KTOR-7075: Zstd compression support

[tre3p]

Subsystem ktor-utils module, Compression plugin

Motivation This PR solves KTOR-7075 ticket by adding support for zstd compression algorithm to Compression plugin.

Solution I've used zstd-jni library which provides JNI binding to zstd compression algorithm implementation.

[coderabbitai[bot]]

[!IMPORTANT]

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

"""

Walkthrough

Zstandard (zstd) compression support was integrated into the codebase. This involved updating dependency management to include the zstd-jni library, introducing ZstdEncoder implementations for all platforms, adding zstd encoding/decoding utilities for JVM, extending the compression plugin configuration, and expanding the test suite to cover zstd-specific scenarios.

Changes

File(s)	Change Summary
gradle/libs.versions.toml	Added zstd-jni version and library entry.
ktor-utils/build.gradle.kts	Added zstd-jni as an API dependency.
ktor-utils/common/src/io/ktor/util/ContentEncoder.kt	Added expected ZstdEncoder implementing ContentEncoder.
ktor-utils/jsAndWasmShared/src/io/ktor/util/ContentEncodersJs.kt ktor-utils/posix/src/io/ktor/util/ContentEncodersNative.kt	Added actual ZstdEncoder objects for JS/WASM and Native, delegating to Identity encoder, with compressionLevel property.
ktor-utils/jvm/src/io/ktor/util/ContentEncodersJvm.kt	Added actual ZstdEncoder object for JVM, delegating to new Zstd encoder with compressionLevel property.
ktor-utils/jvm/src/io/ktor/util/EncodersJvm.kt	Added Zstd encoder implementation with configurable compressionLevel.
ktor-utils/jvm/src/io/ktor/util/ZstdEncoding.kt	Introduced coroutine-based extension functions for zstd compression and decompression on ByteReadChannel and ByteWriteChannel.
ktor-server/ktor-server-plugins/ktor-server-compression/jvm/src/io/ktor/server/plugins/compression/Config.kt	Added zstd() encoder registration, included ZstdEncoder in default encoders, and added compressionLevel property support.
ktor-server/ktor-server-tests/jvm/test/io/ktor/server/plugins/CompressionTest.kt	Expanded tests to cover zstd compression/decompression, including new test cases, decoding endpoint, and response decoding logic.
ktor-server/ktor-server-plugins/ktor-server-compression/api/ktor-server-compression.api	Added compressionLevel property to CompressionEncoderBuilder and CompressionEncoderConfig; added zstd configuration functions.
ktor-utils/api/ktor-utils.api	Added Zstd and ZstdEncoder classes and ZstdEncodingKt utility functions to API.
ktor-utils/api/ktor-utils.klib.api	Added ZstdEncoder object with compressionLevel property and encode/decode methods.

Suggested reviewers

• bjhham
• e5l """

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

🪧 Tips

Chat

There are 3 ways to chat with CodeRabbit:

• Review comments: Directly reply to a review comment made by CodeRabbit. Example:
  • I pushed a fix in commit <commit_id>, please review it.
  • Explain this complex logic.
  • Open a follow-up GitHub issue for this discussion.
• Files and specific lines of code (under the "Files changed" tab): Tag @coderabbitai in a new review comment at the desired location with your query. Examples:
  • @coderabbitai explain this code block.
  • @coderabbitai modularize this function.
• PR comments: Tag @coderabbitai in a new PR comment to ask questions about the PR branch. For the best results, please provide a very specific query, as very limited context is provided in this mode. Examples:
  • @coderabbitai gather interesting stats about this repository and render them as a table. Additionally, render a pie chart showing the language distribution in the codebase.
  • @coderabbitai read src/utils.ts and explain its main purpose.
  • @coderabbitai read the files in the src/scheduler package and generate a class diagram using mermaid and a README in the markdown format.
  • @coderabbitai help me debug CodeRabbit configuration file.

Support

Need help? Create a ticket on our support page for assistance with any issues or questions.

Note: Be mindful of the bot's finite context window. It's strongly recommended to break down tasks such as reading entire modules into smaller chunks. For a focused discussion, use review comments to chat about specific files and their changes, instead of using the PR comments.

CodeRabbit Commands (Invoked using PR comments)

• @coderabbitai pause to pause the reviews on a PR.
• @coderabbitai resume to resume the paused reviews.
• @coderabbitai review to trigger an incremental review. This is useful when automatic reviews are disabled for the repository.
• @coderabbitai full review to do a full review from scratch and review all the files again.
• @coderabbitai summary to regenerate the summary of the PR.
• @coderabbitai generate docstrings to generate docstrings for this PR.
• @coderabbitai generate sequence diagram to generate a sequence diagram of the changes in this PR.
• @coderabbitai resolve resolve all the CodeRabbit review comments.
• @coderabbitai configuration to show the current CodeRabbit configuration for the repository.
• @coderabbitai help to get help.

Other keywords and placeholders

• Add @coderabbitai ignore anywhere in the PR description to prevent this PR from being reviewed.
• Add @coderabbitai summary to generate the high-level summary at a specific location in the PR description.
• Add @coderabbitai anywhere in the PR title to generate the title automatically.

CodeRabbit Configuration File (.coderabbit.yaml)

• You can programmatically configure CodeRabbit by adding a .coderabbit.yaml file to the root of your repository.
• Please see the configuration documentation for more information.
• If your editor has YAML language server enabled, you can add the path at the top of this file to enable auto-completion and validation: # yaml-language-server: $schema=https://coderabbit.ai/integrations/schema.v2.json

Documentation and Community

• Visit our Documentation for detailed information on how to use CodeRabbit.
• Join our Discord Community to get help, request features, and share feedback.
• Follow us on X/Twitter for updates and announcements.

[tre3p]

@bjhham Hey! Made some changes according to your comments, thanks for them! Please, take a look at this changes and also at my comment about existing test I've changed. Thanks!

[osipxd]

I'm sorry. After merging 3.3.0-eap into main this PR got closed. Could you open a new one? 🙏