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An Introduction To PHP Sessions

How Can I Send Headers Then Start A Session?

Earlier we mentioned that you cannot send anything to the browser before session_start(). This is because when you set a header, you cannot do it twice. When you send text to the browser, headers are sent also.

However, PHP does provide a method to set headers, send text, and still be able to start your session. The ob_start() function allows you to buffer your output till you are ready to send content to the browser.

Listing 24 ob.php (listing-24.php)
  // make it or break it
  // begin output buffering
  // send a header
  header ("Pragma: no-cache");
  // send some text to the browser
  echo 'This is a line of text';
  // then we start our session
  // set the value of the session variable 'foo'
  // flush the buffer

Run this snippet of code and it will output the text

Listing 25 Browse output from using output buffering (listing-25.txt)
This is a line of text

First we sent a header with the no-cache, then echoed some text and finally started a session and set a session variable.

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