initial commit

httpd.d

@@ -0,0 +1,231 @@
+module httpd;
+
+import std.algorithm;
+import std.array;
+import std.conv;
+import std.exception;
+import std.format;
+import std.socket;
+import std.stdio;
+import std.string;
+
+enum HTTPMethod
+{
+	GET,
+	HEAD,
+	POST,
+	PUT,
+	DELETE,
+	CONNECT,
+	OPTIONS,
+	TRACE,
+	invalid
+}
+
+struct HTTPRequest
+{
+	HTTPMethod method;
+	string resource;
+	string[string] parameters;
+	string[string] headers;
+	string httpVersion = "HTTP/1.1";
+
+	alias path = resource;
+}
+
+struct HTTPResponse
+{
+	string status;
+	string[string] headers;
+	string responseBody;
+	string httpVersion = "HTTP/1.1";
+}
+
+class HttpdException : Exception
+{
+	mixin basicExceptionCtors;
+}
+
+int
+main(string[] args)
+{
+	char[1024] buffer;
+	Socket[] clients;
+	SocketSet readSet;
+	Socket listener;
+
+	listener = new Socket(AddressFamily.INET, SocketType.STREAM);
+	listener.bind(new InternetAddress("127.0.0.1", 80));
+	listener.listen(32);
+
+	readSet = new SocketSet();
+
+	while (true) {
+		readSet.reset();
+		readSet.add(listener);
+		foreach (Socket client; clients) {
+			readSet.add(client);
+		}
+
+		if (Socket.select(readSet, null, null)) {
+			foreach (ulong i, Socket client; clients) {
+				if (readSet.isSet(client)) {
+					client.send(tryRequest(buffer[0 .. client.receive(buffer)]));
+					clients.remove(i);
+				}
+			}
+			if (readSet.isSet(listener)) {
+				clients ~= listener.accept();
+			}
+		}
+	}
+	return 0;
+}
+
+string
+tryRequest(char[] requestBody)
+{
+	HTTPRequest rq;
+
+	try {
+		rq = parseHTTPRequest(requestBody);
+		if (rq.method != HTTPMethod.GET)
+			return failurePage("405 Method Not Allowed");
+		return rq.resource == "/"
+			|| rq.resource == "/index.html"
+			? respondWithPage(import("index.html"))
+			: failurePage("404 Not Found");
+	} catch (HttpdException e)
+		return failurePage(e.msg);
+}
+
+string
+failurePage(string status)
+{
+	return respondWithPage(
+		import("fail.html")
+			.replace("{status}", status),
+		status);
+}
+
+string
+respondWithPage(string pageBody, string status = "200 OK",
+	string contentType = "text/html")
+{
+	return makeHTTPResponse(
+		HTTPResponse(
+			status,
+			["Content-Type": contentType],
+			pageBody));
+}
+
+string
+makeHTTPResponse(in HTTPResponse resp)
+{
+	string[string] defaultHeaders, headers;
+	char[] result;
+
+	defaultHeaders = [
+		"Content-Length": resp.responseBody.length.to!string(),
+		"Server": "Jeremy's httpd"
+	];
+
+	result = (resp.httpVersion ~ ' ' ~ resp.status).dup();
+
+	headers = mergeHeaders(defaultHeaders, resp.headers);
+	foreach (string header; headers.byKey()) {
+		result ~= "\r\n" ~ header ~ ": " ~ headers[header];
+	}
+
+	finishResponse:
+	return result.idup() ~ "\r\n\r\n" ~ resp.responseBody;
+}
+
+string[string]
+mergeHeaders(const(string[string]) a1, const(string[string]) a2)
+{
+	string[string] result = cast(string[string])a1.dup();
+
+	foreach (string key; a2.byKey()) {
+		result[key] = a2[key];
+	}
+
+	return result;
+}
+
+HTTPRequest
+parseHTTPRequest(in char[] request)
+{
+	HTTPRequest result;
+
+	result = parseHTTPRequestHeading(request
+		.findSplitBefore("\r\n")[0]
+		.idup());
+	return result;
+}
+
+HTTPRequest
+parseHTTPRequestHeading(string heading)
+{
+	HTTPRequest result;
+	string methodString, path, params;
+
+	heading = heading.dup();
+
+	auto tup = heading.findSplit(" ");
+	methodString = tup[0];
+	heading = tup[2];
+
+	switch (methodString) {
+	case "GET":
+		result.method = HTTPMethod.GET;
+		break;
+	case "HEAD":
+		result.method = HTTPMethod.HEAD;
+		break;
+	case "POST":
+		result.method = HTTPMethod.POST;
+		break;
+	case "PUT":
+		result.method = HTTPMethod.PUT;
+		break;
+	case "DELETE":
+		result.method = HTTPMethod.DELETE;
+		break;
+	case "CONNECT":
+		result.method = HTTPMethod.CONNECT;
+		break;
+	case "OPTIONS":
+		result.method = HTTPMethod.OPTIONS;
+		break;
+	case "TRACE":
+		result.method = HTTPMethod.TRACE;
+		break;
+	default:
+		throw new HttpdException("400 Bad Request");
+	}
+
+	tup = heading.findSplit(" ");
+	path = tup[0];
+	params = path.findSplitAfter("?")[1];
+	heading = tup[2];
+
+	params = params.length == path.length ? "" : params;
+
+	if (path.length == 0 || path[0] != '/')
+		throw new HttpdException("400 Bad Request");
+
+	result.path = path;
+
+	if (params.length == 0)
+		return result;
+
+	foreach (string param; params.split("&")) {
+		auto pair = param.findSplit("=");
+		result.parameters[pair[0]] = pair[2];
+	}
+
+	result.httpVersion = heading.strip();
+
+	return result;
+}