Project assignment 4. Due Monday, April 28 at midnight.

For this part of the project you need to provide forms for users to post and comment, validate the user data and store it in the database. Validation must be done using regular expressions.

User posts

Add a form to let the user post a new post. Make sure the form is accessible from the front page (and possibly from other pages, as a part of the menu bar, if any) to let the user post a new post. The post form should require a user to enter the following data:

1. their login name (this will go away after we implement sessions and login, but we need it for now).
2. the post subject (can be empty)
3. the post contents

When the server recieves the data, it must validate it as follows:

1. Check that the user name is no more than 10 characters long and consists only of valid characters (letters, digits, and underscores). Note that you need to check this before the next step (why?)
2. Check that the user name exists in the database. You may want to get the user ID as well since you will need it for the post to be added to the database.
3. Check that the subject is not too long and has only valid characters (you probably want to allow spaces in addition to the symbols in part 1, what else?)
4. Check that the post message is not too long and not empty. Check that there is no more than three a tags in the post: posts with a large number of links are often spam.
   Some HTML tags should be disallowed - form tag, for instance. You don't need to make a full-proof checking system, just demonstrate how you would allow some tags but not other ones. Write (in comments) what is allowed in posts and what is not allowed.
   Here is the list of all HTML tags.

If the data did not pass validation on any of the counts, display the form with a meaningful error message to the user. Make sure to redisplay all entries that passed the validation so that they don't need to be retyped (we will see an example in class on how to do this).

After the data has been validated you need to add it to the database. Use your group login name and password to connect to the database.

• Make sure to fill in all relevant fields: post_author, post_date, post_content, post_title, and comment_count (set to 0).
• Use the function mysql_real_escape_string to put appropriate escape characters before adding text fields to the database (see the example of inserting data into the database that we considered in class)
• When adding posts and comments to the database, make sure to lock and unlock tables as needed.

User comments

The user should be able to comment on a post by clicking the "Comment on this" link of the post. The link should bring the user to a page with a form. Note that you need to pass the post ID (through a GET method) to the comment form. Since you need to pass it further to the php file that handles the comment form, you may either still use the GET method or include it as a hidden field in the form:

<input type="hidden" name="post_id" value="..."

where the value is the post ID. Then you can access it in the php file that handles the form like this: $_POST["post_id"].

The rest of the comment form is similar to the post form. It requires the user to enter (at least):

1. their login name
2. the comment contents

You need to check the validity of both (you may use the same functions as you used for validating post data, in this case store the functions in a separate file and include the file in both files that handle forms).

After you have validated the data, store it in the database. Make sure to increment the comment count in the wp_posts table and set the user display name.
Test your forms carefully to make sure that all the data is stored correctly and that the data is validated so that the incorrect data does not get stored. Also make sure that when the user enters incorrect or incomplete data, the form with wrong fields marked is displayed.

Project groups of three

Groups of three should have all three of their features implemented at least partially.

Additional features

All groups are required to implement at least one additional feature (of your choice) for the final installment; groups of three are required to implement three features. Here are some suggestions:

1. Threads of comments (the ability to reply to a comment rather than just a post)
2. Post categories - let the user choose a category (out of a pull-down menu?) for their posts and provide a search option to find all posts in a category.
3. Allow the user to turn off comments for their own post (set comment_status to "close" and check before inserting a comment; you might also just not provide the comment link for such posts)
4. Allow deleting a post or a comment. Make sure that the correct user login is provided (i.e. a person is allowed to delete only their own posts or comments). When deleting a post, make sure that all its comments are deleted as well.

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