htaccess に次のコードを書く。
RewriteEngine on
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} ^example\.com<span class="katex"><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.138em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mord mathnormal">u</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord"><span class="mord mathnormal">e</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.888em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mopen mtight">(</span></span></span></span></span></span></span></span><span class="mord">.</span><span class="mord">∗</span><span class="mclose">)</span></span></span></span> https://www.example.com/<span class="katex"><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">1</span><span class="mopen">[</span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">301</span><span class="mpunct">,</span><span class="mspace" style="margin-right:0.1667em;"></span><span class="mord mathnormal">L</span><span class="mclose">]</span><span class="mord cjk_fallback">ドメインが</span><span class="mord mathnormal">co</span><span class="mord">.</span><span class="mord mathnormal" style="margin-right:0.05724em;">j</span><span class="mord mathnormal">p</span><span class="mord cjk_fallback">などの場合は次のとおり。</span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.05764em;">E</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">in</span><span class="mord mathnormal">eo</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.07153em;">C</span><span class="mord mathnormal">o</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.07153em;">C</span><span class="mord mathnormal">o</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span></span></span></span>
RewriteRule ^(.*)<span class="katex"><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">h</span><span class="mord mathnormal">ttp</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">//</span><span class="mord mathnormal" style="margin-right:0.02691em;">www</span><span class="mord">.</span><span class="mord mathnormal">e</span><span class="mord mathnormal">x</span><span class="mord mathnormal">am</span><span class="mord mathnormal" style="margin-right:0.01968em;">pl</span><span class="mord mathnormal">e</span><span class="mord">.</span><span class="mord mathnormal">co</span><span class="mord">.</span><span class="mord mathnormal" style="margin-right:0.05724em;">j</span><span class="mord mathnormal">p</span><span class="mord">/</span></span></span></span>1 [R=301,L]
これで https かつ www ありでリダイレクトされる。
example.com → www.example.com
www.example.com → www.example.com
もし上のコードでリダイレクトされない場合、htaccess ファイルが間違った場所にあるか
Options +FollowSymLinks
などの記述がない可能性がある。
