File Manipulation Functions
$Header: /cvsroot/aolserver/aolserver.com/docs/devel/tcl/api/file.html,v 1.1 2002/03/07 19:15:35 kriston Exp $
Change a file's access permissions.
Syntax
ns_chmod filename mode
Description
ns_chmod changes the specified file's permissions to mode, in the same
manner as the Unix chmod(1) command-line utility.
Copy one file to another.
Syntax
ns_cp -preserve file1 file2
Description
ns_cp copies the contents of file1 to file2, just like the Unix "cp"
command. The default directory is the home directory for the server.
If -preserve is specified, the copied file will retain the creation
time, modification time, owner, and mode of the original file, just
like the Unix "cp -p" command.
Copy a specified number of bytes from one file to another.
Syntax
ns_cpfp fileid1 fileid2 ?nbytes?
Description
ns_cpfp copies information from one file (fileid1) to another
(fileid2). If you specify a number of bytes in the nbytes argument,
only the specified number of bytes will be copied. By default, the
entire file is copied.
Truncate an open file to a specified length.
Syntax
ns_ftruncate fileid ?length?
Description
ns_ftruncate causes the open file specified by fileid to have a size
of length bytes. If length is not specified, it causes the file to
have a size of zero bytes. The file must be open and be a regular
file.
Read CSV data from a file.
Syntax
ns_getcsv fileId varName
Description
ns_getcsv reads one line of CSV data from the specified file and and
sets the variable specified by varName to a list of the elements in
that row. Any quotes in the line of data are removed. ns_getcsv
returns the number of elements in the row.
If there are no more lines in the file to read, varName does not get
set, and ns_getcsv returns -1 as the number of elements in the row.
A CSV file is an ASCII file containing rows of data in the following
syntax:
* Elements in each row must be separated by commas.
* Each row must end with either \n, \r, or \r\n.
* Elements that contain commas, newlines, or carriage returns can be
surrounded by double quotes (e.g., "foo,bar").
* If an element surrounded by double quotes also contains a double
quote, you can escape the interior double quote by using two
double quotes (e.g., "Evander ""Real Deal"" Holyfield"
* White space that isn't inside double quotes is ignored. For
example, the line: 'bob, sarah, mary' will result in the list {bob
sarah mary}.
* Null entries are okay, either embedded in the line or at the end
of a line. For example, the line: 'bob,,sarah, ' will result in
the list: {bob {} sarah {}}.
Determine the width and height of a GIF87 or GIF89 image.
Syntax
ns_gifsize file
Description
ns_gifsize returns a list of two elements, the width and height of the
GIF file specified by file. An error is generated if the file does not
exist or if it is not a GIF file.
Determine the width and height of a JPEG image.
Syntax
ns_jpegsize file
Description
ns_jpegsize returns a list of two elements, the width and height of
the JPEG file specified by file. An error is generated if the file
does not exist or if it is not a JPEG file.
Create a link.
Syntax
ns_link ?-nocomplain? filename1 filename2
Description
ns_link creates a link named filename2 that points to the file
specified by filename1. If the link fails, a Tcl error is generated,
unless -nocomplain is specified.
Create a directory.
Syntax
ns_mkdir path
Description
ns_mkdir creates the directory named PATH, just like the Unix mkdir
command. By default, under Unix the directory is created with the file
permissions set to 0755 (rwxr-xr-x.). These permissions can be
modified by setting the umask parameter for the server.
Return a unique file name based on a template.
Syntax
ns_mktemp template
Description
ns_mktemp returns a unique filename based on the template you specify.
The string in the template should contain a string with 6 trailing Xs.
ns_mktemp will replace the Xs with a letter and the current process
id. The letter will be chosen to make the filename unique. For
example, ns_mktemp "/tmp/fooXXXXXX" will return something like:
"/tmp/fooa000BH".
ns_mktemp is analogous to the Unix C library mktemp function.
Rename a file.
Syntax
ns_rename file1 file2
Description
ns_rename renames the first file (file1) to the file name specified by
file2. Make sure that the files and the directories in which the
files exist are read/write accessible to the username that's
running the AOLserver.
Remove a directory.
Syntax
ns_rmdir path
Description
ns_rmdir removes the directory named path, just like the Unix rmdir
command. The directory must already be empty.
Roll an arbitrary file.
Syntax
ns_rollfile file backupMax
Description
This function rolls the specified file, keeping a number of backup
copies up to backupMax.
Create a symbolic link.
Syntax
ns_symlink ?-nocomplain? filename1 filename2
Description
ns_symlink creates a symbolic link named filename2 that points to the
file specified by filename1. If the link fails, a Tcl error is
generated, unless -nocomplain is specified.
Remove a file.
Syntax
ns_unlink [-nocomplain] filename
Description
ns_unlink attempts to remove the file filename. If -nocomplain is not
passed in and the removal fails, a Tcl error is generated.
Truncate a file to a specified length.
Syntax
ns_truncate filename ?length?
Description
ns_truncate causes the file specified by filename to have a size of
length bytes. If length is not specified, it causes filename to have a
size of zero bytes. The file must exist and be a regular file.
Generate a temporary file name.
Syntax
ns_tmpnam
Description
ns_tmpnam generates a filename that can safely be used for a temporary
file. ns_tmpnam calls tmpnam(), and the results will depend on your
operating system. On Irix, for example, tmpnam() always generates a
file name using the path-prefix defined as P_tmpdir in the
header file, which is "/var/tmp/".
Alternatively, you can use the ns_mktemp function to create a unique
file name.
Write file contents to the connection.
Syntax
ns_writefp fileid ?nbytes?
Description
ns_writefp writes the contents of the specified file to the
connection. You can specify the number of bytes to be copied in the
nbytes argument. By default, the entire file is copied.
Example
ns_register_proc GET /sampleWriteFp sampleWriteFp
proc sampleWriteFp { conn ignore } {
set file [open "/home/people/juan/machine.txt" r]
ns_writefp $file
close $file
}
Normalize a path.
Syntax
ns_normalizepath path
Description
ns_normalizepath removes any extraneous slashes from the path and
resolves "." and ".." references. For example:
[ns_normalizepath /dog/cat/../.. /rat/../../dog//mouse/..]
returns:
/dog