add HTTP headers referer for script manager requests

src/browser/Page.zig

@@ -171,6 +171,9 @@ url: [:0]const u8,
 // If null the url must be used.
 base_url: ?[:0]const u8,
 
+// referer header cache.
+referer_header: ?[:0]const u8,
+
 // Arbitrary buffer. Need to temporarily lowercase a value? Use this. No lifetime
 // guarantee - it's valid until someone else uses it.
 buf: [BUF_SIZE]u8,
@@ -294,6 +297,7 @@ fn reset(self: *Page, comptime initializing: bool) !void {
     self.version = 0;
     self.url = "about:blank";
     self.base_url = null;
+    self.referer_header = null;
 
     self.document = (try self._factory.document(Node.Document.HTMLDocument{ ._proto = undefined })).asDocument();
 
@@ -390,6 +394,32 @@ pub fn getOrigin(self: *Page, allocator: Allocator) !?[]const u8 {
     return try URL.getOrigin(allocator, self.url);
 }
 
+// Add comon headers for a request:
+// * cookies
+// * referer
+pub fn headersForRequest(self: *Page, temp: Allocator, url: [:0]const u8, headers: *Http.Headers) !void {
+    try self.requestCookie(.{}).headersForRequest(temp, url, headers);
+
+    // Build the referer
+    const referer = blk: {
+        if (self.referer_header == null) {
+            // build the cache
+            if (std.mem.startsWith(u8, self.url, "http")) {
+                self.referer_header = try std.mem.concatWithSentinel(self.arena, u8, &.{ "Referer: ", self.url }, 0);
+            } else {
+                self.referer_header = "";
+            }
+        }
+
+        break :blk self.referer_header.?;
+    };
+
+    // If the referer is empty, ignore the header.
+    if (referer.len > 0) {
+        try headers.add(referer);
+    }
+}
+
 const GetArenaOpts = struct {
     debug: []const u8,
 };

src/browser/ScriptManager.zig

@@ -138,6 +138,12 @@ fn clearList(list: *std.DoublyLinkedList) void {
     }
 }
 
+pub fn getHeaders(self: *ScriptManager, url: [:0]const u8) !Http.Headers {
+    var headers = try self.client.newHeaders();
+    try self.page.headersForRequest(self.page.arena, url, &headers);
+    return headers;
+}
+
 pub fn addFromElement(self: *ScriptManager, comptime from_parser: bool, script_element: *Element.Html.Script, comptime ctx: []const u8) !void {
     if (script_element._executed) {
         // If a script tag gets dynamically created and added to the dom:
@@ -252,14 +258,11 @@ pub fn addFromElement(self: *ScriptManager, comptime from_parser: bool, script_e
             script.deinit(true);
         }
 
-        var headers = try self.client.newHeaders();
-        try page.requestCookie(.{}).headersForRequest(page.arena, url, &headers);
-
         try self.client.request(.{
             .url = url,
             .ctx = script,
             .method = .GET,
-            .headers = headers,
+            .headers = try self.getHeaders(url),
             .blocking = is_blocking,
             .cookie_jar = &page._session.cookie_jar,
             .resource_type = .script,
@@ -357,9 +360,6 @@ pub fn preloadImport(self: *ScriptManager, url: [:0]const u8, referrer: []const
         .manager = self,
     };
 
-    var headers = try self.client.newHeaders();
-    try self.page.requestCookie(.{}).headersForRequest(self.page.arena, url, &headers);
-
     if (comptime IS_DEBUG) {
         var ls: js.Local.Scope = undefined;
         self.page.js.localScope(&ls);
@@ -377,7 +377,7 @@ pub fn preloadImport(self: *ScriptManager, url: [:0]const u8, referrer: []const
         .url = url,
         .ctx = script,
         .method = .GET,
-        .headers = headers,
+        .headers = try self.getHeaders(url),
         .cookie_jar = &self.page._session.cookie_jar,
         .resource_type = .script,
         .start_callback = if (log.enabled(.http, .debug)) Script.startCallback else null,
@@ -452,9 +452,6 @@ pub fn getAsyncImport(self: *ScriptManager, url: [:0]const u8, cb: ImportAsync.C
         } },
     };
 
-    var headers = try self.client.newHeaders();
-    try self.page.requestCookie(.{}).headersForRequest(self.page.arena, url, &headers);
-
     if (comptime IS_DEBUG) {
         var ls: js.Local.Scope = undefined;
         self.page.js.localScope(&ls);
@@ -480,7 +477,7 @@ pub fn getAsyncImport(self: *ScriptManager, url: [:0]const u8, cb: ImportAsync.C
     try self.client.request(.{
         .url = url,
         .method = .GET,
-        .headers = headers,
+        .headers = try self.getHeaders(url),
         .ctx = script,
         .resource_type = .script,
         .cookie_jar = &self.page._session.cookie_jar,