Initial implementation

.github/workflows/tests.yaml

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+name: Tests and linting
+
+on:
+    push:
+    pull_request:
+    schedule:
+        - cron:  '0 3 * * *'
+
+jobs:
+    unit-tests:
+        runs-on: ubuntu-latest
+
+        strategy:
+            matrix:
+                php-version: ['7.4']
+                dependencies: ['']
+                include:
+                    - { php-version: '7.4', dependencies: '--prefer-lowest --prefer-stable' }
+
+        name: Unit tests - PHP ${{ matrix.dependencies }}
+
+        steps:
+            - uses: actions/checkout@v2
+
+            - name: Setup PHP
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: ${{ matrix.php-version }}
+                  extensions: json, mbstring
+                  coverage: xdebug
+
+            - name: Install dependencies
+              run: composer update --no-progress --no-interaction ${{ matrix.dependencies }}
+
+            - name: Run tests
+              run: |
+                  composer tests-ci
+
+            - name: Submit coverage to Coveralls
+              env:
+                  COVERALLS_REPO_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+                  COVERALLS_PARALLEL: true
+                  COVERALLS_FLAG_NAME: ${{ github.job }}-PHP-${{ matrix.php-version }} ${{ matrix.dependencies }}
+              run: |
+                  composer global require php-coveralls/php-coveralls
+                  ~/.composer/vendor/bin/php-coveralls --coverage_clover=./reports/clover.xml --json_path=./reports/coveralls-upload.json -v
+
+    finish-tests:
+        name: Tests finished
+        needs: [unit-tests]
+        runs-on: ubuntu-latest
+        steps:
+            - name: Notify Coveralls
+              uses: coverallsapp/github-action@master
+              with:
+                  github-token: ${{ secrets.GITHUB_TOKEN }}
+                  parallel-finished: true
+
+    codestyle:
+        name: "Code style and static analysis"
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+
+            - name: Setup PHP
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: '7.4'
+                  extensions: json, mbstring
+
+            - name: Install dependencies
+              run: composer update --no-progress
+
+            - name: Run checks
+              run: composer analyze

.gitignore

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+/bin/
+/vendor/
+composer.lock
+
+.phpunit.result.cache
+/reports/

README.md

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+LMC CQRS Handlers
+=================
+
+[![cqrs-types](https://img.shields.io/badge/cqrs-types-purple.svg)](https://github.com/lmc-eu/cqrs-types)
+[![Tests and linting](https://github.com/lmc-eu/cqrs-handler/actions/workflows/tests.yaml/badge.svg)](https://github.com/lmc-eu/cqrs-handler/actions/workflows/tests.yaml)
+[![Coverage Status](https://coveralls.io/repos/github/lmc-eu/cqrs-handler/badge.svg?branch=main)](https://coveralls.io/github/lmc-eu/cqrs-handler?branch=main)
+
+> This library contains a base implementation for [CQRS/Types](https://github.com/lmc-eu/cqrs-types).
+
+## Table of contents
+- [Installation](#installation)
+- Queries
+    - [Query Fetcher](#query-fetcher)
+    - [Query Handlers](#query-handlers)
+    - [Query](#query)
+- Commands
+    - [Command Sender](#command-sender)
+    - [Send Command Handlers](#send-command-handlers)
+    - [Command](#command)
+- [ProfilerBag](#profiler-bag)
+
+## Installation
+```shell
+composer require lmc/cqrs-handler
+```
+
+## Query Fetcher
+Base implementation for a Query Fetcher Interface (see [Types/QueryFetcherInterface](https://github.com/lmc-eu/cqrs-types#query-fetcher-interface)).
+
+It is responsible for
+- finding a Query Handler based on Query request type
+- handle all Query features
+    - caching
+        - requires an instance of `Psr\Cache\CacheItemPoolInterface`
+    - profiling
+        - requires an instance of `Lmc\Cqrs\Handler\ProfilerBag`
+- decoding a response from the Query Handler
+
+### Usage
+If you are not using a [CQRS/Bundle](https://github.com/lmc-eu/cqrs-bundle) you need to set up a Query Fetcher yourself.
+
+Minimal Initialization
+```php
+$queryFetcher = new QueryFetcher(
+    // Cache
+    false,  // disabled cache
+    null,   // no cache pool -> no caching
+
+    // Profiling
+    null    // no profiler bag -> no profiling
+);
+```
+
+Full Initialization with all features.
+```php
+$profilerBag = new ProfilerBag();
+
+$queryFetcher = new QueryFetcher(
+    // Cache
+    true,           // is cache enabled
+    $cache,         // instance of Psr\Cache\CacheItemPoolInterface
+
+    // Profiling
+    $profilerBag,   // collection of profiled information
+
+    // Custom handlers
+    // NOTE: there is multiple ways of defining handler
+    [
+        [new TopMostHandler(), PrioritizedItem::PRIORITY_HIGHEST],                      // Array definition of priority
+        new OtherHandler(),                                                             // Used with default priority of 50
+        new PrioritizedItem(new FallbackHandler(), PrioritizedItem::PRIORITY_LOWEST)    // PrioritizedItem value object definition
+    ],
+
+    // Custom response decoders
+    // NOTE: there is multiple ways of defining response decoders
+    [
+        [new TopMostDecoder(), PrioritizedItem::PRIORITY_HIGHEST],                      // Array definition of priority
+        new OtherDecoder(),                                                             // Used with default priority of 50
+        new PrioritizedItem(new FallbackDecoder(), PrioritizedItem::PRIORITY_LOWEST)    // PrioritizedItem value object definition
+    ]
+);
+```
+
+You can add handlers and decoders by `add` methods.
+```php
+$this->queryFetcher->addHandler(new MyQueryHandler(), PrioritizedItem::PRIORITY_MEDIUM);
+$this->queryFetcher->addDecoder(new MyQueryResponseDecoder(), PrioritizedItem::PRIORITY_HIGH);
+```
+
+Fetching a query
+
+You can do whatever you want with a response, we will persist a result into db, for an example or log an error.
+```php
+// with continuation
+$this->queryFetcher->fetch(
+    $query,
+    fn ($response) => $this->repository->save($response),
+    fn (\Throwable $error) => $this->logger->critical($error->getMassage())
+);
+
+// with return
+try {
+    $response = $this->queryFetcher->fetchAndReturn($query);
+    $this->repository->save($response);
+} catch (\Throwable $error) {
+    $this->logger->critical($error->getMessage());
+}
+```
+
+## Query Handlers
+It is responsible for handling a specific Query request and passing a result into `OnSuccess` callback. [See more here](https://github.com/lmc-eu/cqrs-types#query-handler-interface).
+
+### GetCachedHandler
+This handler is automatically created `QueryFetcher` and added amongst handlers with priority `80` when an instance of `CacheItemPoolInterface` is passed into `QueryFetcher`.
+
+It supports queries implementing `CacheableInterface` with `cacheTime > 0`. The second condition allows you to avoid caching in queries with `CacheableInterface` by just a cache time value.
+There is also `CacheTime::noCache()` named constructor to make it explicit.
+
+It handles a query by retrieving a result out of a cache (if the cache has the item and is `hit` (see [PSR-6](https://www.php-fig.org/psr/psr-6/) for more).
+
+### CallbackQueryHandler
+This handler supports a query with request type of `"callable"`, `"Closure"` or `"callback"` (which all stands for a `callable` request).
+
+It simply calls a created request as a function and returns a result to `OnSuccess` callback.
+
+## Query
+Query is a request which fetch a data without changing anything. [See more here](https://github.com/lmc-eu/cqrs-types#query-interface)
+
+### CachedDataQuery
+This is a predefined implementation for a Query with `CacheableInterface`.
+
+It is handy for in-app queries where you want to use cache for a result. You can also extend it and add more features.
+
+```php
+$query = new CallbackQueryHandler(
+    fn () => $this->repository->fetchData(),
+    new CacheKey('my-data-key'),
+    CacheTime::oneHour()
+);
+```
+
+### ProfiledCachedDataQuery
+This is a predefined implementation for a Query with `CacheableInterface` and `ProfileableInterface`.
+
+It is handy for in-app queries where you want to use cache for a result and also profile it. You can also extend it and add more features.
+
+```php
+$query = new ProfiledCallbackQueryHandler(
+    fn () => $this->repository->fetchData(),
+    new CacheKey('my-data-key'),
+    CacheTime::oneHour(),
+    'my-profiler-key',
+    ['additional' => 'data']  // optional
+);
+```
+
+---
+
+## Command Sender
+Base implementation for a Command Sender Interface (see [Types/CommandSenderInterface](https://github.com/lmc-eu/cqrs-types#commmand-sender-interface)).
+
+It is responsible for
+- finding a Send Command Handler based on Command request type
+- handle all Command features
+    - profiling
+        - requires an instance of `Lmc\Cqrs\Handler\ProfilerBag`
+- decoding a response from the Send Command Handler
+
+### Usage
+If you are not using a [CQRS/Bundle](https://github.com/lmc-eu/cqrs-bundle) you need to set up a Command Sender yourself.
+
+Minimal Initialization
+```php
+$commandSender = new CommandSender(
+    // Profiling
+    null    // no profiler bag -> no profiling
+);
+```
+
+Full Initialization with all features.
+```php
+$profilerBag = new ProfilerBag();
+
+$commandSender = new CommandSender(
+    // Profiling
+    $profilerBag,   // collection of profiled information
+
+    // Custom handlers
+    // NOTE: there is multiple ways of defining handler
+    [
+        [new TopMostHandler(), PrioritizedItem::PRIORITY_HIGHEST],                      // Array definition of priority
+        new OtherHandler(),                                                             // Used with default priority of 50
+        new PrioritizedItem(new FallbackHandler(), PrioritizedItem::PRIORITY_LOWEST)    // PrioritizedItem value object definition
+    ],
+
+    // Custom response decoders
+    // NOTE: there is multiple ways of defining response decoders
+    [
+        [new TopMostDecoder(), PrioritizedItem::PRIORITY_HIGHEST],                      // Array definition of priority
+        new OtherDecoder(),                                                             // Used with default priority of 50
+        new PrioritizedItem(new FallbackDecoder(), PrioritizedItem::PRIORITY_LOWEST)    // PrioritizedItem value object definition
+    ]
+);
+```
+
+You can add handlers and decoders by `add` methods.
+```php
+$this->commandSender->addHandler(new MyCommandHandler(), PrioritizedItem::PRIORITY_MEDIUM);
+$this->commandSender->addDecoder(new MyCommandResponseDecoder(), PrioritizedItem::PRIORITY_HIGH);
+```
+
+Sending a command
+
+You can do whatever you want with a response, we will persist a result into db, for an example or log an error.
+```php
+// with continuation
+$this->commandSender->send(
+    $command,
+    fn ($response) => $this->repository->save($response),
+    fn (\Throwable $error) => $this->logger->critical($error->getMassage())
+);
+
+// with return
+try {
+    $response = $this->commandSender->sendAndReturn($query);
+    $this->repository->save($response);
+} catch (\Throwable $error) {
+    $this->logger->critical($error->getMessage());
+}
+```
+
+## Send Command Handlers
+It is responsible for handling a specific Command request and passing a result into `OnSuccess` callback. [See more here](https://github.com/lmc-eu/cqrs-types#send-command-handler-interface).
+
+### CallbackSendCommandHandler
+This handler supports a command with request type of `"callable"`, `"Closure"` or `"callback"` (which all stands for a `callable` request).
+
+It simply calls a created request as a function and returns a result to `OnSuccess` callback.
+
+## Command
+Command is a request which change a data and may return result data. [See more here](https://github.com/lmc-eu/cqrs-types#command-interface)
+
+### ProfiledDataCommand
+This is a predefined implementation for a Command with `ProfileableInterface`.
+
+It is handy for in-app commands where you want to profile it. You can also extend it and add more features.
+
+```php
+$command = new ProfiledDataCommand(
+    fn () => $this->repository->fetchData(),
+    new CacheKey('my-data-key'),
+    CacheTime::oneHour(),
+    'my-profiler-key',
+    ['additional' => 'data']  // optional
+);
+```
+
+## ProfilerBag
+Service, which is a collection of all profiler information in the current request.
+If you pass it to the `QueryFetcher` or `CommandSender`, they will profile query/command implementing `ProfileableInterface` to the `ProfilerBag`.
+
+The information inside are used by a `CqrsDataCollector`, which shows them in the Symfony profiler (used in [CQRS/Bundle](https://github.com/lmc-eu/cqrs-bundle)).