37 lines
2.1 KiB
Plaintext
37 lines
2.1 KiB
Plaintext
= Idempotency
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Idempotency is the way to make sure your specific action is only executed once.
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For example, if you have a button that is supposed to send a repayment, you don’t want to repayment twice if the user clicks the button twice. Idempotency is a way to make sure that the action is only executed once.
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There are two ways to use idempotency:
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* HTTP Request with idempotency key header
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* Batch request with batch item header
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== How it works
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The `idempotency key` with `action name` and `entity name` is unique, and identify a specific command in the system.
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If no idempotency key is assigned to the request, the system will generate one for you.
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1. User send a request
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2. The system checks there are already executed commands with the same `idempotency key` and `action name` and `entity name`
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3. The action based on the result of the check
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* If the request is completed the system return with the already generated result
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* If not completed, return HTTP 409 response
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* If the request is not completed, we process the requests and store the results in the database
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== Idempotency in HTTP requests
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To achieve idempotency in HTTP requests, you can use the HTTP header from `fineract.idempotency-key-header-name` configuration variables (default `Idemptency-Key`). This header is a unique identifier for the request. If you send the same request twice, the second request will be ignored and the response from the first request will be returned.
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== Idempotency in Batch requests
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In batch requests, you can set the idempotency key for every batch item, in the batch item `header` fields. The header key is from `fineract.idempotency-key-header-name` configuration variables (default `Idemptency-Key`).
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== Result of the request
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* When the request is already executed and completed, the system will return a `x-served-from-cache` header with the value `true` in the response and return the original request body.
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* When the request is already executed but still not completed, the system will return to HTTP 409 error code
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* When the request is not executed, the system runs it normally and stores the result in the date
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