package httpserver;

import java.io.IOException;

import java.io.BufferedReader;

import java.lang.RuntimeException;

import java.net.URI;

import java.net.URISyntaxException;

import java.util.HashMap;

import java.util.Set;

public class HttpRequest {

// Possible HTTP request methods.

static enum Method {GET, HEAD}; // POST,PUT, ...

protected Method requestMethod;

protected String path;

protected HashMap<String, String> headers;

private String lastHeader;

/**

* Request factory

*

* Creates a factory by reading the socket input stream.

*/

public static HttpRequest fromReader(BufferedReader socketReader)

throws IOException, HttpError, NoRequestException

{

// The first line is the request line.

HttpRequest request = new HttpRequest(socketReader.readLine());

// Next lines are the headers.

boolean processing_headers = true;

String headerLine;

while (processing_headers) {

headerLine = socketReader.readLine();

if (headerLine == null || headerLine.equals("")) {

// The headers are terminated by a blank line.

processing_headers = false;

} else {

request.parseHeaderLine(headerLine);

}

}

return request;

}

public HttpRequest() {

requestMethod = Method.GET;

path = "/";

headers = new HashMap<String, String>();

lastHeader = null;

}

public HttpRequest(String requestLine)

throws HttpError, NoRequestException

{

parseRequestLine(requestLine);

headers = new HashMap<String, String>();

lastHeader = null;

}

public String toString() {

return String.format("%1s %2s HTTP/1.1", requestMethod, path);

}

private void parseRequestLine(String requestLine)

throws HttpError, NoRequestException

{

// Catch empty input streams.

if (requestLine == null) {

throw new NoRequestException();

}

String[] rlParts = requestLine.split(" ");

// Exactly 3 parts are expected.

if (rlParts.length != 3) {

throw new HttpError(HttpStatus.BadRequest(), "Malformed request line.");

}

// Check and select method enum.

switch (rlParts[0]) {

case "GET":

requestMethod = Method.GET;

break;

case "HEAD":

requestMethod = Method.HEAD;

break;

default:

throw new HttpError(HttpStatus.NotImplemented(), rlParts[0]);

}

// Parse the target to get the path.

try {

URI uri = new URI(rlParts[1]);

path = uri.getPath();

} catch (URISyntaxException urise) {

throw new HttpError(HttpStatus.BadRequest(), "Malformed target in request line.");

}

// Check Protocol.

if (!rlParts[2].equals("HTTP/1.1")) {

throw new HttpError(HttpStatus.HttpVersionNotSupported(), rlParts[2]);

}

}

private void parseHeaderLine(String headerLine) throws HttpError {

String key, value;

if (headerLine.startsWith(" ") || headerLine.startsWith("\t")) {

// Header continuation.

// Multi-line headers are deprecated and must be converted to

// single-line before further processing (RFC 7230 3.2.4)

if (lastHeader == null) {

// No header to continue.

throw new HttpError(HttpStatus.BadRequest(), "Malformed header: " + headerLine);

}

key = lastHeader;

value = headers.get(key) + " " + headerLine.trim();

} else {

String[] keyvalue = headerLine.split(": *", 2);

if (keyvalue.length != 2) {

throw new HttpError(HttpStatus.BadRequest(), "Malformed header: " + headerLine);

}

key = keyvalue[0].toLowerCase();

value = keyvalue[1].trim();

}

headers.put(key, value);

lastHeader = key;

}

public Method getMethod() {

return requestMethod;

}

public String getHeader(String headerName) {

return headers.get(headerName.toLowerCase());

}

public Set<String> getHeaderNames() {

return headers.keySet();

}

}