There are three key and pervasive things that happened to the File API between Drupal 6 and Drupal 7:
- Any API that used to take a traditional filepath like "sites/default/files/something.txt" now must take a stream-oriented file path like "public://something.txt" or "private://something.txt".
- Many APIs used to take a string if they were acting on an unmanaged file, or a file object if acting on a managed file. Now those functions have been split out, so we now have file_copy() (which takes a file object) and file_unmanaged_copy() (which takes a stream-oriented filepath like "public://example.txt").
- file_create_path() and file_check_directory() were merged into file_prepare_directory().
- A smaller item: drupal_realpath() must be used in place of realpath().
Summary of managed/unmanaged File API changes
|Drupal 6||Drupal 7||Description|
|file_copy()||file_unmanaged_copy()||Copy a file to a new location without saving a record in the database.|
|n/a||file_copy()||Copies a file to a new location and adds a file record to the database. Also invokes hook_file_copy() so that other modules may act on the copy action.|
|file_move()||file_unmanaged_move()||Move a file to a new location but make no changes to the database.|
|n/a||file_move()||Move a file to a new location and update the file's database entry. Also invokes hook_file_move() so that other modules may act on the move action.|
|file_delete()||file_unmanaged_delete()||Delete a file.|
|n/a||file_delete()||Delete a file and its database record. Also invokes hook_file_delete() to let other modules perform clean-up actions when file is deleted.|
|file_save_data()||file_unmanaged_save_data()||Save a string to the specified destination but makes no changes to the database.|
|n/a||file_save_data()||Save a string to the specified destination and create a database file entry.|
|n/a||file_load()||Load a file object from the database. Also invokes hook_file_load() to allow other modules to do things as the file is loaded.|
|n/a||file_validate()||Check that a file meets the criteria specified by the validators. Accepts an associative array of callback functions used to validate the file. Also calls hook_file_validate() to let other modules perform validation on the new file.|
|n/a||file_save()||Save a file object to the database. Calls either hook_file_insert() or hook_file_update(), depending on whether a $file->fid is specified.|
file_copy($source, $paths['target'] . $base); $paths['files'] = $source;
$filepath = file_unmanaged_copy($source, $paths['target'] . $base); $paths['files'] = $filepath;
|Drupal 6||Drupal 7||Notes|
|file_check_directory()||file_prepare_directory(FILE_MODIFY_PERMISSIONS)||Probably most of the time people who just want to make sure a directory exists and is writable will use file_prepare_directory(FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS)|
Many other functions used before Drupal 7 will no longer be necessary, as, for example, there is normally no need to check where on the filesystem the "public" file directory is -- you use use the streamwrapper notation and everything is done for you.