6 ms·

Creating a Virtual Printer Using Node.js [video]

75 points by watson 11y ago

mtharrison 11y ago
This is really cool
brudgers 11y ago
Github: https://github.com/watson/ipp-printer https://github.com/watson/ipp-printer
- watson 11y ago
  Here are the rest of the links: https://github.com/watson/ipp-encoder https://github.com/watson/ipp-encoder https://github.com/watson/printcat https://github.com/watson/printcat http://printb.in http://printb.in
creshal 11y ago
Printers and Javascript, a match made in hell.
- wavefunction 11y ago
  JavaScript is great. I do enjoy all the posts about how it sucks. First it was a toy language. Now people complain that it's a weakly typed language replacing strongly-typed languages they prefer... I'm interested to see the next iteration of this phenomenon. Meanwhile I just enjoy developing in it every day. Other than having to maintain the odd ExtJS app, it's simply the best. cue triumphant sax
  - monk_e_boy 11y ago
    The first 30 lines of this file are a 'joy' https://github.com/js-cookie/js-cookie/blob/master/src/js.cookie.js https://github.com/js-cookie/js-cookie/blob/master/src/js.co... I'm sure js could be nice, but it never seems to be.
    - tracker1 11y ago
      The syntax could be a lot cleaner... the Universal Module Definition (UMD) pattern at the top makes it a bit quirky... A lot of people have moved towards using CommonJS (cjs/node-style) exports with tooling such as browserift/webpack and/or babel (for es6 modules) in order to clean up the source syntax. What you're looking at is a relatively poor example. In es6, that could be ... exports default function... without all the cruft around it, also the module itself could be cleaner. Similar to: var cookies = parse(); export function set({key, value, days=null}) { ... } export function get(key) { ... } export const remove = (key) => set({key, value:null}); export function parse(values = document && document.cookie || '') { ... }
      - monk_e_boy 11y ago
        Classes and modules in almost any other modern language are much easier to read and write. Ruby, python, heck even php are better than JS. That's my real issue with JS. If we had a browser that had lots of languages baked into it, none of use would choose to use JS ;) node.js would never have been invented...
  - _pmf_ 11y ago
    > Now people complain that it's a weakly typed language replacing strongly-typed languages they prefer... The first step would be to understand the difference between weak/strong and dynamic/static typing.
    - krisdol 11y ago
      Can we just use the term "duck-typed" already? There's a significant difference between weakly-typed C, strongly-typed rust, and "strongly"-typed JavaScript/Ruby. Besides, weak-typing is relative. Javascript does some type conversion, but because it does less than C, it is more strongly typed than C, but it is more weakly typed than some other languages.
      - jerf 11y ago
        No, duck typing is not a very good distinguishing characteristic anymore. "Interfaces", "traits", and "concepts", to say nothing of other things, all in various ways make static languages have something that looks something like statically-checked duck typing. Duck typing isn't unique to dynamic languages.
  - nanny 11y ago
    >Now people complain that it's a weakly typed language replacing strongly-typed languages they prefer Firstly, that's a strawman. I prefer strongly-typed dynamic languages and I still think JavaScript sucks. Secondly, I think you're confusing strong vs. weak with dynamic vs. static. JavaScript's weak typing is unequivocally one of the worst things about the language.
    - adrusi 11y ago
      I'm not Javascript's biggest fan, but the weak typing argument is a little... weak. You never run into problems with weak typing as long as you follow a few rules like using === over ==. Javascript is poorly designed because there are these rules you need to learn and because there are some language features that you just don't use. Some other reasons too, but the way people write it, Javascript may as well be strongly typed.
      - nanny 11y ago
        >the weak typing argument is a little... weak. I think you contradict this in the rest of your comment: >Javascript is poorly designed because there are these rules you need to learn and because there are some language features that you just don't use. One rule you've mentioned: >using === over == Which is a result of weak typing. So maybe weak typing is a language feature "that you just don't use"? Which, according to you, makes weak typing a reason why JavaScript is poorly designed.
        adrusi 11y ago
        It was not my intention to imply that javascript is not weakly typed. And I think we have collectively determined (correctly) that weak typing is a burden in a general-purpose language. So yes, your conclusion is correct, weak typing is "a reason" that javascript is poorly designed. But your claim wasn't "weak typing was a bad design decision", it was "JavaScript's weak typing is unequivocally one of the worst things about the language". I think it's silly to call a mis-feature "unequivocally one of the worst things" when people who write javascript basically never run into, and when it can be completely avoided by using unintrusive tooling like a linter.
  - Kurtz79 11y ago
    The "problem" I have with Javascript is when people try to use it for everything. https://en.wikipedia.org/wiki/Law_of_the_instrument https://en.wikipedia.org/wiki/Law_of_the_instrument
  - diek 11y ago
    Just out of curiosity, what other languages do you have experience with?
    - moosterv 11y ago
      I started off developing in C, then C++. Then I did Java (late 90's till 2010 or so). I toyed around with PHP and perl somewhere in between. I love modern Javascript, and would be hard pressed to go back to something else.
    - wavefunction 11y ago
      C++, Java, Groovy, C#, Perl, Python, PHP, Ruby, Smalltalk, Objective-C, *86 Assembly, and played around with Go, Swift, Lisp and Haskell oh, and Visual Basic!!! I didn't say JavaScript is all anyone needs for every situation, just that it's great imo.
- mvonthron 11y ago
  It can only print text in Comic Sans!
  - watson 11y ago
    Funny you mention that :) I was actually thinking of creating a version of the printer where all print jobs would have the typeface swapped for Comic Sans. It's been pretty hard so far though to figure out how to do this replacement in PostScript :(
    - tlrobinson 11y ago
      If you could make a proxy to your office's printer that would be a fantastic April fools joke, actually.
- mhd 11y ago
  I remember having to debug the printing system (lpq, converters etc.) on my first Slackware system back in the early years of the second age, with plenty of shell scripts and literal postscript output. So I regard this with a certain amount of schadenfreude. (Although the "printer" part of the headline makes this sound much more fancy and hardware-oriented than what it is, yet another HTTP-based protocol that's parsed enough to work for a few use cases).
- tomswartz07 11y ago
  `Uncaught TypeError: PC Load Letter?` What the fuck does that mean? https://www.youtube.com/watch?v=5QQdNbvSGok https://www.youtube.com/watch?v=5QQdNbvSGok
  - jbuzbee 11y ago
    That's boring. Hopefully he's implemented "Lp0 on fire" https://en.wikipedia.org/wiki/Lp0_on_fire https://en.wikipedia.org/wiki/Lp0_on_fire
- brudgers 11y ago
  It is Atwood's law in action: any application that can be written in JavaScript, will eventually be written in JavaScript. http://blog.codinghorror.com/the-principle-of-least-power/ http://blog.codinghorror.com/the-principle-of-least-power/
ackfoo 11y ago
It would be so helpful if the author would make a simple statement at the beginning of the video about what this does and why it is useful. Over ten minutes into the video, we have no idea. Read the project description on Github, still no idea. Why not start with, "This project creates a virtual printer that advertises itself with Bonjour and writes a postscript file to local storage." Follow that with a simple statement about why that is cool and what you can do with the file, which is still not apparent. Obfuscation has become the norm.
- watson 11y ago
  Would a better description under the video on YouTube help, or would you want me to have mentioned it on a slide?
  - sabujp 11y ago
    put the desc under the video
blisterpeanuts 11y ago
I've just recently discovered NodeJS -- heard about it for years, of course. I was able to create a web server for one of my group's web apps in about 5 lines of code. It's a bit weird to wrap one's mind around it at first, but then it starts to make a lot of sense. This IPP server is cool, though I'm not sure what uses it has yet. Maybe just a handy way to print to disk without having to choose a folder and file name. Or use as a proxy to redirect print requests to different printers depending on size or type of print job. Or a way to queue up print requests until off-hours. This is just off the top of my head and I'll bet there are other cool uses as well.
nicky0 11y ago
Is this any different to "Save as PDF"?
- watson 11y ago
  Save to PDF would just give you a PDF. The idea here is that you can do whatever you like with the print-job as long as you can program it. So print to PDF is just the most simple example. I mention a few low hanging fruits in the talk like "print to bookkeeping" - but that's just one use-case. Consider that you can use it as a printing proxy and divert jobs to different printers or implement an authentication system or a payment system before printing. There are a lot of options...
  - tracker1 11y ago
    Print to bookkeeping is actually a pretty brilliant idea... I'm planning to start doing itemized taxes for the coming year, and this could be useful as a basis for capturing receipts... Combined with cloud print... snap a photo of the receipt on my phone, print to bookkeeping, sort it out later. Might even be able to combine with GPS info in the image to log where the receipt is from, etc. This could be a pretty decent idea for adding to online bookkeeping services... so that you can tag receipts, for tracking the taxable portion of them, etc. Advance print queues for printing services could be another thing...
    - vbit 11y ago
      How is that better than 'print to google drive' from chrome or android?
      - tracker1 11y ago
        The printer endpoint could be integrated into a web-based accounting platform.
mrweasel 11y ago
That had absolutely nothing to do with making printers great (again). Printers suck a putting stuff on paper, doing a digital copy via a printer protocol doesn't fix that. It's neat and there might be some interesting use cases, but it doesn't fix what's wrong with printers. I'm not even sure that printers where ever that great. Printers seems like devices that sort of peaked 40 years ago. Since then they have gradually decreased in quality. Printing 1000+ pages a day seems to be a little much to ask from many printers, they simply wear out to quickly. The whole process of looping paper around inside something that fits on a desk (sort of), combined with cheap plastic parts is a receipt for disaster. Software-wise the manufacture should stop trying to add more feature that no one while ever use and instead work on making "cancel print job" actually work. The number of times a printer (driver?) has chosen to pick the wrong paper-tray is mind boggling. Why are there even multiple trays, we only ever need to print on standard A4 paper? Sadly picking a printer where the hardware quality will support the volume also result in feature bloat. I really hate printers, and no amount of Javascript will make them any better.
- DanBC 11y ago
  > I'm not even sure that printers where ever that great. Printers seems like devices that sort of peaked 40 years ago. Since then they have gradually decreased in quality. Printing 1000+ pages a day seems to be a little much to ask from many printers, they simply wear out to quickly. The whole process of looping paper around inside something that fits on a desk (sort of), combined with cheap plastic parts is a receipt for disaster. If you get an old LaserJet they're industrial beasts. But no-one wants to pay money for a printer, so we end up with two markets: the very expensive, but good, professional printers, and the domestic horrible printers. If you're printing 2 reams a day you can afford to invest in a decent printer. > Why are there even multiple trays, we only ever need to print on standard A4 paper? You only need that. A bunch of offices need to print on A4, and C5 envelopes, and sometimes A5 and sometimes on labels.
  - mrweasel 11y ago
    >You only need that. A bunch of offices need to print on A4, and C5 envelopes, and sometimes A5 and sometimes on labels. I understand that. My point was that perhaps it would easier to build high quality printer dedicated to specific tasks. I would guess that the majority of printers in something like financial departs won't ever print on more than one type of paper. Honestly I don't even feel that paying for the expensive printer, like high-end HPs, will get you above "okay". They still do weird stuff and the internal plastic parts will break easily.
deleted 11y ago
[deleted]

75 points by watson 11y ago

mtharrison 11y ago

This is really cool

brudgers 11y ago

Github: https://github.com/watson/ipp-printer https://github.com/watson/ipp-printer

watson 11y ago
Here are the rest of the links: https://github.com/watson/ipp-encoder https://github.com/watson/ipp-encoder https://github.com/watson/printcat https://github.com/watson/printcat http://printb.in http://printb.in

creshal 11y ago

Printers and Javascript, a match made in hell.

wavefunction 11y ago
JavaScript is great. I do enjoy all the posts about how it sucks. First it was a toy language. Now people complain that it's a weakly typed language replacing strongly-typed languages they prefer... I'm interested to see the next iteration of this phenomenon. Meanwhile I just enjoy developing in it every day. Other than having to maintain the odd ExtJS app, it's simply the best. cue triumphant sax
- monk_e_boy 11y ago
  The first 30 lines of this file are a 'joy' https://github.com/js-cookie/js-cookie/blob/master/src/js.cookie.js https://github.com/js-cookie/js-cookie/blob/master/src/js.co... I'm sure js could be nice, but it never seems to be.
  - tracker1 11y ago
    The syntax could be a lot cleaner... the Universal Module Definition (UMD) pattern at the top makes it a bit quirky... A lot of people have moved towards using CommonJS (cjs/node-style) exports with tooling such as browserift/webpack and/or babel (for es6 modules) in order to clean up the source syntax. What you're looking at is a relatively poor example. In es6, that could be ... exports default function... without all the cruft around it, also the module itself could be cleaner. Similar to: var cookies = parse(); export function set({key, value, days=null}) { ... } export function get(key) { ... } export const remove = (key) => set({key, value:null}); export function parse(values = document && document.cookie || '') { ... }
    - monk_e_boy 11y ago
      Classes and modules in almost any other modern language are much easier to read and write. Ruby, python, heck even php are better than JS. That's my real issue with JS. If we had a browser that had lots of languages baked into it, none of use would choose to use JS ;) node.js would never have been invented...
- _pmf_ 11y ago
  > Now people complain that it's a weakly typed language replacing strongly-typed languages they prefer... The first step would be to understand the difference between weak/strong and dynamic/static typing.
  - krisdol 11y ago
    Can we just use the term "duck-typed" already? There's a significant difference between weakly-typed C, strongly-typed rust, and "strongly"-typed JavaScript/Ruby. Besides, weak-typing is relative. Javascript does some type conversion, but because it does less than C, it is more strongly typed than C, but it is more weakly typed than some other languages.
    - jerf 11y ago
      No, duck typing is not a very good distinguishing characteristic anymore. "Interfaces", "traits", and "concepts", to say nothing of other things, all in various ways make static languages have something that looks something like statically-checked duck typing. Duck typing isn't unique to dynamic languages.
- nanny 11y ago
  >Now people complain that it's a weakly typed language replacing strongly-typed languages they prefer Firstly, that's a strawman. I prefer strongly-typed dynamic languages and I still think JavaScript sucks. Secondly, I think you're confusing strong vs. weak with dynamic vs. static. JavaScript's weak typing is unequivocally one of the worst things about the language.
  - adrusi 11y ago
    I'm not Javascript's biggest fan, but the weak typing argument is a little... weak. You never run into problems with weak typing as long as you follow a few rules like using === over ==. Javascript is poorly designed because there are these rules you need to learn and because there are some language features that you just don't use. Some other reasons too, but the way people write it, Javascript may as well be strongly typed.
    - nanny 11y ago
      >the weak typing argument is a little... weak. I think you contradict this in the rest of your comment: >Javascript is poorly designed because there are these rules you need to learn and because there are some language features that you just don't use. One rule you've mentioned: >using === over == Which is a result of weak typing. So maybe weak typing is a language feature "that you just don't use"? Which, according to you, makes weak typing a reason why JavaScript is poorly designed.
      - adrusi 11y ago
        It was not my intention to imply that javascript is not weakly typed. And I think we have collectively determined (correctly) that weak typing is a burden in a general-purpose language. So yes, your conclusion is correct, weak typing is "a reason" that javascript is poorly designed. But your claim wasn't "weak typing was a bad design decision", it was "JavaScript's weak typing is unequivocally one of the worst things about the language". I think it's silly to call a mis-feature "unequivocally one of the worst things" when people who write javascript basically never run into, and when it can be completely avoided by using unintrusive tooling like a linter.
- Kurtz79 11y ago
  The "problem" I have with Javascript is when people try to use it for everything. https://en.wikipedia.org/wiki/Law_of_the_instrument https://en.wikipedia.org/wiki/Law_of_the_instrument
- diek 11y ago
  Just out of curiosity, what other languages do you have experience with?
  - moosterv 11y ago
    I started off developing in C, then C++. Then I did Java (late 90's till 2010 or so). I toyed around with PHP and perl somewhere in between. I love modern Javascript, and would be hard pressed to go back to something else.
  - wavefunction 11y ago
    C++, Java, Groovy, C#, Perl, Python, PHP, Ruby, Smalltalk, Objective-C, *86 Assembly, and played around with Go, Swift, Lisp and Haskell oh, and Visual Basic!!! I didn't say JavaScript is all anyone needs for every situation, just that it's great imo.
mvonthron 11y ago
It can only print text in Comic Sans!
- watson 11y ago
  Funny you mention that :) I was actually thinking of creating a version of the printer where all print jobs would have the typeface swapped for Comic Sans. It's been pretty hard so far though to figure out how to do this replacement in PostScript :(
  - tlrobinson 11y ago
    If you could make a proxy to your office's printer that would be a fantastic April fools joke, actually.
mhd 11y ago
I remember having to debug the printing system (lpq, converters etc.) on my first Slackware system back in the early years of the second age, with plenty of shell scripts and literal postscript output. So I regard this with a certain amount of schadenfreude. (Although the "printer" part of the headline makes this sound much more fancy and hardware-oriented than what it is, yet another HTTP-based protocol that's parsed enough to work for a few use cases).
tomswartz07 11y ago
`Uncaught TypeError: PC Load Letter?` What the fuck does that mean? https://www.youtube.com/watch?v=5QQdNbvSGok https://www.youtube.com/watch?v=5QQdNbvSGok
- jbuzbee 11y ago
  That's boring. Hopefully he's implemented "Lp0 on fire" https://en.wikipedia.org/wiki/Lp0_on_fire https://en.wikipedia.org/wiki/Lp0_on_fire
brudgers 11y ago
It is Atwood's law in action: any application that can be written in JavaScript, will eventually be written in JavaScript. http://blog.codinghorror.com/the-principle-of-least-power/ http://blog.codinghorror.com/the-principle-of-least-power/

ackfoo 11y ago

It would be so helpful if the author would make a simple statement at the beginning of the video about what this does and why it is useful. Over ten minutes into the video, we have no idea. Read the project description on Github, still no idea. Why not start with, "This project creates a virtual printer that advertises itself with Bonjour and writes a postscript file to local storage." Follow that with a simple statement about why that is cool and what you can do with the file, which is still not apparent. Obfuscation has become the norm.

watson 11y ago
Would a better description under the video on YouTube help, or would you want me to have mentioned it on a slide?
- sabujp 11y ago
  put the desc under the video

blisterpeanuts 11y ago

I've just recently discovered NodeJS -- heard about it for years, of course. I was able to create a web server for one of my group's web apps in about 5 lines of code. It's a bit weird to wrap one's mind around it at first, but then it starts to make a lot of sense. This IPP server is cool, though I'm not sure what uses it has yet. Maybe just a handy way to print to disk without having to choose a folder and file name. Or use as a proxy to redirect print requests to different printers depending on size or type of print job. Or a way to queue up print requests until off-hours. This is just off the top of my head and I'll bet there are other cool uses as well.

nicky0 11y ago

Is this any different to "Save as PDF"?

watson 11y ago
Save to PDF would just give you a PDF. The idea here is that you can do whatever you like with the print-job as long as you can program it. So print to PDF is just the most simple example. I mention a few low hanging fruits in the talk like "print to bookkeeping" - but that's just one use-case. Consider that you can use it as a printing proxy and divert jobs to different printers or implement an authentication system or a payment system before printing. There are a lot of options...
- tracker1 11y ago
  Print to bookkeeping is actually a pretty brilliant idea... I'm planning to start doing itemized taxes for the coming year, and this could be useful as a basis for capturing receipts... Combined with cloud print... snap a photo of the receipt on my phone, print to bookkeeping, sort it out later. Might even be able to combine with GPS info in the image to log where the receipt is from, etc. This could be a pretty decent idea for adding to online bookkeeping services... so that you can tag receipts, for tracking the taxable portion of them, etc. Advance print queues for printing services could be another thing...
  - vbit 11y ago
    How is that better than 'print to google drive' from chrome or android?
    - tracker1 11y ago
      The printer endpoint could be integrated into a web-based accounting platform.

mrweasel 11y ago

That had absolutely nothing to do with making printers great (again). Printers suck a putting stuff on paper, doing a digital copy via a printer protocol doesn't fix that. It's neat and there might be some interesting use cases, but it doesn't fix what's wrong with printers. I'm not even sure that printers where ever that great. Printers seems like devices that sort of peaked 40 years ago. Since then they have gradually decreased in quality. Printing 1000+ pages a day seems to be a little much to ask from many printers, they simply wear out to quickly. The whole process of looping paper around inside something that fits on a desk (sort of), combined with cheap plastic parts is a receipt for disaster. Software-wise the manufacture should stop trying to add more feature that no one while ever use and instead work on making "cancel print job" actually work. The number of times a printer (driver?) has chosen to pick the wrong paper-tray is mind boggling. Why are there even multiple trays, we only ever need to print on standard A4 paper? Sadly picking a printer where the hardware quality will support the volume also result in feature bloat. I really hate printers, and no amount of Javascript will make them any better.

DanBC 11y ago
> I'm not even sure that printers where ever that great. Printers seems like devices that sort of peaked 40 years ago. Since then they have gradually decreased in quality. Printing 1000+ pages a day seems to be a little much to ask from many printers, they simply wear out to quickly. The whole process of looping paper around inside something that fits on a desk (sort of), combined with cheap plastic parts is a receipt for disaster. If you get an old LaserJet they're industrial beasts. But no-one wants to pay money for a printer, so we end up with two markets: the very expensive, but good, professional printers, and the domestic horrible printers. If you're printing 2 reams a day you can afford to invest in a decent printer. > Why are there even multiple trays, we only ever need to print on standard A4 paper? You only need that. A bunch of offices need to print on A4, and C5 envelopes, and sometimes A5 and sometimes on labels.
- mrweasel 11y ago
  >You only need that. A bunch of offices need to print on A4, and C5 envelopes, and sometimes A5 and sometimes on labels. I understand that. My point was that perhaps it would easier to build high quality printer dedicated to specific tasks. I would guess that the majority of printers in something like financial departs won't ever print on more than one type of paper. Honestly I don't even feel that paying for the expensive printer, like high-end HPs, will get you above "okay". They still do weird stuff and the internal plastic parts will break easily.

deleted 11y ago

[deleted]