FileOpen

Description

Opens an on-disk or in-memory file to read, write, or append. Use this function with the FileRead function to read large files.

Returns

A file object that represents the open file.

Category

System functions

Function syntax

FileOpen(filepath, [mode, charset])

See also

FileClose, FileCopy, FileReadBinary, FileRead, FileReadLine, FileWrite, cffile

History

ColdFusion 8: Added this function.

Parameters

Usage

The file does not have to exist before you open it. To write a new file, open it for writing, and then write it.

The file object is a handle to a file. You can use the object as a structure to access the following information:

• filename Name of the file you opened

• filepath Absolute path and filename

• lastmodified The time when the file was most recently modified

• mode The action for which the file was opened

• size The file size in bytes

• status Whether the file object is open or closed

The following opens a file, and then displays the absolute path and filename of that file:

<cfscript>  
myfile = FileOpen("c:\temp\test1.txt", "read"); 
</cfscript> 
myfile refers to: 
<cfdump var="#myfile.filepath#">

Use the following syntax to specify an in-memory file, which is not written to disk. In-memory files speed processing of transient data.

ram:///filepath

The filepath can include directories, for example ram:///petStore/images/poodle.jpg. Create the directories in the path before you specify the file. For more information on using in-memory files, see Optimizing transient files in the Developing ColdFusion Applications.

Always close a file after opening it. When you use the FileOpen function to open a file, the file stream from the disk is opened and contents are read from or written to it. The FileClose function closes the stream. If you do not close a file, the stream remains open; in that case, the operating system can lock the file, which results in the file not being usable until the server is restarted.

Example

The following example opens a file, reads and outputs each line of the file, then closes the file.

<h3>FileOpen Example</h3> 
 
<cfscript>  
myfile = FileOpen("c:\temp\test1.txt", "read"); 
while(NOT FileIsEOF(myfile)) 
{ 
x = FileReadLine(myfile); 
WriteOutput("#x# <br>"); } 
FileClose(myfile); 
</cfscript>