Composer, Google, Calendars and ProcessWire

This week we've been focused on one of the major 3.x roadmap items, which is to have strong Composer support in ProcessWire. In this post, we now have an outlined process and a full proof-of-concept module built to demonstrate it all, plus info on how other module authors can support Composer as an alternative installation method. To add to that, we get into Google's Client API with a new 3.x specific module and how to connect Google's Calendar services with ProcessWire.

ProcessWire and Composer

Finding a place for Composer in the PW ecosystem

I personally haven't experienced a lot of the benefits of Composer because the type of sites/apps I build rarely have 3rd party dependencies, and when they do, they are already part of the ProcessWire ecosystem. I suspect this is likely the case for many of us. Though I don't think it's the case in the larger PHP community outside of our ecosystem. ProcessWire already manages its own 3rd party libraries (modules) and dependencies in a manner more targeted to PW, so the case for Composer has always been a bit of a hard sell in our context.

Still, I've always stood on the side admiring what Composer did (and what some of you are doing with it), but never quite able to find a useful place for it in my own workflow. Yet, if ProcessWire is going to have strong Composer support in 3.x, then it's got to become part of my workflow too... otherwise how am I going to support it? So I've been waiting around looking for a good use case to implement Composer further in PW3, and this week one appeared. So I jumped at the chance and enthusiastically moved forward with it.

What I found is that once you do get Composer into your workflow, the case becomes more compelling in ProcessWire, even if you thought it appeared a little redundant from the outside. Composer support is something more than just point to be met on our roadmap. There are some people that will benefit significantly from using it, and some that won't benefit at all, but either way it's something to open yourself up to in ProcessWire. Sooner or later you will find a strong use case for it, especially if bringing other 3rd party libraries into PW. I also think PW recognizing and supporting it has potential to drive a lot more PHP developers to the project.

Using Composer

The Google Client API module

Today I'm releasing a new module (GoogleClientAPI) that demonstrates how Composer can be beneficial in ProcessWire. It's a module that would have been a lot trouble to build and maintain without Composer, due to its 3rd party dependencies. So it ends up being that use case I was looking for in order to really dive in to our Composer support.

The purpose of the module is not just to demonstrate Composer in ProcessWire though. The module is something I've needed and something I know others have too. It is a Google Client API module that enables you to connect your site with various Google web services via OAuth2. It picks up where Google's own PHP client leaves off, managing the connection to a Google account, maintaining the access and refresh tokens, and more. Handling this with only Google's API client library has been a pain (as I've used it on a few occasions in the past), and this GoogleClientAPI makes it a whole lot simpler and more bulletproof.

Where might you use this GoogleClientAPI module? Google provides a lot of different web services that you could use it with, but my own primary use case has been with Google Calendar. So that's also my primary focus for this module in the tutorial below.

Live examples

It helps to see what we're talking about. Here's a few examples of of the Google Client API module implemented with with Google's Calendar service:

There's no eye candy here, but the benefits of pulling from Google's services (like Calendar) aren't so much in the output of examples like this, but instead in the fact that their website is connected to a bigger ecosystem. An ecosystem the client can manage in various places and with various people, various devices and so on. A service like Calendar can also be subscribed to by other users and is generally a lot more broadly "connected" than an individual website would be. Being able to make the website part of that bigger network of activity is a real benefit to clients. And the fact that it's essentially free, while more capable and powerful than almost any paid option is definitely a mountain of icing on the cake.

Successor to MarkupLoadGCal

While GoogleClientAPI can use more than just Google's calendar services, it was the calendar services that motivated its development. Some of you might remember a previous module of mine called MarkupLoadGCal, which enabled one to pull events from a Google Calendar and display them in a site using your own markup.

The problem with that module was Google's changing strategy. In 2014 they dropped the publicly accessible verbose feeds to Google Calendar, leaving just the basic feed. So MarkupLoadGCal was updated with a reduced feature set to accept that limitation and just use the basic feed. Then just recently, they dropped the basic feed, leaving the MarkupLoadGCal module unable to read from anything, making it useless.

Now the only way to access a Google Calendar is with an OAuth2 authenticated account to Google using their Client API library – a lot more trouble! Though I really can't complain, as these Google services have always been free, so some "having to work with the system" is fine. Though using an authenticated account opens up the possibility of not just reading data, but writing it too. We won't get into that in this post, other than to say that the option is there if you need it.

Installing the module with Composer

In this section, we'll use the GoogleClientAPI module as an example, but this can be replaced with any ProcessWire module available on Packagist. I'm not sure there are any others at the moment, but hopefully that will change when modules move to exclusive ProcessWire 3.x versions perhaps later this year. The tutorial here requires ProcessWire 3.x, as does the GoogleClientAPI module.

1. Install Composer and ensure your composer.json file is up-to-date.

  • If you do not already have Composer installed, see the installation instructions.

  • Update your composer.json file in the root of your ProcessWire installation with the latest composer.json from ProcessWire 3.0.11.

  • Note the workflow with Composer is one you'll more likely use on your local dev environment than on your live server, though it could certainly be either.

2. Install the GoogleClientAPI module with Composer.

Once Composer is installed, open a terminal to the root of your ProcessWire installation (where the index.php file is located), and execute the following command:

composer require processwire/google-client-api

The above command installs the ProcessWire GoogleClientAPI module and all required dependencies. There's also a little bit of magic going on here that may not be immediately obvious, thanks to the work of Hari KT. We'll cover some more details on that further down in this post.

3. Enable the GoogleClientAPI module in ProcessWire.

  • Login to your ProcessWire admin and click to Modules > Refresh so that ProcessWire can find new modules.

  • In the "Site" tab of your Modules list, scroll to "Google" and click "Install" for the Google Client API module.

  • You should now be on the module configuration screen for the module you installed. If GoogleClientAPI is the module you've installed here, you'll want to move forward with the next section of this tutorial.

Setting up your Google API account and connecting it to your site

1. Go to and login.

  • Before you move forward, Google may want you to "Enable and Manage APIs" or accept some terms or the like. You know the drill.

  • We're just using free services here, do not click on the "Sign up for Free Trial" button, that's not what you want.

2. Once API access is enabled, click to "Create a new project."

  • Give your project a name, or accept the default, and continue.

3. Next, at the "Add credentials to your project" screen…

  • For "What API are you using?" select "Calendar API" (or a different API that you intend to use).

  • For "Where will you be calling the API from?" select "Web server".

  • For "What data will you be accessing?" select "User data".

4. Click the "What credentials do I need?" button…

  • This will take you to a screen where you "Add credentials to your project".

  • Under the headline "Create an OAuth 2.0 client ID" look for the field "Authorized redirect URIs".

  • Switch to your ProcessWire screen and copy the redirect URL that you see at the bottom of the GoogleClientAPI module settings.

  • Paste this URL into the "Authorized redirect URIs" field that you see in your Google window.

  • When done, click the "Create client ID" button, which will take you to the "Set up the OAuth 2.0 consent screen."

5. On the "Set up the OAuth 2.0 consent" screen…

  • Under the "Product name shown to users", enter "Events calendar" (or whatever you'd like).

  • Click the submit button when done.

6. Now you will be on the "Download credentials" section.

  • Click the "Download" button to download the JSON file that it provides to you.

  • Make note of where it saves to as you will need it shortly. Or just go ahead and open it up in a text editor now if you'd like.

  • Click the "Done" button.

Configuring the Google Client API module

1. Back to your PW admin > Google Client API module settings.

  • For "Application name" enter the "Product name shown to users" that you provided to Google. For example, "Events Calendar".

  • For "Authentication config / client secret JSON", open the JSON file that you downloaded from Google earlier into a text editor. Copy the JSON data from it and paste into this field.

  • Click the "Submit" button to save your configuration.

2. It will now take you to a Google authentication page.

  • Login with the account that you want to use calendars from (if not logged in already).

  • When Google asks you to allow access to view calendars, click the "Allow" button.

3. If everything was successful…

  • You should now be back at the module configuration screen and you are now ready to start using the Calendar API!

Setting up Google Calendar

1. While logged into your Google account, open Google Calendar.

  • Unless you are already focused in on a specific calendar, you will be viewing your "primary" calendar.

  • If the "primary" calendar is the one you would like to use on your website then stop here and skip ahead of the "Adding a Calendar to your Website" section.

  • If you would like to create a new calendar for your website: Under "My calendars" create a new calendar and start adding events to it.

  • If you would like to subscribe to an existing calendar: In the "Other calendars" sidebar section, click the small down-arrow box next to the headline. If you are just testing and aren't sure what to add, you might click the "Browse interesting calendars" link and subscribe to one available in there. For instance, I have subscribed to the "Holidays in the United States" calendar.

2. Go to the calendar settings

  • When you've determined what calendar to use, and have subscribed to it, click the little down-arrow box next to it, and click "Calendar Settings".

  • Note the "Calendar Address" label and within that you'll see a "Calendar ID". For instance, the calendar ID for "Holidays in the United States" is: Make note of your calendar ID, as you'll need it in the next step.

Adding the calendar to your website

With everything setup from the Google side, and with your GoogleClientAPI module now installed, you are ready to work with the calendar from the ProcessWire API.

You may already have a place in mind where you'd like you calendar to go, in which case start editing the appropriate template file. Otherwise, open an existing template file to test with, or create a new one. For instance, I have created /site/templates/calendar.php, and likewise created a page called /calendar/ in my site that uses this template.

The following code in your template file will enable you to list events from the calendar. Note the first line with the Calendar ID, which you should copy/paste from Google Calendar. Or if using the primary calendar, you should make your $calendarID be 'primary'.

$calendarID = '';
$google = $modules->get('GoogleClientAPI');
$events = $google->getCalendarEvents($calendarID);
echo "<h3>Upcoming events</h3><ul>";
foreach($events->getItems() as $event) {
  $summary = $sanitizer->entities($event->getSummary());
  $date = $event->start->dateTime; // date AND time
  if(empty($date)) $date = $event->start->date; // just date
  echo "<li>$summary ($date)</li>";
echo "</ul>";

The above is a really simple example of using Google's Client API to list events in a calendar, but of course much more is possible. After implementing calendars with it on a few sites, I found a lot of things that could be further simplified and abstracted from Google's API, and have included a new module for that purpose called MarkupGoogleCalendar. It's included with the GoogleClientAPI module as an example of implementation. We'll take a look at using that module next.

Calendars made easy: the MarkupGoogleCalendar module

The MarkupGoogleCalendar module comes with the GoogleClientAPI module and serves as a demonstration of using the Google Client API. However, if you are implementing a calendar in your site, I think you'll find it much nicer and simpler to use the MarkupGoogleCalendar module rather than the GoogleClientAPI module directly. That's because it handles most of the mundane details like date conversions, entity encoding, and converting events to markup.

Note that the MarkupGoogleCalendar module uses the GoogleClientAPI module, it just abstracts a lot of the usual work away so that implementing a calendar becomes even simpler. Here's how to use the MarkupGoogleCalendar module:

1. Install the MarkupGoogleCalendar module

  • In your ProcessWire admin, go to Modules > Site > Markup > Google Calendar.

  • Click the "Install" button.

2. Copy the event template file (optional, recommended):

3. Add the Calendar API code to a template file

Open any template file where you want to place the calendar output, and add the following:

$cal = $modules->get('MarkupGoogleCalendar');
$cal->calendarID = '';
echo $cal->renderUpcoming(10); 

The above would render the next 10 upcoming events. Change out the 'calendarID' to be the ID of the calendar you want to display.

4. Take a look at that /site/templates/_mgc-event.php file

  • Each event that you see output from the example above is output using the markup from this file.

  • Feel free to adjust the markup in this file to be whatever you'd like.

  • The default markup outputs an event using the HTML5 Event type in RDFa format, but you can make it output the event however you'd like.

5. Want to render all the events for a given month?

Here's how you'd do that for the month of April 2016:

echo $cal->renderMonth(4, 2016);

There is a lot more you can do with MarkupGoogleCalendar! The module includes several other convenience methods and properties that you can customize, so be sure to take a look at the module documentation if you decide to use it.

More on ProcessWire and Composer

Analyzing the benefits

The tutorial above begins by guiding you through installing a ProcessWire module with Composer, something that is new with ProcessWire 3.x. (Though it was possible in previous versions of ProcessWire as well, with a little more setup on your part.)

This installation method made a lot of sense for the GoogleClientAPI module because it has dependencies on Google's official google-api-php-client library, which in turn has several dependencies of it's own. But we didn't have to bundle any of these dependencies with the GoogleClientAPI module, nor did you have to install them yourself. Instead, Composer took care of all of it, and it will likewise take care of keeping them up-to-date. That's where Composer really starts to become compelling.

Admittedly, there aren't a lot of modules that have these kinds of dependencies in ProcessWire. But I've been looking for a good opportunity to explore how such a scenario would be handled in ProcessWire, especially since we are now officially supporting Composer in ProcessWire 3.x. The GoogleClientAPI module turned out to be a very good test and example.

If there are other current and/or future modules that also have dependencies on libraries available through Packagist, then the Composer installation method proves to be a very simple and useful way to maintain them. Though even if a module has no external dependencies, the Composer installation method is still worthwhile. I think it's something we should strive to support in all PW 3.x modules, as an alternative installation method for those that wish to use it. If you are a module developer, I'll cover how you can support it further in this post.

How is it possible to install and update modules with Composer?

Installation of modules via Composer is thanks to the handiwork of Hari KT (@harikt). He devised a clever system whereby ProcessWire modules could be installed with Composer, while stepping outside Composer's usual boundaries (related blog post). Usually when libraries are installed in Composer, it keeps them all under a /vendor/ directory off of your installation root. But when your module lists hari/pw-module as one of its dependencies, and pw-module as the "type" in the composer.json file, Composer treats the installation differently, completing the installation in ProcessWire's /site/modules/ModuleName/ rather than /vendor/.

This is the bit of magic that is taking place behind the scenes. Huge thanks to Hari KT for coming up with this Composer installation method… something that he did a couple of years ago actually. I think ProcessWire 3.x is the time for us to start putting it to good use for those that want to maintain their modules with Composer. As a result, we'll be officially documenting and supporting this installation method as an alternative from this point forward in ProcessWire 3.x.

How else might you benefit from Composer in ProcessWire?

If your site/application ever needs any external libraries available through Packagist, you can have composer maintain them for you in the same way that it did for the GoogleClientAPI module. You would just install it from the command line like you did in the tutorial above, replacing "vendor/package" with the vendor and package name of the library you want to install:

composer require vendor/package

Once you've done that, you can call upon the library from anywhere in ProcessWire, whether in your template files, modules, hooks, etc. It's basically available for your use from anywhere. And like many ProcessWire modules, it doesn't actually get loaded in memory unless you call upon it.

When will ProcessWire itself be available through Composer?

When ProcessWire 3.0 is released as the new stable branch, it will likewise become available through Packagist (and thus installable by Composer). Meaning, you'll be able to install ProcessWire like this, when it suits your need:

composer require processwire/processwire

Git tags and Packagist

Some have asked about the use of git tags on the ProcessWire core. In the past we haven't given much focus to them because there wasn't any particularly compelling reason to do so. (Other than perhaps for past version download links.) Packagist changes that, as it's the means by which it is best able to identify the version, and thus identify when something needs an update. That's a very strong reason to maintain granular tags with each version, regardless of how major or minor. So you'll see us adopting this strategy as soon as the core is on Packagist and thus installable via Composer.

Composer for module developers

We encourage all modules designed for ProcessWire 3.x to support Composer as an alternative installation method, and it's really quite simple to add this support. We'll cover the few steps necessary below.

Three easy steps + one optional step

1. Add a composer.json file as part of your module's files.

Using the following as your template/starting point:

  "name": "your-vendor-name/your-module-name",
  "type": "pw-module",
  "description": "Description of module",
  "keywords": [ "processwire", "module" ],
  "homepage": "",
  "license": "MPL-2.0",
  "authors": [
      "name": "Your Name",
      "email": "",
      "homepage": "",
      "role": "Developer"
  "require": {
    "hari/pw-module": "~1.0",

Properties above that you'll want to update specific to your module are: name, description, homepage, license, and authors. You'll also want to append any other "require" dependencies when applicable.

Note that the "type" of pw-module and the "require" line containing hari/pw-module are needed in order for the module to be installable via Composer, so make sure you keep those.

2. Upload and maintain your module at GitHub or BitBucket.

  • Most module developers already use GitHub, so this step is likely already taken care of. Otherwise you can upload and maintain your module at GitHub, BitBucket, or any repository service supported by Packagist.

  • In your repository, you'll need to maintain your module version numbers as Git tags–see the section on "Module version numbers" below for more information on how to do this.

3. Put your module on Packagist.

  • To do this, you'll need to create an account there (if you haven't already) and add your module as a package. It's quite easy and it'll guide you through it.

  • Packagist has more information on how to submit packages here.

4. Connect Packagist with GitHub (or other service).

  • This step is optional but recommended. Packagist will guide you through connecting Packagist with GitHub service hooks, so that Packagist is notified whenever you push an update to your module.

  • This ensures that Composer can see your version updates as soon as you make them, without you having to click the manual "Update" button in Packagist.

Module version numbers and Git tags

You'll have to maintain your module version number not only in your ProcessWire getModuleInfo() array, but also with Git tags. This is because Composer and Packagist don't know about the ProcessWire module conventions, and instead can use Git tags in order to identify version numbers. You'll want to use Semantic Versioning, or something that looks like it, which means versions in the format 1.2.3 or v1.2.3. The following is quoted from

The easiest way to manage versioning is to just omit the version field from the composer.json file. The version numbers will then be parsed from the tag and branch names. Tag/version names should match 'X.Y.Z', or 'vX.Y.Z', with an optional suffix for RC, beta, alpha or patch versions. Here are a few examples of valid tag names:


In your module's getModuleInfo() array, if your 'version' property is using the X.Y.Z (string) version format, then you can use the same for your Git tag. If you are using an integer for your 'version' property, we suggest translating them to your Git tags as follows:

1 = 0.0.1
12 = 0.1.2
123 = 1.2.3

This is consistent with how ProcessWire translates integers to 3-part version numbers. If you outgrow the bounds of what is supported by an integer version number, you can always switch to an X.Y.Z string.

How to tag a version number for your module

To tag a version number just open a terminal window to your module source code and make sure you are on the branch/commit that you want to tag. Then type the following:

git tag 1.0.0
git push origin --tags 

The first line above adds the tag "1.0.0", which you'll want to replace with your actual version. The second line pushes it to the remote repository.

Modules directory support for Composer

Once ProcessWire 3.x is stable (or sooner if possible), the Modules directory will be updated to automatically identify composer.json files from your module repositories and indicate that as an installation option for modules that support it.


  • Netcarver


    • 8 years ago
    • 70

    Very excited to see composer support in PW at last. Glad that Hari KT's composer package allows for such easy integration too.


  • Hari KT

    Hari KT

    • 8 years ago
    • 72

    Hi Ryan,

    Thank you for the wonderful post introducing composer to processwire. And thank you for all your praise :-).

    I would like to add one more thing where you mentioned about copying the file from the module folder to the templates folder.

    If you are using composer, in the modules composer.json you can add a post-install-cmd which can do the work for you.

    Here is the reference to the documentation : .

    Thank you once again for promoting composer in the processwire ecosystem.

  • Micha Okkerman

    Micha Okkerman

    • 8 years ago
    • 11

    Great post! Can't wait to start using it.

  • Alan Bristow

    Alan Bristow

    • 8 years ago
    • 00

    Wow, this looks like a big and beautiful step for PW, thanks Ryan, Hari KT and others.

    I once used (and loved) Flourish in a PW project, I assume this would be a suitable candidate for management via Composer as it's here

    Is that right?

  • thetuningspoon


    • 8 years ago
    • 10

    I have not used Composer, but I did recently go through the process on one of our recent sites of manually setting up a Google Calendar connection as described above.

    This is probably a dumb question, but if Composer is auto-updating code in the background without my say-so, wouldn't that be more likely to break my site?

  • Hari KT

    Hari KT

    • 8 years ago
    • 00

    @THETUNINGSPOON not really. That is where is to help you. So if the api breaks increase the version number.

    Something like X.Y.Z => Major(Feature).Minor(Feature).BugFix etc.


Latest news

  • ProcessWire Weekly #518
    The 518th issue of ProcessWire Weekly brings in all the latest news from the ProcessWire community. Modules, sites, and more. Read on! / 13 April 2024
  • ProFields Table Field with Actions support
    This week we have some updates for the ProFields table field (FieldtypeTable). These updates are primarily focused on adding new tools for the editor to facilitate input and management of content in a table field.
    Blog / 12 April 2024
  • Subscribe to weekly ProcessWire news

“…building with ProcessWire was a breeze, I really love all the flexibility the system provides. I can’t imagine using any other CMS in the future.” —Thomas Aull