Method mapping: Added support to map HTTP methods

Author: nawaz1991

include/oas_validator.hpp

@@ -18,6 +18,7 @@
 #include <exception>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 
 class ValidatorInitExc; ///< Forward declaration for the custom exception class.
 class OASValidatorImp; ///< Forward declaration for the implementation class.
@@ -56,13 +57,29 @@ class OASValidator
 
 public:
     /**
-     * @brief Constructor that takes the path to the OAS specification file.
+     * @brief Constructor that takes the path to the OAS specification file and an optional method mapping.
+     *
      * @param oas_specs File path to the OAS specification in JSON format or JSON string containing the OAS
      * specification.
      *
-     * @note The OAS specification can be provided as a file path or as a JSON string.
+     * @param method_map An optional unordered_map where each key is an HTTP method and the value is an unordered_set
+     * of methods that can be treated as the key method. This allows certain HTTP methods to be treated as others.
+     *
+     * For example:
+     * @code
+     * std::unordered_map<std::string, std::unordered_set<std::string>> method_map = {
+     *     {"OPTIONS", {"GET", "POST", "PUT", "DELETE", "HEAD", "PATCH"}},
+     *     {"HEAD", {"GET"}} // Treat HEAD request as GET
+     * };
+     * OASValidator validator(oas_specs, method_map);
+     * @endcode
+     *
+     * @note The OAS specification can be provided as a file path or as a JSON string. If the method map is provided,
+     * it allows certain HTTP methods to be treated as others. For instance, with the mapping {"HEAD", {"GET"}},
+     * a HEAD request can be validated as the GET request, if HEAD method is not defined.
      */
-    explicit OASValidator(const std::string& oas_specs);
+    explicit OASValidator(const std::string& oas_specs,
+                          const std::unordered_map<std::string, std::unordered_set<std::string>>& method_map = {});
 
     /**
      * @brief Copy constructor.

include/oas_validator_imp.hpp

@@ -15,7 +15,8 @@
 class OASValidatorImp
 {
 public:
-    explicit OASValidatorImp(const std::string& oas_specs);
+    explicit OASValidatorImp(const std::string& oas_specs,
+                             const std::unordered_map<std::string, std::unordered_set<std::string>>& method_map = {});
     ValidationError ValidateRoute(const std::string& method, const std::string& http_path, std::string& error_msg);
     ValidationError ValidateBody(const std::string& method, const std::string& http_path, const std::string& json_body,
                                  std::string& error_msg);
@@ -45,9 +46,14 @@ class OASValidatorImp
         PathTrie path_trie{};
     };
 
+    const std::unordered_map<std::string, std::unordered_set<std::string>> method_map_;
     std::array<PerMethod, static_cast<size_t>(HttpMethod::COUNT)> oas_validators_{};
     MethodValidator method_validator_{};
 
+    ValidationError GetValidators(const std::string& method, const std::string& mapped_method,
+                                  const std::string& http_path, ValidatorsStore*& validators, std::string& error_msg,
+                                  std::unordered_map<size_t, ParamRange>* param_idxs = nullptr,
+                                  std::string* query = nullptr);
     ValidationError GetValidators(const std::string& method, const std::string& http_path, ValidatorsStore*& validators,
                                   std::string& error_msg, std::unordered_map<size_t, ParamRange>* param_idxs = nullptr,
                                   std::string* query = nullptr);

src/oas_validator.cpp

@@ -8,8 +8,9 @@
 
 #include "oas_validator_imp.hpp"
 
-OASValidator::OASValidator(const std::string& oas_specs)
-    : impl_(new OASValidatorImp(oas_specs))
+OASValidator::OASValidator(const std::string& oas_specs,
+                           const std::unordered_map<std::string, std::unordered_set<std::string>>& method_map)
+    : impl_(new OASValidatorImp(oas_specs, method_map))
 {
 }
 

src/oas_validator_imp.cpp

@@ -9,7 +9,9 @@
 #include <rapidjson/istreamwrapper.h>
 #include <sstream>
 
-OASValidatorImp::OASValidatorImp(const std::string& oas_specs)
+OASValidatorImp::OASValidatorImp(const std::string& oas_specs,
+                                 const std::unordered_map<std::string, std::unordered_set<std::string>>& method_map)
+    : method_map_(method_map)
 {
     rapidjson::Document doc;
     ParseSpecs(oas_specs, doc);
@@ -175,7 +177,30 @@ ValidationError OASValidatorImp::GetValidators(const std::string& method, const
     auto err_code = method_validator_.Validate(method, error_msg);
     CHECK_ERROR(err_code)
 
-    auto enum_method = kStringToMethod.at(method);
+    err_code = GetValidators(method, method, http_path, validators, error_msg, param_idxs, query);
+    if (ValidationError::INVALID_ROUTE == err_code) {
+        try {
+            auto mapped_methods = method_map_.at(method);
+            for (const auto& mapped_method : mapped_methods) {
+                err_code = GetValidators(method, mapped_method, http_path, validators, error_msg, param_idxs, query);
+                if (ValidationError::NONE == err_code) {
+                    return err_code;
+                }
+            }
+        } catch (const std::out_of_range&) {
+            return err_code;
+        }
+    }
+
+    return err_code;
+}
+
+ValidationError OASValidatorImp::GetValidators(const std::string& method, const std::string& mapped_method,
+                                               const std::string& http_path, ValidatorsStore*& validators,
+                                               std::string& error_msg,
+                                               std::unordered_map<size_t, ParamRange>* param_idxs, std::string* query)
+{
+    auto enum_method = kStringToMethod.at(mapped_method);
 
     auto query_pos = http_path.find('?');
     if (std::string::npos != query_pos && query) {