Separate out api url parser

src/api_url_parser.cpp

@@ -0,0 +1,115 @@
+#include "api_url_parser.hpp"
+
+#include <string_view>
+
+namespace {
+
+// A simplified helper to split a string_view, similar to std::string::find.
+// Returns a pair of views, the part before the delimiter and the part after.
+std::pair<std::string_view, std::string_view> split_view(std::string_view view,
+                                                         char delimiter) {
+  size_t pos = view.find(delimiter);
+  if (pos == std::string_view::npos) {
+    return {view, ""};
+  }
+  return {view.substr(0, pos), view.substr(pos + 1)};
+}
+
+// Maps a string parameter key to its corresponding enum value.
+// Unrecognized keys are ignored as per the design.
+[[nodiscard]] std::optional<ApiParameterKey>
+to_api_parameter_key(std::string_view key) {
+  if (key == "request_id")
+    return ApiParameterKey::RequestId;
+  if (key == "min_version")
+    return ApiParameterKey::MinVersion;
+  if (key == "wait")
+    return ApiParameterKey::Wait;
+  if (key == "timeout")
+    return ApiParameterKey::Timeout;
+  if (key == "verbose")
+    return ApiParameterKey::Verbose;
+  return std::nullopt;
+}
+
+// Parses the query string part of a URL.
+void parse_query_string(std::string_view query_string, RouteMatch &match) {
+  while (!query_string.empty()) {
+    auto [key_value_pair, rest] = split_view(query_string, '&');
+    auto [key, value] = split_view(key_value_pair, '=');
+
+    if (auto key_enum = to_api_parameter_key(key)) {
+      match.params[static_cast<size_t>(*key_enum)] = value;
+    }
+
+    query_string = rest;
+  }
+}
+
+} // namespace
+
+RouteMatch ApiUrlParser::parse(std::string_view method, std::string_view url) {
+  RouteMatch result;
+
+  auto [path, query] = split_view(url, '?');
+  parse_query_string(query, result);
+
+  if (method == "GET") {
+    if (path == "/v1/version") {
+      result.route = HttpRoute::GetVersion;
+      return result;
+    }
+    if (path == "/v1/subscribe") {
+      result.route = HttpRoute::GetSubscribe;
+      return result;
+    }
+    if (path == "/v1/status") {
+      result.route = HttpRoute::GetStatus;
+      return result;
+    }
+    if (path.starts_with("/v1/retention")) {
+      result.route = HttpRoute::GetRetention;
+      // Note: This matches both /v1/retention and /v1/retention/{id}
+      // The handler will need to check for the presence of the PolicyId param.
+      if (path.length() > 13) { // length of "/v1/retention"
+        std::string_view policy_id =
+            path.substr(14); // length of "/v1/retention/"
+        if (!policy_id.empty()) {
+          result.params[static_cast<size_t>(ApiParameterKey::PolicyId)] =
+              policy_id;
+        }
+      }
+      return result;
+    }
+    if (path == "/metrics") {
+      result.route = HttpRoute::GetMetrics;
+      return result;
+    }
+    if (path == "/ok") {
+      result.route = HttpRoute::GetOk;
+      return result;
+    }
+  } else if (method == "POST") {
+    if (path == "/v1/commit") {
+      result.route = HttpRoute::PostCommit;
+      return result;
+    }
+  } else if (method == "PUT") {
+    if (path.starts_with("/v1/retention/")) {
+      result.route = HttpRoute::PutRetention;
+      std::string_view policy_id = path.substr(14);
+      result.params[static_cast<size_t>(ApiParameterKey::PolicyId)] = policy_id;
+      return result;
+    }
+  } else if (method == "DELETE") {
+    if (path.starts_with("/v1/retention/")) {
+      result.route = HttpRoute::DeleteRetention;
+      std::string_view policy_id = path.substr(14);
+      result.params[static_cast<size_t>(ApiParameterKey::PolicyId)] = policy_id;
+      return result;
+    }
+  }
+
+  result.route = HttpRoute::NotFound;
+  return result;
+}