Vladislav Subbotin Subb98

## System Design.md

      
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                vasanthk
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              October 22, 2025 09:01
            
              
                System Design Cheatsheet
              
          
    System Design Cheatsheet


Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps


Clarify and agree on the scope of the system


User cases (description of sequences of events that, taken together, lead to a system doing something useful)

Who is going to use it?
How are they going to use it?


## download-image-from-http.php
<?php
/**
 * Saves remote image using Curl request
 * @param string $img URL from which image is to be retrieved
 * @param string $fullpath Full path to the image
 * @param string $imageVerify Fullpath where image will be saved.
 * @see http://stackoverflow.com/questions/10890617/grabbing-image-with-curl-php
 */
function saveImage($img, $fullpath = null, $imageVerify = true) {

## strip HTML tags
# copied from (thanks!): http://codesnippets.joyent.com/posts/show/615

str = <<HTML_TEXT
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<html>
<body>
  <h1>Application error</h1>
  <p>Change this error message for exceptions thrown outside of an action (like
in Dispatcher setups or broken Ruby code) in public/500.html</p>
	<?php
	/**
	* Saves remote image using Curl request
	* @param string $img URL from which image is to be retrieved
	* @param string $fullpath Full path to the image
	* @param string $imageVerify Fullpath where image will be saved.
	* @see http://stackoverflow.com/questions/10890617/grabbing-image-with-curl-php
	*/
	function saveImage($img, $fullpath = null, $imageVerify = true) {
	# copied from (thanks!): http://codesnippets.joyent.com/posts/show/615

	str = <<HTML_TEXT
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
	"http://www.w3.org/TR/html4/loose.dtd">
	<html>
	<body>
	<h1>Application error</h1>
	<p>Change this error message for exceptions thrown outside of an action (like
	in Dispatcher setups or broken Ruby code) in public/500.html</p>