Add C API to retrieve matched rules from a transaction

headers/modsecurity/transaction.h

@@ -739,6 +739,12 @@
 /** @ingroup ModSecurity_C_API */
 int msc_set_request_hostname(Transaction *transaction, const unsigned char *hostname);
 
+/** @ingroup ModSecurity_C_API */
+size_t msc_get_matched_rules_count(Transaction *transaction);
+
+/** @ingroup ModSecurity_C_API */
+int64_t msc_get_matched_rule_id(Transaction *transaction, size_t index);
+
 #ifdef __cplusplus
 }
 }  // namespace modsecurity

src/transaction.cc

@@ -28,6 +28,7 @@
 #include <fstream>
 #include <iomanip>
 #include <iostream>
+#include <iterator>
 #include <set>
 #include <unordered_map>
 #include <vector>
@@ -2325,5 +2326,47 @@
 }
 
 
+/**
+ * @name    msc_get_matched_rules_count
+ * @brief   Retrieve the number of matched rules on a transaction.
+ *
+ * Returns the number of rule-match records held on the transaction.
+ * Every rule that matched (disruptive or not) contributes one entry.
+ *
+ * @param transaction ModSecurity transaction.
+ *
+ * @returns The number of matched rule records on the transaction.
+ *
+ */
+extern "C" size_t msc_get_matched_rules_count(Transaction *transaction) {
+    return transaction->m_rulesMessages.size();
+}
+
+
+/**
+ * @name    msc_get_matched_rule_id
+ * @brief   Retrieve the rule id of the n-th matched rule.
+ *
+ * Returns the rule id of the n-th matched rule (0-based).
+ *
+ * @param transaction ModSecurity transaction.
+ * @param index       Zero-based index into the matched rule records.
+ *
+ * @returns The rule id at the given index.
+ * @retval >0 Rule id of the matched rule at the given index.
+ * @retval  0 Index is out of range.
+ *
+ */
+extern "C" int64_t msc_get_matched_rule_id(Transaction *transaction,
+    size_t index) {
+    if (index >= transaction->m_rulesMessages.size()) {
+        return 0;
+    }
+    auto it = transaction->m_rulesMessages.begin();
+    std::advance(it, index);
+    return it->m_rule.m_ruleId;
+}
+
+
 }  // namespace modsecurity