org.http4k.core.parser.kt Maven / Gradle / Ivy

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package org.http4k.core

fun Request.Companion.parse(request: String, lineBreak: String = "\r\n"): Request {
    val lines = lines(request, lineBreak)
    val (method, uri) = parseRequestLine(lines[0])
    val headers = parseHeaders(headerLines(lines))
    val body = parseBody(bodyLines(lines))
    return headers.fold(Request(method, uri).body(body)
    ) { memo, (first, second) -> memo.header(first, second) }
}

fun Response.Companion.parse(response: String, lineBreak: String = "\r\n"): Response {
    val lines = lines(response, lineBreak)
    val status = parseStatus(lines[0])
    val headers = parseHeaders(headerLines(lines))
    val body = parseBody(bodyLines(lines))
    return headers.fold(Response(status).body(body)) { memo, (first, second) -> memo.header(first, second) }
}

private fun lines(message: String, lineBreak: String): List =
    if (message.isBlank()) throw IllegalArgumentException("Empty message") else
        message.split(lineBreak)

private fun parseStatus(value: String): Status {
    val values = value.split(" ", limit = 3)
    if (values.size < 2) throw IllegalArgumentException("Invalid status line: $value")
    val code = values[1].toIntOrNull() ?: throw IllegalArgumentException("Invalid HTTP status: ${values[1]}")
    return Status(code, values.getOrElse(2) { "" })
}

private fun parseBody(bodyLines: List): Body = Body(bodyLines.joinToString(""))

private fun bodyLines(lines: List): List = lines.subList(lines.indexOf("") + 1, lines.size)

private fun parseHeaders(headerLines: List): Parameters = headerLines.map(::parseHeader)

private fun parseHeader(line: String) = line.split(": ").let { it[0] to it[1] }

private fun headerLines(lines: List) = lines.subList(1, lines.indexOf(""))

private fun parseRequestLine(line: String): Pair =
    with(line.split(" ")) {
        when {
            size < 2 -> throw IllegalArgumentException("Invalid request line: $line")
            else -> try {
                Method.valueOf(this[0]) to Uri.of(this[1])
            } catch (e: Exception) {
                throw IllegalArgumentException("Invalid method: ${this[0]}")
            }
        }
    }