Tuesday, April 17, 2018

Using The Coldfusion XMLValidate Function To Validate User Content

Sometimes you want to allow a limited set of HTML tags in user generated content.  This can be done with the XMLValidate function in Coldfusion as long as the content is valid XHTML.

Several years ago I read an article about escaping form values posted by Ben Nadel on his site www.bennadel.com. Some discussion came up in the comments about allowing a limited set of html tags for paragraphs, bold text, and so on.  I had a need to do this for forum comments on a site that I was working on. This site was written in Coldfusion so I was looking at some of the same options mentioned in Ben's article. I ended up doing something a little different though.

We were using TinyMCE for the forum comments. TinyMCE produces XHTML code so I was able to use Coldfusion's abilities to handle XML to accomplish this task. Using the XMLValidate function and an XML schema that was modified to accept a small list of tags and attributes the comments were correctly limited. Here is the relevant portion of the code.  Below is an explanation of how it works. 


Sunday, April 15, 2018

Setting Up an Angular 5 site on Github Pages

Getting Started

This article will go over all the steps to setup an Angular site on GitHub pages.  The site will use Angular's AOT compiling and be served from the docs folder of the repository.

To start with you can follow the guide here to setup a new Angular project. Then you will need to setup a repository on Github.com.  The name of the repository doesn't matter, this site will use the docs folder, not the specially named repository with USERNAME.github.io as the name.


Friday, April 13, 2018

Listening For JS Error Events

I was recently reading a blog article, Ben Nadel JS Error.   In the article Ben showed how to setup an error event handler that would be triggered for any failed image loads on a page.  This was done by attaching an error event handler to the body element.  Also he had to pass the last argument to addEventListener as true so that it would trigger in the capture phase of the event. This event handler will run whenever an external resource like an image or a style sheet fails to load on the page.

After some experimenting I found that if I attach the event to the window object it is triggered for all the failed resources and also for any javascript errors that happen on the page.  Setting this up on a site with quite a bit of traffic from different browsers was very interesting.  It was a bit overwhelming at first until some things were fixed and some checking was added to filter out some of the errors.  In the event handler the event and error information is being posted back to a server and then sent in an email so it can be reviewed.


Wednesday, April 11, 2018

My First Memories of Coding

The first time I remember writing code was in grade school in the computer lab.  We were learning Basic.  I'm not sure how old I was, but it would have been sometime in the late '80s or early '90s.  I remember they had us write a program that would take some numbers from the user and print out the average.  I had to ask how to do division. I had only seen it with the standard division symbol in math class, not the forward slash.  Soon after that I was able to get Basic on my home PC.  Actually I think it was included in MS-DOS.

At school and in the beginning at home I was using Basic where you had to use line numbers to write your code.  Then to edit a line you had to retype that line with the number.  Soon after that I was able to get QBasic and a book to help me get started.


Coding

  I'm not sure where I heard this, and it wasn't worded this way, but it helps to think about coding this way. Basically, any progra...