# Idempotent Library for Spring MVC

**Repository Path**: booting/idem4j

## Basic Information

- **Project Name**: Idempotent Library for Spring MVC
- **Description**: Spring Boot based idempotent library
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2020-05-19
- **Last Updated**: 2022-06-06

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Idempotent Library for Spring MVC

[![Booting/Idempotent Library for Spring MVC](https://gitee.com/booting/idem4j/widgets/widget_card.svg?colors=393222,ebdfc1,fffae5,d8ca9f,393222,a28b40)](https://gitee.com/booting/idem4j)

*Jira* address : https://issues.sonatype.org/browse/OSSRH-58103

## Usage

Just put `idem4j-core` into your `pom.xml` as following:

```xml
<dependencies>
  <groupId>com.gitee.booting</groupId>
  <artifactId>idem4j-core</artifactId>
  <version>VERSION</version>
</dependencies>
```

> Please check [release](https://gitee.com/booting/idem4j/releases) for list of `VERSION`s.

To make it work, a `RedisTemplate` instance and proper mapping patterns are required. A valid configuration perhaps looks like as following:

```yaml
idem4j:
  mapping:
    '[/api/v1/hello]':
      # generator: () -> java.util.UUID.randomUUID().toString()
      fail-on-absent: true
spring:
  data:
    redis:
      host: localhost
      port: 6379
```

Which means only `/api/v1/hello` should keep idempotent. Please remember, keys of `idem4j.mapping` will be treated as regular expressions, which will be applied to `Pattern.compile()` to generate pre-compiled instances. As a example, key `/api/v1/.*` means all APIs start with `/api/v1` will be checked to keep them idempotent.

A valid request (such as `/api/v1/hello`) should have a proper header named as `X-Idempotent-Token` with a fresh token generated by calling API `/api/v1/idem4j-token` (`data` field of the response, valid in `3` minutes) as its value. Otherwise, `403` response will be returned.

> You do not need to specify `idem4j.mapping.[key].generator` if `UUID.randomUUID().toString()`(the default idempotent token generator) is enough.

## How to make a contribute?

- `fork` this repository
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- Commit your changes
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- No more action is required