Swift implementation of Binary HTTP

Description

This project is a Swift language implementation of the Binary HTTP format, according to RFC9292 "Binary Representation of HTTP Messages". It allows serializing Apple Foundation types such as URLRequest and HTTPURLResponse into binary data and back from it. This allows for encoding HTTP messages that can be conveyed outside of the HTTP protocol, for example, to use in Oblivious HTTP.

Table of Contents

• Installation
• Usage
• Limitations

Installation

Swift Package Manager

You can use The Swift Package Manager to install BHTTPSwift by adding the dependency to your Package.swift file:

// swift-tools-version:4.0
import PackageDescription


let package = Package(
    name: "YOUR_PROJECT_NAME",
    dependencies: [
        .package(url: "[email protected]:flohealth/bhttp-swift.git", from: "0.1.0"),
    ]
)

Usage

Importing the BHTTPSwift module allows using methods provided by extensions to URLRequest and HTTPURLResponse:

// Import the Binary HTTP library
import BHTTPSwift


// Encode URLRequest into Data
let request: URLRequest = URLRequest(...)
let requestData: Data = try request.asBinaryHTTP()


// Decode HTTPURLResponse from Data
let responseData: Data = Data(...)
let decodedResponse = try HTTPURLResponse.from(url: url, binaryHTTPData: responseData)

Feature support

Binary HTTP specification defines two formats of messages (meaning both requests and responses): Known-Length Messages and Indeterminate-Length Messages. Ideally, this library could support serialization and deserialization of both formats for both request and response. Current support is limited to Known-Length Messages only and two possible translations that are required by client applications:

1. Serialization of URLRequest into Known-Length Request
2. Deserialization of HTTPURLResponse from Known-Length Response

Supported translations matrix

Message Type	To Binary	From Binary
Known-Length Request	supported	X
Known-Length Response	X	supported
Indeterminate-Length Request	X	X
Indeterminate-Length Response	X	X

Limitations

HTTP Fields encoding

This library uses ASCII to encode and decode string data for URL and HTTP header fields and their values. It does not implement automatic encoding of any non-ASCII characters into ASCII and will throw an error if it encounters any. In particular:

• If a non-ASCII character is encountered in the URL or a header field (field name or value) of an URLRequest, RequestCreationError will be thrown, indicating the point of failure
• If header data of a response cannot be decoded into String using ASCII, BinaryHTTPDecodingError.asciiDecodingError will be thrown

If you still need to pass non-ASCII values, encode them into ASCII before calling this library. For example, use percent-encoding for request URLs, etc.

License

Released under MIT License.