FileAccess
继承： RefCounted < Object
Provides methods for file reading and writing operations.
描述
This class can be used to permanently store data in the user device's file system and to read from it. This is useful for store game save data or player configuration files.
Here's a sample on how to write and read from a file:
func save_to_file(content):
var file = FileAccess.open("user://save_game.dat", FileAccess.WRITE)
file.store_string(content)
func load_from_file():
var file = FileAccess.open("user://save_game.dat", FileAccess.READ)
var content = file.get_as_text()
return content
public void SaveToFile(string content)
{
using var file = FileAccess.Open("user://save_game.dat", FileAccess.ModeFlags.Write);
file.StoreString(content);
}
public string LoadFromFile()
{
using var file = FileAccess.Open("user://save_game.dat", FileAccess.ModeFlags.Read);
string content = file.GetAsText();
return content;
}
In the example above, the file will be saved in the user data folder as specified in the Data paths documentation.
FileAccess will close when it's freed, which happens when it goes out of scope or when it gets assigned with null. close can be used to close it before then explicitly. In C# the reference must be disposed manually, which can be done with the using statement or by calling the Dispose method directly.
Note: To access project resources once exported, it is recommended to use ResourceLoader instead of FileAccess, as some files are converted to engine-specific formats and their original source files might not be present in the exported PCK package.
Note: Files are automatically closed only if the process exits "normally" (such as by clicking the window manager's close button or pressing Alt + F4). If you stop the project execution by pressing F8 while the project is running, the file won't be closed as the game process will be killed. You can work around this by calling flush at regular intervals.
属性
方法
枚举
enum ModeFlags:
ModeFlags READ = 1
Opens the file for read operations. The cursor is positioned at the beginning of the file.
ModeFlags WRITE = 2
Opens the file for write operations. The file is created if it does not exist, and truncated if it does.
Note: When creating a file it must be in an already existing directory. To recursively create directories for a file path, see DirAccess.make_dir_recursive.
ModeFlags READ_WRITE = 3
Opens the file for read and write operations. Does not truncate the file. The cursor is positioned at the beginning of the file.
ModeFlags WRITE_READ = 7
Opens the file for read and write operations. The file is created if it does not exist, and truncated if it does. The cursor is positioned at the beginning of the file.
Note: When creating a file it must be in an already existing directory. To recursively create directories for a file path, see DirAccess.make_dir_recursive.
enum CompressionMode:
CompressionMode COMPRESSION_FASTLZ = 0
Uses the FastLZ compression method.
CompressionMode COMPRESSION_DEFLATE = 1
Uses the DEFLATE compression method.
CompressionMode COMPRESSION_ZSTD = 2
Uses the Zstandard compression method.
CompressionMode COMPRESSION_GZIP = 3
Uses the gzip compression method.
CompressionMode COMPRESSION_BROTLI = 4
Uses the brotli compression method (only decompression is supported).
flags UnixPermissionFlags:
UnixPermissionFlags UNIX_READ_OWNER = 256
Read for owner bit.
UnixPermissionFlags UNIX_WRITE_OWNER = 128
Write for owner bit.
UnixPermissionFlags UNIX_EXECUTE_OWNER = 64
Execute for owner bit.
UnixPermissionFlags UNIX_READ_GROUP = 32
Read for group bit.
UnixPermissionFlags UNIX_WRITE_GROUP = 16
Write for group bit.
UnixPermissionFlags UNIX_EXECUTE_GROUP = 8
Execute for group bit.
UnixPermissionFlags UNIX_READ_OTHER = 4
Read for other bit.
UnixPermissionFlags UNIX_WRITE_OTHER = 2
Write for other bit.
UnixPermissionFlags UNIX_EXECUTE_OTHER = 1
Execute for other bit.
UnixPermissionFlags UNIX_SET_USER_ID = 2048
Set user id on execution bit.
UnixPermissionFlags UNIX_SET_GROUP_ID = 1024
Set group id on execution bit.
UnixPermissionFlags UNIX_RESTRICTED_DELETE = 512
Restricted deletion (sticky) bit.
属性说明
bool big_endian
If true, the file is read with big-endian endianness. If false, the file is read with little-endian endianness. If in doubt, leave this to false as most files are written with little-endian endianness.
Note: big_endian is only about the file format, not the CPU type. The CPU endianness doesn't affect the default endianness for files written.
Note: This is always reset to false whenever you open the file. Therefore, you must set big_endian after opening the file, not before.
方法说明
void close ( )
Closes the currently opened file and prevents subsequent read/write operations. Use flush to persist the data to disk without closing the file.
Note: FileAccess will automatically close when it's freed, which happens when it goes out of scope or when it gets assigned with null. In C# the reference must be disposed after we are done using it, this can be done with the using statement or calling the Dispose method directly.
Returns true if the file cursor has already read past the end of the file.
Note: eof_reached() == false cannot be used to check whether there is more data available. To loop while there is more data available, use:
while file.get_position() < file.get_length():
# Read data
while (file.GetPosition() < file.GetLength())
{
// Read data
}
bool file_exists ( path: String ) static2
Returns true if the file exists in the given path.
Note: Many resources types are imported (e.g. textures or sound files), and their source asset will not be included in the exported game, as only the imported version is used. See ResourceLoader.exists for an alternative approach that takes resource remapping into account.
For a non-static, relative equivalent, use DirAccess.file_exists.
void flush ( )
Writes the file's buffer to disk. Flushing is automatically performed when the file is closed. This means you don't need to call flush manually before closing a file. Still, calling flush can be used to ensure the data is safe even if the project crashes instead of being closed gracefully.
Note: Only call flush when you actually need it. Otherwise, it will decrease performance due to constant disk writes.
Returns the next 8 bits from the file as an integer. See store_8 for details on what values can be stored and retrieved this way.
Returns the next 16 bits from the file as an integer. See store_16 for details on what values can be stored and retrieved this way.
Returns the next 32 bits from the file as an integer. See store_32 for details on what values can be stored and retrieved this way.
Returns the next 64 bits from the file as an integer. See store_64 for details on what values can be stored and retrieved this way.
String get_as_text ( skip_cr: bool = false ) const1
Returns the whole file as a String. Text is interpreted as being UTF-8 encoded.
If skip_cr is true, carriage return characters (\r, CR) will be ignored when parsing the UTF-8, so that only line feed characters (\n, LF) represent a new line (Unix convention).
PackedByteArray get_buffer ( length: int ) const1
Returns next length bytes of the file as a PackedByteArray.
PackedStringArray get_csv_line ( delim: String = "," ) const1
Returns the next value of the file in CSV (Comma-Separated Values) format. You can pass a different delimiter delim to use other than the default "," (comma). This delimiter must be one-character long, and cannot be a double quotation mark.
Text is interpreted as being UTF-8 encoded. Text values must be enclosed in double quotes if they include the delimiter character. Double quotes within a text value can be escaped by doubling their occurrence.
For example, the following CSV lines are valid and will be properly parsed as two strings each:
Alice,"Hello, Bob!"
Bob,Alice! What a surprise!
Alice,"I thought you'd reply with ""Hello, world""."
Note how the second line can omit the enclosing quotes as it does not include the delimiter. However it could very well use quotes, it was only written without for demonstration purposes. The third line must use "" for each quotation mark that needs to be interpreted as such instead of the end of a text value.
Returns the next 64 bits from the file as a floating-point number.
Returns the last error that happened when trying to perform operations. Compare with the ERR_FILE_* constants from Error.
PackedByteArray get_file_as_bytes ( path: String ) static2
Returns the whole path file contents as a PackedByteArray without any decoding.
Returns an empty PackedByteArray if an error occurred while opening the file. You can use get_open_error to check the error that occurred.
String get_file_as_string ( path: String ) static2
Returns the whole path file contents as a String. Text is interpreted as being UTF-8 encoded.
Returns an empty String if an error occurred while opening the file. You can use get_open_error to check the error that occurred.
Returns the next 32 bits from the file as a floating-point number.
bool get_hidden_attribute ( file: String ) static2
Returns true, if file hidden attribute is set.
Note: This method is implemented on iOS, BSD, macOS, and Windows.
Returns the size of the file in bytes.
Returns the next line of the file as a String. The returned string doesn't include newline (\n) or carriage return (\r) characters, but does include any other leading or trailing whitespace.
Text is interpreted as being UTF-8 encoded.
String get_md5 ( path: String ) static2
Returns an MD5 String representing the file at the given path or an empty String on failure.
int get_modified_time ( file: String ) static2
Returns the last time the file was modified in Unix timestamp format, or 0 on error. This Unix timestamp can be converted to another format using the Time singleton.
Error get_open_error ( ) static2
Returns the result of the last open call in the current thread.
String get_pascal_string ( )
Returns a String saved in Pascal format from the file.
Text is interpreted as being UTF-8 encoded.
Returns the path as a String for the current open file.
String get_path_absolute ( ) const1
Returns the absolute path as a String for the current open file.
Returns the file cursor's position.
bool get_read_only_attribute ( file: String ) static2
Returns true, if file read only attribute is set.
Note: This method is implemented on iOS, BSD, macOS, and Windows.
Returns the next bits from the file as a floating-point number.
String get_sha256 ( path: String ) static2
Returns an SHA-256 String representing the file at the given path or an empty String on failure.
UnixPermissionFlags get_unix_permissions ( file: String ) static2
Returns file UNIX permissions.
Note: This method is implemented on iOS, Linux/BSD, and macOS.
Variant get_var ( allow_objects: bool = false ) const1
Returns the next Variant value from the file. If allow_objects is true, decoding objects is allowed.
Internally, this uses the same decoding mechanism as the @GlobalScope.bytes_to_var method.
Warning: Deserialized objects can contain code which gets executed. Do not use this option if the serialized object comes from untrusted sources to avoid potential security threats such as remote code execution.
Returns true if the file is currently opened.
FileAccess open ( path: String, flags: ModeFlags ) static2
Creates a new FileAccess object and opens the file for writing or reading, depending on the flags.
Returns null if opening the file failed. You can use get_open_error to check the error that occurred.
FileAccess open_compressed ( path: String, mode_flags: ModeFlags, compression_mode: CompressionMode = 0 ) static2
Creates a new FileAccess object and opens a compressed file for reading or writing.
Note: open_compressed can only read files that were saved by Godot, not third-party compression formats. See GitHub issue #28999 for a workaround.
Returns null if opening the file failed. You can use get_open_error to check the error that occurred.
FileAccess open_encrypted ( path: String, mode_flags: ModeFlags, key: PackedByteArray ) static2
Creates a new FileAccess object and opens an encrypted file in write or read mode. You need to pass a binary key to encrypt/decrypt it.
Note: The provided key must be 32 bytes long.
Returns null if opening the file failed. You can use get_open_error to check the error that occurred.
FileAccess open_encrypted_with_pass ( path: String, mode_flags: ModeFlags, pass: String ) static2
Creates a new FileAccess object and opens an encrypted file in write or read mode. You need to pass a password to encrypt/decrypt it.
Returns null if opening the file failed. You can use get_open_error to check the error that occurred.
Resizes the file to a specified length. The file must be open in a mode that permits writing. If the file is extended, NUL characters are appended. If the file is truncated, all data from the end file to the original length of the file is lost.
void seek ( position: int )
Changes the file reading/writing cursor to the specified position (in bytes from the beginning of the file).
void seek_end ( position: int = 0 )
Changes the file reading/writing cursor to the specified position (in bytes from the end of the file).
Note: This is an offset, so you should use negative numbers or the cursor will be at the end of the file.
Error set_hidden_attribute ( file: String, hidden: bool ) static2
Sets file hidden attribute.
Note: This method is implemented on iOS, BSD, macOS, and Windows.
Error set_read_only_attribute ( file: String, ro: bool ) static2
Sets file read only attribute.
Note: This method is implemented on iOS, BSD, macOS, and Windows.
Error set_unix_permissions ( file: String, permissions: UnixPermissionFlags ) static2
Sets file UNIX permissions.
Note: This method is implemented on iOS, Linux/BSD, and macOS.
void store_8 ( value: int )
Stores an integer as 8 bits in the file.
Note: The value should lie in the interval [0, 255]. Any other value will overflow and wrap around.
To store a signed integer, use store_64, or convert it manually (see store_16 for an example).
void store_16 ( value: int )
Stores an integer as 16 bits in the file.
Note: The value should lie in the interval [0, 2^16 - 1]. Any other value will overflow and wrap around.
To store a signed integer, use store_64 or store a signed integer from the interval [-2^15, 2^15 - 1] (i.e. keeping one bit for the signedness) and compute its sign manually when reading. For example:
const MAX_15B = 1 << 15
const MAX_16B = 1 << 16
func unsigned16_to_signed(unsigned):
return (unsigned + MAX_15B) % MAX_16B - MAX_15B
func _ready():
var f = FileAccess.open("user://file.dat", FileAccess.WRITE_READ)
f.store_16(-42) # This wraps around and stores 65494 (2^16 - 42).
f.store_16(121) # In bounds, will store 121.
f.seek(0) # Go back to start to read the stored value.
var read1 = f.get_16() # 65494
var read2 = f.get_16() # 121
var converted1 = unsigned16_to_signed(read1) # -42
var converted2 = unsigned16_to_signed(read2) # 121
public override void _Ready()
{
using var f = FileAccess.Open("user://file.dat", FileAccess.ModeFlags.WriteRead);
f.Store16(unchecked((ushort)-42)); // This wraps around and stores 65494 (2^16 - 42).
f.Store16(121); // In bounds, will store 121.
f.Seek(0); // Go back to start to read the stored value.
ushort read1 = f.Get16(); // 65494
ushort read2 = f.Get16(); // 121
short converted1 = (short)read1; // -42
short converted2 = (short)read2; // 121
}
void store_32 ( value: int )
Stores an integer as 32 bits in the file.
Note: The value should lie in the interval [0, 2^32 - 1]. Any other value will overflow and wrap around.
To store a signed integer, use store_64, or convert it manually (see store_16 for an example).
void store_64 ( value: int )
Stores an integer as 64 bits in the file.
Note: The value must lie in the interval [-2^63, 2^63 - 1] (i.e. be a valid int value).
void store_buffer ( buffer: PackedByteArray )
Stores the given array of bytes in the file.
void store_csv_line ( values: PackedStringArray, delim: String = "," )
Store the given PackedStringArray in the file as a line formatted in the CSV (Comma-Separated Values) format. You can pass a different delimiter delim to use other than the default "," (comma). This delimiter must be one-character long.
Text will be encoded as UTF-8.
void store_double ( value: float )
Stores a floating-point number as 64 bits in the file.
void store_float ( value: float )
Stores a floating-point number as 32 bits in the file.
void store_line ( line: String )
Stores line in the file followed by a newline character (\n), encoding the text as UTF-8.
void store_pascal_string ( string: String )
Stores the given String as a line in the file in Pascal format (i.e. also store the length of the string).
Text will be encoded as UTF-8.
void store_real ( value: float )
Stores a floating-point number in the file.
void store_string ( string: String )
Stores string in the file without a newline character (\n), encoding the text as UTF-8.
Note: This method is intended to be used to write text files. The string is stored as a UTF-8 encoded buffer without string length or terminating zero, which means that it can't be loaded back easily. If you want to store a retrievable string in a binary file, consider using store_pascal_string instead. For retrieving strings from a text file, you can use get_buffer(length).get_string_from_utf8() (if you know the length) or get_as_text.
void store_var ( value: Variant, full_objects: bool = false )
Stores any Variant value in the file. If full_objects is true, encoding objects is allowed (and can potentially include code).
Internally, this uses the same encoding mechanism as the @GlobalScope.var_to_bytes method.
Note: Not all properties are included. Only properties that are configured with the @GlobalScope.PROPERTY_USAGE_STORAGE flag set will be serialized. You can add a new usage flag to a property by overriding the Object._get_property_list method in your class. You can also check how property usage is configured by calling Object._get_property_list. See PropertyUsageFlags for the possible usage flags.
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本方法无副作用，不会修改该实例的任何成员变量。
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本方法用于构造某个类型。
调用本方法无需实例，可直接使用类名进行调用。
本方法描述的是使用本类型作为左操作数的有效运算符。
这个值是由下列位标志构成位掩码的整数。
无返回值。