title: how to Integrate my custom php application into joomla?
body: <p>Maybe there is some links or tutorials for that but found nothing for this, 
  my problem is that I have a joomla 3 application and some components installed on it like seo and shopping cart,</p>
  
  <p>and i have another php application (it uses codeigniter php framework), now i want to some integration between this two,</p>
  
  <p>for example: i have some users , some user groups and some access levels in joomla3 installation, now i want all joomla users can login to my custom application with their joomla username/password, or better if a user logins to joomla (frontend or backend) he/she be able to use my application without need to login again,</p>
  
  <p>or , i be able to check user's joomla ACLs and user groups within my custom application.</p>
  
  <p>one way my be connect to joomla DB and read data, there are 2 problems also, joomla encrypt passwords so i need do the same (how) , and it will be perfect if there is some API or classes for using them in my custom application.</p>
  
  <p>and other way (that i think i can use) to create some components for joomla and create my own apis in it and include/use them in my application (but how?)</p>
  
  <p>any one can please help me to solve this? i am very little experience with creating joomla component.</p>