Ruby open temporary file

So although this class does not explicitly document all instance methods supported by File, you can in fact call any File instance method on a Tempfile object. When a Tempfile object is garbage collected, or when the Ruby interpreter exits, its associated temporary file is automatically deleted. This means that's it's unnecessary to explicitly delete a Tempfile after use, though it's good practice to do so: not explicitly deleting unused Tempfiles can potentially leave behind large amounts of tempfiles on the filesystem until they're garbage collected.

The existence of these temp files can make it harder to determine a new Tempfile filename. Therefore, one should always call unlink or close in an ensure block, like this:. This removes the filesystem entry without closing the file handle, so it ensures that only the processes that already had the file handle open can access the file's contents.

It's strongly recommended that you do this if you do not want any other processes to be able to read from or write to the Tempfile , and you do not need to know the Tempfile's filename either. For example, a practical use case for unlink-after-creation would be this: you need a large byte buffer that's too large to comfortably fit in RAM, e. Please refer to unlink for more information and a code example. Tempfile's filename picking method is both thread-safe and inter-process-safe: it guarantees that no other threads or processes will pick the same filename.

Tempfile itself however may not be entirely thread-safe. If you access the same Tempfile object from multiple threads then you should protect it with a mutex. Creates a temporary file as usual File object not Tempfile.

It doesn't use finalizer and delegation. If no block is given, this is similar to Tempfile. The created file is not removed automatically. You should use File. If a block is given, then a File object will be constructed, and the block is invoked with the object as the argument.

The File object will be automatically closed and the temporary file is removed after the block terminates. The call returns the value of the block. The basename parameter is used to determine the name of the temporary file. You can either pass a String or an Array with 2 String elements. In the former form, the temporary file's base name will begin with the given string. In the latter form, the temporary file's base name will begin with the array's first element, and end with the second element.

For example:. The temporary file will be placed in the directory as specified by the tmpdir parameter. By default, this is Dir. Please note that ENV values are tainted by default, and Dir. You can also pass an options hash. Under the hood, Tempfile creates the temporary file using File. These options will be passed to File. This is mostly useful for specifying encoding options, e. How to append text to a file with Ruby.

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