Secure temporary file

Create a temporary file, securely and exclusively (opening it such that there are no possible race conditions). It's fine assuming local filesystem semantics (NFS or other networking filesystems can have signficantly more complicated semantics for satisfying the "no race conditions" criteria). The function should automatically resolve name collisions and should only fail in cases where permission is denied, the filesystem is read-only or full, or similar conditions exist (returning an error or raising an exception as appropriate to the language/environment).

Ada

Ada creates a temporary file whenever the create procedure is called with file name. That temporary file is automatically deleted at the end of the program creating the file.

This example creates a temporary file, writes to the file, then reads from the file.

with Ada.Text_Io; use Ada.Text_Io;

procedure Temp_File is
   Temp : File_Type;
   Contents : String(1..80);
   Length : Natural;
begin
   -- Create a temporary file
   Create(File => Temp);
   Put_Line(File => Temp, Item => "Hello World");
   Reset(File => Temp, Mode => In_File);
   Get_Line(File => Temp, Item => Contents, Last => Length);
   Put_Line(Contents(1..Length));  
end Temp_File;

Python

Works with: Python version 2.3+

In both cases, the temporary file will be deleted automatically when the file is closed. The invisible file will not be accessible on UNIX-like systems. You can use os.link to preserve the visible temporary file contents.

>>> import tempfile
>>> invisible = tempfile.TemporaryFile()
>>> invisible.name
'<fdopen>'
>>> visible = tempfile.NamedTemporaryFile()
>>> visible.name
'/tmp/tmpZNfc_s'
>>> visible.close()
>>> invisible.close()

More low level way, if you have special needs. This was the only option before Python 2.3:

fd, path = tempfile.mkstemp()
try:
    # use the path or the file descriptor
finally:
    os.close(fd)