71 lines
2.6 KiB
Markdown
71 lines
2.6 KiB
Markdown
## bindata
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This tool converts any file into managable Go source code. Useful for embedding
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binary data into a go program. The file data is gzip compressed before being
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converted to a raw byte slice.
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### Usage
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The simplest invocation is to pass it only the input file name.
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The output file and code settings are inferred from this automatically.
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$ bindata -i testdata/gophercolor.png
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[w] No output file specified. Using 'testdata/gophercolor.png.go'.
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[w] No package name specified. Using 'main'.
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[w] No function name specified. Using 'gophercolor_png'.
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[i] Done.
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This creates the "testdata/gophercolor.png.go" file which has a package
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declaration with name 'main' and one function named 'gophercolor_png'.
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It looks like this:
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// gophercolor_png returns the decompressed binary data.
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// It panics if an error occurred.
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func gophercolor_png() []byte {
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gz, err := gzip.NewReader(bytes.NewBuffer([]byte{
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...
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}))
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if err != nil {
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panic("Decompression failed: " + err.Error())
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}
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var b bytes.Buffer
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io.Copy(&b, gz)
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gz.Close()
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return b.Bytes()
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}
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You can now simply include the new .go file in your program and call
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gophercolor_png() to get the uncompressed image data. The function panics
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if something went wrong during decompression. This makes any faults appearant
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during initialization of your program, so it can quickly be fixed. Additionally,
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this approach allows us to assign the decompressed file data to global
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variables where necessary.
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See the testdata directory for example input and output.
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Aternatively, you can pipe the input file data into stdin. bindata will then
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spit out the generated Go code to stdout. This does require explicitly naming
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the desired function name, as it can not be inferred from the input data.
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The package name will still default to 'main'.
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$ cat testdata/gophercolor.png | ./bindata -f gophercolor_png | gofmt
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Invoke the program with the -h flag for more options.
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### Optional compression
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When the `-u` flag is given, the supplied resource is *not* GZIP compressed
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before being turned into Go code. This also alters the generated output in that
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we no longer need a function that decompresses the data. The resource's raw
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byte data is simply assigned to a global variable of the same name as the
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function would otherwise get. This feature is useful if you do not care for
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compression, or the supplied resource is already compressed. Doing it again
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would not add any value and may even increase the size of the data.
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The default behaviour of the program is to use compression.
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