8 ms·

VNC over gif

206 points by waxzce 13y ago

jstanley 13y ago
This is genius! I was just this week trying to think of some way to abuse slow-loading of images by generating the image as data comes in. This is perfect.
- endergen 13y ago
  I too had idly been thinking about this while viewing a few Vine videos that were all using it seemed h264 on iOS.
- caissy 13y ago
  There was a post on HN a few months back of a gif-based realtime message transport : https://github.com/videlalvaro/gifsockets#readme https://github.com/videlalvaro/gifsockets#readme
- shurcooL 13y ago
  One way to improve my Instant Background Uploader app [1] and make it actually instant would be by doing just that. Generate the image URL right away and start streaming it while the upload continues. Instead of waiting for upload to finish before giving you a URL. But you'd need control over the image hosting backend cuz ImageShack won't let you do it. [1] https://github.com/shurcooL/InstantBackgroundUploader_OS-X https://github.com/shurcooL/InstantBackgroundUploader_OS-X https://github.com/shurcooL/InstantBackgroundUploader_Windows https://github.com/shurcooL/InstantBackgroundUploader_Window...
  - jstanley 13y ago
    Interestingly, I already have an image uploading service (that only I use). It may be a little complicated to make it do this, given how it works currently, but I might try it out.
- matrix9 13y ago
  Great idea. But I guess the performance and latency must be an issue.
aespinoza 13y ago
This is amazing!!!
- imperialdrive 13y ago
  agreed - for whatever reason, very very very cool!
shawnz 13y ago
Interesting that npm is being used to deploy a regular old CLI application that has essentially nothing to do with javascript development. Are we seeing the future of package management with these distribution-agnostic tools?
- tokenizerrr 13y ago
  It's written in javascript and requires nodejs to function, which comes with npm
- jonpaul 13y ago
  This is a very common practice if the CLI application depends upon Node.js.
- phillmv 13y ago
  No, you're just seeing javascript come into its own as a general purpose language community. The surprising part isn't that it's being shipped in npm, it's more that people like programming these sorts of tools in javascript. This sort of thing is common in Ruby and Python-land. And infinitely better than the `curl foo.io/trolol.sh | sh` we've seen emerge in the last couple of years.
  - deleted 13y ago
    [deleted]
  - philsnow 13y ago
    s/emerge/re-emerge/ This kind of thing was somewhat common back when rsh / telnet were the usual ways of accessing remote systems.
- staunch 13y ago
  People have been doing this with CPAN for many years. See: LWP and it's GET, POST, lwp-request utilities.
- shurcooL 13y ago
  I really want to try the functionality of this, but I don't have npm... I might just have to get it. :(
tokenizerrr 13y ago
Does the browser keep the entire gif in memory? That could be a problem with long lasting sessions...
- MarkHarmon 13y ago
  The code creates a new buffer for each frame and then pushes that into the gif. There is no freeing of memory or any kind of ring buffer being setup. So yes, it keeps eating memory.
  - codereflection 13y ago
    Perhaps a periodic page refresh would work around the issue. Then that brings up another question, is any part of the gif cached by the browser or downstream proxies / web accelerators?
    - lightblade 13y ago
      The client side could wrap the gif image in iframe to control the refresh.
  - camus 13y ago
    i saw a site linked on HN that was using that kind of technique to siplay public camera feeds, if anyone remember the link , would be great to share it again.
    - flippyhead 13y ago
      I'd like to see this too
    - darsham 13y ago
      you're probably thinking about this (which now 404s): http://cryptogasm.com/webcams/ http://cryptogasm.com/webcams/ Don't know why it was taken down. Here is the old thread : https://news.ycombinator.com/item?id=5543465 https://news.ycombinator.com/item?id=5543465 which mentions the Content-Type "multipart/x-mixed-replace" technique used to constantly update jpegs in the browser.
JeremyMorgan 13y ago
Just remember how it's pronounced
- ritonlajoie 13y ago
  can you explain?
  - sidorares 13y ago
    http://bits.blogs.nytimes.com/2013/05/21/an-honor-for-the-creator-of-the-gif/?smid=tw-nytimes http://bits.blogs.nytimes.com/2013/05/21/an-honor-for-the-cr...
- MacsHeadroom 13y ago
  Choosy programmers choose gif.
arturadib 13y ago
Doesn't work out of the box on OS X: https://github.com/sidorares/vnc-over-gif/issues/1 https://github.com/sidorares/vnc-over-gif/issues/1
jabz 13y ago
Very interesting. I have a tool that I use for supporting our iOS apps that streams screenshots of the users session to a browser window. Right now I just have that browser window refreshing every 2 - 3 seconds but this could be a much more interesting way to stream those screenshots. Non-technical users + no screen sharing on iOS is absolutely awful for supporting SaaS applications.
mzs 13y ago
Cool, mjpeg might make more sense for vnc though, they animate fine ff at least.
arde 13y ago
This nicely solves a problem I've been asked about: how to share a screen securely (read-only). VNC protocol and implementations are too complex/sloppy so I don't trust them. An endless GIF, on the other hand...
- Falling3 13y ago
  What about a service like join.me or gotomeeting?
  - arde 13y ago
    For this use case I don't trust implementations that I have source code for, due to their complexity. This is intended to share screens that lie behind a firewall. It wouldn't make sense to trust third-party code with closed source code and a similarly complex protocol (and undocumented). Neither would be logical to add this third party, the middle-man, as a point of failure and attack.
- zanny 13y ago
  > VNC protocol and implementations are too complex/sloppy so I don't trust them. The protocol is 50 pages long with pretty reasonable margins and it even has pictures: http://www.realvnc.com/docs/rfbproto.pdf http://www.realvnc.com/docs/rfbproto.pdf It is an afternoon read. Most desktop environments in Linux implement their own VNC server just because it isn't that complex and you can implement a subset of the protocol for a server anyway. I imagine if there was a protocol flaw revealed (or even in the many implementations like libvncserver) it would be patched overnight. All of them support viewer-only mode. I like krfb, because by default it only uses access passes rather than a global password, so unless you give someone credentials of an access ticket nobody can login. I bet an exploitation in the way gifs download and how http resolves file transfers in the dozens of implementations of both is much more likely to have an exploitable man in the middle or other mechanism to eavesdrop, if not take remote control.
  - sidorares 13y ago
    +1 rfb protocol is not complex and properly documented
anonymfus 13y ago
Is it possible to add mouse clicks via html image maps?
- sidorares 13y ago
  Yes, I was thinking about server-side image maps and link with target in invisible frame. Mouse movements are harder (if possible) to send without client side javascript
Aqwis 13y ago
Is this supposed to install on Windows? I get a whole bunch of errors when I run "npm install -g vnc-over-gif", most of which seem to be related to node-gif. Edit: Apparently they're related to unistd.h, which doesn't exist on Windows platforms. Too bad.
- sidorares 13y ago
  I might hack a bit on JS-only gif encoder this weekend but at the moment yes, you need to have proper development environment to compile under windows. unistd.h dependency might be an easy fix though
zachc 13y ago
A few years ago I leveraged some reverse engineering to stream individual windows as GIF images. More info if you're interested: http://zachcimafonte.com/GIF-Window-Server http://zachcimafonte.com/GIF-Window-Server
- ma2rten 13y ago
  Is the source code available?
ma2rten 13y ago
I am also currently working on a web-based remote desktop app as a side project. I am using socket.io (python port) and pngs, using transparency to only update the part of the image that changed between frames. However, I also thought about using long-loading animated gifs, because: 1. Run-length encoding seems to be ideal for screenshots. 2. You can use transparency to only update pixels that changed between frames without need for an alpha layer. 3. Palette-based does not seem to be a big issue for screenshots, which typically have few colors. 4. You use an additional frames to update colors that are off [1]. That way you get the best of both worlds: low latency and high quality images. Do you have any issues using gifs? Memory usage, closing connections, etc...? [1] http://phil.ipal.org/tc.html# http://phil.ipal.org/tc.html#
- pornel 13y ago
  GIF doesn't have RLE. It only has dictionary built from "previous pattern + 1 new pixel", so even transparent areas are wasteful (1+2+3+4+5+6px etc in optimal case and you have to restart when 4K-entry dictionary fills up).
csears 13y ago
"Requirements... netscape 2.0+" Made me chuckle, but probably quite accurate.

206 points by waxzce 13y ago

This is genius! I was just this week trying to think of some way to abuse slow-loading of images by generating the image as data comes in. This is perfect.

endergen 13y ago
I too had idly been thinking about this while viewing a few Vine videos that were all using it seemed h264 on iOS.
caissy 13y ago
There was a post on HN a few months back of a gif-based realtime message transport : https://github.com/videlalvaro/gifsockets#readme https://github.com/videlalvaro/gifsockets#readme
shurcooL 13y ago
One way to improve my Instant Background Uploader app [1] and make it actually instant would be by doing just that. Generate the image URL right away and start streaming it while the upload continues. Instead of waiting for upload to finish before giving you a URL. But you'd need control over the image hosting backend cuz ImageShack won't let you do it. [1] https://github.com/shurcooL/InstantBackgroundUploader_OS-X https://github.com/shurcooL/InstantBackgroundUploader_OS-X https://github.com/shurcooL/InstantBackgroundUploader_Windows https://github.com/shurcooL/InstantBackgroundUploader_Window...
- jstanley 13y ago
  Interestingly, I already have an image uploading service (that only I use). It may be a little complicated to make it do this, given how it works currently, but I might try it out.
matrix9 13y ago
Great idea. But I guess the performance and latency must be an issue.

aespinoza 13y ago

This is amazing!!!

imperialdrive 13y ago
agreed - for whatever reason, very very very cool!

shawnz 13y ago

Interesting that npm is being used to deploy a regular old CLI application that has essentially nothing to do with javascript development. Are we seeing the future of package management with these distribution-agnostic tools?

tokenizerrr 13y ago
It's written in javascript and requires nodejs to function, which comes with npm
jonpaul 13y ago
This is a very common practice if the CLI application depends upon Node.js.
phillmv 13y ago
No, you're just seeing javascript come into its own as a general purpose language community. The surprising part isn't that it's being shipped in npm, it's more that people like programming these sorts of tools in javascript. This sort of thing is common in Ruby and Python-land. And infinitely better than the `curl foo.io/trolol.sh | sh` we've seen emerge in the last couple of years.
- deleted 13y ago
  [deleted]
- philsnow 13y ago
  s/emerge/re-emerge/ This kind of thing was somewhat common back when rsh / telnet were the usual ways of accessing remote systems.
staunch 13y ago
People have been doing this with CPAN for many years. See: LWP and it's GET, POST, lwp-request utilities.
shurcooL 13y ago
I really want to try the functionality of this, but I don't have npm... I might just have to get it. :(

tokenizerrr 13y ago

Does the browser keep the entire gif in memory? That could be a problem with long lasting sessions...

MarkHarmon 13y ago
The code creates a new buffer for each frame and then pushes that into the gif. There is no freeing of memory or any kind of ring buffer being setup. So yes, it keeps eating memory.
- codereflection 13y ago
  Perhaps a periodic page refresh would work around the issue. Then that brings up another question, is any part of the gif cached by the browser or downstream proxies / web accelerators?
  - lightblade 13y ago
    The client side could wrap the gif image in iframe to control the refresh.
- camus 13y ago
  i saw a site linked on HN that was using that kind of technique to siplay public camera feeds, if anyone remember the link , would be great to share it again.
  - flippyhead 13y ago
    I'd like to see this too
  - darsham 13y ago
    you're probably thinking about this (which now 404s): http://cryptogasm.com/webcams/ http://cryptogasm.com/webcams/ Don't know why it was taken down. Here is the old thread : https://news.ycombinator.com/item?id=5543465 https://news.ycombinator.com/item?id=5543465 which mentions the Content-Type "multipart/x-mixed-replace" technique used to constantly update jpegs in the browser.

JeremyMorgan 13y ago

Just remember how it's pronounced

ritonlajoie 13y ago
can you explain?
- sidorares 13y ago
  http://bits.blogs.nytimes.com/2013/05/21/an-honor-for-the-creator-of-the-gif/?smid=tw-nytimes http://bits.blogs.nytimes.com/2013/05/21/an-honor-for-the-cr...
MacsHeadroom 13y ago
Choosy programmers choose gif.

arturadib 13y ago

Doesn't work out of the box on OS X: https://github.com/sidorares/vnc-over-gif/issues/1 https://github.com/sidorares/vnc-over-gif/issues/1

jabz 13y ago

Very interesting. I have a tool that I use for supporting our iOS apps that streams screenshots of the users session to a browser window. Right now I just have that browser window refreshing every 2 - 3 seconds but this could be a much more interesting way to stream those screenshots. Non-technical users + no screen sharing on iOS is absolutely awful for supporting SaaS applications.

mzs 13y ago

Cool, mjpeg might make more sense for vnc though, they animate fine ff at least.

arde 13y ago

This nicely solves a problem I've been asked about: how to share a screen securely (read-only). VNC protocol and implementations are too complex/sloppy so I don't trust them. An endless GIF, on the other hand...

Falling3 13y ago
What about a service like join.me or gotomeeting?
- arde 13y ago
  For this use case I don't trust implementations that I have source code for, due to their complexity. This is intended to share screens that lie behind a firewall. It wouldn't make sense to trust third-party code with closed source code and a similarly complex protocol (and undocumented). Neither would be logical to add this third party, the middle-man, as a point of failure and attack.
zanny 13y ago
> VNC protocol and implementations are too complex/sloppy so I don't trust them. The protocol is 50 pages long with pretty reasonable margins and it even has pictures: http://www.realvnc.com/docs/rfbproto.pdf http://www.realvnc.com/docs/rfbproto.pdf It is an afternoon read. Most desktop environments in Linux implement their own VNC server just because it isn't that complex and you can implement a subset of the protocol for a server anyway. I imagine if there was a protocol flaw revealed (or even in the many implementations like libvncserver) it would be patched overnight. All of them support viewer-only mode. I like krfb, because by default it only uses access passes rather than a global password, so unless you give someone credentials of an access ticket nobody can login. I bet an exploitation in the way gifs download and how http resolves file transfers in the dozens of implementations of both is much more likely to have an exploitable man in the middle or other mechanism to eavesdrop, if not take remote control.
- sidorares 13y ago
  +1 rfb protocol is not complex and properly documented

anonymfus 13y ago

Is it possible to add mouse clicks via html image maps?

sidorares 13y ago
Yes, I was thinking about server-side image maps and link with target in invisible frame. Mouse movements are harder (if possible) to send without client side javascript

Aqwis 13y ago

Is this supposed to install on Windows? I get a whole bunch of errors when I run "npm install -g vnc-over-gif", most of which seem to be related to node-gif. Edit: Apparently they're related to unistd.h, which doesn't exist on Windows platforms. Too bad.

sidorares 13y ago
I might hack a bit on JS-only gif encoder this weekend but at the moment yes, you need to have proper development environment to compile under windows. unistd.h dependency might be an easy fix though

zachc 13y ago

A few years ago I leveraged some reverse engineering to stream individual windows as GIF images. More info if you're interested: http://zachcimafonte.com/GIF-Window-Server http://zachcimafonte.com/GIF-Window-Server

ma2rten 13y ago
Is the source code available?

ma2rten 13y ago

I am also currently working on a web-based remote desktop app as a side project. I am using socket.io (python port) and pngs, using transparency to only update the part of the image that changed between frames. However, I also thought about using long-loading animated gifs, because: 1. Run-length encoding seems to be ideal for screenshots. 2. You can use transparency to only update pixels that changed between frames without need for an alpha layer. 3. Palette-based does not seem to be a big issue for screenshots, which typically have few colors. 4. You use an additional frames to update colors that are off [1]. That way you get the best of both worlds: low latency and high quality images. Do you have any issues using gifs? Memory usage, closing connections, etc...? [1] http://phil.ipal.org/tc.html# http://phil.ipal.org/tc.html#

pornel 13y ago
GIF doesn't have RLE. It only has dictionary built from "previous pattern + 1 new pixel", so even transparent areas are wasteful (1+2+3+4+5+6px etc in optimal case and you have to restart when 4K-entry dictionary fills up).

csears 13y ago

"Requirements... netscape 2.0+" Made me chuckle, but probably quite accurate.