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Is there a way to handle file upload ?

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fblanvil

Is there a way to handle file upload ?

Hi,

Is there a way to handle file uploads with ratpack with an <input type="file" ?

Also related, is there a clean way to bypass the 65536 bytes post size limitation ? (found this limit hardcoded in RatpackChannelInitializer).

Thanks a lot.

Luke Daley

Re: Is there a way to handle file upload ?

Administrator

Hi,

There's currently no built in support for file handling unfortunately. I've raised an issue for this.

https://github.com/ratpack/ratpack/issues/54

Would you be interested in helping to add it?

fblanvil

Re: Is there a way to handle file upload ?

Thanks for your response.

I'm currently trying to hack something like :

handler('publish-image') {
methods.get {
get(TemplateRenderer).render "upload-image.html"
}.post {
DefaultFullHttpRequest nettyRequest = request.nettyRequest
HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE)
HttpPostRequestDecoder decoder = new HttpPostRequestDecoder(factory, nettyRequest)
HttpContent chunk = (HttpContent) nettyRequest;
decoder.offer(chunk)
String resp = ""
while (decoder.hasNext()) {
InterfaceHttpData data = decoder.next()
switch (data.httpDataType) {
case InterfaceHttpData.HttpDataType.Attribute:
Attribute attribute = (Attribute) data
resp += "${attribute.name}: ${attribute.value}\n"
break
case InterfaceHttpData.HttpDataType.FileUpload:
FileUpload fileUpload = (FileUpload) data
if (fileUpload.completed) {
resp += "file : ${data.name} (${fileUpload.length()} bytes)\n"
}
}
}
response.send("post")
}.send()
}

from https://github.com/netty/netty/blob/master/example/src/main/java/io/netty/example/http/upload/HttpUploadServerHandler.java

But it doesn't work very well for now.

I'm absolutely not experienced in web servers, except to drop my war in; However I would be interested to try to help on this (with no guarantee!).

I imagine that org.ratpackframework.bootstrap.internal.NettyHandlerAdapter would be a place to start, but I would be grateful to have some directions and hints here. Also I don't really understand how Guice ties the components up.

Cheers

fblanvil

Re: Is there a way to handle file upload ?

For the hacky records, this works:

handler('publish-image') {
methods.get {
get(TemplateRenderer).render "upload-image.html"
}.post {
DefaultFullHttpRequest nettyRequest = request.nettyRequest
HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE)
HttpPostRequestDecoder decoder = new HttpPostRequestDecoder(factory, nettyRequest)
HttpContent chunk = (HttpContent) nettyRequest;
decoder.offer(chunk)
Map <String, Object> multipartForm = [:]
try {
while (decoder.hasNext()) {
InterfaceHttpData data = decoder.next()
switch (data.httpDataType) {
case InterfaceHttpData.HttpDataType.Attribute:
Attribute attribute = (Attribute) data
multipartForm."${attribute.name}" = attribute.value
break
case InterfaceHttpData.HttpDataType.FileUpload:
FileUpload fileUpload = (FileUpload) data
if (fileUpload.completed) { // which is right because of the HttpObjectAggregator
File file = fileUpload.file
multipartForm."${data.name} (${file.name})" = file
}
}
}
} catch (HttpPostRequestDecoder.EndOfDataDecoderException e) {
// This ugly empty catch is hit everytime and is therefore necessary
}
response.send(multipartForm.toString())
}.send()
}

For this hack to work for files larger than 65536 bytes, this ratpack code chunk needs to be changed accordingly:
(org.ratpackframework.bootstrap.internal.RatpackChannelInitializer)

pipeline.addLast("decoder", new HttpRequestDecoder());
pipeline.addLast("aggregator", new HttpObjectAggregator(65536));
pipeline.addLast("encoder", new HttpResponseEncoder());
pipeline.addLast("chunkedWriter", new ChunkedWriteHandler());

Luke Daley

Re: Is there a way to handle file upload ?

Administrator

That's great stuff :)

We should put this behind some kind of method on the request object. What kind of API do you suggest?

I'm not quite sure how to make that max size configurable at this minute. I'll work something out soon though.

fblanvil

Re: Is there a way to handle file upload ?

Without much thoughts, I was thinking for the ease of use to integrate the files directly in the form object.
But the signature would have to change from
Map<String, List<String>> getForm();
to
Map<String, List<Object>> getForm(); // to accept File objects.
which might be not pleasant for Java users.

I didn't investigate about that but I suppose this approach has some problems since it doesn't seems to be the usual way to do. What do you think ?

Another way would be to add a
Map<String, List<File>> getFiles(); // method to the Request interface.

I'll be pretty busy by the end of the week, but I should be able to work on this during next week :-)

Luke Daley

Re: Is there a way to handle file upload ?

Administrator

Really sorry, I missed the notification about your response.

I think we want a separate method, like…

RequestBody getBody()

Where RequestBody has a method…

FileUpload file(String name)

And FileUpload is something like…

interface FileUpload {
  String getContentType()
  File getFile()
}