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open files for buffered reading and writing in #golang
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-- import ""

xopen makes it easy to get buffered (possibly gzipped) readers and writers. and close all of the associated files. Ropen opens a file for reading. Wopen opens a file for writing. Both will use gzip when appropriate and will use buffered IO.


Here's how to get a buffered reader:

// gzipped
rdr, err := xopen.Ropen("some.gz")
// normal
rdr, err := xopen.Ropen("some.txt")
// stdin (possibly gzipped)
rdr, err := xopen.Ropen("-")
// https://
rdr, err := xopen.Ropen("")
// Cmd
rdr, err := xopen.Ropen("|ls -lh somefile.gz")
// User directory:
rdr, err := xopen.Ropen("~/brentp/somefile")

Get a buffered writer with xopen.Wopen. Get a temp file with xopen.Wopen("tmp:prefix")

func CheckBytes

func CheckBytes(b *bufio.Reader, buf []byte) (bool, error)

CheckBytes peeks at a buffered stream and checks if the first read bytes match.

func IsGzip

func IsGzip(b *bufio.Reader) (bool, error)

IsGzip returns true buffered Reader has the gzip magic.

func IsStdin

func IsStdin() bool

IsStdin checks if we are getting data from stdin.

func XReader

func XReader(f string) (io.Reader, error)

XReader returns a reader from a url string or a file.

type Reader

type Reader struct {

Reader is returned by Ropen

func Buf

func Buf(r io.Reader) *Reader

Return a buffered reader from an io.Reader If f == "-", then it will attempt to read from os.Stdin. If the file is gzipped, it will be read as such.

func Ropen

func Ropen(f string) (*Reader, error)

Ropen opens a buffered reader.

func (*Reader) Close

func (r *Reader) Close() error

Close the associated files.

type Writer

type Writer struct {

Writer is returned by Wopen

func Wopen

func Wopen(f string) (*Writer, error)

Wopen opens a buffered reader. If f == "-", then stdout will be used. If f endswith ".gz", then the output will be gzipped. If f startswith "tmp:" then a tempfile will be created with a prefix of the string following ":"

func (*Writer) Name

func (w *Writer) Name() string

The path to the underlying file handle.

func (*Writer) Close

func (w *Writer) Close() error

Close the associated files.

func (*Writer) Flush

func (w *Writer) Flush()

Flush the writer.

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