Making a customized Firefox search plug-in (Shallow Thoughts)

Akkana's Musings on Open Source Computing and Technology, Science, and Nature.

Sat, 14 Mar 2015

Making a customized Firefox search plug-in

It's getting so that I dread Firefox's roughly weekly "There's a new version -- do you want to upgrade?" With every new upgrade, another new crucial feature I use every day disappears and I have to spend hours looking for a workaround.

Last week, upgrading to Firefox 36.0.1, it was keyword search: the feature where, if I type something in the location bar that isn't a URL, Firefox would instead search using the search URL specified in the "keyword.URL" preference.

In my case, I use Google but I try to turn off the autocomplete feature, which I find it distracting and unhelpful when typing new search terms. (I say "try to" because complete=0 only works sporadically.) I also add the prefix allintext: to tell Google that I only want to see pages that contain my search term. (Why that isn't the default is anybody's guess.) So I set keyword.URL to: http://www.google.com/search?complete=0&q=allintext%3A+ (%3A is URL code for the colon character).

But after "up"grading to 36.0.1, search terms I typed in the location bar took me to Yahoo search. I guess Yahoo is paying Mozilla more than Google is now.

Now, Firefox has a Search tab under Edit->Preferences -- but that just gives you a list of standard search engines' default searches. It would let me use Google, but not with my preferred options.

If you follow the long discussions in bugzilla, there are a lot of people patting each other on the back about how much easier the preferences window is, with no discussion of how to specify custom searches except vague references to "search plugins". So how do these search plugins work, and how do you make one?

Fortunately a friend had a plugin installed, acquired from who knows where. It turns out that what you need is an XML file inside a directory called searchplugins in your profile directory. (If you're not sure where your profile lives, see Profiles - Where Firefox stores your bookmarks, passwords and other user data, or do a systemwide search for "prefs.js" or "search.json" or "cookies.sqlite" and it should lead you to your profile.)

Once you have one plugin installed, it's easy to edit it and modify it to do anything you want. The XML file looks roughly like this:

<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/" xmlns:os="http://a9.com/-/spec/opensearch/1.1/">
<os:ShortName>MySearchPlugin</os:ShortName>
<os:Description>The search engine I prefer to use</os:Description>
<os:InputEncoding>UTF-8</os:InputEncoding>
<os:Image width="16" height="16">data:image/x-icon;base64,ICON GOES HERE</os:Image>
<SearchForm>http://www.google.com/</SearchForm>
<os:Url type="text/html" method="GET" template="https://www.google.com/search">
  <os:Param name="complete" value="0"/>
  <os:Param name="q" value="allintext: {searchTerms}"/>
  <!--os:Param name="hl" value="en"/-->
</os:Url>
</SearchPlugin>

There are four things you'll want to modify. First, and most important, os:Url and os:Param control the base URL of the search engine and the list of parameters it takes. {searchTerms} in one of those Param arguments will be replaced by whatever terms you're searching for. So <os:Param name="q" value="allintext: {searchTerms}"/> gives me that allintext: parameter I wanted.

(The other parameter I'm specifying, <os:Param name="complete" value="0"/>, used to make Google stop the irritating autocomplete every time you try to modify your search terms. Unfortunately, this has somehow stopped working at exactly the same time that I upgraded Firefox. I don't see how Firefox could be causing it, but the timing is suspicious. I haven't been able to figure out another way of getting rid of the autocomplete.)

Next, you'll want to give your plugin a ShortName and Description so you'll be able to recognize it and choose it in the preferences window.

Finally, you may want to modify the icon: I'll tell you how to do that in a moment.

Using your new search plugin

[Firefox search prefs]

You've made all your modifications and saved the file to something inside the searchplugins folder in your Firefox profile. How do you make it your default?

I restarted firefox to make sure it saw the new plugin, though that may not have been necessary. Then Edit->Preferences and click on the Search icon at the top. The menu near the top under Default search engine is what you want: your new plugin should show up there.

Modifying the icon

Finally, what about that icon?

In the plugin XML file I was copying, the icon line looked like:

<os:Image width="16"
height="16">data:image/x-icon;base64,AAABAAEAEBAAAAEAIABoBAAAFgAAACgAAAAQAAAAIAAAAAEAIAAAAAAAAAAAAAAA
... many more lines like this then ... ==</os:Image>
So how do I take that and make an image I can customize in GIMP?

I tried copying everything after "base64," and pasting it into a file, then opening it in GIMP. No luck. I tried base64 decoding it (you do this with base64 -d filename >outfilename) and reading it in with GIMP. Still no luck: "Unknown file type".

The method I found is roundabout, but works:

  1. Copy everything inside the tag: data:image/x-icon;base64,AA ... ==
  2. Paste that into Firefox's location bar and hit return. You'll see the icon from the search plugin you're modifying.
  3. Right-click on the image and choose Save image as...
  4. Save it to a file with the extension .ico -- GIMP won't open it without that extension.
  5. Open it in GIMP -- a 16x16 image -- and edit to your heart's content.
  6. File->Export as...
  7. Use the type "Microsoft Windows icon (*.ico)"
  8. Base64 encode the file you just saved, like this: base64 yourfile.ico >newfile
  9. Copy the contents of newfile and paste that into your os:Image line, replacing everything after data:image/x-icon;base64, and before </os:Image>

Whew! Lots of steps, but none of them are difficult. (Though if you're not on Linux and don't have the base64 command, you'll have to find some other way of encoding and decoding base64.)

But if you don't want to go through all the steps, you can download mine, with its lame yellow smiley icon, as a starting point: Google-clean plug-in.

Happy searching! See you when Firefox 36.0.2 comes out and they break some other important feature.

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[ 12:35 Mar 14, 2015    More tech/web | permalink to this entry | comments ]
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