Make the request body limit configurable (and increase the default)

src/ServerMain.cpp

@@ -122,6 +122,10 @@ int main(int argc, char** argv) {
       "variables that are unbound in the query throw an exception. These "
       "queries technically are allowed by the SPARQL standard, but typically "
       "are the result of typos and unintended by the user");
+  add("request-body-limit",
+      optionFactory.getProgramOption<"request-body-limit">(),
+      "Set the maximum size for the body of requests the server will process. "
+      "Set to zero to disable the limit.");
   po::variables_map optionsMap;
 
   try {

src/global/RuntimeParameters.h

@@ -63,6 +63,8 @@ inline auto& RuntimeParameters() {
         // Determines whether the cost estimate for a cached subtree should be
         // set to zero in query planning.
         Bool<"zero-cost-estimate-for-cached-subtree">{false},
+        // Maximum size for the body of requests that the server will process.
+        MemorySizeParameter<"request-body-limit">{1_MB},
     };
   }();
   return params;

src/util/http/HttpServer.h

@@ -10,6 +10,7 @@
 #include <future>
 
 #include "absl/cleanup/cleanup.h"
+#include "global/RuntimeParameters.h"
 #include "util/Exception.h"
 #include "util/Log.h"
 #include "util/http/HttpUtils.h"
@@ -245,11 +246,18 @@ CPP_template(typename HttpHandler, typename WebSocketHandler)(
       try {
         // Set the timeout for reading the next request.
         stream.expires_after(std::chrono::seconds(30));
-        http::request<http::string_body> req;
 
-        // Read a request
-        co_await http::async_read(stream, buffer, req,
+        // Read a request. Use a parser so that we can control the limit of the
+        // request size.
+        http::request_parser<http::string_body> requestParser;
+        auto bodyLimit =
+            RuntimeParameters().get<"request-body-limit">().getBytes();
+        requestParser.body_limit(bodyLimit == 0
+                                     ? boost::none
+                                     : boost::optional<uint64_t>(bodyLimit));
+        co_await http::async_read(stream, buffer, requestParser,
                                   boost::asio::use_awaitable);
+        http::request<http::string_body> req = requestParser.release();
 
         // Let request be handled by `WebSocketSession` if the HTTP
         // request is a WebSocket handshake