| = Design Overview |
| |
| NOTE: The implementation of the platform code to process commands through handlers whilst supporting maker-checker and authorisation checks is a little bit convoluted at present and is an area pin-pointed for clean up to make it easier to on board new platform developers. In the mean time below content is used to explain its workings at present. |
| |
| .CQRS |
| image::{imagesdir}/command-query.png[] |
| |
| Taking into account example shown above for the *users* resource. |
| |
| * Query: GET /users |
| * HTTPS API: retrieveAll method on *org.apache.fineract.useradministration.api.UsersApiResource* invoked |
| * UsersApiResource.retrieveAll: Check user has permission to access this resources data. |
| * UsersApiResource.retrieveAll: Use 'read service' to fetch all users data ('read services' execute simple SQL queries against Database using JDBC) |
| * UsersApiResource.retrieveAll: Data returned to converted into JSON response |
| * Command: POST /users (Note: data passed in request body) |
| * HTTPS API: create method on org.apache.fineract.useradministration.api.UsersApiResource invoked |
| |
| .UsersApiResource.create |
| [source,java] |
| ---- |
| include::{rootdir}/fineract-provider/src/main/java/org/apache/fineract/useradministration/api/UsersApiResource.java[lines=168..188] |
| ---- |
| |
| .Create a CommandWrapper object that represents this create user command and JSON request body. Pass off responsibility for processing to PortfolioCommandSourceWritePlatformService.logCommandSource |
| [source,java] |
| ---- |
| include::{rootdir}/fineract-core/src/main/java/org/apache/fineract/commands/service/PortfolioCommandSourceWritePlatformServiceImpl.java[lines=69..129] |
| ---- |
| |
| .Check user has permission for this action. if ok, a) parse the json request body, b) create a JsonCommand object to wrap the command details, c) use CommandProcessingService to handle command |
| [source,java] |
| ---- |
| include::{rootdir}/fineract-core/src/main/java/org/apache/fineract/commands/service/SynchronousCommandProcessingService.java[lines=84..150] |
| ---- |
| |
| NOTE: if a RollbackTransactionAsCommandIsNotApprovedByCheckerException occurs at this point. The original transaction will of been aborted and we only log an entry for the command in the audit table setting its status as 'Pending'. |
| |
| * Check that if maker-checker configuration enabled for this action. If yes and this is not a 'checker' approving the command - rollback at the end. We rollback at the end in order to test if the command will pass 'domain validation' which requires commit to database for full check. |
| * findCommandHandler - Find the correct Handler to process this command. |
| * Process command using handler (In transactional scope). |
| * CommandSource object created/updated with all details for logging to 'm_portfolio_command_source' table. |
| * In update scenario, we check to see if there where really any changes/updates. If so only JSON for changes is stored in audit log. |
