https://github.com/orcaman/writerseeker

WriterSeeker is the in-memory io.WriteSeeker implementation missing in the standard lib
https://github.com/orcaman/writerseeker

Last synced: 2 months ago
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WriterSeeker is the in-memory io.WriteSeeker implementation missing in the standard lib

• Host: GitHub
• URL: https://github.com/orcaman/writerseeker
• Owner: orcaman
• License: mit
• Created: 2017-08-23T11:55:53.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2020-06-21T08:55:26.000Z (over 4 years ago)
• Last Synced: 2024-10-20T17:26:48.187Z (3 months ago)
• Language: Go
• Homepage:
• Size: 11.7 KB
• Stars: 63
• Watchers: 7
• Forks: 10
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# WriterSeeker [![CircleCI](https://circleci.com/gh/orcaman/writerseeker.svg?style=svg)](https://circleci.com/gh/orcaman/writerseeker) [![GoDoc](https://godoc.org/github.com/orcaman/writerseeker?status.svg)](https://godoc.org/github.com/orcaman/writerseeker)

WriterSeeker is the in-memory io.WriteSeeker implementation missing in the standard lib :-)

## Use-case

In serverless / PaaS environments there is usually no file system access - you cannot read or write files to the container you are running in. This means that if you are using a function or library in Go that expects a `File` type (which implements the `io.WriteSeeker` interface), you are pretty much screwed. WriterSeeker solves this by letting you write and seek inside an in-memory buffer.

## Usage Example

Let's say that you are using a library to generate PDF files. The library usually expects a `File` type to perform the writing to. You would create a `File` by using `os.Open` and then feed this to the `Write` function like so:

```go

fWrite, err := os.Create(outputPath)

if err != nil {

    return err

}

defer fWrite.Close()

err = pdfWriter.Write(fWrite)

```

With `WriterSeeker`, you do not need the file, just work in-memory:

```go

writerSeeker := &writerseeker.WriterSeeker{}

err = pdfWriter.Write(writerSeeker)

```

Now you can get a an `io.Reader` from the `writerSeeker` instance and boogie! for example, copy it's buffer to an `io.Writer`.

```go

r := writerSeeker.Reader()

w := getWriter()

if _, err := io.Copy(w, r); err != nil {

 ...

 ...

 ...

}

```

## License

The code is MIT licensed. It uses code from [this post](https://stackoverflow.com/questions/45836767/using-an-io-writeseeker-without-a-file-in-go/45837752#45837752) on StackOverflow, and according to the [official docs](https://meta.stackexchange.com/questions/271080/the-mit-license-clarity-on-using-code-on-stack-overflow-and-stack-exchange) this code can be safely used with MIT license.