path: root/lib/ssl/doc/src/ssl_session_cache_api.xml

<?xml version="1.0" encoding="iso-8859-1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>1999</year><year>2010</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.

      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.

    </legalnotice>
    <title>ssl</title>
    <file>ssl_session_cache_api.xml</file>
  </header>
  <module>ssl_session_cache_api</module>
  <modulesummary>Defines the API for the TLS session cache so
    that the data storage scheme can be replaced by
    defining a new callback module implementing this API.</modulesummary>

  <section>
    <title>Common Data Types</title>

    <p>The following data types are used in the functions below:
    </p>

    <p><c>cache_ref() = opaque()</c></p> 
    
    <p><c>key() = {partialkey(), session_id()}</c></p>
    
    <p><c>partialkey() = opaque()</c></p>
    
    <p><c>session_id() = binary()</c></p>

    <p><c>session() = opaque()</c></p>
    
  </section>
  
  <funcs>   

    <func>
      <name>delete(Cache, Key) -> _</name>
      <fsummary></fsummary>
      <type>
	<v> Cache = cache_ref()</v>
	<v> Key  = key()</v>
      </type>
      <desc>
	<p> Deletes a cache entry. Will only be called from the cache
	handling process.
	</p>
      </desc>
    </func>

    <func>
      <name>foldl(Fun, Acc0, Cache) -> Acc</name>
      <fsummary></fsummary>
      <type>
	<v></v>
      </type>
      <desc>
	<p>Calls Fun(Elem, AccIn) on successive elements of the
	cache, starting with AccIn == Acc0. Fun/2 must return a new
	accumulator which is passed to the next call. The function returns
	the final value of the accumulator. Acc0 is returned if the cache is
	empty. 
	</p>
      </desc>
    </func>

    <func>
      <name>init() -> opaque() </name>
      <fsummary>Return cache reference</fsummary>
      <type>
	<v></v>
      </type>
      <desc>
	<p>Performs possible initializations of the cache and returns
	a reference to it that will be used as parameter to the other
	api functions. Will be called by the cache handling processes
	init function, hence putting the same requirements on it as
	a normal process init function.
	</p>
      </desc>
    </func>

    <func>
      <name>lookup(Cache, Key) -> Entry</name>
      <fsummary> Looks up a cache entry.</fsummary>
      <type>
	<v> Cache = cache_ref()</v>
	<v> Key  = key()</v>
	<v> Entry = session() | undefined </v>
      </type>
      <desc>
	<p>Looks up a cache entry. Should be callable from any
         process.
         </p>
      </desc>
    </func>
    
    <func>
      <name>select_session(Cache, PartialKey) -> [session()]</name>
      <fsummary>>Selects sessions that could be reused.</fsummary>
      <type>
	<v> Cache = cache_ref()</v>
	<v> PartialKey = partialkey()</v>
	<v> Session = session()</v>
      </type>
      <desc>
	<p>Selects sessions that could be reused. Should be callable
	from any process.
	</p>
      </desc>
    </func>

    <func>
      <name>terminate(Cache) -> _</name>
      <fsummary>Called by the process that handles the cache when it
      is about to terminate.</fsummary>
      <type>
	<v>Cache = term()  - as returned by init/0</v>
      </type>
      <desc>
	<p>Takes care of possible cleanup that is needed when the
	cache handling process terminates.
	</p>
      </desc>
    </func>

    <func>
      <name>update(Cache, Key, Session) -> _</name>
      <fsummary> Caches a new session or updates a already cached one.</fsummary>
      <type>
	<v> Cache = cache_ref()</v>
	<v> Key  = key()</v>
	<v> Session = session()</v>
      </type>
      <desc>
	<p> Caches a new session or updates a already cached one. Will
	only be called from the cache handling process.
	</p>
      </desc>
    </func>
    
  </funcs> 
  
</erlref>