define HTTP request methods at module level outside of class

This is a refactor to prepare for matching the API of HTTPRequest
definitions in both namespaces http_bitcoin and http_libevent. In
particular, to provide a consistent return type for GetRequestMethod()
in both classes.

src/httprpc.cpp

@@ -157,7 +157,7 @@ static bool RPCAuthorized(const std::string& strAuth, std::string& strAuthUserna
 static bool HTTPReq_JSONRPC(const std::any& context, HTTPRequest* req)
 {
     // JSONRPC handles only POST
-    if (req->GetRequestMethod() != HTTPRequest::POST) {
+    if (req->GetRequestMethod() != HTTPRequestMethod::POST) {
         req->WriteReply(HTTP_BAD_METHOD, "JSONRPC server handles only POST requests");
         return false;
     }

src/httpserver.cpp

@@ -243,18 +243,18 @@ static bool InitHTTPAllowList()
 }
 
 /** HTTP request method as string - use for logging only */
-std::string RequestMethodString(HTTPRequest::RequestMethod m)
+std::string RequestMethodString(HTTPRequestMethod m)
 {
     switch (m) {
-    case HTTPRequest::GET:
+    case HTTPRequestMethod::GET:
         return "GET";
-    case HTTPRequest::POST:
+    case HTTPRequestMethod::POST:
         return "POST";
-    case HTTPRequest::HEAD:
+    case HTTPRequestMethod::HEAD:
         return "HEAD";
-    case HTTPRequest::PUT:
+    case HTTPRequestMethod::PUT:
         return "PUT";
-    case HTTPRequest::UNKNOWN:
+    case HTTPRequestMethod::UNKNOWN:
         return "unknown";
     } // no default case, so the compiler can warn about missing cases
     assert(false);
@@ -297,7 +297,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
     }
 
     // Early reject unknown HTTP methods
-    if (hreq->GetRequestMethod() == HTTPRequest::UNKNOWN) {
+    if (hreq->GetRequestMethod() == HTTPRequestMethod::UNKNOWN) {
         LogDebug(BCLog::HTTP, "HTTP request from %s rejected: Unknown HTTP request method\n",
                  hreq->GetPeer().ToStringAddrPort());
         hreq->WriteReply(HTTP_BAD_METHOD);
@@ -710,19 +710,19 @@ std::string HTTPRequest::GetURI() const
     return evhttp_request_get_uri(req);
 }
 
-HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod() const
+HTTPRequestMethod HTTPRequest::GetRequestMethod() const
 {
     switch (evhttp_request_get_command(req)) {
     case EVHTTP_REQ_GET:
-        return GET;
+        return HTTPRequestMethod::GET;
     case EVHTTP_REQ_POST:
-        return POST;
+        return HTTPRequestMethod::POST;
     case EVHTTP_REQ_HEAD:
-        return HEAD;
+        return HTTPRequestMethod::HEAD;
     case EVHTTP_REQ_PUT:
-        return PUT;
+        return HTTPRequestMethod::PUT;
     default:
-        return UNKNOWN;
+        return HTTPRequestMethod::UNKNOWN;
     }
 }
 

src/httpserver.h

@@ -37,6 +37,14 @@ struct evhttp_request;
 struct event_base;
 class CService;
 
+enum HTTPRequestMethod {
+    UNKNOWN,
+    GET,
+    POST,
+    HEAD,
+    PUT
+};
+
 namespace http_libevent {
 class HTTPRequest;
 
@@ -88,14 +96,6 @@ public:
     explicit HTTPRequest(struct evhttp_request* req, const util::SignalInterrupt& interrupt, bool replySent = false);
     ~HTTPRequest();
 
-    enum RequestMethod {
-        UNKNOWN,
-        GET,
-        POST,
-        HEAD,
-        PUT
-    };
-
     /** Get requested URI.
      */
     std::string GetURI() const;
@@ -106,7 +106,7 @@ public:
 
     /** Get request method.
      */
-    RequestMethod GetRequestMethod() const;
+    HTTPRequestMethod GetRequestMethod() const;
 
     /** Get the query parameter value from request uri for a specified key, or std::nullopt if the
      * key is not found.

src/test/fuzz/http_request.cpp

@@ -22,12 +22,13 @@
 
 extern "C" int evhttp_parse_firstline_(struct evhttp_request*, struct evbuffer*);
 extern "C" int evhttp_parse_headers_(struct evhttp_request*, struct evbuffer*);
+
+std::string RequestMethodString(HTTPRequestMethod m);
+
 FUZZ_TARGET(http_request)
 {
     using http_libevent::HTTPRequest;
 
-    std::string RequestMethodString(HTTPRequest::RequestMethod m);
-
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
     evhttp_request* evreq = evhttp_request_new(nullptr, nullptr);
     assert(evreq != nullptr);
@@ -51,7 +52,7 @@ FUZZ_TARGET(http_request)
 
     util::SignalInterrupt interrupt;
     HTTPRequest http_request{evreq, interrupt, true};
-    const HTTPRequest::RequestMethod request_method = http_request.GetRequestMethod();
+    const HTTPRequestMethod request_method = http_request.GetRequestMethod();
     (void)RequestMethodString(request_method);
     (void)http_request.GetURI();
     (void)http_request.GetHeader("Host");