ShipStream Merchant Plugin Middleware

The ShipStream Merchant Plugin Middleware is a lightweight, abstracted version of ShipStream's production environment. With it, you can develop and test plugins destined to become integrated ShipStream WMS plugins, or use it as a standalone "middle-man" app between your systems and ShipStream.

Features

ShipStream Merchant Plugins support the following features which work exactly the same in both the middleware environment (this repository) and the production environment (ShipStream WMS).

Interact with ShipStream's Merchant API either as an embedded plugin or over https
Easily add configuration fields to the GUI
Run actions on demand
Run actions periodically via cron jobs
Respond to ShipStream events in real time (via Webhooks if using the middleware environment)
Respond to third-party webhook events and remote callbacks
Queue tasks to be executed in the background with error reporting and user-directed retries
Use state management and caching for ease of use and efficiency
Global locking to solve tricky race conditions
Perform OAuth authentication via command line or web browser

A plugin that is installed on the production environment can be configured by the user via the Merchant Panel as a "Subscription" or run in the middleware environment with a very simple installation using Docker Compose. Either way, the functionality of the plugin should be identical. While the "middleware" is intended to be mainly a development environment, you can just as well use it as the basis for your integration or as a standalone app on your own hosting environment.

Subscriptions

In the production environment a plugin runs in the context of a single merchant after being added as a "Subscription" via the ShipStream Admin or Client user interface. A merchant can have multiple subscriptions and the configuration and state data is not shared between subscriptions even if they are used by the same merchant or use the same key names (state keys are namespaced to each subscription to avoid conflicts). Keep this in mind while developing the plugin as there may be legitimate use cases for a single merchant having multiple subscriptions installed, such as if they use multiple brands names and have a separate shopping cart for each brand name.

Requirements

A fully operational development environment is provided by Docker and Docker Compose.

A publicly accessible URL is required if your plugin receives third-party webhooks or responds to events from ShipStream via ShipStream's webhooks. For development environments this can be obtained easily and for free with ngrok or localhost.run.

Windows

Developing on Windows requires bash and therefore WSL2 (Windows Subsystem for Linux) and Docker Desktop for Windows are recommended.

Mac

Developing on Mac requires Docker Desktop for Mac.

Installation

Clone this repository to a new directory and update files permissions and install dependencies:

$ git clone https://github.com/shipstream/middleware.git
$ cd middleware
$ chmod go+rwX tmp logs
$ bin/update

Setup the API connection the ShipStream instance:

$ cp app/etc/local.sample.xml app/etc/local.xml
$ chmod 666 app/etc/local.xml
$ bin/mwrun --setup-api
...
API credentials saved to /var/www/html/app/etc/local.xml

Your app/etc/local.xml file should look something like this:

<?xml version="1.0"?>
<config>
  <default>
    <middleware>
      <system>
        <base_url>http://localhost/</base_url>
        <app_title>ACME Fulfillment</app_title>
        <log>stdout</log>
        <timezone>America/New_York</timezone>
      </system>
      <api>
        <base_url>https://example.shipstream.app/api/jsonrpc/</base_url>
        <login>{your_api_username}</login>
        <password>{your_api_password}</password>
        <secret_key></secret_key>
      </api>
    </middleware>
  </default>
</config>

Clone the ShipStream_Test plugin:

$ bin/modman init
$ bin/modman clone https://github.com/shipstream/plugin-test.git
$ bin/mwrun --list-plugins
                          Plugin Code                             Plugin Name
                          -----------                             -----------
                      ShipStream_Test                             Test Plugin
$ bin/mwrun ShipStream_Test --list-actions
update_ip
     * Fetches your public IP, saves it in the remote storage, fetches it and logs it.
...

The source code for the ShipStream_Test plugin will be located at .modman/plugin-test because the bin/modman clone ... command effectively performs (cd .modman; git clone ...); bin/modman deploy .... The modman utility creates the symlinks as defined in the module's modman file so your repository files can all stay in one place for easy git workflows.

Run the update_ip action for the ShipStream_Test plugin to confirm a successful connection:

$ bin/mwrun ShipStream_Test update_ip
Agent 007's IP is x.x.x.x, last updated at 2020-01-19T14:41:23+00:00.

If you completed all of the steps above successfully, your environment is working properly and you can now start developing your plugin!

Advanced

You can use a .env file in the root of the project to set some configuration options:

DEBUG Enable for HTTP request logging and other debug features (default is disabled).
HOST_PORT Choose a different port to expose (default is 80).

HTTPS Tunnel

If you need to support events, callbacks or webhooks (all use http requests from systems not in your local development environment), you need your middleware url to be publicly accessible. One easy and free way to accomplish this is to use ngrok or localhost.run which are simple tunneling services which can expose your local development environment to a publicly-accessible https url.

The ngrok service uses its own command line interface and is more robust, while localhost.run only requires the common ssh command. Tip: Create an account with ngrok to get one free persistent subdomain which makes it easier to configure webhooks.

$ ngrok http 80

Or:

$ ssh -R 80:localhost:80 [email protected]

If you changed the HOST_PORT in your .env file you will need to specify the correct port in the ssh command:

$ source .env
$ ngrok http $HTTP_PORT

Or:

$ source .env
$ ssh -R 80:localhost:${HOST_PORT} [email protected]

Upon a successful connection, you will be given a unique domain name like 4c0dfddeedc0d8.lhr.life. On the free plans this will only last a few hours before it needs to be refreshed with a new domain name. Use this url in the app/etc/local.xml config file for the default/middleware/system/base_url value:

<?xml version="1.0"?>
<config>
    <default>
        <middleware>
            <system>
                <base_url>https://4c0dfddeedc0d8.lhr.life/</base_url>
                ...
            </system>
            ...
        </middleware>
    </default>
</config>

Note: Any time your public url changes (e.g. your proxy disconnects and you reconnect with a new randomly generated url), you will need to register or re-register a webhook for any plugins that you are developing so that you can receive the real-time events.

Update app/etc/local.xml with the new base_url value as described above.

With your https tunnel running, register a webhook for the plugin so you can receive events:

$ bin/mwrun ShipStream_Test --setup-webhook
Secret Key saved to /var/www/html/app/etc/local.xml
Webhook created for https://....

Create an order for the same merchant as your API key, wait a few seconds for the webhook to process, and check the logs for the event:

$ tail logs/webhooks.log 
2024-09-13T16:10:58+00:00 Received webhook for order:created topic with message: {"merchant_id":"9","merchant_code":"acme_inc","topic":"order:created","
$ tail logs/main.log
2024-09-13T16:10:58+00:00 Order # 1100000116 was created.

Developer Guide

The easiest way to start your own plugin is to fork the ShipStream_Test project which you would have cloned in step 3 and then rename and edit it as needed.

Debug Mode

Debug mode can be enabled in one of the following ways:

Use the DEBUG environment variable when running a command
```
$ DEBUG=1 bin/mwrun ShipStream_Test update_ip
```

Pass the --debug argument at the end of a command

$ bin/mwrun ShipStream_Test update_ip --debug

Set the DEBUG environment variable in the .env file
```
$ echo 'DEBUG=1' >> .env
```

Plugin Skeleton

The minimal required file structure from the root of the middleware directory is as follows:

app/code/community/{COMPANY_NAME}/{MODULE_NAME}
- etc
  - config.xml
  - plugin.xml
  - system.xml
- Plugin.php
app/etc/modules
- {COMPANY_NAME}_{MODULE_NAME}.xml
modman

Additional libraries and files may be added within the module directory as necessary and autoloaded using either the underscore separated path name convention for autoloading or composer autoloading.

Plugin Class

The bulk of your plugin logic will exist in a PHP class which extends Plugin_Abstract and implements Plugin Interface. These classes expose a common interface allowing the plugin to be transferable between the middleware and production environments. The file name is Plugin.php and the class name follows PSR-1 naming conventions so for example the Plugin.php file for the ShipStream_Test plugin would exist at app/code/community/ShipStream/Test/Plugin.php and contain the class definition like so:

<?php

class ShipStream_Test_Plugin extends Plugin_Abstract
{
    // ...
}

modman

Rather than mix your plugin files into the middleware environment it is recommended to use bin/modman to symlink the files into the project directories so the modman file for the ShipStream_Test plugin may look like this:

code                   app/code/community/ShipStream/Test/
ShipStream_Test.xml    app/etc/modules/

After modifying the modman file be sure to run the modman deploy command to update symlinks:

$ bin/modman deploy-all

Register Plugin

The plugin is registered to the production environment using an XML file placed in app/etc/modules named after the plugin namespace. This file is not required for the middleware environment to function.

Example file contents for app/etc/modules/ShipStream_Test.xml:

<?xml version="1.0"?>
<config>
    <modules>
        <ShipStream_Test>
            <codePool>community</codePool>
            <active>true</active>
        </ShipStream_Test>
    </modules>
</config>

config.xml

The config.xml is used to set the plugin version and the default configuration values. Here is a config.xml example for the ShipStream_Test plugin which sets the version to '0.1' and adds some default configuration values.

<?xml version="1.0"?>
<config>
    <modules>
        <ShipStream_Test>
            <version>0.1</version>
        </ShipStream_Test>
    </modules>
    <default>
        <plugin>
            <ShipStream_Test>
                <whoami>Your Name</whoami>
                <service_url>http://ipinfo.io/ip</service_url>
                <events>
                    <order>
                        <created>1</created>
                    </order>
                </events>
            </ShipStream_Test>
        </plugin>
    </default>
</config>

See the ShipStream Events section for more on the <events> node and plugin.xml for more on making the configuration accessible to the user.

plugin.xml

The plugin.xml file provides the remaining plugin metadata in the following nodes:

<info> Plugin information and feature flags (Plugin Information)
<actions> Buttons that the user can click in the UI to trigger manual actions. (Manual Actions)
<config> Form fields that will be presented to the user for configuring the subscription (Plugin Configuration > plugin.xml)
<routes> Definition of urls which should map to plugin method for receiving external requests (Third-party Remote Callbacks)
<crontab> Cron tasks which will be automatically run in the production environment (Cron Tasks)

system.xml

The system.xml file is used to define the configuration fields for the whole system rather than a specific instance of the plugin. That is, all plugin subscriptions will share the same configuration values defined in this file and only administrators will be able to set the values. This file is not always required, but is typically used for things like OAuth 2.0 app credentials or other global settings. See system.xml for more information.

Plugin Information

The plugin information is defined in the <info> node of the plugin.xml file under the correct namespace (e.g. <SchipStream_Test>).

The name, author, license and description fields may be presented to the user when creating or editing a subscription.

The <oauth> node defines if OAuth is enabled and which config nodes are required to have non-empty values in order for OAuth authentication to be attempted. See OAuth for more info.

<?xml version="1.0" encoding="utf-8"?>
<plugin>
    <ShipStream_Test>
        <info>
            <name>Test Plugin</name>
            <author>ShipStream, LLC</author>
            <license>
                <name>OSL 3.0</name>
                <url>http://opensource.org/licenses/osl-3.0.php</url>
            </license>
            <homepage>https://github.com/shipstream/plugin-test</homepage>
            <description><![CDATA[
                This is a <em>barebones</em> example to demonstrate what a plugin looks like.
            ]]></description>
            <oauth>
                <enabled>1</enabled>
                <required_config>whoami</required_config>
            </oauth>
        </info>
        <!-- ... -->
    </ShipStream_Test>
</plugin>

The plugin info can be accessed in the PHP plugin code using the getPluginInfo method:

$name = $this->getPluginInfo('info/name');
// $name = 'Test Plugin'

However, data that does not have to do with the plugin description or OAuth configuration belongs in the config.xml file (see Plugin Configuration).

Plugin Configuration

The <default> node in config.xml allows you to organize configuration that has default values but can be also manipulated by users through the ShipStream user interface.

Configuration that is highly sensitive can be encrypted in storage by defining the value with the "backend_model" attribute. Note, however that encrypted values will not be visible to users so if the configuration field does not pose a security threat by being visible to users it may be preferable to leave it unencrypted for convenience to the user.

The user interface for the configuration is defined in plugin.xml for instance-specific configuration and system.xml for global configuration using matching node names. For example, the default value for the whoami config field defined at config/default/plugin/ShipStream_Test/whoami in config.xml corresponds to the field definition at plugin/ShipStream_Test/config/whoami in plugin.xml and the default value for the fulfillment_service field defined at config/default/plugin/ShipStream_Test/fulfillment_service in config.xml corresponds to the field definition at config/sections/plugin/groups/ShipStream_Test/fields/fulfillment_service in system.xml.

Each config field definition can contain the following elements:

<label> The name of the field presented to the user
<type> The type of field presented to the user. Supported types are: 'text', 'url', 'email', 'tel', 'date', 'time', 'password', 'obscure', 'textarea', 'date', 'select', 'script'
<sort_order> The sort order of the field relative to other fields (lowest first)
<source> Required only for 'select' type fields, this is the source model for the options which is a class name containing a method with a signature like public function getOptions(Plugin_Abstract $plugin) which will return an array of options (e.g. return [['label' => 'Zero', 'value' => '0']]).
<comment> A comment that will appear below the field to give additional context to the user. May contain HTML; use CDATA to avoid character encoding issues in the XML file.

config.xml

<?xml version="1.0"?>
<config>
    <default>
        <plugin>
            <ShipStream_Test>
                <whoami>Your Name</whoami>
                <service_url>http://ipinfo.io/ip</service_url>
                <fulfillment_service>ShipStream</fulfillment_service>
                <secret_key backend_model="adminhtml/system_config_backend_encrypted"/>
            </ShipStream_Test>
        </plugin>
    </default>
</config>

plugin.xml

<?xml version="1.0" encoding="utf-8"?>
<plugin>
    <ShipStream_Test>
        <!-- ... -->
        <config>
            <whoami>
                <label>Who Am I</label>
                <type>text</type>
                <sort_order>0</sort_order>
                <comment>Enter a name. Be creative.</comment>
            </whoami>
            <service_url>
                <label>Service Url</label>
                <type>select</type>
                <source>ShipStream_Test_Source_Serviceurl</source>
                <sort_order>10</sort_order>
                <comment>Choose the service to use to discover your IP address.</comment>
            </service_url>
            <secret_key>
                <label>Secret Key</label>
                <type>obscure</type>
                <sort_order>20</sort_order>
                <comment>Just demonstrating an obscured input field.</comment>
            </secret_key>
        </config>
    </ShipStream_Test>
</plugin>

system.xml

Like plugin.xml, the fields defined in this file correspond to the default config values that may be set in config.xml and just allow the configuration to be set via the Admin UI, so it only affects the rendering of the configuration pages and not the values in any way.

<?xml version="1.0"?>
<config>
  <sections>
    <plugin>
      <groups>
        <!-- Section name must be exact same as the plugin name so that plugin code can read it -->
        <ShipStream_Test translate="label" module="plugin">
          <label>Test Plugin</label>
          <sort_order>900</sort_order>
          <show_in_default>1</show_in_default>
          <comment><model>ShipStream_Test_GroupComment</model></comment>
          <sort_fields>
            <by>label</by>
          </sort_fields>
          <fields>
            <fulfillment_service translate="label" module="plugin">
              <label>Fulfillment Service Name</label>
              <sort_order>0</sort_order> <!-- Sort order relative to other fields if sort_fields->by is not specified -->
              <show_in_default>1</show_in_default>
              <comment><![CDATA[
                            The name for the Fulfillment Service and Location to register in the Shopify store.<br/>
                            <b>Warning:</b> If this value is changed you will need to Deactivate and Activate all
                            subscriptions and all associated products and open fulfillments will be disassociated.
                            ]]></comment>
            </fulfillment_service>
          </fields>
        </ShipStream_Test>
      </groups>
    </plugin>
  </sections>
</config>

The config/sections/plugin/groups/{Plugin_Namepsace}/fields/{field_name} nodes may contain child nodes such as:

label – The label of the configuration field
sort_order – The field position inside the configuration group
frontend_type - The field input type for displaying of the form item. If a value is not specified, the text input type will be used. Common values are:
- text – Text input field
- textarea – Textarea field
- select – Dropdown field. Options for this field are retrieved from source_model
- multiselect – Multiselect field. Options for this field are retrieved from source_model
- obscure - A password input that displays only a masked value. You must also specify <backend_model>adminhtml/system_config_backend_encrypted</backend_model> for the field in system.xml and backend_model="adminhtml/system_config_backend_encrypted" for the field in config.xml.
can_be_empty – Indicates that multiselect field can contain no values selected, otherwise empty selection will not be saved
source_model – Specifies the source model that returns option list for select and multiselect fields types. List of mostly used source models:
- adminhtml/system_config_source_locale_country – returns list of localized country names
- adminhtml/system_config_source_enabledisable – return list of two options (“Enable” and “Disable”)
- adminhtml/system_config_source_notoptreq – return list of three options: ("Not", "Optional", "Required")
- adminhtml/system_config_source_yesno – return boolean options (“Yes”, “No”)
show_in_default - Should pretty much always be set to 1
tooltip – A tooltip text for the field. This text is displayed when the mouse is over the field. If you want to specify custom html block for text in tooltip, you should use tooltip_block
tooltip_block – A block class name that will be used as tooltip for this field instead of tooltip text
validate - A CSS class name that will be applied to form field. Used for validation of the field input. Some usual values:
- required-entry – validates field value as non empty
- validate-number – validates field value as numeric
- validate-email – validates field value as valid email address
comment - Text that will be displayed below the form field. Also, this field can use a comment generator model in which case you need specify the following children for it:
- model – The model class name that should implement the getCommentText() method with public access. Parameters those are passed to this method are the following:
  - $element – configuration node itself
  - $currentValue – current field value
depends – This node contains a list of dependencies of the current field to other fields. The structure of this node is very simple. The child node name is name of field on what this one depends, and the node value is value for make this field visible. For example such configuration:
```
<depends>
    <field_name>1</field_name>
</depends>
```
will add a rule for displaying of the current field only if the value of field called “field_name” equals to 1.

Activation

A plugin may optionally implement some methods which aid in initializing the plugin state when it is created, and destroying it when it is deactivated. For example, it may need to register a webhook with the integration and then unregister the webhook when it is deactivated to prevent the webhook from continuing to fire when the plugin is no longer active.

hasActivation(): bool - Return true if the activate() method needs to do anything upon activation.
activate(): string[] - Return an array of messages for the end-user.
deactivate(): string[] - Return an array of messages for the end-user.
reinstall(): array - Non-destructively update the plugin state - for example, will be run if the public url is updated so that webhooks and callbacks can be updated.

These methods can be called with the bin/mwrun cli tool but in the production environment will be called automatically based on user interactions with the GUI.

$ bin/mwrun ShipStream_Test activate

ShipStream API Calls

You may call ShipStream API methods from the plugin using the call method so there is no need to deal with an HTTP client or authentication. In production this will call methods directly and in the middleware environment there will be a synchronous HTTP request for every invocation, but the return values will be the same.

See the API Documentation for information on specific API methods and their arguments and responses.

Example:

/* @var $this Plugin_Abstract */
$inventory = $this->call('inventory.list', 'SKU-A');
// [['sku' => 'SKU-A', 'qty_advertised' => '0.0000', ...]]

HTTP Client

Use the getHttpClient method to obtain an instance of \GuzzleHttp\Client. This allows the production environment to perform proper logging and monitoring to ensure optimum functionality. The Guzzle client is very versatile, so it is recommended to wrap it as needed or use it as-is, but avoid using other http clients as they may not be supported.

/* @var $this Plugin_Abstract */
/* @var $client \GuzzleHttp\Client */
$client = $this->getHttpClient([
    'base_uri' => 'http://requestbin.net/r/chs4u8vm',
    'auth' => ['username', 'password'],
]);
$response = $client->get('/test', ['query' => ['foo' => 'bar']]);
$response->getStatusCode(); // 200

The request and response will be logged to logs/http_client.log if debug mode is enabled.

See the Guzzle Documentation for more information.

State Management

ShipStream provides a general-purpose storage mechanism to hold state data like the last time a sync was completed. Do not use this to store an unbounded number of values or values that will be "leaked" over time such as a status for every order. For example, if your plugin registers a webhook with a third-party you could store the id of the webhook so that it can be easily updated or deleted later.

This state data is properly namespaced so it cannot conflict with or be ready by other plugin subscriptions.

$this->setState('test', array(
    'my_name' => $this->getConfig('whoami'),
    'last_updated' => time(),
));

$data = $this->getState('test');
$this->log("{$data['my_name']} last updated at ".date('c', $data['last_updated']).".");

Manual Actions

Any public plugin method can be run by executing the following command in the command line specifying the plugin namespace and method name. You can also allow the user on production to trigger methods manually by defining an "action" node in the plugin.xml file which will render a button on the Subscription page.

For example, running the following console command is equivalent to the user clicking "Update IP" in the user interface, both will run the update_ip method defined in the PHP class with the proper environment context.

$ bin/mwrun ShipStream_Test update_ip

plugin.xml:

<?xml version="1.0" encoding="utf-8"?>
<plugin>
    <ShipStream_Test>
        <!-- ... -->
        <actions>
            <update_ip>
                <label>Update IP</label>
                <comment>Update the IP address stored in the plugin state data.</comment>
            </update_ip>
        </actions>
    </ShipStream_Test>
</plugin>

Hiding actions

By specifying a plugin method name in either an <if> or <unless> node for the action the presence of the button in the user interface can be disabled to hide actions that are not applicable. For example, you could hide a "Upgrade Plugin" button if the upgrade has already been performed by adding a node <unless>hasUpgradeBeenPerformed</unless> and implementing a method with the same name which returns true if the upgrade has already been performed.

Cron Tasks

If just hacking on a plugin, you do not need to schedule a crontab task; you can just run the cron task methods using mwrun as any other method. If you want to schedule a crontab task in the production environment you can do so by defining a task in plugin.xml. The available schedules are:

every_five_minutes
every_ten_minutes
every_one_hour
every_day_midnight
every_day_morning
every_day_evening

For example, the task defined in this plugin.xml file will run the method ShipStream_Test_Plugin::cronImportFulfillments every ten minutes.

<?xml version="1.0" encoding="utf-8"?>
<plugin>
    <ShipStream_Test>
        <!-- ... -->
        <crontab>
            <every_ten_minutes>
                <import_fulfillments>cronImportFulfillments</import_fulfillments>
            </every_ten_minutes>
        </crontab>
    </ShipStream_Test>
</plugin>

An important consideration when using cron tasks is to ensure that the time between tasks is significantly greater than the time required to complete the task once in a worst-case scenario. Use webhooks and events to make your integration nearly real-time where possible and use polling and batch jobs only as a fallback if possible.

If you need a cron schedule that is not provided please request it with an explanation for your use-case.

ShipStream Events

Your plugin can receive immediate notifications from ShipStream with valuable metadata which can make developing an effective integration much easier and with the end result being much more robust. The events the plugin can receive are the same as the Webhook Topics and in fact the middleware environment uses webhooks to receive these events.

Installation

To receive ShipStream Events, Callbacks and generic Webhooks in the middleware environment you will need your Docker container to be accessible by the ShipStream instance over http(s) and to know the url that can be used to reach your local environment. For example, if your ShipStream instance is local it could be http://localhost/ or if it is remote it could be your public site address or a reverse proxy running an SSH Tunnel to your localhost.

Webhook setup

Since the middleware environment runs by itself, to receive events from ShipStream you must setup a webhook in ShipStream for the events you wish to receive. The following steps will guide you through the process:

Configure the correct url for your environment in app/etc/local.xml at the middleware/system/base_url config node. This is the public url of your development environment.
Run bin/mwrun <your-plugin> --respond-url to get the full url for the webhook endpoint. This is the base url plus the path and query parameters needed to route the request.
Test that the url is reachable as expected using curl. For example: curl -X POST --data '{"topic":"order:created","message":{"unique_id":"1234"}}' -D - "$(bin/mwrun ShipStream_Test --respond-url)"
Verify that the request was received by inspecting logs/webhooks.log and logs/main.log for any errors.
Add a webhook to ShipStream at System > Plugins > Webhooks > Create Webhook using your url from step 2 with the topics that your plugin shall respond to.
Click the newly added Webhook and click "Send Test Event" to verify a successful connection
Inspect logs/webhooks.log to verify the webhook was received

If your public url changes (such as is common when using the free version of ngrok) you will need to update the Webhook Url in ShipStream accordingly (steps 1 and 2).

Subscribing to topics

To receive an event for a topic, add the XML elements into your config.xml file corresponding to the event topic you would like to receive. For example, to receive the order:created topic, your config.xml file would look like this:

<?xml version="1.0"?>
<config>
    <default>
        <plugin>
            <ShipStream_Test>
                <events>
                    <order>
                        <created>1</created>
                    </order>
                </events>
            </ShipStream_Test>
        </plugin>
    </default>
</config>

Create a method in your Plugin.php file by camel-casing the topic name and prefixing the method name with 'respond'.

class ShipStream_Test_Plugin extends Plugin_Abstract
{
    /**
     * Respond to order:created events.
     *
     * @param array $data
     */
    public function respondOrderCreated($data)
    {
        $this->log("Order # {$data['unique_id']} was created.");
    }
}

Third-party Webhooks

You may receive webhooks from third-party sources as well by defining the necessary methods which verify and handle the webhook request and payload.

The url to use when registering webhooks with a third-party can be generated using the getWebhookUrl method. An optional $method parameter allows you to ensure the url ends with a specific string or to ensure it is unique.

$url = $this->getWebhookUrl('someTopic');

Or via the CLI:

$ bin/mwrun ShipStream_Test --webhook-url

The following example demonstrates how to handle Shopify webhooks using HMAC to verify the authenticity for security:

class ShipStream_Test_Plugin extends Plugin_Abstract
{
    /**
     * Return FALSE if the webhook cannot be verified to prevent further execution
     * 
     * @param array  $query
     * @param array  $headers
     * @param string $data
     * @return bool
     */
    public function verifyWebhook($query, $headers, $data)
    {
        $calculated_hmac = base64_encode(hash_hmac('sha256', $data, $this->getConfig('oauth_api_secret'), true));
        $hmac_header = $headers['X_SHOPIFY_HMAC_SHA256'];
        return strcmp($hmac_header, $calculated_hmac) === 0;
    }

    /**
     * Return TRUE if the webhook was handled successfully.
     * 
     * @param array  $query
     * @param array  $headers
     * @param string $data
     * @return bool
     * @throws Plugin_Exception
     */
    public function handleWebhook($query, $headers, $data)
    {
        $data = @json_decode($data, TRUE);
        if (NULL === $data || json_last_error() != JSON_ERROR_NONE) {
            throw new Plugin_Exception('An error occurred while decoding JSON encoded string.');
        }

        switch (str_replace('.', '/', $query['topic']))
        {
            case 'fulfillments/create':
                $this->fulfillmentCreateWebhook($data);
                return TRUE;
        }
        return FALSE;
    }

    /**
     * Fulfillment create webhook callback
     *
     * @param string $data
     * @return void
     * @throws Plugin_Exception
     */
    public function fulfillmentCreateWebhook($fulfillmentData)
    {
        if (empty($fulfillmentData['order_id'])) {
            throw new Plugin_Exception('Unknown order id.');
        }
        $orderId       = $fulfillmentData['order_id'];
        $fulfillmentId = $fulfillmentData['id'];
        $orderName     = preg_replace('/\.\d$/', '', $fulfillmentData['name']);

        if ($fulfillmentData['status'] != 'pending') {
            $this->log(sprintf('Skipping import of fulfillment %s with status %s', $fulfillmentId, $fulfillmentData['status']));
            return;
        }

        $this->addEvent('importFulfillmentEvent', ['order_id' => $orderId, 'fulfillment_id' => $fulfillmentId, 'order_name' => $orderName]);
        $this->log(sprintf('Webhook queued import for order %s, fulfillment %s', $orderId, $fulfillmentId));
    }
}

It is important to note that many webhook systems have retries and expect to receive a success response within a short amount of time, so it is advised to use the job queue to perform any potentially long-running work in the background. The middleware environment doesn't have a real job queue mechanism, so the jobs will be executed in the foreground.

Third-party Remote Callbacks

Similarly to webhooks you can register specific callback methods which can be executed remotely. The primary difference between webhooks and remote callbacks is that the latter maps one url to a specific method and the method can return a payload in the HTTP response (vs just a 200 status).

Generate the url for the callback using getCallbackUrl and map this public method name to the plugin's PHP method using the plugin.xml file.

$url = $this->getCallbackUrl('testCallback');

plugin.xml:

<?xml version="1.0" encoding="utf-8"?>
<plugin>
    <ShipStream_Test>
        <routes>
            <testCallback>myCallbackMethod</testCallback>
        </routes>
    </ShipStream_Test>
</plugin>

class ShipStream_Test_Plugin extends Plugin_Abstract
{
    public function myCallbackMethod($query, $headers, $data)
    {
        $rawData = $data;
        try {
            $data = json_decode($data, TRUE);
            if (NULL === $data || json_last_error() != JSON_ERROR_NONE) {
                throw new Plugin_Exception('An error occurred while decoding JSON encoded string.');
            }

            // Perform data validation
            if ( ! isset($data['payload'])) {
                throw new Plugin_Exception('Invalid data format.');
            }

            // Do something...
            
            $this->resolveError($rawData);
            return json_encode(['success' => TRUE]);
        } catch (Plugin_Exception $e) {
            $this->log($e->getMessage(), self::ERR, 'myCallbackMethod.log');
        } catch (Exception $e) {
            $this->log(get_class($e).': '.$e->getMessage(), self::ERR, 'myCallbackMethod.log');
            $this->logException($e);
        }
        $this->reportError($e, $rawData, TRUE, 'My Callback');
        throw $e;
    }
}

The callback url should be automatically registered with the third-party, but you can get the url generated for testing with the following command:

$ bin/mwrun ShipStream_Test --callback-url testCallback

Error Handling and Reporting

The only exception class that should be thrown from a plugin is Plugin_Exception, all other exceptions should be caught and handled internally and re-thrown with Plugin_Exception passing the original exception as the third parameter ($previousException). These exceptions may be visible to the end users so they should not contain sensitive data, and they should be clear and descriptive to help end users understand what the problem is.

On the production environment, errors may be reported to the user through the ShipStream Admin UI and Client UI allowing the user to view the error information in a grid using the reportError method. If an error is automatically resolved due to an issue being fixed externally or by an automatic retry, your plugin should mark it as resolved using the resolveError method. Errors are identified using a hash of the raw data passed when the error is recorded so they cannot be duplicated. To mark an error resolved you must pass the same raw data that was originally passed when the error was reported.

$rawData = json_encode($data);
try {
    $this->doSomething($data);
    $this->resolveError($rawData);
} catch (Plugin_Exception $e) {
    $this->reportError($e, $rawData, TRUE, 'Do Something');
}

On the middleware environment the reportError and resolveError methods will have no effect other than to log the error to logs/errors.log.

Any methods that use the Job Queue (described below) will automatically report errors and resolve errors based on if the event callback throws an error (error is reported) or not (error is resolved). So for job queue callbacks just throw or re-throw a Plugin_Exception rather than reporting and resolving errors directly.

Job Queue

For any actions that may take a significant amount of time or need to be retried later, you should not run them directly but rather run them using the job queue using addEvent. For example, if an action discovers 100 new orders to be created, do not create them all serially in the foreground but rather create a separate job for each order so that the errors can be reported and handled for each order individually. Jobs added to the queue which resulted in an error can be viewed and retried by the user via the user interface.

$this->addEvent('importOrderEvent', [
    'order_id' => $data['id'],
    'order_uuid' => $data['uuid'],
    'order_name' => $data['order_name'],
]);
$this->log(sprintf('Queued import for order %s (%s)', $data['id'], $data['uuid']), self::DEBUG);

The first parameter is the method name which will be called and the second parameter is an array that will be converted to a Varien_Object instance and passed to the method as the first parameter. Throw an exception to indicate a failure which should be reported to the user and that can be retried by the user.

    /**
     * Import a new order
     *
     * @param Varien_Object $data
     * @throws Plugin_Exception
     */
    public function importOrderEvent(Varien_Object $data)
    {
        if ( ! $data->hasData('id')) {
            throw new Plugin_Exception('The order data is invalid.');
        }
        // import the order...
    }

An optional third parameter can be used to set a future timestamp (Unix timestamp integer) at which the event should be executed. The system does not guarantee that it is executed at this exact time, only on or after.

Instant run

In some cases you may need the job to run in the foreground but still want to take advantage of the ability to let the users retry failed jobs which is afforded by using addEvent. In this case you may use callEvent in the same manner. This injects an event into the job queue in an already running state and then immediately calls the job method in the foreground.

Global Locking

Use this sparingly!!

If you absolutely must use global locking to put certain actions in lock step with one another you can use the lock object to do so but make sure the usage is justified and the locking time is minimized as much as possible.

// Process 1
$lock = $this->getLock('my_lock_namespace');
$lock->lock();
if ( ! $lock->isLocked()) {
    $this->log('Process locked, will try again later.');
    return;
}
try {
    $this->doSomething();
} finally {
    $lock->unlock();
}

// Process 2
$lock = $this->getLock('my_lock_namespace');
$lock->lockAndBlock();
try {
    $this->doSomethingElse();
} finally {
    $lock->unlock();
}

Logging

Log information that may be valuable for debugging, both successes and failures. Don't go overboard but disk space is cheap compared to your time and conditions from a production environment are sometimes very difficult to recreate so log plenty of information without logging useless stuff.

Note, when using the recommended HTTP client the requests and responses are already logged so you do not need to add your own logging for these, just make sure debug mode is enabled.

/* @var $this Plugin_Abstract */
$this->isDebug() and $this->log('Hello log.', self::DEBUG, 'hello.log');
$this->log('Something terrible happened!', self::ERR);
try {
    // do something
} catch (Exception $e) {
    $this->logException($e);
    throw new Plugin_Exception('An unexpected error occurred while doing something.', 0, $e);
}

Caching

In situations where you have to get some expensive data for a process you can cache it so it can be used between invocations of the plugin. This data should not be considered safe in that it can be invalidated before the expiration, or it might not even be cached at all so do not try to use it as shared-memory!

Do not cache data that you cannot reasonably know that it will not become stale. For example, inventory data is ever-changing and so should not be cached but if you have a good mechanism to invalidate product data (such as a "product was updated" webhook or a fast query to get the most recently updated timestamp) then caching product data may be perfectly valid. Another example would be some metadata that changes very infrequently and the impact of using stale data is negligible.

/* @var $this Plugin_Abstract */

// Get and cache some expensive data
if (($data = $this->loadCache('some_data')) === NULL) {
    $data = $this->getExpensiveData();
    $this->saveCache('some_data', $data, 3600);
}
$this->doSomething($data);


// Get and cache some expensive data with freshness check
// Caution: This is subject to race conditions and clock skew!! 
if ($cachedTime = $this->cacheTimestamp('some_data')) {
    $latestData = $this->getExpensiveDataUpdatedTimestamp();
    if ($latestData > $cachedTime || ($data = $this->loadCache('some_data')) === NULL) {
        $data = $this->getExpensiveData();
        $this->saveCache('some_data', $data, 3600);
    }
}
$this->doSomething($data);

// Invalidate the expensive data when it is expected to be stale
$this->removeCache('some_data');

OAuth

Several OAuth methods are defined in the interface to provide an abstracted support for performing authentication workflows whereby the user authenticates and authorizes the plugin through a redirect to the third-party system with which the plugin is integrating. These methods are:

oauthHandleRedirect(request: array): void
oauthGetRedirectUrl(area: string, bypassGateway: bool): string
oauthGetConnectUrl([redirectUrl: null|string = NULL]): string
oauthGetConnectButton([connectParams: array = [...]]): string
oauthDisconnect([params: array = [...]]): void
oauthSetTokenData(accessToken: string): mixed
oauthGetTokenData(): array|null|string
oauthValidateConfig(): void
oauthTest(): string[]

Therefore, it should not be necessary in most cases to write a custom controller for each new OAuth integration as these methods should be able to handle the redirection and capture of the token data in a way that provides enough flexibility to handle any typical OAuth provider.

A rudimentary user interface is provided to render the OAuth connection button and handle the OAuth redirect and token response. Configure your plugin in app/etc/local.xml and then visit your middleware instance in a browser to see the OAuth page at <middleware/system/base_url>/oauth.php?plugin=<plugin-code>.

The page that the OAuth flow will return to is <middleware/system/base_url>/oauth.php?plugin=<plugin-code>&action=redirect. Therefore, you can test your OAuth connection by visiting the OAuth page and clicking the "Connect" button and then the app upon authenticating should redirect you to the redirect page which is handled by the plugin's oauthHandleRedirect() method.

Note, if the app makes a POST to another url after the OAuth flow is complete, you can set up a Callback to handle this. Be careful to authenticate the callback request to ensure it is coming from the app and not a malicious actor. For example, generate a random string and save it in the state data and then require that the callback include this string in the callback payload or else reject the request.

Diagnostics

A good plugin helps the user know when things are working and also when they are not. Implement the class methods hasConnectionConfig and connectionDiagnostics to provide useful information to the end user about the configuration (don't expose any sensitive credentials) and the connection status and any other important plugin information.

For example, make at least one API call to confirm the authentication actually works and show some information to prove it like a store name. You can also show important state data such as the timestamp of the last successful order sync.

Use the following command to display the diagnostics information, this will be almost exactly what the users of the web app will see:

$ bin/mwrun ShipStream_Test --diagnostics

Composer Dependencies

Composer is currently not supported but we're considering it so let us know if you have a need for it.

Name		Name	Last commit message	Last commit date
Latest commit History 85 Commits
.github/workflows		.github/workflows
app		app
assets		assets
bin		bin
docker		docker
lib		lib
logs		logs
pub		pub
tmp		tmp
views		views
.gitignore		.gitignore
README.md		README.md
composer.json		composer.json
composer.lock		composer.lock
docker-compose.yml		docker-compose.yml
run.php		run.php

ShipStream/middleware

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ShipStream Merchant Plugin Middleware

Table of Contents

Features

Subscriptions

Requirements

Windows

Mac

Installation

Advanced

HTTPS Tunnel

Developer Guide

Debug Mode

Plugin Skeleton

Plugin Class

modman

Register Plugin

config.xml

plugin.xml

system.xml

Plugin Information

Plugin Configuration

config.xml

plugin.xml

system.xml

Activation

ShipStream API Calls

HTTP Client

State Management

Manual Actions

Hiding actions

Cron Tasks

ShipStream Events

Installation

Webhook setup

Subscribing to topics

Third-party Webhooks

Third-party Remote Callbacks

Error Handling and Reporting

Job Queue

Instant run

Global Locking

Logging

Caching

OAuth

Diagnostics

Composer Dependencies

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