propensive / zeppelin

Work with ZIP files in Scala

Zeppelin

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Zeppelin makes it easy to work with ZIP files in Scala, providing methods for efficiently reading and writing files within a ZIP archive, in a streaming or random access style.

Features

• provides methods for reading and writing ZIP files
• integrates seamlessly with Galilei and third-party file representations
• both streaming and random-access APIs are provided
• integrates directly with Turbulence readable and writable types

Availability Plan

Zeppelin has not yet been published. The medium-term plan is to build Zeppelin with Fury and to publish it as a source build on Vent. This will enable ordinary users to write and build software which depends on Zeppelin.

Subsequently, Zeppelin will also be made available as a binary in the Maven Central repository. This will enable users of other build tools to use it.

For the overeager, curious and impatient, see building.

Getting Started

Creating a ZIP file

A ZIP file can be constructed from an existing file by passing it to the ZipFile constructor. Provided there is an appropriate GenericPathReader and GenericPathMaker (from Anticipation) in scope, any file representation (such as java.io.File) may be used. For example,

import zeppelin.*
import diuretic.*
val file: java.io.File = java.io.File("/home/work/data.zip")
val zip = ZipFile(file)

or,

import zeppelin.*
import anticipation.fileApi.galileiApi
val file: galilei.DiskPath = Unix / p"home" / p"work" / p"data.zip"
val zip = ZipFile(file)

ZipFile provides several methods for working with the file.

Reading entries from a ZIP file

To read every entry from a ZipFile, call ZipFile#entries(). This will return a LazyList[ZipEntry], a stream of ZipEntrys in the order they are stored within the file, each one consisting of a Relative path (relative to the root of the ZIP file) and a method to get its contents.

ZipEntrys support Turbulence's Readable interface, so they can be read as any type for which an Aggregable instance exists.

Appending files to an existing ZIP file

To add additional entries to a ZipFile, use ZipFile#append, which takes a LazyList of ZipEntrys to append.

This method includes two additional parameters: a prefix, a Bytes (IArray[Byte]) value to be inserted in raw form at the start of the ZIP file, typically used to make the ZIP file executable; and a timestamp value for specifying the timestamp of each entry appended to the ZIP file. If no timestamp is specified, the current time will be used.

Status

Zeppelin is classified as fledgling. For reference, Scala One projects are categorized into one of the following five stability levels:

• embryonic: for experimental or demonstrative purposes only, without any guarantees of longevity
• fledgling: of proven utility, seeking contributions, but liable to significant redesigns
• maturescent: major design decisions broady settled, seeking probatory adoption and refinement
• dependable: production-ready, subject to controlled ongoing maintenance and enhancement; tagged as version 1.0.0 or later
• adamantine: proven, reliable and production-ready, with no further breaking changes ever anticipated

Projects at any stability level, even embryonic projects, can still be used, as long as caution is taken to avoid a mismatch between the project's stability level and the required stability and maintainability of your own project.

Zeppelin is designed to be small. Its entire source code currently consists of 177 lines of code.

Building

Zeppelin will ultimately be built by Fury, when it is published. In the meantime, two possibilities are offered, however they are acknowledged to be fragile, inadequately tested, and unsuitable for anything more than experimentation. They are provided only for the necessity of providing some answer to the question, "how can I try Zeppelin?".

1. Copy the sources into your own project

   Read the fury file in the repository root to understand Zeppelin's build structure, dependencies and source location; the file format should be short and quite intuitive. Copy the sources into a source directory in your own project, then repeat (recursively) for each of the dependencies.

   The sources are compiled against the latest nightly release of Scala 3. There should be no problem to compile the project together with all of its dependencies in a single compilation.

2. Build with Wrath

   Wrath is a bootstrapping script for building Zeppelin and other projects in the absence of a fully-featured build tool. It is designed to read the fury file in the project directory, and produce a collection of JAR files which can be added to a classpath, by compiling the project and all of its dependencies, including the Scala compiler itself.

   Download the latest version of wrath, make it executable, and add it to your path, for example by copying it to /usr/local/bin/.

   Clone this repository inside an empty directory, so that the build can safely make clones of repositories it depends on as peers of zeppelin. Run wrath -F in the repository root. This will download and compile the latest version of Scala, as well as all of Zeppelin's dependencies.

   If the build was successful, the compiled JAR files can be found in the .wrath/dist directory.

Contributing

Contributors to Zeppelin are welcome and encouraged. New contributors may like to look for issues marked beginner.

We suggest that all contributors read the Contributing Guide to make the process of contributing to Zeppelin easier.

Please do not contact project maintainers privately with questions unless there is a good reason to keep them private. While it can be tempting to repsond to such questions, private answers cannot be shared with a wider audience, and it can result in duplication of effort.

Author

Zeppelin was designed and developed by Jon Pretty, and commercial support and training on all aspects of Scala 3 is available from Propensive OÜ.

Name

Like a ZIP file, a zeppelin airship may be inflated or deflated, and the name furthermore is an allusion to _zip_ping.

In general, Scala One project names are always chosen with some rationale, however it is usually frivolous. Each name is chosen for more for its uniqueness and intrigue than its concision or catchiness, and there is no bias towards names with positive or "nice" meanings—since many of the libraries perform some quite unpleasant tasks.

Names should be English words, though many are obscure or archaic, and it should be noted how willingly English adopts foreign words. Names are generally of Greek or Latin origin, and have often arrived in English via a romance language.

Logo

The logo shows the overlaid shapes of three zippers.

License

Zeppelin is copyright © 2024 Jon Pretty & Propensive OÜ, and is made available under the Apache 2.0 License.

zeppelin's Issues

Use contextual values to decide whether to create parent directories for `ZipFile.create`

Use Contingency for errors

Redesign logo

I don't think the old one is sufficiently interesting.