The context of this problem is weird (a magic trick that occurred to me), so I will skip that explanation and go straight to the point.
What I want: a set of QR codes (it can be just 1, or 2 different ones, either way will work for me). These QR codes may be scanned with a regular smartphone QR scanner to show some kind of text. My initial idea was a simple HTML page with the message in plain text. The difficult part is this:
Whenever someone scans the QR for the first time, certain message is show. But the second time, another message is shown. If it's just one QR code, I would like it to follow that sequence (alternating between the two messages). If there are 2 QR codes, I would want the first one scanned to display the first message (always) and the second one scanned to show the second one (always); the first scanned QR would determine which message will be shown in each one. The scan of one QR by one cell should not affect the scan of another phone (their functionality flow is independent).
I got some limitations though:
It must work just with the QR scanner a regular Android smartphone has (don't want the person installing any app).
I would like avoiding having to pay a server to store a page that has the functionality. The ideal scenery is the QR behaving like this by itself (maybe containing the proper script inside the QR).
I know how to generate QR codes and how to store HTML code in them using data:text/html protocol. My problem is the design of this functionality. Is there a way I can embed that functionality into a QR code (or two) without it being an URL to a web that stores the functionality? If not, which is the easiest way to achieve this?
Any help will be appreciated, thanks in advance.
Related
I have this project where I need to know if a visitor legitimately arrived from a QR code. Document.referrer value from a QR code shows blank. I have looked at some answers suggesting to put parameter in the query string (e.g. ?source=qr), but anyone could easily add the parameter into the URL and my code would believe it is from a QR code (e.g. www.project.com/check.page?source=qr) . I have thought of adding codes to make sure it is from a mobile phone / tablet as secondary way to authenticate but many browsers have add-ons to fool websites.
Any suggestions would be greatly appreciated.
Thanks in advance.
I think the best solution for you is creating your regional QR Codes pointing to:
Region 1) http://example.com/?qr=f61060194c9c6763bb63385782aa216f
Region 2) http://example.com/?qr=731417b947aa548528344fab8e0f29b6
Region 3) http://example.com/?qr=df189e7f7c8b89edd05ccc6aec36c36d
if the value of the parameter qr is anything other than f61060194c9c6763bb63385782aa216f, 731417b947aa548528344fab8e0f29b6 or df189e7f7c8b89edd05ccc6aec36c36d, then you can ignore it and assume the user didn't come from any QR Code.
Of course, any user can remove the source parameter. But at least he can't add a valid one, unless he really had access to the code.
...but anyone could easily add the parameter into the URL and my code would believe it is from a QR code
Well, anyone could also scan the QR code, view the link, and remove the source=qr from it.
Data collection is never 100% reliable. Users can change their browser's user agent, inject cookies with some strange values, open your page through a proxy server, and so on.
You could create your own device or App for scanning the QR-code. If you read the post I've linked, you will see that this is a waste of time and resources.
So, what is left is to make a solution which will work for most of the users. Appending a source=qr parameter to your URL seems to be the simplest solution. You could also link to an entirely different domain and redirect the request, so it would be more fraud-safe. But it will never be 100% accurate.
I am trying to create a circular QR Code. I understand that the typical circular codes require customer readers (Facebook, Kik, TikTok, ShotCode, etc.), but I would like this code to be able to be read by standard devices (ex.: the built-in reader in iOS devices).
I have looked at a stack of reference materials, including:
How can I generate a circular qr-code like a messenger or a kik code?
Generate circular qr-code like a messenger or a kik code using Python
Generate QR codes missing the corner
I've also dug into the (really in-depth) tutorial at thonky.com, and tried to create my own:
From what I can tell, I've kept the finder patterns, the alignment pattern, the timing patterns, the separators, and the dark module intact (see details here). But still no love when I try to read it.
Admittedly, I've taken an existing code (it contains the URL 'https://www.stackoverflow.com') and just chopped off the corners to make it fit. So my assumption is that I've damaged the code enough that the error correction isn't working.
But, would this work at all anyway? If I figured out how to encode it correctly, would it work without the corners? Or is this a useless endeavor to start with?
There is a basic structure for QR codes with specific elements that take part in the decoding process. Some of them are the alignment, the timing pattern, and the finder pattern. One of the elements which seems to be missing is the quiet zone. It's used to separate the code from other objects and surrounds all the data including structuring elements in the code. Have a look on the outer side of codes here and notice the difference. Also, if you look at the points that represent your data cells, some of them partially exist. In other words, some half and quarter circles exist and others are unknown behind the outer frame of your code design. How would it be figured out if it's black or white to be used for decoding? This is the problem. Please check this image to see how data look missing when you crop it with the circle.
Also, if you use any regular QR coder reading application, you will notice that circular QR codes require custom readers. So, the answer to your question is yes. The corners are necessary if you don't use a custom reader and if data exists on them.
If you are interested in academic research details, see this. I hope my answer helps you. :)
I have been exploring Azure Form Recognizer for one of my project where we wants to perform OCR on some hand written texts.
The problem is that when we give scanned images to the tool to process, it some time doesn't even recognize the text written on it (even if it is clearly written). I tried multiple type of images by performing enhancement on it and also the B/W or colored copy of it but it doesn't works.
Some times it recognize value of two fields as one and this leads to incorrect data where one field is completely blank and other is having value of other one along with its own.
When there is NO VALUE in the tagged field in the testing data, it try to read the from some other place which is not even closer to that field or sometimes un-tagged
Could you please help with these queries.
Thanks in advance.
Can you please share also sample forms please make sure data is anonymized and without any real data ?
Please contact customer service to debug this issue.
Thanks,
Neta - MSFT
I am using Google Charts API to generate QR code as referred in this link https://www.gregorystrike.com/2011/01/26/how-to-use-google-charts-api-to-generate-your-own-qr-code/
In this as the parameters are visible it seems to be insecure
Users can change the values available in the parameters using developer tools like inspector element of Firefox. Is there a secure way to generate QR codes
Thanks
QR codes are insecure anyway, anyone can see the data you place in it, by using any reader.
If want to use QR Codes in any sort of secure sense or to store sensitive data you will have to manage encryption and decryption of that data yourself, there a few encrypted examples but its not a heavily used function. Now we are past the Fab stage of QR Codes, they mainly used like barcodes for identification, with the ability to store more information if needed and the odd URL embedded link.
Although the limit is quite large this is still a limit to the amount of data you can place in a QR Code.
Lots of information on the Wikipedia page https://en.wikipedia.org/wiki/QR_code
I am tasked with writing a program that, given a search term and the HTML source of a page representing search results of some unknown search engine (it can really be anything, a blog, a shop, Google, eBay, ...), needs to build a data structure of the results containing "what's in the results": a title for earch result, the "details" link, the position within the results etc. It is not known whether the results page contains any of the data at all, and whether there are any search results. The goal is to feed the data structure into another program that extracts meaning.
What I am looking for is not BeautifulSoup or a RegExp but rather some clever ideas or algorithms on how to interpret the HTML source. What do I do to find out what part of the page constitutes a single result item? How do I filter the markup noise to extract the important bits? What would you do? Pointers to fields of research covering what I try to to are aly greatly appreciated.
Thanks, Simon
I doubt that there exist a silver-bullet algorithm that without any training will just work on any arbitrary search query output.
However, this task can be solved and is actually solved in many applications, but with different approach. First you have to define general structure of single search result item based on what you actually going to do with it (it could be name, date, link, description snippet, etc.), and then write number of html parsers that will extract necessary necessary fields from search result output of particular web sites.
I know it is not super sexy solution, but it probably the only one that works. And it is not rocket science. Writing parsers is actually extremly simple, you can make dozen per day. If you will look into html source of search result, you will notice that output results are typically very structured and marked with specific div sections or class atributes, so it is very easy to find it in the document. You dont have even use any complicated HTML parsing library for that, something grep-like will be enough.
For example, on this particular page your question starts with <div class="post-text"> and ends with </div>. Everything in between is actually a post text with some HTML formatting that you may want to remove along with extra spaces and "\n". And this <div class="post-text"> appears on the page only once.
Once you go at large scale with your retrieval applicaiton, you will find out that there is not that big variety of different search engines on different sites, and you will be able to re-use already created parsers for sties using similar search engines.
The only thing you have to remember is built-in self-testing. Sites tend to upgrade and change design from time to time. If your application is going to live for some time, you will need to include into your parsers some logic that will check validity of their results and notify you every time search output has changed and is not compatible anymore with your parser. Then you will have to modify particular parser or write new one.
Hope this helps.