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https://issues.apache.org/jira/browse/COMPRESS-550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17179089#comment-17179089
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Scott Frederick commented on COMPRESS-550:
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{quote}I think you mean _zip --adjust-sfx test_ instead of _zip --adjust-sfx
test.zip_ in your example.
{quote}
Yes, thank you.
{quote}I'm not clear why we need a self-extracting zip.
{quote}
There are lots of reasons that someone could want a self-extracting zip. The
example provided was the simplest one I could find to illustrate a workflow
that's possible with Linux command-line tools but not possible currently with
Commons Compress.
{quote}I checked your issue of real-world use case about spring-boot. Seems
there are Maven/Gradle build plugins that can only produce self-extracting zips
instead of normal zips. Is it so?
{quote}
The Spring Boot plugins for Maven and Gradle generate Java jar files, which of
course use the zip format. The jar files can be executed with a _java_ command
like:
{noformat}
$ java -jar myapp.jar{noformat}
Spring Boot provides an option to prepend an executable script to the generated
jar file to make it self-executable. If this option is used, the jar file can
be executed with just:
{noformat}
$ ./myapp.jar{noformat}
With this specific use case, the jar/zip is not self-extracting, but is
self-executing.
As with the _cat_ example in the CLI workflow, prepending the Spring Boot
executable script to the jar file results in a file with a central directory
that is invalid. Spring Boot uses Commons Compress for all jar/zip file reading
and writing, so having the ability to generate a self-executing jar file with a
valid central directory using Commons Compress would improve the user
experience.
> Support writing self-extracting preamble data to a zip archive
> --------------------------------------------------------------
>
> Key: COMPRESS-550
> URL: https://issues.apache.org/jira/browse/COMPRESS-550
> Project: Commons Compress
> Issue Type: New Feature
> Components: Archivers
> Affects Versions: 1.20
> Reporter: Scott Frederick
> Priority: Major
>
> On Linux, it is possible to create a self-extracting zip file by prepending a
> script or other executable to the zip file. For example, this can be done
> from the command line with the following commands:
> {code:bash}
> $ echo "test file text" > test.txt
> $ zip test.zip test.txt
> adding: test.txt (stored 0%)
> $ cat /usr/bin/unzipsfx test.zip > test
> $ zipinfo test
> Archive: test
> Zip file size: 101568 bytes, number of entries: 1
> warning [test]: 101392 extra bytes at beginning or within zipfile
> (attempting to process anyway)
> -rw-r--r-- 3.0 unx 10 tx stor 20-Jul-30 15:43 test.txt
> 1 file, 10 bytes uncompressed, 10 bytes compressed: 0.0%
> $ zip --adjust-sfx test.zip
> Zip entry offsets appear off by 101392 bytes - correcting...
> $ zipinfo test
> Archive: test
> Zip file size: 101568 bytes, number of entries: 1
> -rw-r--r-- 3.0 unx 10 tx stor 20-Jul-30 15:43 test.txt
> 1 file, 10 bytes uncompressed, 10 bytes compressed: 0.0%
> $ chmod 755 test
> {code}
> Note that the first invocation of "zipinfo" reports that the central
> directory is invalid because of extra bytes at the beginning of the zip file.
> "zip --adjust-sfx" can be used to adjust the central directory to account for
> the self-extracting preamble bytes.
> It would be nice to be able to prepend this kind of self-extracting preamble
> to a zip using Apache Commons Compress.
> A method like the following on ZipArchiveOutputStream seems to provide this
> behavior:
> {code:java}
> public void writePreamble(byte[] preamble) throws IOException {
> if (entry != null) {
> throw new IllegalStateException("Preamble must be written before
> creating an entry");
> }
> this.streamCompressor.writeCounted(preamble);
> }
> {code}
>
>
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