Initial Commit

src/main/kotlin/AccessControl.kt

@@ -0,0 +1,135 @@
+package fr.dcproject.common.security
+
+/** Responses of AccessControl */
+enum class AccessDecision {
+    GRANTED,
+    DENIED;
+
+    /**
+     * Convert decision to boolean
+     */
+    fun toBoolean(): Boolean = when (this) {
+        GRANTED -> true
+        DENIED -> false
+    }
+}
+
+abstract class AccessControl {
+    /**
+     * A Shortcut for return a GrantedResponse
+     */
+    protected fun granted(message: String? = null, code: String? = null): GrantedResponse = GrantedResponse(this, message, code)
+
+    /**
+     * A Shortcut for return a DeniedResponse
+     */
+    protected fun denied(message: String, code: String): DeniedResponse = DeniedResponse(this, message, code)
+
+    /**
+     * Check all responses and return DENIED if one is DENIED
+     *
+     * If the list of responses is empty, return GRANTED
+     */
+    private fun AccessResponses.getOneResponse(): AccessResponse = this.firstOrNull { it.decision == AccessDecision.DENIED } ?: granted()
+
+    /**
+     * A helper to convert a list of subject into one response
+     */
+    protected fun <S : List<T>, T> canAll(items: S, action: (T) -> AccessResponse): AccessResponse = items
+        .map { action(it) }
+        .getOneResponse()
+}
+
+/**
+ * Throw an Exception if AccessControl return a DENIED response
+ */
+fun <T : AccessControl> T.assert(action: T.() -> AccessResponse) {
+    action().assert()
+}
+
+/**
+ * Check all responses and return DENIED if one is DENIED
+ *
+ * If the list of responses is empty, return GRANTED
+ */
+fun AccessResponses.getOneResponse(): AccessResponse = this.firstOrNull { it.decision == AccessDecision.DENIED } ?: GrantedResponse(first().accessControl)
+
+/**
+ * Throw an Exception if one response is DENIED
+ */
+fun AccessResponses.assert() = this.getOneResponse().assert()
+
+class AccessDeniedException(private val accessResponses: AccessResponses) : Throwable(accessResponses.first().message) {
+    constructor(accessResponse: AccessResponse) : this(listOf(accessResponse))
+
+    /**
+     * Get first response
+     */
+    fun first(): AccessResponse = accessResponses.first()
+
+    /**
+     * Check if the error code is present into the responses
+     */
+    fun hasErrorCode(code: String): Boolean = accessResponses
+        .filter { it.decision == AccessDecision.DENIED }
+        .any { it.code == code }
+
+    /**
+     * Find and return the response than match with the error code
+     */
+    fun getErrorCode(code: String): AccessResponse? = accessResponses
+        .firstOrNull { it.decision == AccessDecision.DENIED && it.code == code }
+
+    /**
+     * Get a list of messages of all responses
+     */
+    fun getMessages(): List<String> = accessResponses
+        .mapNotNull { it.message }
+
+    /**
+     * Get the first message
+     */
+    fun getFirstMessage(): String? = accessResponses
+        .first()
+        .message
+}
+
+/**
+ * The response that all AccessControl method return
+ * @see GrantedResponse
+ * @see DeniedResponse
+ */
+sealed class AccessResponse(
+    val decision: AccessDecision,
+    val accessControl: AccessControl,
+    val message: String?,
+    val code: String?
+) {
+    /**
+     * Convert response as boolean
+     */
+    fun toBoolean(): Boolean = decision.toBoolean()
+
+    /**
+     * Throw Exception if response if DENIED
+     */
+    fun assert() {
+        if (this.decision == AccessDecision.DENIED) {
+            throw AccessDeniedException(this)
+        }
+    }
+}
+
+class GrantedResponse(
+    accessControl: AccessControl,
+    message: String? = null,
+    code: String? = null
+) : AccessResponse(AccessDecision.GRANTED, accessControl, message, code)
+
+class DeniedResponse(
+    accessControl: AccessControl,
+    message: String,
+    code: String
+) : AccessResponse(AccessDecision.DENIED, accessControl, message, code)
+
+typealias AccessResponses = List<AccessResponse>