一个基于redis的处理session的方法，如下。
<span> 1</span> <?<span>php
</span><span> 2</span> <span>class</span><span> Session_custom {
</span><span> 3</span> <span>private</span> <span>$redis</span>; <span>//</span><span> redis实例</span>
<span> 4</span> <span>private</span> <span>$prefix</span> = 'sess_'; <span>//</span><span> session_id前缀
</span><span> 5</span>
<span> 6</span> <span> // 会话开始时，会执行该方法，连接redis服务器</span>
<span> 7</span> <span>public</span> <span>function</span> open(<span>$path</span>, <span>$name</span><span>) {
</span><span> 8</span> <span>$this</span>->redis = <span>new</span><span> Redis();
</span><span> 9</span> <span>return</span> <span>$this</span>->redis->connect("127.0.0.1",6379<span>);
</span><span>10</span> <span> }
</span><span>11</span>
<span>12</span> <span>//</span><span> 会话结束时，调用该方法，关闭redis连接</span>
<span>13</span> <span>public</span> <span>function</span><span> close() {
</span><span>14</span> <span>$this</span>->redis-><span>close();
</span><span>15</span> <span>return</span> <span>true</span><span>;
</span><span>16</span> <span> }
</span><span>17</span>
<span>18</span> <span>//</span><span> 会话保存数据时调用该方法，在脚本执行完或session_write_close方法调用之后调用</span>
<span>19</span> <span>public</span> <span>function</span> write(<span>$session_id</span>, <span>$data</span><span>) {
</span><span>20</span> <span>return</span> <span>$this</span>->redis->hMSet(<span>$this</span>->prefix.<span>$session_id</span>, <span>array</span>('expires' => <span>time</span>(), 'data' => <span>$data</span><span>));
</span><span>21</span> <span> }
</span><span>22</span>
<span>23</span> <span>//</span><span> 在自动开始会话或者通过调用 session_start() 函数手动开始会话之后，PHP 内部调用 read 回调函数来获取会话数据。</span>
<span>24</span> <span>public</span> <span>function</span> read(<span>$session_id</span><span>) {
</span><span>25</span> <span>if</span>(<span>$this</span>->redis->exists(<span>$this</span>->prefix.<span>$session_id</span><span>)) {
</span><span>26</span> <span>return</span> <span>$this</span>->redis->hGet(<span>$this</span>->prefix.<span>$session_id</span>, 'data'<span>);
</span><span>27</span> <span> }
</span><span>28</span> <span>return</span> ''<span>;
</span><span>29</span> <span> }
</span><span>30</span>
<span>31</span> <span>//</span><span> 清除会话中的数据，当调用session_destroy()函数，或者调用 session_regenerate_id()函数并且设置 destroy 参数为 TRUE 时,会调用此回调函数。</span>
<span>32</span> <span>public</span> <span>function</span> destroy(<span>$session_id</span><span>) {
</span><span>33</span> <span>if</span>(<span>$this</span>->redis->exists(<span>$this</span>->prefix.<span>$session_id</span><span>)) {
</span><span>34</span> <span>return</span> <span>$this</span>->redis->del(<span>$this</span>->prefix.<span>$session_id</span>) > 0 ? <span>true</span> : <span>false</span><span>;
</span><span>35</span> <span> }
</span><span>36</span> <span>return</span> <span>true</span><span>;
</span><span>37</span> <span> }
</span><span>38</span>
<span>39</span> <span>//</span><span> 垃圾回收函数，调用周期由 session.gc_probability 和 session.gc_divisor 参数控制</span>
<span>40</span> <span>public</span> <span>function</span> gc(<span>$maxlifetime</span><span>) {
</span><span>41</span> <span>$allKeys</span> = <span>$this</span>->redis->keys("{<span>$this</span>->prefix}*"<span>);
</span><span>42</span> <span>foreach</span>(<span>$allKeys</span> <span>as</span> <span>$key</span><span>) {
</span><span>43</span> <span>if</span>(<span>$this</span>->redis->exists(<span>$key</span>) && <span>$this</span>->redis->hGet(<span>$key</span>, 'expires') + <span>$maxlifetime</span> < <span>time</span><span>()) {
</span><span>44</span> <span>$this</span>->redis->del(<span>$key</span><span>);
</span><span>45</span> <span> }
</span><span>46</span> <span> }
</span><span>47</span> <span>return</span> <span>true</span><span>;
</span><span>48</span> <span> }
</span><span>49</span> <span>}
</span><span>50</span>
<span>51</span> <span>//</span><span> 调用自定义的session处理方法</span>
<span>52</span> <span>$handler</span> = <span>new</span><span> Session_custom();
</span><span>53</span> <span>session_set_save_handler</span><span>(
</span><span>54</span> <span>array</span>(<span>$handler</span>, 'open'),
<span>55</span> <span>array</span>(<span>$handler</span>, 'close'),
<span>56</span> <span>array</span>(<span>$handler</span>, 'read'),
<span>57</span> <span>array</span>(<span>$handler</span>, 'write'),
<span>58</span> <span>array</span>(<span>$handler</span>, 'destroy'),
<span>59</span> <span>array</span>(<span>$handler</span>, 'gc'<span>)
</span><span>60</span> <span>);
</span><span>61</span>
<span>62</span> <span>//</span><span> 下面这行代码可以防止使用对象作为会话保存管理器时可能引发的非预期行为,表示当脚本执行之后或调用exit()之后，存储当前会话数据并关闭当前会话</span>
<span>63</span> <span>register_shutdown_function</span>('session_write_close'<span>);
</span><span>64</span>
<span>65</span> <span>session_start</span><span>();
</span><span>66</span>
<span>67</span> <span>//</span><span> 可以使用session了</span>补充：
php.ini文件中的session.gc_probability与session.gc_divisor两个配置选项共同决定gc函数调用的时机。默认值分为为1和1000，表示每个请求只有1/1000的机会调用gc函数。
