So, now we have the final U in CRUD done, and I can finally edit posts. YOU can't edit comments yet, but that's coming soon, probably tomorrow.
That's fun. EDITING ROCKS! It's also a really neat macro that makes it pretty easy to do SQL update statements.
Here's another neat thing: Basically, I use the exact same statement to create and update a post:
(update-record "Posts" Id PosterId PostDate PostSubject PostContent) ; It's the U in CRUD!
(create-record "Posts" Id PosterId PostDate PostSubject PostContent) ; It's the C in CRUD!
There's a lot of stuff going on behind the scenes to translate the above into two very different SQL statements. Basically the Id in the first is to CHECK for Id's value, and in the second statement it is to SET Id to that value. I like the symmetry,
Sometimes SQL injection comes in tricky forms. Often attackers will add on extra junk in the URL to try and confuse SQL into doing something it wasn't intended to do. For example, if the URL for page 2 is:
an attacker might try something like
http://newlisponrockets.com/rockets-main.lsp?p=2 OR 1=1
to try and break the code or inject some other SQL into the query by adding these commands with spaces.
I've added a function called (force-parameters) that makes it easy to prevent this. For example, to get the page number from the URL, I used to call ($GET "p"), which in this case would return "2 OR 1=1".
Now, I use the code:
(set 'current-page (force-parameters 1 ($GET "p"))) ; we only need the first part, ignore anything else
which takes only the first parameter from the URL. You can add as much extra junk after it, but it will only take the "2".
Just a little bold and italics and underlines
and some code samples:
The above code now translates these UBB codes into HTML. Actual HTML is converted to its literal equivalent to avoid cross-site scripting issues.
When I started this little thing a month and a half ago, I didn't expect anyone to notice it right away. The Internet is a big place and Rockets is, for now, quite small.
But a few people have found their way here (welcome guys!) and so I now need a way to send some welcome emails for new users.
I've added a function called (send-mail), which sends an email to a given address. Behind the scenes it uses the Unix command sendmail, so you will need to have that installed on your server (simply type "sudo apt-get install sendmail" on Ubuntu or Debian).
To avoid emails falling into spam traps, you need to be sending from a valid email address that has the same domain as the server that is sending it. The (send-mail) function will take care of all the headers and things automatically.
For example, for new users, I simply use:
(send-mail UserEmail "email@example.com" "Rocket Man" "Welcome to the newLISP on Rockets blog!" welcome-email)
where welcome-email is the string of the body of the email.
Documentation is something I have a particular fondness for. I actually got my start in the software industry as a technical writer, so I appreciate it when things are well-documented. Of course now that I am a developer I find writing documentation to be a chore!
The way I've done documentation in Rockets is to automatically generate it from the comments in the core file that contains all of Rockets' functions. However in order for this to work I had to go back and clean up and standardize all the comments, something that I had been putting off. Oh well, sometimes chores need to be done!
One thing I always disliked about most programming documentation is the requirement to understand and translate some weird meta-language or syntax for the usage of each statement. Usually it was easier to just look at the example and figure out what the author meant. So for Rockets, all my usage statements are in fact examples, albeit using names and strings that describe their actual function. So for example (open-database "database name") is both the usage and the example of opening a database.
This is something really simple, the perfect assignment for a Monday morning.
Go to your site's root directory (usually /var/www) and edit the .htaccess file (type sudo nano .htaccess)
Add the following line to the end of the file:
ErrorDocument 404 /rockets-404.lsp
Now any 404 (page not found) errors will redirect to this page instead of displaying the generic Apache error.
This would be a PERFECT message to test out adding comments to.. if you know what I mean. Hint, hint.Comments (13)
Yes, with Rocket Captcha(tm) and everything!
You can't do anything once you sign in (like post messages or anything) yet but... you'll have an account!
Sometimes you want your application to remember where you were, but the application wants to redirect you to somewhere else.
This is most annoying when you sign in. You probably want to stay on the page you were on instead of being redirected back to the main page.
Rockets adds a global variable called (active-page). You have to set it before you call the navigation bar so it knows which page to highlight. But it also passes this variable as a hidden field in the navigation bar itself, alongside the user email and password, so that the verification script (rockets-verify.lsp) can redirect you back to that page if you either succeeded or failed in signing in.
Paging code is really easy in SQLite. You do a SELECT statement as normally but add the LIMIT clause with two numbers separated by a comma. The first number is the offset, aka where you start from, and the second number is the number of results you want back. So if you wanted ten results starting from the thirtieth, you just SELECT ... LIMIT 30,10 and that's it!
Displaying the current paging links is something I might want to do a lot, so I made a function in Rockets to do it. The function works like this:
(display-paging-links int-start-page int-total-pages int-current-page str-page-url)
So to display the top ten pages you'd call (display-paging-links 1 10 1 "rockets-main").
Neat and easy!