# Part 3: Configuration Details and defining Plugins

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This part of the article series focuses on details of the configuration options available when using coon.core.app.Application from the coon.js-package; we will also take an extended look at configuration options for an application itself, namely how to configure controller-, application- and component- plugins globally.

In the previous part of this article series I gave an introduction to the theory behind configuration options with coon.js-driven Sencha Ext JS applications. This article assumes that you are familiar with the topics covered therein.

## Environment-specific configuration files​

Application and Package configuration files will be looked up in the resource path, followed by the folder that was configured with the coon-js-section of the application's app.json. Example (app.json):

    {        "production": {            "coon-js" : {                "resourcePath": "files",                "env": "prod"            }        },        "development": {            "coon-js" : {                "resourcePath": "files",                "env": "dev"            }        }    }

Environment-specific configuration files will always be given precedence over the default-configuration files.

Depending on the build you are using (in this case either the production- or the development-build), configuration-files will be looked up in resources/files (note that the resources-folder is the folder-name/path returned by a call to Ext.getResourcePath()).

A coon.js-Application will first query configuration files for the build that is being used (by using the name pattern [application_name].[coon-js.env].conf.json), and if that file could not be loaded and results in a HTTP error-code, loading will fall back to [application_name].conf.json. In short, environment-specific configuration files will always be given precedence over the default-configuration files.

### Layout of an application-configuration file​

An application’s configuration file needs to contain valid JSON. The configuration needs to be an object keyed under [application_name].config. For an application with the name conjoon, the structure needs to be initially laid out as follows:

    {        "conjoon": {        }    }

Note how the configuration has to be introduced with the name of the application the configuration is used in, in this case conjoon.

### Sections considered within an application configuration file​

The following sections are considered when reading out a coon.js-application configuration file:

• application: runtime related configuration for the application. Will be available via coon.core.ConfigManager.get([application_name])

• plugins: Controller-/Component-Plugins that need to be registered for various controllers and/or components

• packages: Configuration for packages used by the application. Can also be used to disable/enable packages in a given build

For dynamic package loading, coon.js queries Ext.manifest for packages which are part of the used-configuration in an application's app.json. Those packages need to have a coon-js section configured with a package-entry:

    {        "coon-js": {            "package" : {                "autoLoad" : true            }        }    }

If autoLoad is set to true, these packages will be loaded by this application implementation dynamically upon startup. If configured with the registerController-options set to true, this package's PackageController - if any - will be registered with the application, and during startup, it's preLaunchHook-method is called when the application is ready to settle into its launch()-method. If any of the registered PackageControllers preLaunchHook()-methods return false, the application's launch() will not be called.

More details on Package Controllers on how they help to modularize an application will be part of the next article in this series.

    {        "coon-js": {            "package" : {                "autoLoad" : {                    "registerController": true                }            }        }    }

## Package Configurations​

You can add individual configuration files for your packages — those files must follow the naming scheme [package_name].conf.json, and it’s generally a good idea to save them in the resources-folder as described in the previous section about the coon.js-environment variable, since this folder can serve as the root for all configuration files for your application.

Package configuration files will be considered if a package has the following section set in its package.json, or globally in the application configuration file:

    {        "coon-js": {            "package" : {                "config" : {}            }        }    }

or

    {        "coon-js": {            "package" : {                "config" : true            }        }    }

or

    {        "coon-js": {            "package" : {                "config" : "filename"            }        }    }

While the first two entries will fall back to file names given the pattern [package_name].conf.json, the last example will define the file name explicitly.

Using specific configuration files for packages instead of placing the configuration itself in their package.json can be beneficial when applying larger configurations to packages.

By default, package configuration files will be looked up in the package's resource-folder. If an additional path is specified, this path is interpreted and resolved:

• Resolving to the resource-path of the owning package:
{    "autoLoad": {        "registerController": true    },    "config": "extjs-app-webmail.conf.json"}

or

    {        "autoLoad": {            "registerController": true        },        "config": "${package.resourcePath}/extjs-app-webmail.conf.json" } • Resolving to the application’s resource-path The following resolves to resources/[coon-js.resourcePath]/extjs-app-webmail.conf.json. In this case, configuration will be read out from the resources-folder of the application, not the package itself. This spares developers the tedious task of looking up individual files throughout packages in the file system; it makes it possible to have all configuration centralized at one place, maintaining this one file with .gitignore, if necessary.  { "autoLoad": { "registerController": true }, "config": "${coon-js.resourcePath}/extjs-app-webmail.conf.json"    }

Package configuration files will completely overwrite configuration defined in the package.json-files of the owning package.

### Accessing Package Configuration during runtime​

The configuration’s data is registered with the coon.core.ConfigManager and can be queried by using calls to coon.core.ConfigManager.get([package_name].

## Configuring Plugins for PackageControllers​

coon.core.app.PackageControllers are application controllers that wire additional functionality into the coon.js-application their used with, such as automizing routing or providing navigation options to their package’s views.

They can have an arbitrary number of plugins of the type coon.core.app.plugin.ControllerPlugin which are called by the application during its preLaunchHook-process — which gets called prior to the application’s launch-method.

Regardless of the state of the return-value of a PackageController's preLaunchHook(), all registered plugins will be executed during the preLaunchHookProcess, making sure one can add additional setup instructions prior to calling a package controller’s preLaunchHook.

Figure 1 The preLaunchHookProcess() of coon.core.app.Application will visit every configured controller plugin first, but only calls each controller’s preLaunchHook() until the first “false” is detected as a return value

For registering PluginControllers, either create them and add them to the PackageController manually by using coon.core.app.PackageController#addPlugin(), or use the package’s configuration.

### Using the package’s name to automatically set up the plugin​

You can use the package-name to specify a single ControllerPlugin out of this individual package. The plugin will then be looked up in the specified package’s app-folder given the naming pattern [package-namespace].app.plugin.ControllerPlugin), or by specifying the fully qualified namespace of the ControllerPlugins to load.

Example: plug-cn_themeutil has the namespace coon.plugin.themeutil; coon.js tries to create coon.plugin.themeutil.app.plugin.ControllerPlugin during application startup; the class must therefore be defined and registered so the dependency can be properly resolved by Sencha Ext JS — this simply means that you need to make sure that the defining package of the plugin is defined as a dependency for the application itself, in either the app.json’s requires or uses-property.

    {        "coon-js": {            "package" : {                "config" : {                    "plugins" : {                        "controller" : ["plug-cn_themeutil"]                    }                }            }        }    }

The following is the same as above, but this time we specify the fqn of the plugin (coon.plugin.themeutil.app.plugin.ControllerPlugin)

    {        "coon-js": {            "package" : {                "config" : {                    "plugins" : {                        "controller" :["coon.plugin.themeutil.app.plugin.ControllerPlugin"]                    }                }            }        }    }

### Passing arguments to a controller plugin’s constructor​

A controller plugin can also be configured with arguments that get applied to the constructor of the ControllerPlugin. For specifying constructor arguments, the configuration for the controller plugin has to be an object with the keys xclass holding the fqn of the controller plugin, and args, which is an array of arguments that get passed to the plugin’s constructor.

In the following example, {property: "value"} is passed as the first argument to the plugin’s constructor:

    {        "coon-js": {            "plugins": {                "controller": [                    {                        "xclass": "conjoon.plugin.ControllerPlugin",                        "args": [                            {                                "property": "value"                            }                        ]                    }                ]            }        }    }

Note: Plugins for PackageControllers will only be registered if the PackageController itself is configured as such in the owning package’s configuration (i.e. coon-js.package.controller).

You can add as many plugins as you’d like in the configuration, and mix and match package names with fqns of the ControllerPlugins.

## Configuring Plugins for the Application​

A coon.js-application can also be configured with plugins (read: application plugins). These plugins are loaded globally into the application, and do not depend on PackageControllers per se.

The configuration of application plugins follows the same principles as configuring controller plugins when it comes to resolving dependencies, given either the package name the application plugin can be found in, or the fqn of the application plugin.

There are two (obvious) differences:

1. When not using the fqn, application plugins will be looked up given the naming pattern [package_namespace].app.plugin.ApplicationPlugin

2. application plugins must be configured in the application configuration (see the previous section in this article regarding application configuration), namely in the [application_name].plugins.application section

Example:

The following registers coon.plugin.themeutil.app.plugin.ApplicationPlugin as an application plugin for the owning application:

    {        "conjoon" : {            "plugins": {                "application" : [                    "extjs-plug-themeutil"                ]            }        }    }

## Configuring Component Plugins​

coon.jsprovides funtionality to specify component-plugins using both the application configuration or package configurations. To properly resolve component plugins as dependencies, they need to be loaded by defining them as classes owned by packages (e.g. by specifying those packages in the requires- or uses-section in the app.json) — or in any other way so the Ext JS’ microloader is aware of them. A component plugin configuration has the following key/value-pairs (and can be placed in either the application configuration or a package configuration):

• cmp: A valid component query the application uses to look up the component for which this plugin should be registered

• event: The name of the event that should be listened to for instantiating and registering the plugin

• pclass/fclass: The fqn for the plugin to use. If you are using a plugin that extends Ext.plugin.Abstract, use pclass. If you are referencing a grid-feature (i.e. extending Ext.grid.feature.Feature), use fclass

• args: An array of arguments that get passed to the constructor of the plugin

Internally, the mixin coon.core.app.plugin.ComponentPluginMixin is used by the coon.core.app.Application and coon.core.app.PackageController to manage component plugins.

Example for specifying component plugins using the application configuration
    {        "conjoon" : {            "plugins": {                "components": [                    {                        "cmp": "cn_navport-tbar",                        "pclass": "conjoon.ModeSwitchPlugin",                        "event": "beforerender",                        "args": [{"defaultMode": "dark"}]                    },                    {                        "cmp": "cn_mail-mailmessagegrid",                        "fclass": "conjoon.PreviewTextLazyLoad",                        "event": "cn_init"                    }                ]            }        }    }
Example for specifying component plugins using a package configuration
    {        "coon-js": {            "package" : {                "config" : {                    "plugins" : {                        "controller" : [                            "plug-cn_themeutil"                        ],                        "components": [                            {                                "cmp": "cn_navport-tbar",                                "pclass": "conjoon.ModeSwitchPlugin",                                "event": "beforerender",                                "args": [{"defaultMode": "dark"}]                            },                            {                                "cmp": "cn_mail-mailmessagegrid",                                "fclass": "conjoon.PreviewTextLazyLoad",                                "event": "cn_init"                            }                        ]                    }                }            }        }    }

Use Application Plugins when you want to

• add optional functionality to an application

Use Controller Plugins when you want to

• add optional functionality to a package

Use Component Plugins when you want to

• add optional functionality to a specific component

## Best practices​

It is recommended to use the packages-section of the application configuration to make sure configuration can be edited at a central place. Specifying the packages-section in the application configuration file will make sure that packages configurations defined here completely overwrite the settings found in their original package.json. Configuration of packages in the application configuration is the same as configuring packages in their associated package.json, except for section keys used.

Example for package configuration in the application configuration file
    {        "conjoon": {            "packages" : {                "extjs-app-webmail" : {                    "autoLoad": {                        "registerController": true                    },                    "config": "\${coon-js.resourcePath}/mail.conf.json"                },                "extjs-app-imapuser": {                    "autoLoad": {                        "registerController": true                    },                    "config": {                        "service": {                            "rest-imapuser": {                                "base": "https://rest-imapuser/api/v0"                            }                        }                    }                }            }        }    }

## Real world examples​

A large configurable application built with coon.js can be found in the conjoon-repository.

The next part in this article series will take a look at the concept and usage of PackageControllers.