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Automated merge with ssh://xanthippe//home/dirk/Projekte/Blog
author Dirk Olmes <dirk.olmes@codedo.de>
date Sat, 28 Mar 2020 02:43:15 +0100
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1 Title: New Zipper release
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2 Date: 2007-05-22
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3 Lang: en
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5 I had to debug Mule's build for the upcoming 1.4.1 release a bit, especially the packaging of the JCA distribution. I usually use Zipper to open archives, that's why I wrote it in the first place. It turns out that some file extensions are ambiguous, e.g. a file ending in .rar could either be a rar archive or a Java Resource ARchive which is effectively a zip file. Since the rar packager cannot handle zip files I picked up an idea I had in mind for a long time now: file types should not be determined by their extensions but the way the unix file command does it: by looking for certain patterns inside of a file. I implemented the most simple cases in Zipper now: Zip files begin with
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7 :::shell
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8 { 'P', 'K', 0x003, 0x004 }
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10 and rar files begin with
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12 :::shell
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13 { 'R', 'a', 'r', '!'}
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15 straight from the beginning of the file. When opening a file Zipper asks all registered Archive subclasses for their magic bytes and compares them to the first four bytes of the file. I think I will extend this mechanism a bit in the future so in the end all supported archives will be determined by a file's content and not by its file extension any more.