GzipMiddleware/Sources/GzipMiddleware/GzipMiddleware.swift

67 lines
3.0 KiB
Swift

import HTTP
import Vapor
import Foundation
import ZIPFoundation
/// Server Gzip middlere:
/// 1. checks if the "Accept-Encoding" header contains "gzip"
/// 2. if so, compresses the body and sets the response header "Content-Encoding" to "gzip",
public struct GzipServerMiddleware: Middleware, ServiceType {
public static func makeService(for worker: Container) throws -> GzipServerMiddleware {
return .init()
}
private let shouldGzip: (_ request: Request) -> Bool
/// The `shouldGzip` closure is asked for every request whether that request
/// should allow response gzipping. Returns `true` always by default.
public init(shouldGzip: @escaping (_ request: Request) -> Bool = { _ in true }) {
self.shouldGzip = shouldGzip
}
public func respond(to request: Request, chainingTo next: Responder) throws -> EventLoopFuture<Response> {
let acceptsGzip = request.http.headers[.acceptEncoding].first?.contains("gzip") ?? false
guard acceptsGzip && shouldGzip(request) else {
return try next.respond(to: request)
}
let response = try next.respond(to: request)
return response.flatMap { response in
var headers = response.http.headers
headers.replaceOrAdd(name: .contentEncoding, value: "gzip")
return response.http.body.consumeData(on: request).map { data in
let stream = HTTPChunkedStream(on: request)
let bufSize = 4096
var buffer = ByteBufferAllocator().buffer(capacity: bufSize)
let header : [UInt8] = [0x1f, 0x8b, 0x08, 0x00]
let header2 : [UInt8] = [0x00, 0x03]
buffer.write(bytes: header)
buffer.write(integer: UInt32(Date().timeIntervalSince1970), endianness: .little)
buffer.write(bytes: header2)
var write = stream.write(.chunk(buffer))
let crc32 = try Data.compress(size: data.count, bufferSize: bufSize,
provider: {(offset, readSize) -> Data in
return data.subdata(in: offset..<offset+readSize)
},
consumer: { data -> Void in
write = write.flatMap {
buffer.clear()
buffer.write(bytes: data)
return stream.write(.chunk(buffer))
}
})
write.always {
buffer.clear()
buffer.write(integer: crc32, endianness: .little)
buffer.write(integer: UInt32(data.count), endianness: .little)
stream.write(.chunk(buffer)).always {
_ = stream.write(.end)
}
}
let httpResponse = HTTPResponse(status: response.http.status, headers: headers, body: stream)
return request.response(http: httpResponse)
}
}
}
}