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Enable automatic compression format detection (#208)

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Co-authored-by: Cory Benfield <lukasa@apple.com>
This commit is contained in:
David Nadoba 2024-03-26 09:57:29 +00:00 committed by GitHub
parent 3bbec9883a
commit 8b9030df7c
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GPG Key ID: B5690EEEBB952194
5 changed files with 68 additions and 23 deletions
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45
Sources/NIOHTTPCompression/HTTPDecompression.swift
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@ -94,18 +94,41 @@ public enum NIOHTTPDecompression {
return nil
}
}
var window: CInt {
switch self {
case .deflate:
return 15
case .gzip:
return 15 + 16
}
}
}
struct Decompressor {
/// `15` is the base two logarithm of the maximum window size (the size of the history buffer). It should be in the range 8..15 for this version of the library.
/// `32` enables automatic detection of gzip or zlib compression format with automatic header detection.
///
/// Documentation from https://www.zlib.net/manual.html:
/// The windowBits parameter is the base two logarithm of the maximum window size (the size of the history buffer).
/// It should be in the range 8..15 for this version of the library.
/// The default value is 15 if inflateInit is used instead.
/// windowBits must be greater than or equal to the windowBits value provided to deflateInit2() while compressing,
/// or it must be equal to 15 if deflateInit2() was not used.
/// If a compressed stream with a larger window size is given as input,
/// inflate() will return with the error code Z_DATA_ERROR instead of trying to allocate a larger window.
/// windowBits can also be zero to request that inflate use the window size in the zlib header of the compressed stream.
/// windowBits can also be –8..–15 for raw inflate.
/// In this case, -windowBits determines the window size.
/// inflate() will then process raw deflate data, not looking for a zlib or gzip header, not generating a check value,
/// and not looking for any check values for comparison at the end of the stream.
/// This is for use with other formats that use the deflate compressed data format such as zip.
/// Those formats provide their own check values.
/// If a custom format is developed using the raw deflate format for compressed data,
/// it is recommended that a check value such as an Adler-32 or a CRC-32 be applied to the uncompressed data as is done in the zlib,
/// gzip, and zip formats. For most applications, the zlib format should be used as is.
/// Note that comments above on the use in deflateInit2() applies to the magnitude of windowBits.
/// windowBits can also be greater than 15 for optional gzip decoding.
/// Add 32 to windowBits to enable zlib and gzip decoding with automatic header detection,
/// or add 16 to decode only the gzip format (the zlib format will return a Z_DATA_ERROR).
/// If a gzip stream is being decoded, strm->adler is a CRC-32 instead of an Adler-32.
/// Unlike the gunzip utility and gzread() (see below), inflate() will not automatically decode concatenated gzip members.
/// inflate() will return Z_STREAM_END at the end of the gzip member.
/// The state would need to be reset to continue decoding a subsequent gzip member.
/// This must be done if there is more data after a gzip member, in order for the decompression to be compliant with the gzip standard (RFC 1952).
static let windowBitsWithAutomaticCompressionFormatDetection: Int32 = 15 + 32
private let limit: NIOHTTPDecompression.DecompressionLimit
private var stream = z_stream()
private var inflated = 0
@ -125,13 +148,13 @@ public enum NIOHTTPDecompression {
return result
}
mutating func initializeDecoder(encoding: NIOHTTPDecompression.CompressionAlgorithm) throws {
mutating func initializeDecoder() throws {
self.stream.zalloc = nil
self.stream.zfree = nil
self.stream.opaque = nil
self.inflated = 0
let rc = CNIOExtrasZlib_inflateInit2(&self.stream, encoding.window)
let rc = CNIOExtrasZlib_inflateInit2(&self.stream, Self.windowBitsWithAutomaticCompressionFormatDetection)
guard rc == Z_OK else {
throw NIOHTTPDecompression.DecompressionError.initializationError(Int(rc))
}

2
Sources/NIOHTTPCompression/HTTPRequestDecompressor.swift
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@ -55,7 +55,7 @@ public final class NIOHTTPRequestDecompressor: ChannelDuplexHandler, RemovableCh
let length = head.headers[canonicalForm: "Content-Length"].first.flatMap({ Int($0) })
{
do {
try self.decompressor.initializeDecoder(encoding: algorithm)
try self.decompressor.initializeDecoder()
self.compression = Compression(algorithm: algorithm, contentLength: length)
} catch let error {
context.fireErrorCaught(error)

2
Sources/NIOHTTPCompression/HTTPResponseDecompressor.swift
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@ -71,7 +71,7 @@ public final class NIOHTTPResponseDecompressor: ChannelDuplexHandler, RemovableC
do {
if let algorithm = algorithm {
self.compression = Compression(algorithm: algorithm, compressedLength: 0)
try self.decompressor.initializeDecoder(encoding: algorithm)
try self.decompressor.initializeDecoder()
}
context.fireChannelRead(data)

13
Tests/NIOHTTPCompressionTests/HTTPRequestDecompressorTest.swift
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@ -103,13 +103,20 @@ class HTTPRequestDecompressorTest: XCTestCase {
try channel.pipeline.addHandler(NIOHTTPRequestDecompressor(limit: .none)).wait()
let body = Array(repeating: testString, count: 1000).joined()
let algorithms: [(actual: String, announced: String)?] = [
nil,
(actual: "gzip", announced: "gzip"),
(actual: "deflate", announced: "deflate"),
(actual: "gzip", announced: "deflate"),
(actual: "deflate", announced: "gzip"),
]
for algorithm in [nil, "gzip", "deflate"] {
for algorithm in algorithms {
let compressed: ByteBuffer
var headers = HTTPHeaders()
if let algorithm = algorithm {
headers.add(name: "Content-Encoding", value: algorithm)
compressed = compress(ByteBuffer.of(string: body), algorithm)
headers.add(name: "Content-Encoding", value: algorithm.announced)
compressed = compress(ByteBuffer.of(string: body), algorithm.actual)
} else {
compressed = ByteBuffer.of(string: body)
}

27
Tests/NIOHTTPCompressionTests/HTTPResponseDecompressorTest.swift
View File

@ -166,13 +166,20 @@ class HTTPResponseDecompressorTest: XCTestCase {
for _ in 1...1000 {
body += "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
}
let algorithms: [(actual: String, announced: String)?] = [
nil,
(actual: "gzip", announced: "gzip"),
(actual: "deflate", announced: "deflate"),
(actual: "gzip", announced: "deflate"),
(actual: "deflate", announced: "gzip"),
]
for algorithm in [nil, "gzip", "deflate"] {
for algorithm in algorithms {
let compressed: ByteBuffer
var headers = HTTPHeaders()
if let algorithm = algorithm {
headers.add(name: "Content-Encoding", value: algorithm)
compressed = compress(ByteBuffer.of(string: body), algorithm)
headers.add(name: "Content-Encoding", value: algorithm.announced)
compressed = compress(ByteBuffer.of(string: body), algorithm.actual)
} else {
compressed = ByteBuffer.of(string: body)
}
@ -214,12 +221,20 @@ class HTTPResponseDecompressorTest: XCTestCase {
body += "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
}
for algorithm in [nil, "gzip", "deflate"] {
let algorithms: [(actual: String, announced: String)?] = [
nil,
(actual: "gzip", announced: "gzip"),
(actual: "deflate", announced: "deflate"),
(actual: "gzip", announced: "deflate"),
(actual: "deflate", announced: "gzip"),
]
for algorithm in algorithms {
let compressed: ByteBuffer
var headers = HTTPHeaders()
if let algorithm = algorithm {
headers.add(name: "Content-Encoding", value: algorithm)
compressed = compress(ByteBuffer.of(string: body), algorithm)
headers.add(name: "Content-Encoding", value: algorithm.announced)
compressed = compress(ByteBuffer.of(string: body), algorithm.actual)
} else {
compressed = ByteBuffer.of(string: body)
}