[[UPDATED - 08/11/22 to include Linux paths]]
A lot of people have been having problems getting extensions to work with Prism. This is kind of an expected situation considering that the extensions that are being targeted are designed for use under Firefox, which has a different UI than Prism. This can cause a lot of headaches trying to figure out what’s wrong. There are ways around some of these problems, especially if the extension includes a xul overlay that is compatible with the browser xul for Prism. Or if you can load the chrome url to the main xul overlay in Prism’s input url (which of course requires that you already have the extension installed). Other extensions however, have no hope of working with Prism unless changes are made to the overlays.

I’ve also been running into a problem described by commenter Marcel, here. I’ve been getting a similar error under Windows for different extensions when I try to install them. Don’t know why, and what makes it worse is that these errors crop up in extensions that I’ve had no problems installing before on other computers (maybe I need to have Webrunner installed along side Prism?). I’ve also had problems with version 0.9 not installing and using the included icons for webapp files. I’m going to have to look into that one a bit further before I can comment more on it though.

At any rate, I’m going to list as much information in this post as I can find on Prism to refer back to, then I’m going to create a new post on how to install an extension for Prism manually. I’d also like to post a how-to on getting POW to work under Prism as well, but I don’t know whether or not I’ll get to that (maybe over Thanksgiving break). So, first some links.

LINKS:
Mozilla Labs’ Prism Page - A broad overview of the goals of the Mozilla Prism Project
Mozilla Developer Center’s Prism Page
MDC’s Prism Page on Extensions
Mozilla Labs’ Prism Forum
Mozilla Wiki Prism Page - Along with the Dev Center’s page, a good source for documentation on  Prism
Mark Finkle’s Blog (one of Prism’s developers - BTW - THANK YOU MARK!!!)
SVN for Prism’s source code
List of Prism Contributors on ohloh.net
Douglas Meyer’s Blog post on getting Google Gears to work with Prism
Commenter Manlo’s blog post on getting RTM working with Prism (does not appear to be working)
Wikipedia Entry

Next, here’s a list of all the files that Prism makes use of in the user’s profile directory on Windows and Mac OS X - Linux to come (I don’t have access to my Linux box at the moment).

Default Prisim Folders in User’s Home directory (Windows as of Prism v0.9):

Under C:\Documents and Settings\{user name}\Application Data\

Prism\
Prism\profiles.ini
Prism\Profiles\
Prism\Profiles\{random string}.default\
Prism\Profiles\{random string}.default\cert8.db
Prism\Profiles\{random string}.default\compatibility.ini
Prism\Profiles\{random string}.default\compreg.dat
Prism\Profiles\{random string}.default\cookies.sqlite
Prism\Profiles\{random string}.default\extensions
Prism\Profiles\{random string}.default\extensions.cache
Prism\Profiles\{random string}.default\extensions.ini
Prism\Profiles\{random string}.default\key3.db
Prism\Profiles\{random string}.default\localstore.rdf
Prism\Profiles\{random string}.default\mimeTypes.rdf
Prism\Profiles\{random string}.default\permissions.sqlite
Prism\Profiles\{random string}.default\places.sqlite
Prism\Profiles\{random string}.default\prefs.js
Prism\Profiles\{random string}.default\secmod.db
Prism\Profiles\{random string}.default\xpti.dat
Prism\Profiles\{random string}.default\extensions\

Under C:\Documents and Settings\{user name}\Local Settings\Application Data\

Prism\Prism\
Prism\Prism\updates\
Prism\Prism\updates\0\

For Each WebApp Prism creates (Windows as of Prism v0.9):

Under C:\Documents and Settings\{user name}\Application Data\Prism\

{webapp name}\
{webapp name}\profiles.ini
{webapp name}\Profiles\
{webapp name}\Profiles\{random string}.default\
{webapp name}\Profiles\{random string}.default\cert8.db
{webapp name}\Profiles\{random string}.default\compatibility.ini
{webapp name}\Profiles\{random string}.default\compreg.dat
{webapp name}\Profiles\{random string}.default\cookies.sqlite
{webapp name}\Profiles\{random string}.default\extensions
{webapp name}\Profiles\{random string}.default\extensions.cache
{webapp name}\Profiles\{random string}.default\extensions.ini
{webapp name}\Profiles\{random string}.default\extensions.rdf
{webapp name}\Profiles\{random string}.default\key3.db
{webapp name}\Profiles\{random string}.default\localstore.rdf
{webapp name}\Profiles\{random string}.default\mimeTypes.rdf
{webapp name}\Profiles\{random string}.default\permissions.sqlite
{webapp name}\Profiles\{random string}.default\places.sqlite
{webapp name}\Profiles\{random string}.default\pluginreg.dat
{webapp name}\Profiles\{random string}.default\prefs.js
{webapp name}\Profiles\{random string}.default\secmod.db
{webapp name}\Profiles\{random string}.default\signons3.txt
{webapp name}\Profiles\{random string}.default\xpti.dat
{webapp name}\Profiles\{random string}.default\extensions\

Under C:\Documents and Settings\{user name}\Application Data\WebApps\

{webapp name}@{webappaddr}\
{webapp name}@{webappaddr}\localstore.json
{webapp name}@{webappaddr}\override.ini
{webapp name}@{webappaddr}\webapp.ini
{webapp name}@{webappaddr}\webapp.js
{webapp name}@{webappaddr}\icons\
{webapp name}@{webappaddr}\icons\default\
{webapp name}@{webappaddr}\icons\default\{icons included in webapp bundle}

Under C:\Documents and Settings\{user name}\Local Settings\Application Data\Prism\

{webapp name}\
{webapp name}\Prism\
{webapp name}\Prism\updates\
{webapp name}\Prism\updates\0\
{webapp name}\Profiles\
{webapp name}\Profiles\l05apnbh.default\
{webapp name}\Profiles\l05apnbh.default\XPC.mfl
{webapp name}\Profiles\l05apnbh.default\XUL.mfl
{webapp name}\Profiles\l05apnbh.default\Cache\
{webapp name}\Profiles\l05apnbh.default\Cache\_CACHE_001_
{webapp name}\Profiles\l05apnbh.default\Cache\_CACHE_002_
{webapp name}\Profiles\l05apnbh.default\Cache\_CACHE_003_
{webapp name}\Profiles\l05apnbh.default\Cache\_CACHE_MAP_
{webapp name}\Profiles\l05apnbh.default\Cache\{other cache files}

Default Prisim Folders in User’s Home directory (Mac OS X as of Prism v0.9):
Under /Users/{user name}/Library/Application Support/Prism/

Profiles/
Profiles/profiles.ini
Profiles/{random string}.default/
Profiles/{random string}.default/cert8.db
Profiles/{random string}.default/compatibility.ini
Profiles/{random string}.default/compreg.dat
Profiles/{random string}.default/cookies.sqlite
Profiles/{random string}.default/extensions.cache
Profiles/{random string}.default/extensions.ini
Profiles/{random string}.default/key3.db
Profiles/{random string}.default/localstore.rdf
Profiles/{random string}.default/mimeTypes.rdf
Profiles/{random string}.default/permissions.sqlite
Profiles/{random string}.default/places.sqlite
Profiles/{random string}.default/pluginreg.dat
Profiles/{random string}.default/prefs.js
Profiles/{random string}.default/secmod.db
Profiles/{random string}.default/xpti.dat
Profiles/{random string}.default/extensions/

For Each WebApp Prism creates (Mac OS X as of Prism v0.9):

Under /Users/{user name}/Library/Application Support/{webapp name}/

Profiles/
Profiles/profiles.ini
Profiles/{random string}.default/
Profiles/{random string}.default/cert8.db
Profiles/{random string}.default/compatibility.ini
Profiles/{random string}.default/compreg.dat
Profiles/{random string}.default/cookies.sqlite
Profiles/{random string}.default/extensions.cache
Profiles/{random string}.default/extensions.ini
Profiles/{random string}.default/key3.db
Profiles/{random string}.default/localstore.rdf
Profiles/{random string}.default/mimeTypes.rdf
Profiles/{random string}.default/permissions.sqlite
Profiles/{random string}.default/places.sqlite
Profiles/{random string}.default/pluginreg.dat
Profiles/{random string}.default/prefs.js
Profiles/{random string}.default/secmod.db
Profiles/{random string}.default/xpti.dat
Profiles/{random string}.default/extensions/

Under /Users/{user name}/Library/WebApps/{webapp name}@{webappaddr}/

{webapp name}@{webappaddr}/localstore.json
{webapp name}@{webappaddr}/override.ini
{webapp name}@{webappaddr}/webapp.ini
{webapp name}@{webappaddr}/webapp.js
{webapp name}@{webappaddr}/icons/
{webapp name}@{webappaddr}/icons/default/
{webapp name}@{webappaddr}/icons/default/{icons included in webapp bundle}

Default Prisim Folders in User’s Home directory (Linux as of Prism v0.9):

Under /home/{user name}/

.prism/prismdir.lin.txt
.prism/profiles.ini
.prism/{randomstring}.default/
.prism/{randomstring}.default/Cache/
.prism/{randomstring}.default/cert8.db
.prism/{randomstring}.default/compatibility.ini
.prism/{randomstring}.default/compreg.dat
.prism/{randomstring}.default/cookies.sqlite
.prism/{randomstring}.default/extensions/
.prism/{randomstring}.default/extensions.cache
.prism/{randomstring}.default/extensions.ini
.prism/{randomstring}.default/key3.db
.prism/{randomstring}.default/localstore.rdf
.prism/{randomstring}.default/mimeTypes.rdf
.prism/{randomstring}.default/.parentlock
.prism/{randomstring}.default/permissions.sqlite
.prism/{randomstring}.default/places.sqlite
.prism/{randomstring}.default/prefs.js
.prism/{randomstring}.default/secmod.db
.prism/{randomstring}.default/XPC.mfasl
.prism/{randomstring}.default/xpti.dat
.prism/{randomstring}.default/XUL.mfasl
.prism/{randomstring}.default/Cache/
.prism/{randomstring}.default/Cache/_CACHE_001_
.prism/{randomstring}.default/Cache/_CACHE_002_
.prism/{randomstring}.default/Cache/_CACHE_003_
.prism/{randomstring}.default/Cache/_CACHE_MAP_

For Each WebApp Prism creates (Linux as of Prism v0.9):

Under /home/{user name}/.prism/

{webapp name}/
{webapp name}/{randomstring}.default/
{webapp name}/{randomstring}.default/Cache/
{webapp name}/{randomstring}.default/Cache/_CACHE_001_
{webapp name}/{randomstring}.default/Cache/_CACHE_002_
{webapp name}/{randomstring}.default/Cache/_CACHE_003_
{webapp name}/{randomstring}.default/Cache/_CACHE_MAP_
{webapp name}/{randomstring}.default/cert8.db
{webapp name}/{randomstring}.default/compatibility.ini
{webapp name}/{randomstring}.default/compreg.dat
{webapp name}/{randomstring}.default/cookies.sqlite
{webapp name}/{randomstring}.default/extensions/
{webapp name}/{randomstring}.default/extensions.cache
{webapp name}/{randomstring}.default/extensions.ini
{webapp name}/{randomstring}.default/key3.db
{webapp name}/{randomstring}.default/localstore.rdf
{webapp name}/{randomstring}.default/mimeTypes.rdf
{webapp name}/{randomstring}.default/.parentlock
{webapp name}/{randomstring}.default/permissions.sqlite
{webapp name}/{randomstring}.default/places.sqlite
{webapp name}/{randomstring}.default/prefs.js
{webapp name}/{randomstring}.default/secmod.db
{webapp name}/{randomstring}.default/XPC.mfasl
{webapp name}/{randomstring}.default/xpti.dat
{webapp name}/{randomstring}.default/XUL.mfasl
{webapp name}/profiles.ini

From the above lists of file locations, it should be apparent (okay, if you really really look, hard) that there are two ways to go about installing an extension for Prism. The first is install that extension “globally”, which is to say that you install that extension for every webapp. For this method the extension gets installed into Prism’s extension directory. The second method is to install the extension “locally”, or on a per-webapp basis. In this case each extension is installed in the individual webapp’s extension directory.

The first method is more difficult because by default, installing an extension will be done when you have a webapp loaded, so it will install the extension into that webapp’s extension folder. In order to install a webapp globally, you’ll need to perform a manual installation or open a new webapp that loads the addon’s xul (chrome://global/content/config.xul). I should mention that this worked on Prism/Webrunner 0.8, but I have yet to test this on Prism 0.9, so this may no longer work.

…

So, why they heck would I list all the files and directories here? Well, I want a reference to point at when I start explaining which files to make changes to in order to install an extension manually.

Code Snippit for Prism Extensions’ install.rdf

<em:targetApplication>
  <!– Prism –>
  <Description>
    <em:id>prism@developer.mozilla.org</em:id>
    <em:minVersion>0.8</em:minVersion>
    <em:maxVersion>1.0.0.*</em:maxVersion>
   </Description>
</em:targetApplication>

Code Snippit for Prism Extensions’ extension.rdf (information is required from the **install.rdf**)

<RDF:Description
    RDF:about="urn:mozilla:item:{**extension id from install.rdf**}"
    NS1:installLocation="app-profile"
    NS1:version="**from install.rdf**"
    NS1:optionsURL="**from install.rdf**"
    NS1:iconURL="**from install.rdf**"
    NS1:name="**from install.rdf**"
    NS1:description="**from install.rdf**"
    NS1:creator="**from install.rdf**"
    NS1:homepageURL="http://**from install.rdf**"
    NS1:contributor="**from install.rdf**">

More to come…

I know it’s been a while since I’ve posted. There’s been a lot going on - school, work, home, you get the point. Anyway, I’ve been trying to keep my last post on how to make extensions compatible with Prism up-to-date, but this is turning out to be a difficult task. So I’m just going to post new instructions as needed. Basically, everything remains the same but the version string changes. The DOM inspector is the key to figuring out the correct target to put into your extension’s install.rdf. Clear as mud yet? Well, let me lay out the steps for you again here.

Step 1
Navigate to the Prism installation directory, in Windows this is:
C:\Program Files\Prism\

Open up the extensions folder, then the DOM inspector extension folder:
C:\Program Files\Prism\extensions\inspector@mozilla.org

Now open the “install.rdf” file and find this section of code which can be used (usually) as-is in most extensions pasted in the right place (just use the extension’s preconfigured targets as your guide on where to place it):

<em:targetApplication>
<!– Prism –>
<Description>
<em:id>prism@developer.mozilla.org</em:id>
<em:minVersion>0.4</em:minVersion>
<em:maxVersion>1.0.0.*</em:maxVersion>
</Description>
</em:targetApplication>

Step 2
Open up your extension’s xpi file using 7zip or your favorite archiving tool and extract the install.rdf file.

Open that install.rdf file with a text editor (other than notepad which doesn’t understand the line breaks used by other editors) and find the area where it lists the installation targets and insert your copied text into that or modify one of the install targets with the appropriate information from the DOM inspector extension install.rdf file.

Step 3
Install the extension. This will get tricky due to the way Prism’s developers have modified the profiles and what not. Well, I say that, but it really only gets that tricky if you’re manually installing the extension. Prism developers have seen fit to include the Addons menu item from the Prism menu in the lower right of Prism’s window to help things go more smoothly.

One of the ways to use this new install feature for an extension is globally, which means all webapps will be able to use the extension. This is the least preferred manner due to the fact that you won’t want all extensions available for all webapps in most cases. An example would be having the Better Gmail extension available for Bloglines - don’t think that’s real necessary, do you? So plan accordingly.

Using the second, and more preferred method, you just open your webapp. Open your webapp’s Addons panel, then install by either dragging and dropping the extension onto it, or by clicking the “Install…” button and navigating to the extension and selecting it for installation.

Conclusion
That should be about it. My next Prism post will be about how to make one of two stand alone Firefox/Prism exention webapps - POW local server or Scribefire standalone webapp. Stay tuned, we get to play with chrome!!

Links:

Prism

Link to LifeHacker Post

LifeHacker’s linked to my post on how to install extensions in Prism/Webrunner. For anyone having trouble with some extensions, have a look at my comment dated today (080404), I’ve addressed Better GCal specifically, but this should also work for Better Gmail and a few others as well.

Prism/Webrunner extensions post