Upload attachment in corda - corda

Question

I have tried to upload a attachment in corda.
I have checked https://github.com/corda/corda/tree/release-M14. It is very complex and don't have a UI. When I tried to use some part of code it is showing full errors.
I have tried https://github.com/corda/blacklist . But here hash is finding in HTML page. Can I get a simple example to upload a document using UI and hash finding in kt file?

Answer 1

The blacklist sample here also has an example of uploading an attachment via RPC in Kotlin:
package net.corda.examples.attachments.client
import net.corda.client.rpc.CordaRPCClient
import net.corda.core.crypto.SecureHash
import net.corda.core.messaging.CordaRPCOps
import net.corda.core.utilities.NetworkHostAndPort.Companion.parse
import net.corda.core.utilities.loggerFor
import net.corda.examples.attachments.ATTACHMENT_EXPECTED_CONTENTS
import net.corda.examples.attachments.ATTACHMENT_FILE_NAME
import net.corda.examples.attachments.BLACKLIST_JAR_PATH
import org.slf4j.Logger
import java.io.File
import java.util.jar.JarInputStream
/**
* Uploads the jar of blacklisted counterparties with whom agreements cannot be struck to the node.
*/
fun main(args: Array<String>) {
UploadBlacklistClient().main(args)
}
private class UploadBlacklistClient {
companion object {
val logger: Logger = loggerFor<UploadBlacklistClient>()
}
fun main(args: Array<String>) {
require(args.isNotEmpty()) { "Usage: uploadBlacklist <node address>" }
args.forEach { arg ->
val nodeAddress = parse(arg)
val rpcConnection = CordaRPCClient(nodeAddress).start("user1", "test")
val proxy = rpcConnection.proxy
val attachmentHash = uploadAttachment(proxy, BLACKLIST_JAR_PATH)
logger.info("Blacklist uploaded to node at $nodeAddress")
val attachmentJar = downloadAttachment(proxy, attachmentHash)
logger.info("Blacklist downloaded from node at $nodeAddress")
checkAttachment(attachmentJar, ATTACHMENT_FILE_NAME, ATTACHMENT_EXPECTED_CONTENTS)
logger.info("Attachment contents checked on node at $nodeAddress")
rpcConnection.notifyServerAndClose()
}
}
}
/**
* Uploads the attachment at [attachmentPath] to the node.
*/
private fun uploadAttachment(proxy: CordaRPCOps, attachmentPath: String): SecureHash {
val attachmentUploadInputStream = File(attachmentPath).inputStream()
return proxy.uploadAttachment(attachmentUploadInputStream)
}
/**
* Downloads the attachment with hash [attachmentHash] from the node.
*/
private fun downloadAttachment(proxy: CordaRPCOps, attachmentHash: SecureHash): JarInputStream {
val attachmentDownloadInputStream = proxy.openAttachment(attachmentHash)
return JarInputStream(attachmentDownloadInputStream)
}
/**
* Checks the [expectedFileName] and [expectedContents] of the downloaded [attachmentJar].
*/
private fun checkAttachment(attachmentJar: JarInputStream, expectedFileName: String, expectedContents: List<String>) {
var name = attachmentJar.nextEntry.name
while (name != expectedFileName) {
name = attachmentJar.nextEntry.name
}
val contents = attachmentJar.bufferedReader().readLines()
if (contents != expectedContents) {
throw IllegalArgumentException("Downloaded JAR did not have the expected contents.")
}
}