| Re: [cf-dev] transfer of large files |
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Be aware that CoAP is not designed for bulk data transfer. Californium does not treat Blockwise transfers as streams (because
they are not). The whole message with the complete payload is cached in the BlockwiseLayer. So far, the MID problem only occurred when the JVM was running out of memory. For now, more memory (-Xmx / -Xms) might help. While we will need to check if there is a bug in Block, I would rather look into a secondary TCP-based protocol that can
be signaled through CoAP to do bulk data transfer. Ciao Matthias From: cf-dev-bounces@xxxxxxxxxxx [mailto:cf-dev-bounces@xxxxxxxxxxx]
On Behalf Of Helge Krieg Hello Julien! Thank you for your reply.
The problem occurred always when I tried to transfer the large file of 130MB. Currently, I do not have a unit test for that, but in order to reproduce this behavior just follow these steps:
1) add a new resource within the HelloWorldServer.java: add(new HelloWorldResource(), new FileResource("fileResource", "file.dat")); 2) For the needed FileResource.java use: import java.nio.file.FileSystems; import java.nio.file.Files; import java.nio.file.Path; import org.codehaus.plexus.util.StringUtils; public class FileResource extends CoapResource { private String fileName = "file.dat"; public FileResource(String resourceName, String fileName) { // set resource identifier super(resourceName); this.fileName = fileName; // set display name getAttributes().setTitle("File Resource"); } @Override public void handleGET(CoapExchange exchange) { // respond to the request Path p = FileSystems.getDefault().getPath("C:\\path\\to", fileName); byte[] fileData = null; try { fileData = Files.readAllBytes(p); } catch (IOException e) { System.out.println(StringUtils.join(e.getStackTrace(), "\n")); return; } String string = null; try { string = new String(fileData, "UTF-8"); } catch (UnsupportedEncodingException e) { System.out.println(StringUtils.join(e.getStackTrace(), "\n")); return; } System.out.println("Sending to client."); // exchange.respond(string); exchange.respond(ResponseCode.CONTENT, fileData); } } 3) The file “file.dat“ is some large text document that I simply created with an editor using copy&paste exponentially
J
4) Start the HelloWorldServer 5) Start the GETClient with the argument: “coap://localhost/fileResource” Greetings, Helge Von:
cf-dev-bounces@xxxxxxxxxxx [mailto:cf-dev-bounces@xxxxxxxxxxx]
Im Auftrag von Julien Vermillard Wow 130MB is a lot for CoAP, I wonder if it was ever tested.. It's failing 100% of time? Can you provide detailed debug logs or a JUnit test so we can try to reproduce it? Julien _______________________________________________ |