Scientists are able to measure Brain activity while interfacing brains to electronic devices.It allows you to see which parts of the brain are active during dreams.They would place them in a MRI scan machine and they would have the test subjects fall asleep in the MRI scan machine,and wake them up during the REM cycle (which is where the most vivid dreaming occurs,thus causing you to remember it upon awakening) and ask them what they dreamt. They would use A TON of images from the internet to link and correspond what the subjects saw in their dreams.They would do this about 200 times per person,plugged the information in a learning algorythm and the software was used to interpret their dreams.It wasn't perfect,but it was a start.
Yes, I believe that, eventually, we will be able to record our dreams. Unfortunately, this type of invention will probably come hundreds of years from now, when we better understand technology and how we can make it interact with out brain. As of right now, we have many medical devices that can map brain patterns and functions, so the idea that we may some day be able to record our dreams is not terribly far-fetched. Whatever device that will be able to do this will have some similarities with the machinery and technology that exists today that interact with out brain, such as an FMRi scan.
I do not think we will be able to record our dreams. I think the closest we can come is to record thoughts while dreaming and possibly descriptions of visualizations but record an actual dream is pretty far out there. Also I am sure we can decipher if we are having a dream or nigh terror.