FileAccess Dart Reference Documentation
CkFileAccess
Current Version: 11.6.1
Chilkat.FileAccess
Load or save text and binary files, append data, replace file contents,
and work with explicit character encodings when needed.
Copy, rename, delete, compare, split, reassemble, and inspect files using
straightforward file-system utility methods.
Create, remove, check, and work with directories, and use path helpers to
extract filenames, extensions, directory names, and related path parts.
Open files for lower-level reading or writing, seek within files, read
blocks, and process large files without loading everything at once.
Get or set file times, inspect sizes and existence, and use metadata
helpers when coordinating file processing workflows.
Generate temporary filenames, work with symbolic links, scan for byte
fragments, and perform text replacement in files.
For an extended overview, see
FileAccess Class Overview.
Read, write, compare, copy, split, inspect, and manage files and paths.
Chilkat.FileAccess provides general-purpose file-system
utilities for applications that need direct control over files, directories,
paths, timestamps, and low-level file operations. It can read, write, append,
seek, compare, copy, rename, delete, split, reassemble, and inspect files,
and also includes helpers for directory operations, path parsing, symbolic
links, temporary filenames, block-based reading, fragment scanning, text
replacement, and open-file access.
Read and write files
File management
Directories and paths
Open-file operations
Timestamps and metadata
Special file utilities
FileAccess for local file-system tasks that are outside the
scope of a specific protocol class. It is especially useful for preparing
files before upload, saving downloaded data, comparing or splitting files,
reading large files in blocks, manipulating paths, or performing small
filesystem operations without using platform-specific APIs.
Object Creation
// pubspec.yaml:
// dependencies:
// chilkat: ^11.6.1
import 'package:chilkat/chilkat.dart';
// Once per process, before any other Chilkat call:
Chilkat.unlockBundle('Anything for 30-day trial'); // shorthand for CkGlobal().unlockBundle(..)
final fileAccess = CkFileAccess();
// ... the native object is released when `fileAccess` is garbage collected, or now with fileAccess.dispose().Creates the underlying native Chilkat object. Use a CkFileAccess only from the isolate that created it: Chilkat objects cannot be sent between isolates. Every call is synchronous; in a Flutter app, run long operations (network, large files) inside Isolate.run, creating the Chilkat objects inside the isolate.
Releases the native object immediately instead of waiting for garbage collection (useful for a large CkBinData or an open socket). Calling it more than once is harmless; any other use of the object afterwards throws a StateError. isDisposed tells whether it has been called.
Errors
A method that can fail throws a ChilkatException: a method whose only outcome is success or failure returns void and throws on failure; a method producing a String or an object returns it and throws where Chilkat would have returned null. The exception carries the object's LastErrorText at the time of the failure (lastErrorText), the class and method names (className, methodName) and a one-line message. Properties never throw, and methods that answer a question (has..., is..., ...) return a plain bool.
try {
fileAccess.someMethod(...);
} on ChilkatException catch (e) {
print(e); // CkFileAccess.someMethod failed: <reason>
print(e.lastErrorText); // the full Chilkat log of the failed call
}Properties
CurrentDir
String get currentDir
Returns the current working directory of the calling process. Relative file and directory paths are resolved against this process-wide working directory.
FileAccess object. Changing it can therefore affect relative-path behavior elsewhere in the application.DebugLogFilePath
String get debugLogFilePath
set debugLogFilePath(String value)
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
EndOfFile
bool get endOfFile
Returns true when the currently open file is positioned at end-of-file; otherwise returns false.
OpenForRead, OpenForWrite, OpenForReadWrite, OpenForAppend, or FileOpen.FileOpenError
int get fileOpenError
Provides the detailed open-error code from the most recent call to FileOpen, OpenForRead, OpenForWrite, OpenForReadWrite, or OpenForAppend.
| Code | Meaning |
|---|---|
0 | Success; no open error. |
1 | Access denied. |
2 | File not found. |
3 | General, non-specific open error. |
4 | File already exists. |
5 | The path refers to a directory and the requested access involves writing. |
6 | Too many symbolic links were encountered while resolving the path. |
7 | The process already has the maximum number of files open. |
8 | The pathname is too long. |
9 | The system-wide limit on open files has been reached. |
10 | The pathname refers to a device special file for which no corresponding device exists. |
11 | Insufficient kernel memory was available. |
12 | A file was to be created, but the containing device has no space available. |
13 | A pathname component expected to be a directory is not a directory. |
14 | The regular file is too large to be opened because of an operating-system limitation. |
15 | The path is on a read-only filesystem and write access was requested. |
FileOpenError is useful for programmatic handling; FileOpenErrorMsg provides the corresponding human-readable message.FileOpenErrorMsg
String get fileOpenErrorMsg
Returns the human-readable message corresponding to FileOpenError for the most recent file-open attempt.
LastErrorHtml
String get lastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
String get lastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
String get lastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
bool get lastMethodSuccess
set lastMethodSuccess(bool value)
Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
LockFileOnOpen
bool get lockFileOnOpen
set lockFileOnOpen(bool value)
Windows only. If true, OpenForAppend, OpenForRead, OpenForReadWrite, and OpenForWrite request exclusive access to the file. Other processes are prevented from opening the file until FileClose releases the handle. The default is false.
OpenFor* method.VerboseLogging
bool get verboseLogging
set verboseLogging(bool value)
If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
String get version
Methods
AppendAnsi
Appends text to the currently open file after converting the string to the legacy ANSI character encoding used by Chilkat for the platform.
AppendText or AppendSb when an explicit encoding such as utf-8 is preferred.Returns normally on success; throws a ChilkatException on failure.
AppendBd
Appends all bytes contained in bd to the currently open file without text conversion.
Returns normally on success; throws a ChilkatException on failure.
AppendSb
Appends the text contained in sb to the currently open file using the character encoding specified by charset.
Returns normally on success; throws a ChilkatException on failure.
AppendText
Appends str to the currently open file after encoding the text with the character set named by charset, such as utf-8 or iso-8859-1.
Returns normally on success; throws a ChilkatException on failure.
AppendUnicodeBOM
Appends the UTF-16 little-endian byte-order mark to the currently open file. The two bytes written are FF FE.
Returns normally on success; throws a ChilkatException on failure.
AppendUtf8BOM
Appends the UTF-8 byte-order mark to the currently open file. The three bytes written are EF BB BF.
Returns normally on success; throws a ChilkatException on failure.
DirAutoCreate
Ensures that the directory portion of filePath exists. Any missing parent directories are created; the final path component is treated as a filename and is not created as a directory.
DirAutoCreate when you have a file path. Use DirEnsureExists when the argument itself is a directory path.Returns normally on success; throws a ChilkatException on failure.
DirCreate
Creates the directory specified by dirPath. Parent directories must already exist; use DirEnsureExists when missing parent directories should also be created.
Returns normally on success; throws a ChilkatException on failure.
DirDelete
Deletes the directory specified by dirPath. The directory must be empty; use TreeDelete to recursively delete a directory and its contents.
Returns normally on success; throws a ChilkatException on failure.
DirEnsureExists
Ensures that the complete directory path dirPath exists, creating missing directories along the path as needed.
Returns normally on success; throws a ChilkatException on failure.
DirExists
Returns true if dirPath exists as a directory; otherwise returns false.
FileClose
Closes the currently open file and releases its operating-system file handle. Any exclusive lock obtained through LockFileOnOpen is released at this time.
FileContentsEqual
Compares filePath1 and filePath2 byte-for-byte and returns true only when their contents are identical. File sizes are compared first; when sizes match, the files are compared incrementally rather than being loaded entirely into memory.
FileCopy
Copies existingFilepath to newFilepath. If failIfExists is true and the destination already exists, the copy fails instead of overwriting it.
Returns normally on success; throws a ChilkatException on failure.
FileDelete
Deletes the file specified by filePath.
Returns normally on success; throws a ChilkatException on failure.
FileExists
Returns true if filePath exists; otherwise returns false. Use FileExists3 when the application must distinguish "does not exist" from "could not determine because of an error."
FileExists3
Checks whether path exists and returns a three-state result: 1 if it exists, 0 if it does not exist, and -1 if Chilkat could not determine the result because of permissions or another filesystem error.
FileOpen
Windows-specific low-level open. Opens filePath using arguments modeled after the Win32 CreateFile API. For portable code, prefer OpenForRead, OpenForWrite, OpenForReadWrite, or OpenForAppend.
| Category | Common values |
|---|---|
| Access | GENERIC_READ = 0x80000000, GENERIC_WRITE = 0x40000000 |
| Sharing | FILE_SHARE_READ = 0x1, FILE_SHARE_WRITE = 0x2 |
| Disposition | CREATE_NEW=1, CREATE_ALWAYS=2, OPEN_EXISTING=3, OPEN_ALWAYS=4, TRUNCATE_EXISTING=5 |
FileOpenError and FileOpenErrorMsg for the reason.Returns normally on success; throws a ChilkatException on failure.
FileReadBd
Reads up to maxNumBytes bytes from the current file position and appends the bytes to binData. The file position advances by the number of bytes read.
binData are preserved; newly read bytes are appended.Returns normally on success; throws a ChilkatException on failure.
FileRename
Renames or moves existingFilepath to newFilepath using the local filesystem.
Returns normally on success; throws a ChilkatException on failure.
FileSeek
Moves the current file position by offset bytes relative to origin.
0 | Offset from the beginning of the file. |
1 | Offset from the current file position. |
2 | Offset from end-of-file; negative offsets are commonly used. |
Returns normally on success; throws a ChilkatException on failure.
FileSize
Returns the file size in bytes as a signed 32-bit integer, or -1 on failure.
FileSize64 or FileSizeStr for large files.FileSize64
Returns the size of filePath in bytes as a signed 64-bit integer, or -1 on failure.
FileSizeStr
Returns the size of filePath in bytes as a decimal string. This avoids the range limitation of a 32-bit integer return value.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
FileType
Examines path and classifies the filesystem entry.
-1 | Unable to determine because of permissions or another error. |
0 | Does not exist. |
1 | Regular file. |
2 | Directory. |
3 | Symbolic link. |
4 | Windows shortcut. |
99 | Another filesystem type. |
FileWrite2
Writes exactly szByteData bytes beginning at pByteData to the currently open file at the current file position.
szByteData bytes.Returns normally on success; throws a ChilkatException on failure.
FileWriteBd
Writes bytes from binData to the currently open file. offset selects the starting byte within the BinData; numBytes selects how many bytes to write. Set both to 0 to write the entire BinData, or set numBytes to 0 to write all remaining bytes beginning at offset.
Returns normally on success; throws a ChilkatException on failure.
GenBlockId
Generates a fixed-width decimal block identifier from index, padded to length characters, and then encodes those bytes using encoding (for example base64, hex, or ascii). This utility was originally added for block-oriented uploads such as Azure Blob block uploads.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
GetDirectoryName
Returns the directory portion of path according to Chilkat path-parsing rules.
GetDirectoryName('C:\MyDir\MySubDir\myfile.ext') -> 'C:\MyDir\MySubDir\'
GetDirectoryName('C:\MyDir\MySubDir') -> 'C:\MyDir\'
GetDirectoryName('C:\') -> 'C:\'Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
GetExtension
Returns the filename extension portion of path, including the leading period. A period appearing only in a directory name is not treated as the file extension.
GetExtension('C:\mydir.old\myfile.ext') -> '.ext'
GetExtension('C:\mydir.old\') -> ''Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
GetFileName
Returns the final filename component of path, including its extension. If the path ends with a directory separator, the returned filename is empty.
GetFileName('C:\mydir\myfile.ext') -> 'myfile.ext'
GetFileName('C:\mydir\') -> ''Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
GetFileNameWithoutExtension
Returns the final filename component of path with its extension removed. If path ends with a directory separator, the returned value is empty.
GetFileNameWithoutExtension('C:\mydir\myfile.ext') -> 'myfile'
GetFileNameWithoutExtension('C:\mydir\') -> ''Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
GetFileTimeStr
Returns one file timestamp as an ISO 8601 UTC string in the form YYYY-MM-DDTHH:MM:SSZ. The which argument selects 0 = last-modified, 1 = last-access, or 2 = creation.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
GetNumBlocks
Returns how many blockSize-byte blocks are required to cover the currently open file. A partial final block counts as one block. Returns 0 for an empty file and -1 if no file is open.
ceil(fileSize / blockSize) for a non-empty file.GetTempFilename
Generates a temporary pathname in dirPath using prefix and a random alphanumeric suffix, in the general form prefix_xxxx.TMP. The returned pathname is guaranteed not to already exist at the time it is generated.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
OpenForAppend
Opens filePath for writing at end-of-file. The file is created if it does not exist. Existing content is preserved, and the initial file position is at the end.
FileOpenError and FileOpenErrorMsg. On Windows, LockFileOnOpen can request exclusive access for this method.Returns normally on success; throws a ChilkatException on failure.
OpenForRead
Opens an existing filePath for reading. The file may contain text or binary data and must already exist.
FileOpenError and FileOpenErrorMsg. On Windows, LockFileOnOpen can request exclusive access for this method.Returns normally on success; throws a ChilkatException on failure.
OpenForReadWrite
Opens filePath for both reading and writing. The file is created if necessary. Existing content is preserved, and the initial file position is at the beginning.
FileOpenError and FileOpenErrorMsg. On Windows, LockFileOnOpen can request exclusive access for this method.Returns normally on success; throws a ChilkatException on failure.
OpenForWrite
Opens filePath for writing. The file is created if necessary; if it already exists, it is truncated to zero length when opened.
FileOpenError and FileOpenErrorMsg. On Windows, LockFileOnOpen can request exclusive access for this method.Returns normally on success; throws a ChilkatException on failure.
ReadBinaryToEncoded
Reads the entire file at filePath as binary data and returns an encoded textual representation. Supported encoding names documented for this method include base64, hex, qp, and url.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
ReadBlockBd
Reads the zero-based block blockIndex from the currently open file, using blockSize bytes per block, and appends the bytes to bd. A partial final block is appended at its actual length.
bd are preserved; the block bytes are appended.Returns normally on success; throws a ChilkatException on failure.
ReadEntireTextFile
Reads the entire file at filePath, decodes its bytes using charset, and returns the resulting text.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
ReadNextFragment
Scans the currently open file for the next text fragment beginning with beginMarker and ending with endMarker. The matched fragment, including both markers, is decoded using charset and appended to sb. If startAtBeginning is true, scanning restarts at the beginning of the file; otherwise it continues after the previously matched fragment.
1 | A fragment was found and appended. |
0 | No matching fragment was found. |
-1 | An error occurred while reading. |
ReassembleFile
Reassembles a file previously divided by SplitFile. Parts are read from partsDirPath using the supplied partPrefix and partExtension, and the combined bytes are written to reassembledFilename.
Returns normally on success; throws a ChilkatException on failure.
ReplaceStrings
Reads the file at filePath as text using charset, replaces occurrences of existingString with replacementString, writes the updated text back to the file, and returns the number of replacements made.
SetCurrentDir
Changes the current working directory of the calling process to dirPath.
Returns normally on success; throws a ChilkatException on failure.
SetFileTimes
Sets the creation, last-access, and last-modified timestamps for filePath from the supplied CkDateTime objects. On filesystems that do not support a creation/birth time, createTime is ignored.
Returns normally on success; throws a ChilkatException on failure.
SetLastModified
Sets the last-modified timestamp of filePath from lastModified. The precision actually stored depends on the underlying filesystem.
Returns normally on success; throws a ChilkatException on failure.
SplitFile
Splits fileToSplit into sequential binary parts of up to partSize bytes and writes them to destDir using partPrefix and partExtension. Use ReassembleFile to reconstruct the original file.
Returns normally on success; throws a ChilkatException on failure.
SymlinkCreate
Creates a symbolic link at linkPath that refers to targetPath.
Returns normally on success; throws a ChilkatException on failure.
SymlinkTarget
Returns the resolved target pathname for the symbolic link at linkPath. On Windows, this method also understands Windows shortcut (.lnk) files and returns the absolute target path.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
TreeDelete
Recursively deletes the directory tree rooted at path, including contained files and subdirectories.
path identifies the intended tree before calling it.Returns normally on success; throws a ChilkatException on failure.
Truncate
Truncates the currently open file at the current file position. Bytes at and after that position are removed, making the current position the new end-of-file.
Truncate.Returns normally on success; throws a ChilkatException on failure.
WriteEntireTextFile
Creates or opens filePath, encodes textData using charset, writes the resulting bytes, and closes the file. Existing file content is replaced. If includePreamble is true, an appropriate preamble/BOM is included for encodings such as UTF-8 or UTF-16.
Returns normally on success; throws a ChilkatException on failure.