PHP HTTP Response Handling Summary

See HttpServletResponse for more information on how Java handles HTTP Responses.

See PHP HTTP Request Handling Summary for more information on how PHP handles HTTP requests.

PHP has a fairly simple output mechanism compared to Java Servlets.

• print - Output one or more strings
• printf - Output formated strings
• echo - Output one or more strings (as a function)

The Output Control Functions provide control over the buffering of the content output of the request. They also provide a simple mechanism to stack output filters. See InterceptingFilter.

• flush - Flush the output buffer ( useful to give end users the impression of realtime updates - see The Joy of Flush for details and PEAR::HTML_Progress examples)
• ob_clean - Clean (erase) the output buffer
• ob_end_clean - Clean (erase) the output buffer and turn off output buffering
• ob_end_flush - Flush (send) the output buffer and turn off output buffering
• ob_flush - Flush (send) the output buffer
• ob_get_clean - Get current buffer contents and delete current output buffer
• ob_get_contents - Return the contents of the output buffer
• ob_get_length - Return the length of the output buffer
• ob_get_level - Return the nesting level of the output buffering mechanism
• ob_get_status - Get status of output buffers
• ob_implicit_flush - Turn implicit flush on/off
• ob_start - Turn on output buffering
• mb_output_handler - Callback function converts character encoding in output buffer

output buffer configuration settings (ini)

• output_buffering - enable buffering for all requests
• output_handler - Register an output handling function. Same as ob_start.
• implicit_flush - flush output after every output block (echo, print or printf)

Session Handling Functions provide the capability to use url based session Ids in the content output.

• session.use_trans_sid - when this option is enabled, relative URIs in the response output will be rewritten to contain a session Id.
• url_rewriter.tags - specifies which html tags are rewritten to include session information.

The Zlib Compression Functions can compress output on-the-fly.

• ob_gzhandler - ob_start callback function to gzip output buffer
• zlib_get_coding_type - Returns the coding type used for output compression

Zlib compression configuration options:

• zlib.output_compression - Whether to transparently compress pages
• zlib.output_compression_level - Compression level used for transparent output compression
• zlib.output_handler - similiar to output_handler

Basic HTTP Functions.

• header - Send a raw HTTP header
• setcookie - Send a cookie (see Cookies)
• headers_sent - Checks if or where headers have been sent
• apache_response_headers - Fetch all HTTP response headers (see Apache specific functions)

Output compression configuration

• zlib.output_compression - outputs Content-Encoding and Vary headers when content is compressed.

Several configuration options control how the php session handling functions output cookies for tracking sessions.

• session.auto_start - specifies whether the session module starts a session automatically
• session.name - Used as the cookie name
• session.cookie_lifetime - How long should the browser store the cookie
• session.cookie_path
• session.cookie_domain
• session.cookie_secure
• session.use_cookies - specifies whether the module will use cookies to store the session id on the client side
• session.use_only_cookies - specifies whether the module will only use cookies to store the session id on the client side

functions controling how cookies are output during session handling.

• session_set_cookie_params - Set the session cookie parameters
• session_get_cookie_params - Get the session cookie parameters

Configuration options controlling page caching during a session:

• session.cache_limiter - specifies cache control method to use for session page
• session.cache_expire - specifies time-to-live for cached session pages

Functions controlling page caching during a session:

• session_cache_limiter - Get and/or set the current cache limiter
• session_cache_expire - Return current cache expire

Apache specific functions configuration options

• last_modified - send PHP scripts modification date as Last-Modified: header for the request.

The header function has special case logic to also set the response status code. When the header paramter to the header() function begins with HTTP/, Status:, or Location:, the HTTP response status code is modified.

See HTTP authentication with PHP for more information about setting the response status.

Apache specific functions for response processing

• apache_child_terminate - Terminate apache process after this request
• apache_lookup_uri - Perform a partial request for the specified URI and return all info about it
• apache_setenv - Set an Apache subprocess_env variable
• virtual - Perform an Apache sub-request

The zlib.output_compression configuration option or ob_gzhandler output handler can output Content-Encoding: gzip or Content-Encoding: deflate headers.

The zlib.output_compression configuration option or ob_gzhandler output handler can output Content-Length headers.

The mb_output_handler function and the configuration option mbstring.http_output can add charset information to the Content-Type headers.

The last_modified configuration option send PHP scripts modification date as Last-Modified: header for the request. See Apache specific functions.

The setcookie function is the standard API for developers to output this header. PHP Session Handling Functions Will also set a cookie for tracking session Ids.

The zlib.output_compression configuration option or ob_gzhandler output handler can output Vary: Accept-Encoding headers.