchas I would run into?
    - andyferris 5y ago
      Deno is aiming to have better compatibility with web standards than Node, so you should encounter fewer gotchas from reusing code in backend and frontend.
  - capableweb 5y ago
    No, it never did, Deno always have converted TypeScript into JavaScript that then gets read and executed by the browser, at least according to their own docs but maybe that has changed lately? > At a high level, Deno converts TypeScript (as well as TSX and JSX) into JavaScript. It does this via a combination of the TypeScript compiler, which we build into Deno, and a Rust library called swc. When the code has been type checked and transformed, it is stored in a cache, ready for the next run without the need to convert it from its source to JavaScript again. https://deno.land/manual/typescript/overview https://deno.land/manual/typescript/overview
    - koprulusector 5y ago
Donckele 5y ago
love the chat spamming going on…

186 points by ondras 5y ago

deleted 5y ago

[deleted]

Nice, I like how short and simple it is. The title seems to imply it runs on multiple datacenters. How does it sync messages between those?

jitl 5y ago
I believe the BroadcastChannel implements the server-side distributed messaging.
- paulgb 5y ago
  Neat, it’s a server-side implementation of the browser API for tab-to-tab communication. https://deno.com/deploy/docs/runtime-broadcast-channel/ https://deno.com/deploy/docs/runtime-broadcast-channel/
- rhizome 5y ago
  class BroadcastChannel return `system('ircd')` end Only three lines! :D
ondras 5y ago
Right, as jitl suggested. The BroadcastChannel is used to allow cross-datacenter messaging. So every script instance has its own set of clients and forwards incoming client messages to other script/datacenter instances. I suppose this is not limited to multiple datacenters, but to multiple script instances in one datacenter as well.
schemescape 5y ago
I was also wondering how this worked, and the following Deno Deploy documentation explains it: https://deno.com/deploy/docs/runtime-broadcast-channel/#broadcastchannel https://deno.com/deploy/docs/runtime-broadcast-channel/#broa...

deleted 5y ago

[deleted]

vnglst 5y ago

What I really like about this is that you open the dependency in a web browser and see the human readable source code. No transpiling! https://deno.land/std/http/server.ts https://deno.land/std/http/server.ts

judge2020 5y ago
This is generally already possible with webpack, but many/most websites i've looked at have source maps turned off. Maybe the extra compile time is too much, or they just want to disincentivize client-side reverse engineering.
- tehlike 5y ago
  It's the latter.

honkycat 5y ago

Deno is such a nice little scripting tool. I've been using it for devops glue and scripts lately. Native typescript, easy-as-pie dependency management. its great!

IshKebab 5y ago
I agree - also rock solid IDE support helps. It's really lightyears ahead of any other scripting options (Bash, Python, etc.)
andyfleming 5y ago
Do you have any libraries you use often with scripts or mostly just deno built-ins?
29athrowaway 5y ago
Personally I do not like the fact that it puts too much trust into DNS. DNS wasn't created with security in mind, so to say Deno is secure because it uses a permissions system while relying directly into DNS for imports to me sounds weird.
- IshKebab 5y ago
  It uses https. Are you not satisfied that that is reasonably secure?
- simonw 5y ago
  It's not just DNS, thankfully - deno.land has a TLS certificate too, which I think means that DNS exploits wouldn't succeed in causing clients to install untrusted packages.
- koprulusector 5y ago
  How is this any different than any other package management system? If you npm or pip install a package and import it, you’re still relying on DNS to resolve pypi or npmjs. But with deno, if you’ve just accidentally installed some malicious squatters’ package that mimics the one you meant to use, at least you’ve got less exposure because the malicious code won’t necessarily have blanket permissions to make network calls, read files, etc. virtually any other language/package management system cannot say the same. deno will download and cache the dependencies you import, they’re right in the project folder vs buried in a sea of node_modules. It’s super convenient to look at and inspect, if there’s any doubt or idle curiosity.

ranger_danger 5y ago

what is TS?

ondras 5y ago
TypeScript...
- ranger_danger 5y ago
  what, I'm just supposed to know that?
  - orf 5y ago
    I think it's not unobvious if you open the link
    - capableweb 5y ago
      To be fair, there is absolutely zero information about what technology is being used on the page the submission links to. Clicking the top-left icon brings you to "https://dash.deno.com/projects https://dash.deno.com/projects" which then forces you to login, still not giving any indication on what this thing is about or even written in. I can see how you can get confused, even if I wasn't as I'm around the JS community.
  - Mikeb85 5y ago
    When discussing Deno, yes.
  - agumonkey 5y ago
    Nothing is to be known by everybody. But it's surprising that you don't associate typescript with deno. Unless you didn't know about deno in the first place. Just saying because TS had some kind of popularity these days.

amadeuspagel 5y ago

Here's a version that resets the input field when you hit enter: https://dash.deno.com/playground/careful-toad-72 https://dash.deno.com/playground/careful-toad-72

mwcampbell 5y ago

Has anyone written a comparison of Deno Deploy and Cloudflare Workers yet?

babelfish 5y ago
Deno: 28 datacenters Workers: 200+ datacenters
- Soremwar 5y ago
  Not that simple of a comparison since "data centers" mean a different thing in both cases
- capableweb 5y ago
  Deno: written by a guy who regrets his previous attempt at writing a programming environment CloudFlare: global, huge company who regrets they don't already route 100% of internet traffic Edit: I should add, I commend both efforts, both probably improve the world more than they hurt it, just injecting a bit of humor.

1_player 5y ago

There's few things as fun as a multiplayer notepad that wasn't intended to be an actual chat, before it's invaded by bots and spammers. Congrats on the fella that tried to paste an ascii art version of Pepe the Frog.

ushakov 5y ago
yes, it was me all along https://imgur.com/a/aEHjQcp https://imgur.com/a/aEHjQcp update: the original version was too spammy, i have changed it so that pepe only responds to greetings or when you type "pepe" update 2: i have throttled pepe so it only comes back after minute of cooldown
ushakov 5y ago
code for pepe is now available: https://gist.github.com/mishushakov/eb281f8edbb7e2bd2e6580de193d87f4 https://gist.github.com/mishushakov/eb281f8edbb7e2bd2e6580de...
- Lucasoato 5y ago
  Thanks for posting pepe, my friend

divan 5y ago

Related: https://news.ycombinator.com/item?id=12477190 https://news.ycombinator.com/item?id=12477190

simonw 5y ago

This is such a neat demo. I wrote up an annotated version of the code while I was figuring out exactly how it worked. https://til.simonwillison.net/deno/annotated-deno-deploy-demo https://til.simonwillison.net/deno/annotated-deno-deploy-dem...

mceachen 5y ago
Thanks for sharing! I expect the demo works with or without the await on the listen promise because the listen code runs regardless (and prevents main from exiting).
tomcam 5y ago
Fantastic, thanks.

zcbenz 5y ago

I'm a bit confused when people say "native TypeScript" and "no transpiling" about Deno, does Deno now execute TypeScript without translating it to JavaScript first?

koprulusector 5y ago
It always did. That’s been a core feature / benefit from day 1.
- bryanrasmussen 5y ago
  so question - normally the thing I like about Node.js is not much context switching and ability to rerun code between backend and frontend. I can get the same thing with TS if I compile in both backend and frontend - if in Deno I don't compile and in the frontend I do are there any weird gotchas I would run into?
  - andyferris 5y ago
    Deno is aiming to have better compatibility with web standards than Node, so you should encounter fewer gotchas from reusing code in backend and frontend.
- capableweb 5y ago
  No, it never did, Deno always have converted TypeScript into JavaScript that then gets read and executed by the browser, at least according to their own docs but maybe that has changed lately? > At a high level, Deno converts TypeScript (as well as TSX and JSX) into JavaScript. It does this via a combination of the TypeScript compiler, which we build into Deno, and a Rust library called swc. When the code has been type checked and transformed, it is stored in a cache, ready for the next run without the need to convert it from its source to JavaScript again. https://deno.land/manual/typescript/overview https://deno.land/manual/typescript/overview
  - koprulusector 5y ago

Donckele 5y ago

love the chat spamming going on…