/**
* Accept an image upload via POST and notify a Reactor that the image needs to be thumbnailed.
* Asynchronously respond to the client when the thumbnailing has completed.
*
* @param channel the channel on which to send an HTTP response
* @param thumbnail a reference to the shared thumbnail path
* @param reactor the Reactor on which to publish events
* @return a consumer to handle HTTP requests
*/
public static Consumer<FullHttpRequest> thumbnailImage(
NetChannel<FullHttpRequest, FullHttpResponse> channel,
AtomicReference<Path> thumbnail,
Reactor reactor) {
return req -> {
if (req.getMethod() != HttpMethod.POST) {
channel.send(badRequest(req.getMethod() + " not supported for this URI"));
return;
}
// write to a temp file
Path imgIn = null;
try {
imgIn = readUpload(req.content());
} catch (IOException e) {
throw new IllegalStateException(e.getMessage(), e);
}
// Asynchronously thumbnail the image to 250px on the long side
reactor.sendAndReceive(
"thumbnail",
Event.wrap(imgIn),
ev -> {
thumbnail.set(ev.getData());
channel.send(redirect());
});
};
}
/**
* Respond to GET requests and serve the thumbnailed image, a reference to which is kept in the
* given {@literal AtomicReference}.
*
* @param channel the channel on which to send an HTTP response
* @param thumbnail a reference to the shared thumbnail path
* @return a consumer to handle HTTP requests
*/
public static Consumer<FullHttpRequest> serveThumbnailImage(
NetChannel<FullHttpRequest, FullHttpResponse> channel, AtomicReference<Path> thumbnail) {
return req -> {
if (req.getMethod() != HttpMethod.GET) {
channel.send(badRequest(req.getMethod() + " not supported for this URI"));
} else {
try {
channel.send(serveImage(thumbnail.get()));
} catch (IOException e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
};
}
/**
* Respond to errors occurring on a Reactor by redirecting them to the client via an HTTP 500
* error response.
*
* @param channel the channel on which to send an HTTP response
* @return a consumer to handle HTTP requests
*/
public static Consumer<Throwable> errorHandler(
NetChannel<FullHttpRequest, FullHttpResponse> channel) {
return ev -> {
DefaultFullHttpResponse resp =
new DefaultFullHttpResponse(
HttpVersion.HTTP_1_1, HttpResponseStatus.INTERNAL_SERVER_ERROR);
resp.content().writeBytes(ev.getMessage().getBytes());
resp.headers().set(HttpHeaders.Names.CONTENT_TYPE, "text/plain");
resp.headers().set(HttpHeaders.Names.CONTENT_LENGTH, resp.content().readableBytes());
channel.send(resp);
};
}