1. CRUD

package store.account;

import java.util.List;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;

@FeignClient(name = "account", url = "http://account:8080")
public interface AccountController {

    @PostMapping("/account")
    public ResponseEntity<AccountOut> create(
        @RequestBody AccountIn in
    );

    @GetMapping("/account/{id}")
    public ResponseEntity<AccountOut> findById(
        @PathVariable("id") String id
    );

    @PostMapping("/account/login")
    public ResponseEntity<AccountOut> findByEmailAndPassword(
        @RequestBody AccountIn in
    );

    @GetMapping("/account")
    public ResponseEntity<List<AccountOut>> findAll();

    @DeleteMapping("/account/{id}")
    public ResponseEntity<Void> delete(
        @PathVariable("id") String id
    );

}

package store.account;

import lombok.Builder;

@Builder
public record AccountIn(
    String name,
    String email,
    String password
) {

}

package store.account;

import lombok.Builder;

@Builder
public record AccountOut(
    String id,
    String name,
    String email
) {

}

package store.account;

import lombok.Builder;
import lombok.Data;
import lombok.experimental.Accessors;

@Builder @Data @Accessors(fluent = true, chain = true)
public class Account {

    private String id;
    private String name;
    private String email;
    private String password;
    private String sha256;

}

package store.account;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableFeignClients(basePackages = {
})
@SpringBootApplication
public class AccountApplication {

    public static void main(String[] args) {
        SpringApplication.run(AccountApplication.class, args);
    }

}

package store.account;

import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;
import lombok.AllArgsConstructor;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.experimental.Accessors;

@Entity
@Table(name = "account")
@Setter @Accessors(chain = true, fluent = true)
@NoArgsConstructor @AllArgsConstructor
public class AccountModel {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.UUID)
    private String id;

    @Column(name = "name")
    private String name;

    @Column(name = "email")
    private String email;

    @Column(name = "sha256")
    private String sha256;

    public AccountModel(Account a) {
        this.id = a.id();
        this.name = a.name();
        this.email = a.email();
        this.sha256 = a.sha256();
    }

    public Account to() {
        return Account.builder()
            .id(this.id)
            .name(this.name)
            .email(this.email)
            .sha256(this.sha256)
            .build();
    }

}

package store.account;

import java.util.List;

public class AccountParser {

    public static Account to(AccountIn in) {
        return in == null ? null :
            Account.builder()
                .name(in.name())
                .email(in.email())
                .password(in.password())
                .build();
    }

    public static AccountOut to(Account a) {
        return a == null ? null :
            AccountOut.builder()
                .id(a.id())
                .name(a.name())
                .email(a.email())
                .build();
    }

    public static List<AccountOut> to(List<Account> as) {
        return as == null ? null :
            as.stream().map(AccountParser::to).toList();
    }

}

package store.account;

import java.util.Optional;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface AccountRepository extends CrudRepository<AccountModel, String> {

    AccountModel findByEmail(String email);
    Optional<AccountModel> findByEmailAndSha256(String email, String sha256);

}

package store.account;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

@RestController
public class AccountResource implements AccountController {

    @Autowired
    private AccountService accountService;

    @Override
    public ResponseEntity<AccountOut> create(AccountIn in) {
        // parser AccountIn to Account
        Account account = AccountParser.to(in);

        Account saved = accountService.create(account);

        // parser Account to AccountOut and build to
        // HATEAOS standard
        return ResponseEntity
            .created(
                ServletUriComponentsBuilder.fromCurrentRequest()
                    .path("/{id}")
                    .buildAndExpand(saved.id())
                    .toUri()
            ).body(AccountParser.to(saved));
    }

    @Override
    public ResponseEntity<AccountOut> findById(String id) {
        return ResponseEntity
            .ok(AccountParser.to(accountService.findById(id)));
    }

    @Override
    public ResponseEntity<AccountOut> findByEmailAndPassword(AccountIn in) {
        return ResponseEntity
            .ok()
            .body(AccountParser.to(
                accountService.findByEmailAndPassword(in.email(), in.password())
            ));
    }

    @Override
    public ResponseEntity<List<AccountOut>> findAll() {
        return ResponseEntity
            .ok()
            .body(AccountParser.to(accountService.findAll()));
    }

    @Override
    public ResponseEntity<Void> delete(String id) {
        return ResponseEntity
            .noContent()
            .build();
    }

}

package store.account;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.List;
import java.util.stream.StreamSupport;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;
import org.springframework.web.server.ResponseStatusException;

@Service
public class AccountService {

    private Logger looger = LoggerFactory.getLogger(AccountService.class);

    @Autowired
    private AccountRepository accountRepository;

    public Account create(Account account) {
        if (null == account.password()) {
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST,
                "Password is mandatory!"
            );
        }
        // clean special caracters
        account.password(account.password().trim());
        if (account.password().length() < 4) {
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST,
                "Password is too short!"
            );
        }
        if (null == account.email()) {
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST,
                "Email is mandatory!"
            );
        }

        if (accountRepository.findByEmail(account.email()) != null)
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST,
                "Email already have been registered!"
            );

        account.sha256(hash(account.password()));

        return accountRepository.save(
            new AccountModel(account)
        ).to();
    }

    public List<Account> findAll() {
        return StreamSupport.stream(
            accountRepository.findAll().spliterator(), false)
            .map(AccountModel::to)
            .toList();
    }

    public Account findById(String id) {
        return accountRepository.findById(id).map(AccountModel::to).orElse(null);
    }

    public Account findByEmailAndPassword(String email, String password) {
        String sha256 = hash(password);
        return accountRepository.findByEmailAndSha256(email, sha256).map(AccountModel::to).orElse(null);
    }

    public void delete(String id) {
        accountRepository.delete(new AccountModel().id(id));
    }

    private String hash(String pass) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] encodedHash = digest.digest(
                pass.getBytes(StandardCharsets.UTF_8)
            );
            return Base64.getEncoder().encodeToString(encodedHash);
        } catch (NoSuchAlgorithmException e) {
            throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, e.getMessage(), e);
        }
    }

}