Implement Pre Images and Post Images to support plug-in logic

Introduction:

In the world of Microsoft Power Platform Developer exams, understanding various concepts and features is crucial for success. One such concept that plays a significant role in plug-in logic is the implementation of pre-images and post-images. In this article, we will dive into the notion of pre-images and post-images, their applications, and how they can be utilized to enhance the functionality of Power Platform plug-ins.

Understanding Pre-Images:

Pre-images, also known as ‘pre-entity images,’ refer to the state of an entity record before it undergoes any changes within a plug-in execution pipeline. They provide developers with the ability to access and analyze the values of entity attributes before any modifications occur. By utilizing pre-images, developers can perform comparisons, validations, or other necessary operations based on the initial state of the record.

To retrieve pre-images, Power Platform developers can easily configure them through the Plug-in Registration tool. By selecting the "Pre-image" option when registering a step, developers can designate the entity fields they wish to retrieve, giving them access to the original values before modifications.

Applications of Pre-Images:

1. Data Validation: Pre-images enable developers to validate the initial state of records against certain conditions or business rules before any changes are made. This helps ensure data integrity and prevents unwanted modifications that may impact downstream processes.
2. Field Comparison: Pre-images can be used to compare the values of specific fields before and after changes. By analyzing the differences, developers can trigger specific actions or workflows based on these comparisons, enhancing the automation capabilities of Power Platform solutions.

Understanding Post-Images:

Post-images, also referred to as ‘post-entity images,’ contain the state of an entity record after changes have been made within the plug-in execution pipeline. They allow developers to access and analyze the modified values of entity attributes. Post-images are particularly useful when subsequent actions need to be performed based on the changes made to the record.

Similar to pre-images, post-images can be configured using the Plug-in Registration tool. By selecting the "Post-image" option during the registration process, developers can choose the relevant entity fields they wish to retrieve, providing access to the modified values.

Applications of Post-Images:

1. Trigger Additional Actions: Post-images offer developers the ability to perform additional actions based on the changes made to entity records. This could include triggering other plug-ins, workflows, or actions that are dependent on the modified data.
2. Logging and Auditing: Post-images can be used to capture and log the state of an entity record after plug-in execution. This information can be invaluable for auditing purposes, compliance requirements, or tracking historical data changes.

Conclusion:

Pre-images and post-images are essential tools that enable Microsoft Power Platform developers to enhance the functionality of plug-ins. By utilizing these images, developers can access the original and modified values of entity records, allowing for data validation, comparisons, and trigger actions based on specific conditions. Understanding the applications and configuration of pre-images and post-images is integral to passing the Power Platform Developer exams and harnessing the full power of the platform.