zaterdag, juli 21, 2007
New CAPTCHA control
I started to work on the site again. I keep running into problems related to the CAPTCHA control that I'm using. It's the free one from the Codeproject site that I modified. Today I got InvalidCastException errors for the Anthem.NET Editlabel component due to this CaptchaWebControl control. So I finally gave up on it and started for a replacement.
Accidently I also found out what CAPTCHA stands for : Completely Automated Public Turing test to tell Computers and Humans Apart. Take that for an acronym :-) . It is an established way to protect web forms against robots and usually involves people filling in a code from an image.
First replacement control I tried was the one created by Peter Kellner. This Microsoft MVP did a nice job of a highly customizable component, but I did not run into the same errors. But the looks were a bit not-done and especially the component only works with events. There is no method to call for verification. As my CAPTCHA is at the bottom of every beta page to allow people to post comments on how to improve my site, I wanted to call verification only when the button was pressed. So I decided against this component.
So as a first for the about2findout.com project, I'm going to use a cheap commercial component. The LanapSoft BotDetect control is available from 59$ onwards and has some excellent features. Not only can I now choose between 50 different CAPTCHA rendering styles, it is also solving a major issue with CAPTCHA. Up till now every website using CAPTCHA was not compliant with section 508 and other accessibility standards because blind people cannot see the code and are thus unable to use the site. This component adds a button that reads out the code as well. Very cool indeed. So with a little investment I get a code that (so far) does not generate more trouble than it's worth and makes my site better adhere to accessibility standards.
Accidently I also found out what CAPTCHA stands for : Completely Automated Public Turing test to tell Computers and Humans Apart. Take that for an acronym :-) . It is an established way to protect web forms against robots and usually involves people filling in a code from an image.
First replacement control I tried was the one created by Peter Kellner. This Microsoft MVP did a nice job of a highly customizable component, but I did not run into the same errors. But the looks were a bit not-done and especially the component only works with events. There is no method to call for verification. As my CAPTCHA is at the bottom of every beta page to allow people to post comments on how to improve my site, I wanted to call verification only when the button was pressed. So I decided against this component.
So as a first for the about2findout.com project, I'm going to use a cheap commercial component. The LanapSoft BotDetect control is available from 59$ onwards and has some excellent features. Not only can I now choose between 50 different CAPTCHA rendering styles, it is also solving a major issue with CAPTCHA. Up till now every website using CAPTCHA was not compliant with section 508 and other accessibility standards because blind people cannot see the code and are thus unable to use the site. This component adds a button that reads out the code as well. Very cool indeed. So with a little investment I get a code that (so far) does not generate more trouble than it's worth and makes my site better adhere to accessibility standards.
woensdag, januari 10, 2007
CAPTCHA : to be (human) or not to be (human)
Over 90% of e-mail these days is spam. More than half of blog entries are also spam. Many forums or sites that allow commenting become victim of spam or inappropriate comments. Very often the spam is inserted automatically by bots. One way to fight bots is to check via CAPTCHA.
You have seen it before: the picture with a few characters that you need to type, for example when you sign up for an account or if you want to comment to this post on blogger. (Try it!) The idea is that software agents cannot recognise the characters within the picture.
I just added a CAPTCHA component to my experimental site about2findout.com/6CQuotes. From now on you can no longer suggest a new quote (which sends me a mail) without typing in the CAPTCHA 5-character code.
I've found this excellent CaptchaControl component on The Code Project. It's free to use.
What I learned in my little experiment:
- You can add a control to the Visual Studio toolbox by right-clicking the toolbox, selecting 'choose items...' from the drop down menu, clicking the Browse button and pointing to the DLL file of the provided component.
- You need to add the httphandler section in the web.config file of your application for the CaptchaControl to work. (as described in the CodeProject article or in provided example)
DECISION: I'm going to use CAPCHA on the about2findout.com site for login, setting up an account and posting comments.
You have seen it before: the picture with a few characters that you need to type, for example when you sign up for an account or if you want to comment to this post on blogger. (Try it!) The idea is that software agents cannot recognise the characters within the picture.I just added a CAPTCHA component to my experimental site about2findout.com/6CQuotes. From now on you can no longer suggest a new quote (which sends me a mail) without typing in the CAPTCHA 5-character code.
I've found this excellent CaptchaControl component on The Code Project. It's free to use.
What I learned in my little experiment:
- You can add a control to the Visual Studio toolbox by right-clicking the toolbox, selecting 'choose items...' from the drop down menu, clicking the Browse button and pointing to the DLL file of the provided component.
- You need to add the httphandler section in the web.config file of your application for the CaptchaControl to work. (as described in the CodeProject article or in provided example)
DECISION: I'm going to use CAPCHA on the about2findout.com site for login, setting up an account and posting comments.
Labels: 6C Quotes, asp.net, CAPTCHA
