dqhendricks - Developer IT

Find the new coordinates using a starting point, a distance, and an angle

- by dqhendricks

Okay, say I have a point coordinate. var coordinate = { x: 10, y: 20 }; Now I also have a distance and an angle. var distance = 20; var angle = 72; The problem I am trying to solve is, if I want to travel 20 points in the direction of angle from the starting coordinate, how can I find what my new coordinates will be? I know the answer involves things like sin/cosin, because I used to know how to do this, but I have since forgotten the formula. Can anyone help?

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Having problems getting a PHP regex to match.

- by dqhendricks

Here is my problem. It's probably a simple fix. I have a regex that I am using to replace a url BBCode. What I have right now that is not working looks like this. <?php $input_string = '[url=www.test.com]Test[url]'; $regex = '/\[url=(.+?)](.+?)\[\/url]/is'; $replacement_string = '<a href="$1">$2</a>'; echo preg_replace($regex, $replacement_string, $input_string); ?> This currently outputs the original $input_string, while I would like it to output the following. <a href="www.test.com">Test</a> What am I missing?

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Using bitwise operators on > 32 bit integers

- by dqhendricks

I am using bitwise operations in order to represent many access control flags within one integer. ADMIN_ACCESS = 1; EDIT_ACCOUNT_ACCESS = 2; EDIT_ORDER_ACCESS = 4; var myAccess = 3; // ie: ( ADMIN_ACCESS | EDIT_ACCOUNT_ACCESS ) if ( myAccess & EDIT_ACCOUNT_ACCESS ) { // check for correct access // allow for editing of account } Most of this is occurring on the PHP side of my project. There is one piece however where Javascript is used to join several access flags using | when saving someone's access level. This works fine to a point. I have found that once an integer (flag) gets too large ( 32bit), it no longer works correctly with bitwise operators in Javascript. For instance: alert( 4294967296 | 1 ); // equals 1, but should equal 4294967297 I am trying to find a workaround for this so that I do not have to limit my number of access control flags to 32. Each access control flag is two times the previous control flag so that each control flag will not interfere with other control flags. dec(4) = bin(100) dec(8) = bin(1000) dec(16) = bin(10000) I have noticed that when adding two of these flags together with a simple +, it seems to come out with the same answer as a bitwise or operation, but am having trouble wrapping my head around whether this is a simple substitution, or if there might be problems with doing this. Can anyone comment on the validity of this workaround? Example: (4294967296 | 262144 | 524288) == (4294967296 + 262144 + 524288)

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How to do MVC form url formatting?

- by dqhendricks

I am using PHP. I want to create an MVC setup from scratch to learn more about how MVC works. I want to use clean urls with slashes as delimiters for the arguments. How do people do this when it comes to GET method forms? Or do people avoid GET method forms all together? As of right now the ways I can imagine are: Don't use GET method forms (although this makes it harder to let users bookmark/link in some cases). Use AJAX instead of form submission (although what do you do for SEO and JS disablers?). Have page submit to itself with post method, then reform the post vars into an url, then rerout to that url using headers (seems like wasted resources). Any suggestions or suggested reading welcome.

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Need method to seek next/previous records id without cycling through all records.

- by dqhendricks

I am using MySQL and PHP. I have a MySQL blog post result set with id fields, and publish_date fields. I display one blog post per page, and the script knows which blog post to display based on $_GET['id'], which correlates to each blog entry's id field. I would like to reference them by id in the url, because I would like each blog post to have a perminant url. I would like to order the blog posts by publish date (descending). Now, on each page there will be next and previous links, which contain the $_GET['id'] value for the next and previous blog posts. How can I figure out what the id of the next and previous blog posts (determined by it's publish_date order) without cycling through each mysql result row? I can't mysql_data_seek(), because I do not know the row index of the current blog post id. I do not want to store a row index in a GET variable because the urls would no longer be perminant. I obviously cannot store the row index in a SESSION variable because then direct links to specific blog posts would have broken next and previous links. Any suggestions would be greatly appreciated.

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mysql query trying to search by alias involving CASES and aggregate functions UGH!

- by dqhendricks

I have two tables left joined. The query is grouped by the left table's ID column. The right table has a date column called close_date. The problem is, if there are any right table records that have not been closed (thus having a close_date of 0000-00-00), then I do not want any of the left table records to be shown, and if there are NO right table records with a close_date of 0000-00-00, I would like only the right table record with the MAX close date to be returned. So for simplicity sake, let's say the tables look like this: Table1 id 1 2 Table2 table1_id | close_date 1 | 0000-00-00 1 | 2010-01-01 2 | 2010-01-01 2 | 2010-01-02 I would like the query to only return this: Table1.id | Table2.close_date 2 | 2010-01-02 I tried to come up with an answer using aliased CASES and aggregate functions, but I could not search by the result, and I was attempting not to make a 3 mile long query to solve the problem. I looked through a few of the related posts on here, but none seem to meet the criteria of this particular case. Any pushes in the right direction would be greatly appreciated. Thanks!

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Solution for using `this` keyword in ajax calls within methods?

- by dqhendricks

I am creating a JavaScript class. Some of the methods contain AJAX calls using JQuery. The problem I am comming accross is that I cannot use the this keyword within the AJAX callbacks due to a change in scope. I have come up with a hackey solution, but I am wondering what is the best practice way around this? Here is an example: var someClass = function() { var someElement = $('form'); this.close = function() { someElement.remove(); }; this.query = function() { $.ajax({ url: someurl, success: function() { this.close(); // does not work because `this` is no longer the parent class } }); }; };

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