Assets Canister: include/require don't work with PHP files from assets canister

Problem

When using the assets canister architecture (Issue #192), PHP's include, include_once, require, and require_once statements fail for files stored in the assets canister.

Root Cause

The current implementation fetches PHP files from the assets canister at the HTTP request level:

1. HTTP request arrives at backend canister
2. Backend fetches the requested PHP file from assets canister
3. Content is cached and passed to PHP's eval()

However, when PHP code uses include '/other.php', PHP's internal file handling (zend_stream_fixup → open_file_for_scanning → compile_file) tries to open the file directly from the filesystem. This doesn't go through our Rust code, so it can't access:

• The assets canister
• The asset cache

Error Details

Canister Backtrace:
zend_stream_fixup
open_file_for_scanning  
compile_file
compile_filename
zend_include_or_eval
ZEND_INCLUDE_OR_EVAL_SPEC_CONST_HANDLER

Solution Options

1. Hook PHP's file stream wrapper - Create a custom PHP stream wrapper that intercepts file:// operations and fetches from asset cache
2. Pre-load dependent files - Before running PHP, analyze dependencies and pre-fetch all included files
3. Modify wasp_vfs.c - Hook into C-level file operations to check asset cache
4. Use bundled VFS - Files bundled at build time via bundle_php_app.sh work fine with include

Workaround

For now, use the bundled VFS approach:

./scripts/bundle_php_app.sh path/to/your/php/app
bash wasp_backend/scripts/build_backend_ic.sh
dfx deploy

Files bundled into the WASM binary work correctly with include/require.

Related

• Issue #192: Move WordPress/PHP Static Assets to ICP Assets Canister