[Web] Always return -1 as body length in HTTPClientWeb

doc/classes/HTTPClient.xml

@@ -41,6 +41,7 @@
  <description>
  Returns the response's body length.
  [b]Note:[/b] Some Web servers may not send a body length. In this case, the value returned will be [code]-1[/code]. If using chunked transfer encoding, the body length will also be [code]-1[/code].
+ [b]Note:[/b] This function always returns [code]-1[/code] on the Web platform due to browsers limitations.
  </description>
  </method>
  <method name="get_response_code" qualifiers="const">

platform/web/http_client_web.cpp

@@ -149,7 +149,15 @@ Error HTTPClientWeb::get_response_headers(List<String> *r_response) {
 }
 
 int64_t HTTPClientWeb::get_response_body_length() const {
- return godot_js_fetch_body_length_get(js_id);
+ // Body length cannot be consistently retrieved from the web.
+ // Reading the "content-length" value will return a meaningless value when the response is compressed,
+ // as reading will return uncompressed chunks in any case, resulting in a mismatch between the detected
+ // body size and the actual size returned by repeatedly calling read_response_body_chunk.
+ // Additionally, while "content-length" is considered a safe CORS header, "content-encoding" is not,
+ // so using the "content-encoding" to decide if "content-length" is meaningful is not an option either.
+ // We simply must accept the fact that browsers are awful when it comes to networking APIs.
+ // See GH-47597, and GH-79327.
+ return -1;
 }
 
 PackedByteArray HTTPClientWeb::read_response_body_chunk() {

platform/web/http_client_web.h

@@ -51,7 +51,6 @@ extern int godot_js_fetch_read_headers(int p_id, void (*parse_callback)(int p_si
 extern int godot_js_fetch_read_chunk(int p_id, uint8_t *p_buf, int p_buf_size);
 extern void godot_js_fetch_free(int p_id);
 extern godot_js_fetch_state_t godot_js_fetch_state_get(int p_id);
-extern int godot_js_fetch_body_length_get(int p_id);
 extern int godot_js_fetch_http_status_get(int p_id);
 extern int godot_js_fetch_is_chunked(int p_id);
 

platform/web/js/libs/library_godot_fetch.js

@@ -50,22 +50,17 @@ const GodotFetch = {
  return;
  }
  let chunked = false;
- let bodySize = -1;
  response.headers.forEach(function (value, header) {
  const v = value.toLowerCase().trim();
  const h = header.toLowerCase().trim();
  if (h === 'transfer-encoding' && v === 'chunked') {
  chunked = true;
  }
- if (h === 'content-length') {
- bodySize = parseInt(v, 10);
- }
  });
  obj.status = response.status;
  obj.response = response;
  obj.reader = response.body.getReader();
  obj.chunked = chunked;
- obj.bodySize = bodySize;
  },
 
  onerror: function (id, err) {
@@ -87,7 +82,6 @@ const GodotFetch = {
  reading: false,
  status: 0,
  chunks: [],
- bodySize: -1,
  };
  const id = IDHandler.add(obj);
  const init = {
@@ -224,15 +218,6 @@ const GodotFetch = {
  return p_buf_size - to_read;
  },
 
- godot_js_fetch_body_length_get__sig: 'ii',
- godot_js_fetch_body_length_get: function (p_id) {
- const obj = IDHandler.get(p_id);
- if (!obj || !obj.response) {
- return -1;
- }
- return obj.bodySize;
- },
-
  godot_js_fetch_is_chunked__sig: 'ii',
  godot_js_fetch_is_chunked: function (p_id) {
  const obj = IDHandler.get(p_id);