CefResourceBundle

Header: cef_resource_bundle.h
Interfaces: CefResourceBundle, CefResourceBundleHandler
Category: Core APIs

Overview

Foundational interfaces: process bootstrap, browser lifecycle, frames, DOM, requests, and data objects.

CefResourceBundle

Source File: include/cef_resource_bundle.h

Process / Thread Context: Any thread (per class comment: "The methods of this class may be called on any thread unless otherwise indicated.")

Purpose: USER-CALLED library interface for retrieving resources from the resource bundle (*.pak) files loaded at startup or supplied by CefApp::GetResourceBundleHandler(). Provides localized strings and binary data resources.

Methods

static CefRefPtr<CefResourceBundle> GetGlobal()

Parameters:

• None.

Return Value: The global resource bundle instance.

Usage Instruction: Use to fetch any localized string or binary resource.

Threading Constraint: Any thread.

CefString GetLocalizedString(int string_id)

Parameters:

• string_id: numerical ID. Use cef_id_for_pack_string_name() (see cef_pack_strings.h) to map string IDR names to version-specific numerical IDs.

Return Value: Localized string, or empty if not found.

Usage Instruction: Always use cef_id_for_pack_string_name() for version-safe mapping.

Threading Constraint: Any thread.

CefRefPtr<CefBinaryValue> GetDataResource(int resource_id)

Parameters:

• resource_id: numerical ID. Use cef_id_for_pack_resource_name() for version-safe mapping (see cef_pack_resources.h).

Return Value: Decompressed scale-independent binary resource, or NULL if not found.

Usage Instruction: Use for non-scaled resources (icons, scripts, fonts, etc.).

Threading Constraint: Any thread.

CefRefPtr<CefBinaryValue> GetDataResourceForScale(int resource_id, ScaleFactor scale_factor)

Parameters:

• resource_id: numerical ID; scale_factor: desired scale (use SCALE_FACTOR_NONE for scale-independent resources, or call GetDataResource instead).

Return Value: Decompressed resource nearest to scale_factor, or NULL if not found.

Usage Instruction: Use for scaled images (e.g., 2x assets for HiDPI displays).

Threading Constraint: Any thread.

Usage Example

CefRefPtr<CefResourceBundle> bundle = CefResourceBundle::GetGlobal();
if (bundle) {
  // Version-safe string lookup:
  int id = cef_id_for_pack_string_name("IDS_APP_TITLE");
  CefString title = bundle->GetLocalizedString(id);

  // Scale-independent binary:
  int rid = cef_id_for_pack_resource_name("IDR_LOGO_PNG");
  CefRefPtr<CefBinaryValue> logo = bundle->GetDataResource(rid);

  // Scale-aware image:
  CefRefPtr<CefBinaryValue> logo2x =
      bundle->GetDataResourceForScale(rid, SCALE_FACTOR_200P);
}

CefResourceBundleHandler

Source File: include/cef_resource_bundle_handler.h

Process / Thread Context: Multiple threads (per class comment: "The methods of this class may be called on multiple threads.")

Purpose: USER-IMPLEMENTED interface enabling custom resource bundle overrides. Returned from CefApp::GetResourceBundleHandler(). The methods are called whenever CEF/Chromium requests a localized string or a resource; the implementation can supply the data or defer to the default by returning false.

Usage Example

class MyResourceBundleHandler : public CefResourceBundleHandler {
 public:
  bool GetLocalizedString(int string_id, CefString& string) override {
    auto it = my_translations_.find(string_id);
    if (it != my_translations_.end()) {
      string = it->second;
      return true;
    }
    return false;  // fall back to default pak translation
  }
  bool GetDataResource(int resource_id, void*& data,
                       size_t& data_size) override {
    auto it = my_resources_.find(resource_id);
    if (it != my_resources_.end()) {
      data = it->second.ptr;       // must remain resident in memory
      data_size = it->second.size;
      return true;
    }
    return false;
  }
  bool GetDataResourceForScale(int resource_id, ScaleFactor sf,
                               void*& data, size_t& data_size) override {
    // For simplicity, fall through to the default for all scaled resources.
    return false;
  }
  std::map<int, CefString> my_translations_;
  std::map<int, Blob> my_resources_;
};

// Returned from CefApp::GetResourceBundleHandler().