One problem you're probably going to run into is caches (especially caching proxies) ignoring your nocache header, causing users to see the wrong QR code.
A standard way to avoid this is by making the image URL http://lilqr.com/qr?rand=[nonce], where you'd generate the nonce randomly on each page load. You can ignore it on the server of course.
Your right, some proxies simply ignore the Cache-Control directive. In some cases even Google Chrome handles this directive poorly, as it will serve a cached version when you use the back/forward-buttons between pages no matter what cache directive you give the image. IE and FF are flawless in this regard.
Feel free to suffix the URL with a random get-varaible, as this wont affect the service more then ensuring that proxies and cache hungry browser are less likely to cache the image.
You could also add an optional GET param that allows the user to override the url for which a QR code is generated (so ?url=... would override the default functionality of detecting the url)
This is true unless the image is served from https aswell. In that case referer is sent just as normal. I'm getting a certificate this week to serve https QRs!
I think you need a little more instruction. What does this do?
My first thought was that it would generate a QR code for any string you provide, through url hacking. (i.e anything after the domain name is used as the string to encode) - This doesn't seem to be the case.
Very little instruction on the website, nothing on twitter, and no info here… Could you shed a little light please?
EDIT: As tiwilliam informed me, it uses the HTTP referer to create a QR code that contains a link back to that same HTTP referer. If it is not present, the default is lilqr.com.
It's a nice idea, but I don't see the value in having a QR code that links to the page you are already on? A bit more explanation is still necessary :)
Sorry, I just wanted to launch it as early as possible. Just put the img-tag on whatever page you would like to have a QR code for and it will create one to the URL of that page.
Yes, but what the hell is a QR code? Hehe. Or rather, why do I want one?
I have no idea what this is used for. I'm 1/5th of the way down http://en.wikipedia.org/wiki/QR_code and still have no idea how this applies to websites. Most people who don't know aren't going to take time to go research it.
In a sentence: I have no idea what value benefit this has for me.
I'm telling you this because I want you to succeed, and if you want to gain traction outside if the HN bubble, then you'll probably want to appeal to regular people.
As an example, I use Evernote on my laptop and phone. I never need something like this, though, because Evernote synchronizes my data across devices. Likewise, if I want a convenient link for a long, hard-to-remember url, why not just use a url shortener?
EDIT:
Ah, I think I see your point now. The hypothetical website doesn't have an associated mobile app. If I'm reading the site on my laptop and want to switch to my phone, I could scan the QR code rather than typing in the url.
This got me thinking -- I wish there was a browser extension that would create a QR code for whatever page I'm currently on. (Why? Because often I want to quickly open the URL on my desktop on my mobile.)
I wish someone would create a browser extension (Rapportive, this one is for you!) that would create a QR code for contact info from a person's email signature. If I want to quickly add someone's info from an email to my phone and call them, it's so much easier to scan a QR code than to deal with Address Book and then sync my phone.
if you're running android, give chrome to phone a try. just 1 click and the site will open on your mobile without the hassle of opening a camera app to load the QR code.
This is a really great extension and works with Maps also (to load the Maps app directly). There's an extension for Opera that also utilizes the Chrome to Phone API. Not sure about Firefox.
If you use an Android phone, I would recommend using Firefox on both your phone and as your desktop browser. The latest FF builds (v4 and v5) have a sync feature which synchronizes all your history, bookmarks AND open pages in your browser. The best part about the feature is the ability to add multiple "machines" which I use to easily sync my stuff across my home computer, my work desktop and my mobile.
A very common usage scenario for me: I'm in the midst of reading a couple of webpages (most likely very heavily commented HN articles) and suddenly, I realise my train is arriving soon and I've to make a quick dash to the station. Once I get on the train, fire up FF on my phone, sync and in an instant, all my open tabs on my work computer is on my mobile.
- or - a bookmarklet http://miniqr.com/docs/bookmarklet.php ... per default the url of the webpage you are currently viewing - or the currently selected text
Pretty cool. One downside I see of the easy way of integration (as opposed to having to use a site-specific URL) is that the browser cache cannot be used (and as expected, the image comes back with a "no-cache" header), since the browser might end up using the same image for multiple sites using the feature. Is there any caching on the server to avoid having to generate the image every time?
This is very cool, and through this thread I discovered the Google Chart API for creating QR codes. Here's my snippet that does kind of the same thing you're doing:
I'm going to HAVE to play with this some more. This evening my wife and I were driving around looking at houses for sale and I was thinking that every For Sale sign should have a big old QR code on it that takes you directly to a webpage for that specific house with the listing price and details about the house. I shouldn't have to jump out and grab an info sheet, I should be able to scan the big ol' QR code from my car and see the details about the house.
Personally, I don't think it's a good idea to rely on third party services to do things which can be trivially performed locally.
I agree with you totally. However, there is a whole army of marketeers who can barely manage to paste some javascript into an HTML file without messing the whole thing up. Those are the folks that you can monetize off of projects like this.
Great way to jump on QR trend. Amazingly simple implementation.
Would be nice to have some way to put in the URL on a page and have it generate PNGs of different sized codes, like for printing on a brochure or poster.
I'm working on some basic customization but first up is stats for number of scans, though that would require a redirect through the service (with URL shortening ofcourse). What do you think of that?
Do you do any sort of detection of things like detecting that www.foo.com/bar and foo.com/bar are the same page, so they can share a code? Maybe for advanced users almost like some kind of re-write rules so that requests for/from certain pages can be linked to a static QR code?
I would also require you to create a redirect in some DB every page that a QR code had shown up on. Alternately you could just change the URL to be http://mydomain.com/subdirectory/page.html?QRCode
At Hive13, we are putting QR codes on equipment description pages using a wiki template - http://wiki.hive13.org/Equipment. Our next step is to print the template info to a sticker, which is placed on the equipment described. Then you have an easy link using your phone to further information directly on the tool itself.
Wow, didn't really expect hitting the front page, even less #1. Thanks for all the encouring comments! They're really motivating when you spend your spare time developing an Apache module to generate QR-codes.
In 4 hours we have had 32308 generated QR codes and 5656 visitors!
I intend to keep the service just as simple, but will likely add lilqr.com/qr+ for some of the more advanced features pointed out here.
Once again, thanks!
If it's as you suggest, and there are people that have done this previously. it would seem there was insufficient marketing. It would be interesting to hear the details of this incident and thought process.
SmallQR officially went beta only the day before I see the lilqr domain was registered so perhaps Siavash did not know about it, or perhaps he was inspired by it and thought he could do better. Either way there is a more advanced and refined service out there.
My company uses QR code demonstrations and giveaways to get clients, this might just come in handy for us. Thank you.
ps if anyone out there is interested in selling mobile websites for us, typical commission is around $300 and you do not need to know any coding. please contact me on skype or jobs@sanfranciscomobilewebsites.com
since i see people asking how this can be useful, think about putting this on a coupon page. people are at their computer looking at the coupons before they visit a business. they simply scan the code and it brings up a mobile version with which they can use to redeem the coupon when they go to the business.
A standard way to avoid this is by making the image URL http://lilqr.com/qr?rand=[nonce], where you'd generate the nonce randomly on each page load. You can ignore it on the server of course.