Avoid URL size limit in RPCs with large arguments

2 files changed, 23 insertions, 4 deletions

diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index a5ab90c5..e6c2124f 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -1137,10 +1137,17 @@ function unload() {
     }
 }
 
-function requestUri(xhr, uri, needsSig) {
+function requestUri(xhr, uri, needsSig, isRpc) {
     if (unloading)
         return;
 
+    var extraData = null;
+
+    if (isRpc && uri.length > 2000) {
+        extraData = uri.substring(2000);
+        uri = uri.substring(0, 2000);
+    }
+
     xhr.open("POST", uri, true);
     xhr.setRequestHeader("Content-type", "text/plain");
     try {
@@ -1161,7 +1168,7 @@ function requestUri(xhr, uri, needsSig) {
     }
 
     inFlight = cons(xhr, inFlight);
-    xhr.send(null);
+    xhr.send(extraData);
 }
 
 function xhrFinished(xhr) {
@@ -1211,7 +1218,7 @@ function rc(prefix, uri, parse, k, needsSig) {
         }
     };
 
-    requestUri(xhr, uri, needsSig);
+    requestUri(xhr, uri, needsSig, true);
 }
 
 function path_join(s1, s2) {
@@ -1260,7 +1267,7 @@ function listener() {
     var connect = function () {
         xhr.onreadystatechange = orsc;
         tid = window.setTimeout(onTimeout, timeout * 500);
-        requestUri(xhr, uri, false);
+        requestUri(xhr, uri, false, false);
     }
 
     orsc = function() {
diff --git a/src/cjr_print.sml b/src/cjr_print.sml
index 65344ffb..29b0f5d2 100644
--- a/src/cjr_print.sml
+++ b/src/cjr_print.sml
@@ -2971,6 +2971,18 @@ fun p_file env (ds, ps) =
                      newline,
                      string "if (*request == '/') ++request;",
                      newline,
+                     case ek of
+                         Rpc _ => box [string "if (uw_hasPostBody(ctx)) {",
+                                       newline,
+                                       box [string "uw_Basis_postBody pb = uw_getPostBody(ctx);",
+                                            newline,
+                                            string "if (pb.data[0])",
+                                            newline,
+                                            box [string "request = uw_Basis_strcat(ctx, request, pb.data);"],
+                                            newline],
+                                       string "}",
+                                       newline]
+                       | _ => box [],
                      if couldWrite ek andalso not (Settings.checkNoXsrfProtection s) then
                          box [string "{",
                               newline,