<p>The base tools are the <codeclass="docutils literal notranslate"><spanclass="pre">evennia.search_*</span></code> functions, such as <codeclass="docutils literal notranslate"><spanclass="pre">evennia.search_object</span></code>.</p>
<p>What is returned from the main search functions is actually a <cite>queryset</cite>. They can be
treated like lists except that they can’t modified in-place. We’ll discuss querysets in
the <cite>next lesson</cite><Django-queries>`_.</p>
</div>
<p>Strings are always case-insensitive, so searching for <codeclass="docutils literal notranslate"><spanclass="pre">"rose"</span></code>, <codeclass="docutils literal notranslate"><spanclass="pre">"Rose"</span></code> or <codeclass="docutils literal notranslate"><spanclass="pre">"rOsE"</span></code> give the same results.
It’s important to remember that what is returned from these search methods is a <em>listing</em> of 0, one or more
elements - all the matches to your search. To get the first match:</p>
<p>Often you really want all matches to the search parameters you specify. In other situations, having zero or
more than one match is a sign of a problem and you need to handle this case yourself.</p>
<divclass="highlight-default notranslate"><divclass="highlight"><pre><span></span><spanclass="n">the_one_ring</span><spanclass="o">=</span><spanclass="n">evennia</span><spanclass="o">.</span><spanclass="n">search_object</span><spanclass="p">(</span><spanclass="n">key</span><spanclass="o">=</span><spanclass="s2">"The one Ring"</span><spanclass="p">)</span>
<p>On the <codeclass="docutils literal notranslate"><spanclass="pre">DefaultObject</span></code> is a <codeclass="docutils literal notranslate"><spanclass="pre">.search</span></code> method which we have already tried out when we made Commands. For
this to be used you must already have an object available:</p>
<p>The <codeclass="docutils literal notranslate"><spanclass="pre">.search</span></code> method wraps <codeclass="docutils literal notranslate"><spanclass="pre">evennia.search_object</span></code> and handles its output in various ways.</p>
<ulclass="simple">
<li><p>By default it will always search for objects among those in <codeclass="docutils literal notranslate"><spanclass="pre">obj.location.contents</span></code> and <codeclass="docutils literal notranslate"><spanclass="pre">obj.contents</span></code> (that is,
things in obj’s inventory or in the same room).</p></li>
<li><p>It will always return exactly one match. If it found zero or more than one match, the return is <codeclass="docutils literal notranslate"><spanclass="pre">None</span></code>.</p></li>
<li><p>On a no-match or multimatch, <codeclass="docutils literal notranslate"><spanclass="pre">.search</span></code> will automatically send an error message to <codeclass="docutils literal notranslate"><spanclass="pre">obj</span></code>.</p></li>
</ul>
<p>So this method handles error messaging for you. A very common way to use it is in commands:</p>
<p>Remember, <codeclass="docutils literal notranslate"><spanclass="pre">self.caller</span></code> is the one calling the command. This is usually a Character, which
inherits from <codeclass="docutils literal notranslate"><spanclass="pre">DefaultObject</span></code>! This (rather stupid) Command searches for an object named “foo” in
the same location. If it can’t find it, <codeclass="docutils literal notranslate"><spanclass="pre">foo</span></code> will be <codeclass="docutils literal notranslate"><spanclass="pre">None</span></code>. The error has already been reported
to <codeclass="docutils literal notranslate"><spanclass="pre">self.caller</span></code> so we just abort with <codeclass="docutils literal notranslate"><spanclass="pre">return</span></code>.</p>
<p>You can use <codeclass="docutils literal notranslate"><spanclass="pre">.search</span></code> to find anything, not just stuff in the same room:</p>
<p>With <codeclass="docutils literal notranslate"><spanclass="pre">quiet=True</span></code> the user will not be notified on zero or multi-match errors. Instead you are expected to handle this
yourself and what you get back is now a list of zero, one or more matches!</p>
<p>The <codeclass="docutils literal notranslate"><spanclass="pre">key</span></code> is the name of the entity. Searching for this is always case-insensitive.</p>
<p>Objects and Accounts can have any number of aliases. When searching for <codeclass="docutils literal notranslate"><spanclass="pre">key</span></code> these will searched too,
<p>If the above <codeclass="docutils literal notranslate"><spanclass="pre">rose</span></code> has a <codeclass="docutils literal notranslate"><spanclass="pre">key</span></code><codeclass="docutils literal notranslate"><spanclass="pre">"Rose"</span></code>, it can now also be found by searching for <codeclass="docutils literal notranslate"><spanclass="pre">flower</span></code>. In-game
you can assign new aliases to things with the <codeclass="docutils literal notranslate"><spanclass="pre">alias</span></code> command.</p>
<p>Only Objects (things inheriting from <codeclass="docutils literal notranslate"><spanclass="pre">evennia.DefaultObject</span></code>) has a location. This is usually a room.
The <codeclass="docutils literal notranslate"><spanclass="pre">Object.search</span></code> method will automatically limit it search by location, but it also works for the
general search function. If we assume <codeclass="docutils literal notranslate"><spanclass="pre">room</span></code> is a particular Room instance,</p>
<p>Think of a <aclass="reference internal"href="../../../Components/Tags.html"><spanclass="doc">Tag</span></a> as the label the airport puts on your luggage when flying.
Everyone going on the same plane gets a tag grouping them together so the airport can know what should
go to which plane. Entities in Evennia can be grouped in the same way. Any number of tags can be attached
<p>Tags can also have categories. By default this category is <codeclass="docutils literal notranslate"><spanclass="pre">None</span></code> which is also considered a category.</p>
<p>Note that if you specify the tag you <em>must</em> also include its category, otherwise that category
will be <codeclass="docutils literal notranslate"><spanclass="pre">None</span></code> and find no matches.</p>
<divclass="highlight-default notranslate"><divclass="highlight"><pre><span></span><spanclass="n">all_fantasy_books</span><spanclass="o">=</span><spanclass="n">evennia</span><spanclass="o">.</span><spanclass="n">search_tag</span><spanclass="p">(</span><spanclass="s2">"fantasy"</span><spanclass="p">)</span><spanclass="c1"># no matches! </span>
<p>We can also search by the <aclass="reference internal"href="../../../Components/Attributes.html"><spanclass="doc">Attributes</span></a> associated with entities.</p>
<p>If you have the <codeclass="docutils literal notranslate"><spanclass="pre">Rose</span></code> class already imported you can also pass it directly:</p>
<p>The database id or <codeclass="docutils literal notranslate"><spanclass="pre">#dbref</span></code> is unique and never-reused within each database table. In search methods you can
replace the search for <codeclass="docutils literal notranslate"><spanclass="pre">key</span></code> with the dbref to search for. This must be written as a string <codeclass="docutils literal notranslate"><spanclass="pre">#dbref</span></code>:</p>
<p>Let’s consider a <codeclass="docutils literal notranslate"><spanclass="pre">chest</span></code> with a <codeclass="docutils literal notranslate"><spanclass="pre">coin</span></code> inside it. The chests stand in a room <codeclass="docutils literal notranslate"><spanclass="pre">dungeon</span></code>. In the dungeon is also
a <codeclass="docutils literal notranslate"><spanclass="pre">door</span></code>. This is an exit leading outside.</p>
<ulclass="simple">
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">coin.location</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">chest</span></code>.</p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">chest.location</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">dungeon</span></code>.</p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">door.location</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">dungeon</span></code>.</p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">room.location</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">None</span></code> since it’s not inside something else.</p></li>
</ul>
<p>One can use this to find what is inside what. For example, <codeclass="docutils literal notranslate"><spanclass="pre">coin.location.location</span></code> is the <codeclass="docutils literal notranslate"><spanclass="pre">room</span></code>.
We can also find what is inside each object. This is a list of things.</p>
<ulclass="simple">
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">room.contents</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">[chest,</span><spanclass="pre">door]</span></code></p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">chest.contents</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">[coin]</span></code></p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">coin.contents</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">[]</span></code>, the empty list since there’s nothing ‘inside’ the coin.</p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">door.contents</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">[]</span></code> too.</p></li>
</ul>
<p>A convenient helper is <codeclass="docutils literal notranslate"><spanclass="pre">.contents_get</span></code> - this allows to restrict what is returned:</p>
<ulclass="simple">
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">room.contents_get(exclude=chest)</span></code> - this returns everything in the room except the chest (maybe it’s hidden?)</p></li>
</ul>
<p>There is a special property for finding exits:</p>
<ulclass="simple">
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">room.exits</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">[door]</span></code></p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">coin.exits</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">[]</span></code> (same for all the other objects)</p></li>
</ul>
<p>There is a property <codeclass="docutils literal notranslate"><spanclass="pre">.destination</span></code> which is only used by exits:</p>
<ulclass="simple">
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">door.destination</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">outside</span></code> (or wherever the door leads)</p></li>
<li><p><codeclass="docutils literal notranslate"><spanclass="pre">room.destination</span></code> is <codeclass="docutils literal notranslate"><spanclass="pre">None</span></code> (same for all the other non-exit objects)</p></li>
