SSO Refactoring (#2818)

# Description of Changes

* Refactoring of SSO code around OAuth & SAML 2
* Enabling auto-login with SAML 2 via the new `SSOAutoLogin` property
* Correcting typos & general cleanup

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [x] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [x] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [x] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [x] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

src/main/java/stirling/software/SPDF/model/ApplicationProperties.java

@@ -1,5 +1,7 @@
 package stirling.software.SPDF.model;
 
+import static stirling.software.SPDF.utils.validation.Validator.*;
+
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -12,7 +14,6 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
-import java.util.stream.Collectors;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.context.annotation.Bean;
@@ -34,10 +35,11 @@ import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.SPDF.config.InstallationPathConfig;
 import stirling.software.SPDF.config.YamlPropertySourceFactory;
-import stirling.software.SPDF.model.provider.GithubProvider;
+import stirling.software.SPDF.model.exception.UnsupportedProviderException;
+import stirling.software.SPDF.model.provider.GitHubProvider;
 import stirling.software.SPDF.model.provider.GoogleProvider;
 import stirling.software.SPDF.model.provider.KeycloakProvider;
-import stirling.software.SPDF.model.provider.UnsupportedProviderException;
+import stirling.software.SPDF.model.provider.Provider;
 
 @Configuration
 @ConfigurationProperties(prefix = "")
@@ -136,13 +138,13 @@ public class ApplicationProperties {
                     || loginMethod.equalsIgnoreCase(LoginMethods.ALL.toString()));
         }
 
-        public boolean isOauth2Activ() {
+        public boolean isOauth2Active() {
             return (oauth2 != null
                     && oauth2.getEnabled()
                     && !loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString()));
         }
 
-        public boolean isSaml2Activ() {
+        public boolean isSaml2Active() {
             return (saml2 != null
                     && saml2.getEnabled()
                     && !loginMethod.equalsIgnoreCase(LoginMethods.NORMAL.toString()));
@@ -158,6 +160,7 @@ public class ApplicationProperties {
         @Setter
         @ToString
         public static class SAML2 {
+            private String provider;
             private Boolean enabled = false;
             private Boolean autoCreateUser = false;
             private Boolean blockRegistration = false;
@@ -195,7 +198,7 @@ public class ApplicationProperties {
                 }
             }
 
-            public Resource getidpCert() {
+            public Resource getIdpCert() {
                 if (idpCert == null) return null;
                 if (idpCert.startsWith("classpath:")) {
                     return new ClassPathResource(idpCert.substring("classpath:".length()));
@@ -225,12 +228,11 @@ public class ApplicationProperties {
             private Collection<String> scopes = new ArrayList<>();
             private String provider;
             private Client client = new Client();
+            private String logoutUrl;
 
             public void setScopes(String scopes) {
                 List<String> scopesList =
-                        Arrays.stream(scopes.split(","))
-                                .map(String::trim)
-                                .collect(Collectors.toList());
+                        Arrays.stream(scopes.split(",")).map(String::trim).toList();
                 this.scopes.addAll(scopesList);
             }
 
@@ -243,32 +245,31 @@ public class ApplicationProperties {
             }
 
             public boolean isSettingsValid() {
-                return isValid(this.getIssuer(), "issuer")
-                        && isValid(this.getClientId(), "clientId")
-                        && isValid(this.getClientSecret(), "clientSecret")
-                        && isValid(this.getScopes(), "scopes")
-                        && isValid(this.getUseAsUsername(), "useAsUsername");
+                return !isStringEmpty(this.getIssuer())
+                        && !isStringEmpty(this.getClientId())
+                        && !isStringEmpty(this.getClientSecret())
+                        && !isCollectionEmpty(this.getScopes())
+                        && !isStringEmpty(this.getUseAsUsername());
             }
 
             @Data
             public static class Client {
                 private GoogleProvider google = new GoogleProvider();
-                private GithubProvider github = new GithubProvider();
+                private GitHubProvider github = new GitHubProvider();
                 private KeycloakProvider keycloak = new KeycloakProvider();
 
                 public Provider get(String registrationId) throws UnsupportedProviderException {
-                    switch (registrationId.toLowerCase()) {
-                        case "google":
-                            return getGoogle();
-                        case "github":
-                            return getGithub();
-                        case "keycloak":
-                            return getKeycloak();
-                        default:
-                            throw new UnsupportedProviderException(
-                                    "Logout from the provider is not supported? Report it at"
-                                            + " https://github.com/Stirling-Tools/Stirling-PDF/issues");
-                    }
+                    return switch (registrationId.toLowerCase()) {
+                        case "google" -> getGoogle();
+                        case "github" -> getGithub();
+                        case "keycloak" -> getKeycloak();
+                        default ->
+                                throw new UnsupportedProviderException(
+                                        "Logout from the provider "
+                                                + registrationId
+                                                + " is not supported. "
+                                                + "Report it at https://github.com/Stirling-Tools/Stirling-PDF/issues");
+                    };
                 }
             }
         }
@@ -335,10 +336,10 @@ public class ApplicationProperties {
         @Override
         public String toString() {
             return """
-            Driver {
-              driverName='%s'
-            }
-            """
+                    Driver {
+                      driverName='%s'
+                    }
+                    """
                     .formatted(driverName);
         }
     }

src/main/java/stirling/software/SPDF/model/Provider.java

@@ -1,80 +0,0 @@
-package stirling.software.SPDF.model;
-
-import java.util.Collection;
-
-public class Provider implements ProviderInterface {
-    private String name;
-    private String clientName;
-
-    public String getName() {
-        return name;
-    }
-
-    public String getClientName() {
-        return clientName;
-    }
-
-    protected boolean isValid(String value, String name) {
-        if (value != null && !value.trim().isEmpty()) {
-            return true;
-        }
-        return false;
-    }
-
-    protected boolean isValid(Collection<String> value, String name) {
-        if (value != null && !value.isEmpty()) {
-            return true;
-        }
-        return false;
-    }
-
-    @Override
-    public Collection<String> getScopes() {
-        throw new UnsupportedOperationException("Unimplemented method 'getScope'");
-    }
-
-    @Override
-    public void setScopes(String scopes) {
-        throw new UnsupportedOperationException("Unimplemented method 'setScope'");
-    }
-
-    @Override
-    public String getUseAsUsername() {
-        throw new UnsupportedOperationException("Unimplemented method 'getUseAsUsername'");
-    }
-
-    @Override
-    public void setUseAsUsername(String useAsUsername) {
-        throw new UnsupportedOperationException("Unimplemented method 'setUseAsUsername'");
-    }
-
-    @Override
-    public String getIssuer() {
-        throw new UnsupportedOperationException("Unimplemented method 'getIssuer'");
-    }
-
-    @Override
-    public void setIssuer(String issuer) {
-        throw new UnsupportedOperationException("Unimplemented method 'setIssuer'");
-    }
-
-    @Override
-    public String getClientSecret() {
-        throw new UnsupportedOperationException("Unimplemented method 'getClientSecret'");
-    }
-
-    @Override
-    public void setClientSecret(String clientSecret) {
-        throw new UnsupportedOperationException("Unimplemented method 'setClientSecret'");
-    }
-
-    @Override
-    public String getClientId() {
-        throw new UnsupportedOperationException("Unimplemented method 'getClientId'");
-    }
-
-    @Override
-    public void setClientId(String clientId) {
-        throw new UnsupportedOperationException("Unimplemented method 'setClientId'");
-    }
-}

src/main/java/stirling/software/SPDF/model/ProviderInterface.java

@@ -1,26 +0,0 @@
-package stirling.software.SPDF.model;
-
-import java.util.Collection;
-
-public interface ProviderInterface {
-
-    public Collection<String> getScopes();
-
-    public void setScopes(String scopes);
-
-    public String getUseAsUsername();
-
-    public void setUseAsUsername(String useAsUsername);
-
-    public String getIssuer();
-
-    public void setIssuer(String issuer);
-
-    public String getClientSecret();
-
-    public void setClientSecret(String clientSecret);
-
-    public String getClientId();
-
-    public void setClientId(String clientId);
-}

src/main/java/stirling/software/SPDF/model/UsernameAttribute.java

@@ -0,0 +1,24 @@
+package stirling.software.SPDF.model;
+
+import lombok.Getter;
+
+@Getter
+public enum UsernameAttribute {
+    EMAIL("email"),
+    LOGIN("login"),
+    PROFILE("profile"),
+    NAME("name"),
+    USERNAME("username"),
+    NICKNAME("nickname"),
+    GIVEN_NAME("given_name"),
+    MIDDLE_NAME("middle_name"),
+    FAMILY_NAME("family_name"),
+    PREFERRED_NAME("preferred_name"),
+    PREFERRED_USERNAME("preferred_username");
+
+    private final String name;
+
+    UsernameAttribute(final String name) {
+        this.name = name;
+    }
+}

src/main/java/stirling/software/SPDF/model/exception/NoProviderFoundException.java

@@ -0,0 +1,11 @@
+package stirling.software.SPDF.model.exception;
+
+public class NoProviderFoundException extends Exception {
+    public NoProviderFoundException(String message) {
+        super(message);
+    }
+
+    public NoProviderFoundException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/stirling/software/SPDF/model/exception/UnsupportedProviderException.java

@@ -1,4 +1,4 @@
-package stirling.software.SPDF.model.provider;
+package stirling.software.SPDF.model.exception;
 
 public class UnsupportedProviderException extends Exception {
     public UnsupportedProviderException(String message) {

src/main/java/stirling/software/SPDF/model/exception/UnsupportedUsernameAttribute.java

@@ -0,0 +1,7 @@
+package stirling.software.SPDF.model.exception;
+
+public class UnsupportedUsernameAttribute extends RuntimeException {
+    public UnsupportedUsernameAttribute(String message) {
+        super(message);
+    }
+}

src/main/java/stirling/software/SPDF/model/provider/GitHubProvider.java

@@ -0,0 +1,86 @@
+package stirling.software.SPDF.model.provider;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import lombok.NoArgsConstructor;
+import stirling.software.SPDF.model.UsernameAttribute;
+
+@NoArgsConstructor
+public class GitHubProvider extends Provider {
+
+    private static final String NAME = "github";
+    private static final String CLIENT_NAME = "GitHub";
+    private static final String AUTHORIZATION_URI = "https://github.com/login/oauth/authorize";
+    private static final String TOKEN_URI = "https://github.com/login/oauth/access_token";
+    private static final String USER_INFO_URI = "https://api.github.com/user";
+
+    public GitHubProvider(
+            String clientId,
+            String clientSecret,
+            Collection<String> scopes,
+            UsernameAttribute useAsUsername) {
+        super(
+                null,
+                NAME,
+                CLIENT_NAME,
+                clientId,
+                clientSecret,
+                scopes,
+                useAsUsername != null ? useAsUsername : UsernameAttribute.LOGIN,
+                null,
+                AUTHORIZATION_URI,
+                TOKEN_URI,
+                USER_INFO_URI);
+    }
+
+    @Override
+    public String getAuthorizationUri() {
+        return AUTHORIZATION_URI;
+    }
+
+    @Override
+    public String getTokenUri() {
+        return TOKEN_URI;
+    }
+
+    @Override
+    public String getUserInfoUri() {
+        return USER_INFO_URI;
+    }
+
+    @Override
+    public String getName() {
+        return NAME;
+    }
+
+    @Override
+    public String getClientName() {
+        return CLIENT_NAME;
+    }
+
+    @Override
+    public Collection<String> getScopes() {
+        Collection<String> scopes = super.getScopes();
+
+        if (scopes == null || scopes.isEmpty()) {
+            scopes = new ArrayList<>();
+            scopes.add("read:user");
+        }
+
+        return scopes;
+    }
+
+    @Override
+    public String toString() {
+        return "GitHub [clientId="
+                + getClientId()
+                + ", clientSecret="
+                + (getClientSecret() != null && !getClientSecret().isEmpty() ? "*****" : "NULL")
+                + ", scopes="
+                + getScopes()
+                + ", useAsUsername="
+                + getUseAsUsername()
+                + "]";
+    }
+}

src/main/java/stirling/software/SPDF/model/provider/GithubProvider.java

@@ -1,114 +0,0 @@
-package stirling.software.SPDF.model.provider;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.stream.Collectors;
-
-import stirling.software.SPDF.model.Provider;
-
-public class GithubProvider extends Provider {
-
-    private static final String authorizationUri = "https://github.com/login/oauth/authorize";
-    private static final String tokenUri = "https://github.com/login/oauth/access_token";
-    private static final String userInfoUri = "https://api.github.com/user";
-    private String clientId;
-    private String clientSecret;
-    private Collection<String> scopes = new ArrayList<>();
-    private String useAsUsername = "login";
-
-    public String getAuthorizationuri() {
-        return authorizationUri;
-    }
-
-    public String getTokenuri() {
-        return tokenUri;
-    }
-
-    public String getUserinfouri() {
-        return userInfoUri;
-    }
-
-    @Override
-    public String getIssuer() {
-        return new String();
-    }
-
-    @Override
-    public void setIssuer(String issuer) {}
-
-    @Override
-    public String getClientId() {
-        return this.clientId;
-    }
-
-    @Override
-    public void setClientId(String clientId) {
-        this.clientId = clientId;
-    }
-
-    @Override
-    public String getClientSecret() {
-        return this.clientSecret;
-    }
-
-    @Override
-    public void setClientSecret(String clientSecret) {
-        this.clientSecret = clientSecret;
-    }
-
-    @Override
-    public Collection<String> getScopes() {
-        if (scopes == null || scopes.isEmpty()) {
-            scopes = new ArrayList<>();
-            scopes.add("read:user");
-        }
-        return scopes;
-    }
-
-    @Override
-    public void setScopes(String scopes) {
-        this.scopes =
-                Arrays.stream(scopes.split(",")).map(String::trim).collect(Collectors.toList());
-    }
-
-    @Override
-    public String getUseAsUsername() {
-        return this.useAsUsername;
-    }
-
-    @Override
-    public void setUseAsUsername(String useAsUsername) {
-        this.useAsUsername = useAsUsername;
-    }
-
-    @Override
-    public String toString() {
-        return "GitHub [clientId="
-                + clientId
-                + ", clientSecret="
-                + (clientSecret != null && !clientSecret.isEmpty() ? "MASKED" : "NULL")
-                + ", scopes="
-                + scopes
-                + ", useAsUsername="
-                + useAsUsername
-                + "]";
-    }
-
-    @Override
-    public String getName() {
-        return "github";
-    }
-
-    @Override
-    public String getClientName() {
-        return "GitHub";
-    }
-
-    public boolean isSettingsValid() {
-        return super.isValid(this.getClientId(), "clientId")
-                && super.isValid(this.getClientSecret(), "clientSecret")
-                && super.isValid(this.getScopes(), "scopes")
-                && isValid(this.getUseAsUsername(), "useAsUsername");
-    }
-}

src/main/java/stirling/software/SPDF/model/provider/GoogleProvider.java

@@ -1,116 +1,85 @@
 package stirling.software.SPDF.model.provider;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
-import java.util.stream.Collectors;
 
-import stirling.software.SPDF.model.Provider;
+import lombok.NoArgsConstructor;
+import stirling.software.SPDF.model.UsernameAttribute;
 
+@NoArgsConstructor
 public class GoogleProvider extends Provider {
 
-    private static final String authorizationUri = "https://accounts.google.com/o/oauth2/v2/auth";
-    private static final String tokenUri = "https://www.googleapis.com/oauth2/v4/token";
-    private static final String userInfoUri =
+    private static final String NAME = "google";
+    private static final String CLIENT_NAME = "Google";
+    private static final String AUTHORIZATION_URI = "https://accounts.google.com/o/oauth2/v2/auth";
+    private static final String TOKEN_URI = "https://www.googleapis.com/oauth2/v4/token";
+    private static final String USER_INFO_URI =
             "https://www.googleapis.com/oauth2/v3/userinfo?alt=json";
-    private String clientId;
-    private String clientSecret;
-    private Collection<String> scopes = new ArrayList<>();
-    private String useAsUsername = "email";
 
-    public String getAuthorizationuri() {
-        return authorizationUri;
+    public GoogleProvider(
+            String clientId,
+            String clientSecret,
+            Collection<String> scopes,
+            UsernameAttribute useAsUsername) {
+        super(
+                null,
+                NAME,
+                CLIENT_NAME,
+                clientId,
+                clientSecret,
+                scopes,
+                useAsUsername,
+                null,
+                AUTHORIZATION_URI,
+                TOKEN_URI,
+                USER_INFO_URI);
     }
 
-    public String getTokenuri() {
-        return tokenUri;
+    public String getAuthorizationUri() {
+        return AUTHORIZATION_URI;
     }
 
-    public String getUserinfouri() {
-        return userInfoUri;
+    public String getTokenUri() {
+        return TOKEN_URI;
+    }
+
+    public String getUserinfoUri() {
+        return USER_INFO_URI;
     }
 
     @Override
-    public String getIssuer() {
-        return new String();
+    public String getName() {
+        return NAME;
     }
 
     @Override
-    public void setIssuer(String issuer) {}
-
-    @Override
-    public String getClientId() {
-        return this.clientId;
-    }
-
-    @Override
-    public void setClientId(String clientId) {
-        this.clientId = clientId;
-    }
-
-    @Override
-    public String getClientSecret() {
-        return this.clientSecret;
-    }
-
-    @Override
-    public void setClientSecret(String clientSecret) {
-        this.clientSecret = clientSecret;
+    public String getClientName() {
+        return CLIENT_NAME;
     }
 
     @Override
     public Collection<String> getScopes() {
+        Collection<String> scopes = super.getScopes();
+
         if (scopes == null || scopes.isEmpty()) {
             scopes = new ArrayList<>();
             scopes.add("https://www.googleapis.com/auth/userinfo.email");
             scopes.add("https://www.googleapis.com/auth/userinfo.profile");
         }
+
         return scopes;
     }
 
-    @Override
-    public void setScopes(String scopes) {
-        this.scopes =
-                Arrays.stream(scopes.split(",")).map(String::trim).collect(Collectors.toList());
-    }
-
-    @Override
-    public String getUseAsUsername() {
-        return this.useAsUsername;
-    }
-
-    @Override
-    public void setUseAsUsername(String useAsUsername) {
-        this.useAsUsername = useAsUsername;
-    }
-
     @Override
     public String toString() {
         return "Google [clientId="
-                + clientId
+                + getClientId()
                 + ", clientSecret="
-                + (clientSecret != null && !clientSecret.isEmpty() ? "MASKED" : "NULL")
+                + (getClientSecret() != null && !getClientSecret().isEmpty() ? "*****" : "NULL")
                 + ", scopes="
-                + scopes
+                + getScopes()
                 + ", useAsUsername="
-                + useAsUsername
+                + getUseAsUsername()
                 + "]";
     }
-
-    @Override
-    public String getName() {
-        return "google";
-    }
-
-    @Override
-    public String getClientName() {
-        return "Google";
-    }
-
-    public boolean isSettingsValid() {
-        return super.isValid(this.getClientId(), "clientId")
-                && super.isValid(this.getClientSecret(), "clientSecret")
-                && super.isValid(this.getScopes(), "scopes")
-                && isValid(this.getUseAsUsername(), "useAsUsername");
-    }
 }

src/main/java/stirling/software/SPDF/model/provider/KeycloakProvider.java

@@ -1,106 +1,72 @@
 package stirling.software.SPDF.model.provider;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
-import java.util.stream.Collectors;
 
-import stirling.software.SPDF.model.Provider;
+import lombok.NoArgsConstructor;
+import stirling.software.SPDF.model.UsernameAttribute;
 
+@NoArgsConstructor
 public class KeycloakProvider extends Provider {
 
-    private String issuer;
-    private String clientId;
-    private String clientSecret;
-    private Collection<String> scopes = new ArrayList<>();
-    private String useAsUsername = "email";
+    private static final String NAME = "keycloak";
+    private static final String CLIENT_NAME = "Keycloak";
 
-    @Override
-    public String getIssuer() {
-        return this.issuer;
+    public KeycloakProvider(
+            String issuer,
+            String clientId,
+            String clientSecret,
+            Collection<String> scopes,
+            UsernameAttribute useAsUsername) {
+        super(
+                issuer,
+                NAME,
+                CLIENT_NAME,
+                clientId,
+                clientSecret,
+                scopes,
+                useAsUsername,
+                null,
+                null,
+                null,
+                null);
     }
 
     @Override
-    public void setIssuer(String issuer) {
-        this.issuer = issuer;
+    public String getName() {
+        return NAME;
     }
 
     @Override
-    public String getClientId() {
-        return this.clientId;
-    }
-
-    @Override
-    public void setClientId(String clientId) {
-        this.clientId = clientId;
-    }
-
-    @Override
-    public String getClientSecret() {
-        return this.clientSecret;
-    }
-
-    @Override
-    public void setClientSecret(String clientSecret) {
-        this.clientSecret = clientSecret;
+    public String getClientName() {
+        return CLIENT_NAME;
     }
 
     @Override
     public Collection<String> getScopes() {
+        Collection<String> scopes = super.getScopes();
+
         if (scopes == null || scopes.isEmpty()) {
             scopes = new ArrayList<>();
             scopes.add("profile");
             scopes.add("email");
         }
+
         return scopes;
     }
 
-    @Override
-    public void setScopes(String scopes) {
-        this.scopes =
-                Arrays.stream(scopes.split(",")).map(String::trim).collect(Collectors.toList());
-    }
-
-    @Override
-    public String getUseAsUsername() {
-        return this.useAsUsername;
-    }
-
-    @Override
-    public void setUseAsUsername(String useAsUsername) {
-        this.useAsUsername = useAsUsername;
-    }
-
     @Override
     public String toString() {
         return "Keycloak [issuer="
-                + issuer
+                + getIssuer()
                 + ", clientId="
-                + clientId
+                + getClientId()
                 + ", clientSecret="
-                + (clientSecret != null && !clientSecret.isEmpty() ? "MASKED" : "NULL")
+                + (getClientSecret() != null && !getClientSecret().isBlank() ? "*****" : "NULL")
                 + ", scopes="
-                + scopes
+                + getScopes()
                 + ", useAsUsername="
-                + useAsUsername
+                + getUseAsUsername()
                 + "]";
     }
-
-    @Override
-    public String getName() {
-        return "keycloak";
-    }
-
-    @Override
-    public String getClientName() {
-        return "Keycloak";
-    }
-
-    public boolean isSettingsValid() {
-        return isValid(this.getIssuer(), "issuer")
-                && isValid(this.getClientId(), "clientId")
-                && isValid(this.getClientSecret(), "clientSecret")
-                && isValid(this.getScopes(), "scopes")
-                && isValid(this.getUseAsUsername(), "useAsUsername");
-    }
 }

src/main/java/stirling/software/SPDF/model/provider/Provider.java

@@ -0,0 +1,134 @@
+package stirling.software.SPDF.model.provider;
+
+import static stirling.software.SPDF.model.UsernameAttribute.EMAIL;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import stirling.software.SPDF.model.UsernameAttribute;
+import stirling.software.SPDF.model.exception.UnsupportedUsernameAttribute;
+
+@Data
+@NoArgsConstructor
+public class Provider {
+
+    public static final String EXCEPTION_MESSAGE = "The attribute %s is not supported for %s.";
+
+    private String issuer;
+    private String name;
+    private String clientName;
+    private String clientId;
+    private String clientSecret;
+    private Collection<String> scopes;
+    private UsernameAttribute useAsUsername;
+    private String logoutUrl;
+    private String authorizationUri;
+    private String tokenUri;
+    private String userInfoUri;
+
+    public Provider(
+            String issuer,
+            String name,
+            String clientName,
+            String clientId,
+            String clientSecret,
+            Collection<String> scopes,
+            UsernameAttribute useAsUsername,
+            String logoutUrl,
+            String authorizationUri,
+            String tokenUri,
+            String userInfoUri) {
+        this.issuer = issuer;
+        this.name = name;
+        this.clientName = clientName;
+        this.clientId = clientId;
+        this.clientSecret = clientSecret;
+        this.scopes = scopes == null ? new ArrayList<>() : scopes;
+        this.useAsUsername =
+                useAsUsername != null ? validateUsernameAttribute(useAsUsername) : EMAIL;
+        this.logoutUrl = logoutUrl;
+        this.authorizationUri = authorizationUri;
+        this.tokenUri = tokenUri;
+        this.userInfoUri = userInfoUri;
+    }
+
+    public void setScopes(String scopes) {
+        if (scopes != null && !scopes.isBlank()) {
+            this.scopes =
+                    Arrays.stream(scopes.split(",")).map(String::trim).collect(Collectors.toList());
+        }
+    }
+
+    private UsernameAttribute validateUsernameAttribute(UsernameAttribute usernameAttribute) {
+        switch (name) {
+            case "google" -> {
+                return validateGoogleUsernameAttribute(usernameAttribute);
+            }
+            case "github" -> {
+                return validateGitHubUsernameAttribute(usernameAttribute);
+            }
+            case "keycloak" -> {
+                return validateKeycloakUsernameAttribute(usernameAttribute);
+            }
+            default -> {
+                return usernameAttribute;
+            }
+        }
+    }
+
+    private UsernameAttribute validateKeycloakUsernameAttribute(
+            UsernameAttribute usernameAttribute) {
+        switch (usernameAttribute) {
+            case EMAIL, NAME, GIVEN_NAME, FAMILY_NAME, PREFERRED_USERNAME -> {
+                return usernameAttribute;
+            }
+            default ->
+                    throw new UnsupportedUsernameAttribute(
+                            String.format(EXCEPTION_MESSAGE, usernameAttribute, clientName));
+        }
+    }
+
+    private UsernameAttribute validateGoogleUsernameAttribute(UsernameAttribute usernameAttribute) {
+        switch (usernameAttribute) {
+            case EMAIL, NAME, GIVEN_NAME, FAMILY_NAME -> {
+                return usernameAttribute;
+            }
+            default ->
+                    throw new UnsupportedUsernameAttribute(
+                            String.format(EXCEPTION_MESSAGE, usernameAttribute, clientName));
+        }
+    }
+
+    private UsernameAttribute validateGitHubUsernameAttribute(UsernameAttribute usernameAttribute) {
+        switch (usernameAttribute) {
+            case LOGIN, EMAIL, NAME -> {
+                return usernameAttribute;
+            }
+            default ->
+                    throw new UnsupportedUsernameAttribute(
+                            String.format(EXCEPTION_MESSAGE, usernameAttribute, clientName));
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "Provider [name="
+                + getName()
+                + ", clientName="
+                + getClientName()
+                + ", clientId="
+                + getClientId()
+                + ", clientSecret="
+                + (getClientSecret() != null && !getClientSecret().isEmpty() ? "*****" : "NULL")
+                + ", scopes="
+                + getScopes()
+                + ", useAsUsername="
+                + getUseAsUsername()
+                + "]";
+    }
+}