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Use string comparison instead of regex in the HTTPProtocolSwitcher #618

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Merged
merged 1 commit into from
Nov 5, 2019
Merged

Use string comparison instead of regex in the HTTPProtocolSwitcher #618

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16 changes: 8 additions & 8 deletions Package.resolved
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44 changes: 17 additions & 27 deletions Sources/GRPC/HTTPProtocolSwitcher.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -84,15 +84,28 @@ extension HTTPProtocolSwitcher: ChannelInboundHandler, RemovableChannelHandler {
// couldn't be detected.
var inBuffer = self.unwrapInboundIn(data)
guard let initialData = inBuffer.readString(length: inBuffer.readableBytes),
let preamble = initialData.split(separator: "\r\n",
maxSplits: 1,
omittingEmptySubsequences: true).first,
let version = protocolVersion(String(preamble)) else {
let firstLine = initialData.split(
separator: "\r\n",
maxSplits: 1,
omittingEmptySubsequences: true
).first else {
self.logger.error("unable to determine http version")
context.fireErrorCaught(HTTPProtocolVersionError.invalidHTTPProtocolVersion)
return
}

let version: HTTPProtocolVersion

if firstLine.contains("HTTP/2") {
version = .http2
} else if firstLine.contains("HTTP/1") {
version = .http1
} else {
self.logger.error("unable to determine http version")
context.fireErrorCaught(HTTPProtocolVersionError.invalidHTTPProtocolVersion)
return
}

self.logger.info("determined http version", metadata: ["http_version": "\(version)"])

// Once configured remove ourself from the pipeline, or handle the error.
Expand Down Expand Up @@ -161,27 +174,4 @@ extension HTTPProtocolSwitcher: ChannelInboundHandler, RemovableChannelHandler {
context.fireErrorCaught(error)
}
}

/// Peek into the first line of the packet to check which HTTP version is being used.
private func protocolVersion(_ preamble: String) -> HTTPProtocolVersion? {
let range = NSRange(location: 0, length: preamble.utf16.count)
let regex = try! NSRegularExpression(pattern: "^.*HTTP/(\\d)\\.\\d$")
guard let result = regex.firstMatch(in: preamble, options: [], range: range) else {
return nil
}

let versionRange = result.range(at: 1)

let start = String.Index(utf16Offset: versionRange.location, in: preamble)
let end = String.Index(utf16Offset: versionRange.location + versionRange.length, in: preamble)

switch String(preamble.utf16[start..<end])! {
case "1":
return .http1
case "2":
return .http2
default:
return nil
}
}
}