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Add a very basic HTTP server that generates labyrinths via GET requests to /create
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This commit is contained in:
Manuel Friedli 2020-10-05 20:15:40 +02:00
parent 8c1dc92cc8
commit ccba8a9a11
2 changed files with 223 additions and 28 deletions
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18
src/main/java/ch/fritteli/labyrinth/Main.java
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@ -1,18 +1,33 @@
package ch.fritteli.labyrinth;
import ch.fritteli.labyrinth.model.Labyrinth;
import ch.fritteli.labyrinth.net.TheListener;
import ch.fritteli.labyrinth.renderer.html.HTMLRenderer;
import ch.fritteli.labyrinth.renderer.htmlfile.HTMLFileRenderer;
import ch.fritteli.labyrinth.renderer.pdffile.PDFFileRenderer;
import ch.fritteli.labyrinth.renderer.text.TextRenderer;
import ch.fritteli.labyrinth.renderer.textfile.TextFileRenderer;
import io.vavr.control.Try;
import lombok.NonNull;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
public class Main {
public static void main(@NonNull final String[] args) {
public static void main(@NonNull final String[] args) throws IOException {
final String listenerPort = System.getProperty("fritteli.labyrinth.listenerport");
if (listenerPort != null) {
final Try<Integer> portTry = Try.of(() -> Integer.valueOf(listenerPort));
if (portTry.isFailure()) {
System.err.println("Invalid port specified via sysprop 'fritteli.labyrinth.listenerport': " + listenerPort + ". Not starting webserver.");
} else {
final TheListener listener = new TheListener(portTry.get());
listener.start();
System.out.println("Listening on port " + portTry.get());
}
} else {
System.out.println("In order to start the webserver, specify the port to listen to via the system property 'fritteli.labyrinth.listenerport', i.e.: -Dfritteli.labyrinth.listenerport=12345");
int width = 100;
int height = 100;
final Labyrinth labyrinth = new Labyrinth(width, height/*, 0*/);
@ -42,6 +57,7 @@ public class Main {
// Render PDF to file
System.out.println(pdfFileRenderer.render(labyrinth));
}
}
private static String getBaseFilename(@NonNull final Labyrinth labyrinth) {
return "labyrinth-" + labyrinth.getWidth() + "x" + labyrinth.getHeight() + "-" + labyrinth.getRandomSeed();

179
src/main/java/ch/fritteli/labyrinth/net/TheListener.java Normal file
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@ -0,0 +1,179 @@
package ch.fritteli.labyrinth.net;
import ch.fritteli.labyrinth.model.Labyrinth;
import ch.fritteli.labyrinth.renderer.html.HTMLRenderer;
import ch.fritteli.labyrinth.renderer.pdf.PDFRenderer;
import ch.fritteli.labyrinth.renderer.text.TextRenderer;
import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpServer;
import io.vavr.collection.HashMap;
import io.vavr.collection.HashSet;
import io.vavr.collection.List;
import io.vavr.collection.Map;
import io.vavr.collection.Set;
import io.vavr.collection.Stream;
import io.vavr.control.Option;
import io.vavr.control.Try;
import lombok.Getter;
import lombok.NonNull;
import org.jetbrains.annotations.Nullable;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.nio.charset.StandardCharsets;
import java.util.function.Function;
public class TheListener {
private final HttpServer httpServer;
public TheListener(final int port) throws IOException {
this.httpServer = HttpServer.create(new InetSocketAddress(port), 0);
this.httpServer.createContext("/create", exchange -> {
final String requestMethod = exchange.getRequestMethod();
if (!requestMethod.equals("GET")) {
exchange.getResponseBody().close();
exchange.sendResponseHeaders(405, -1);
exchange.close();
return;
}
final Map<RequestParameter, String> requestParams = this.parseQueryString(exchange.getRequestURI().getQuery());
final int width = this.getOrDefault(requestParams.get(RequestParameter.WIDTH), Integer::valueOf, 1);
final int height = this.getOrDefault(requestParams.get(RequestParameter.HEIGHT), Integer::valueOf, 1);
final Option<Long> seedOption = requestParams.get(RequestParameter.ID).toTry().map(Long::valueOf).toOption();
final long seed;
final Option<OutputType> outputOption = requestParams.get(RequestParameter.OUTPUT).flatMap(OutputType::ofString);
final OutputType output;
final Headers responseHeaders = exchange.getResponseHeaders();
boolean needsRedirect = false;
if (seedOption.isEmpty()) {
needsRedirect = true;
seed = System.nanoTime();
} else {
seed = seedOption.get();
}
if (outputOption.isEmpty()) {
needsRedirect = true;
output = OutputType.HTML;
} else {
output = outputOption.get();
}
if (needsRedirect) {
responseHeaders.add("Location", "/create?width=" + width + "&height=" + height + "&output=" + output.toString() + "&id=" + seed);
exchange.sendResponseHeaders(302, -1);
exchange.close();
return;
}
responseHeaders.add("Content-type", output.getContentType());
exchange.sendResponseHeaders(200, 0);
final Labyrinth labyrinth = new Labyrinth(width, height, seed);
final byte[] render = output.render(labyrinth);
final OutputStream responseBody = exchange.getResponseBody();
responseBody.write(render);
responseBody.flush();
exchange.close();
});
}
private <T> T getOrDefault(@NonNull final Option<String> input, @NonNull final Function<String, T> mapper, @Nullable final T defaultValue) {
return input.toTry().map(mapper).getOrElse(defaultValue);
}
@NonNull
private Map<RequestParameter, String> parseQueryString(@Nullable final String query) {
if (query == null) {
return HashMap.empty();
}
HashMap<RequestParameter, String> result = HashMap.empty();
final String[] parts = query.split("&");
for (final String part : parts) {
final int split = part.indexOf('=');
if (split == -1) {
final Try<RequestParameter> tryKey = Try.of(() -> this.normalizeParameterName(part));
if (tryKey.isSuccess()) {
result = result.put(tryKey.get(), null);
}
} else {
final String key = part.substring(0, split);
final String value = part.substring(split + 1);
final Try<RequestParameter> tryKey = Try.of(() -> this.normalizeParameterName(key));
if (tryKey.isSuccess()) {
result = result.put(tryKey.get(), value);
}
}
}
return result;
}
private RequestParameter normalizeParameterName(final String paramName) {
return RequestParameter.parseName(paramName).get();
}
public void start() {
this.httpServer.start();
}
public void stop() {
this.httpServer.stop(10);
}
private enum RequestParameter {
WIDTH("w", "width"),
HEIGHT("h", "height"),
ID("i", "id"),
OUTPUT("o", "output");
private final Set<String> names;
RequestParameter(@NonNull final String... names) {
this.names = HashSet.of(names);
}
static Option<RequestParameter> parseName(@Nullable final String name) {
if (name == null) {
return Option.none();
}
final String nameLC = name.toLowerCase();
return Stream.of(values())
.find(param -> param.names.contains(nameLC));
}
}
private enum OutputType {
TEXT_PLAIN("text/plain; charset=UTF-8", labyrinth -> TextRenderer.newInstance().render(labyrinth).getBytes(StandardCharsets.UTF_8), "t", "text"),
HTML("text/html", labyrinth -> HTMLRenderer.newInstance().render(labyrinth).getBytes(StandardCharsets.UTF_8), "h", "html"),
PDF("application/pdf", labyrinth -> PDFRenderer.newInstance().render(labyrinth), "p", "pdf");
@Getter
@NonNull
private final String contentType;
@NonNull
private final List<String> names;
@NonNull
private final Function<Labyrinth, byte[]> render;
OutputType(@NonNull final String contentType, @NonNull final Function<Labyrinth, byte[]> render, @NonNull final String... names) {
this.contentType = contentType;
this.render = render;
this.names = List.of(names);
}
static Option<OutputType> ofString(@Nullable final String name) {
if (name == null) {
return Option.none();
}
final String nameLC = name.toLowerCase();
return Stream.of(values())
.find(param -> param.names.contains(nameLC));
}
@Override
public String toString() {
return this.names.last();
}
byte[] render(@NonNull final Labyrinth labyrinth) {
return this.render.apply(labyrinth);
}
}
}