Firefox Hacks [Electronic resources] نسخه متنی

Hack 41. Create Your Own Search Plug-in

Found a search engine that suits you? Put it up
front on the Search bar.

Now that we've looked at a sample plug-in [Hack #36], let's
make
our own. We'll query for articles in the CNET
News.com archive.

The first step is to visit the web site and conduct a sample query,
to see how the query URL is formed. Go to http://www.news.com, enter
firefox in the Search box, and click on
"See all matching results." This
submits the following
query:

http://news.search.com/search?q=firefox&cat=230&int.1278=1

From this we can deduce the following items for our plug-in:

The action parameter in the search tag is
http://news.search.com/search.

The input parameter q is set to
our user-specified input.

The input parameters cat and
int.1278 should also be specified.

4.10.1. Building the Plug-in

With the information in the previous section in hand, we have enough
details to build most of our plug-in:

<search
version="1.0"
name="CNET News.com"
description="Search CNET News.com"
method="GET"
action="http://news.search.com/search"
>
<input name="q" user>
<input name="cat" value="230">
<input name="int.1278" value="1">
<input name="sourceid" value="Mozilla-search">

If we look at the HTML source, we can see that the results are neatly
captured as an enumerated list, with each news story as a list item.
We can use this information to build the interpret
tag in the following code. We'll also add a
browser tag, so we can make our plug-in available
to other users and enable them to retrieve updates automatically when
the site changes and we change our plug-in to accommodate it:

<interpret
resultListStart="<ol start="
resultListEnd="</ol>"
resultItemStart="<li>"
resultItemEnd="<br>"
>
<browser
update="http://www.kswartz.com/kswartz/projects/mycroft/cnetnews.src"
updateIcon="http://www.kswartz.com/kswartz/projects/mycroft/cnetnews.png"
updateCheckDays=3
/>
</search>

There's a lot more that can be done with Mycroft
plug-ins than just tabulating simple results. For a complete
definition of the plug-in syntax, read the Mycroft
Developer's Guide at http://mycroft.mozdev.org/deepdocsl.

All that's left now is to create a 16 16 icon for
the site, which is left as an exercise for the reader. Remember to
save it with the same basename as your search plug-in.

One easy trick is to capture the site's favicon.ico file, if it has one. Just type its URL to get it: http://www.example.com/favicon.ico. Such files are conveniently 16 16 pixels in size. Just use a freeware tool such as Icon2Png or the GIMP to convert it to a .png, .jpg, or .gif file.

4.10.2. Installing the Plug-in

Before we install the plug-in, it's usually a good
idea to run it through a validator, such as the one available at
http://www.mindzilla.com/auditform.php. You
can use this page to verify your plug-in syntax, as well as to verify
your list and item start/end identifiers.

If the validation page reports no errors in your plug-in,
it's time to install it. There are two ways you can
install your plug-in. If you are only developing the plug-in for
yourself, you can manually install it by copying the file to the
searchplugins directory where Firefox is
installed and restarting your browser to have it reread that
directory.

Alternatively, you can post the files to a web site, and use this
JavaScript code to download the files to the
searchplugins directory and dynamically update
the list of known plug-ins:

<script type="text/javascript">
function addEngine(name,ext) {
if ((typeof window.sidebar == "object") &&
(typeof window.sidebar.addSearchEngine == "function")) {
window.sidebar.addSearchEngine(
"http://mycroft.mozdev.org/plugins/"+name+".src",
"http://mycroft.mozdev.org/plugins/"+name+"."+ext,
name, '');
}
}
</script>

Include the preceding code on an HTML page, and then link to your
search plug-in with the following line:

<a href="'myplugin','png')">Install myplugin</a>

At this point, you should see the icon and name of your plug-in in
the drop-down list of the Search box, as shown in Figure 4-20.

Figure 4-20. Searching with your new plug-in

Your new search plug-in is ready to use!

Keith M. Swartz