Get File from AzureBlob using CPI: Using Azure Storage jar

Introduction:

I have described how to upload a file in azureblob storage container in my previous blog post

In this blog post I will discuss about downloading file from AzureBlob container using standard jar available in maven repository.

Steps to Configure:

Step 1: I downloaded Azure Storage Client SDK from https://mvnrepository.com/artifact/com.microsoft.azure/azure-storage/

Step 2: I uploaded this .jar file as resource to my iFlow:

Step 3: I added properties using content modifier and externalized so that I can configure as per my need. Please note I have saved the Azure account key as secure parameter in security material.

Step 4: I created a Groovy script to directly download the file from the container and set as body.

/*
Script to download file to Azure Blob folder using parameters provided
 */
import com.sap.gateway.ip.core.customdev.util.Message
import java.util.HashMap
import com.microsoft.azure.storage.*
import com.microsoft.azure.storage.blob.*
import com.sap.it.api.ITApiFactory;
import com.sap.it.api.securestore.SecureStoreService;
import com.sap.it.api.securestore.UserCredential;
import com.sap.it.api.securestore.exception.SecureStoreException;

def Message processData(Message message) {
    def body = message.getBody(java.lang.String) as String
    map = message.getProperties()
    String accountKey = null;
    String accountName=map.get("AzureAccountName")
    String AzureAccountKey = map.get("AzureAccountKey")
    String containerRef =map.get("ContainerRef")
	String fileName = map.get("Filename")
	def securestoreApi = ITApiFactory.getService(com.sap.it.api.securestore.SecureStoreService.class, null)
	try{
	    accountKey = String.valueOf(securestoreApi.getUserCredential(AzureAccountKey).getPassword())
	} catch(Exception e){
        throw new SecureStoreException("Secure Parameter not available")
    }
    String storageConnectionString = "DefaultEndpointsProtocol=https;" + "AccountName=" + accountName+ ";" + "AccountKey=" + accountKey
try{
    CloudStorageAccount account = CloudStorageAccount.parse(storageConnectionString)
    CloudBlobClient serviceClient = account.createCloudBlobClient()

    CloudBlobContainer container = serviceClient.getContainerReference(containerRef)
    CloudBlockBlob blob = container.getBlockBlobReference(fileName)

    message.setBody(blob.downloadText())
}
catch(Exception e){
    throw new Exception("file can't be downloaded")
}
    return message;
}

I have configured trigger to schedule the CPI flow to run at particular time. When the CPI flow runs successfully, file is downloaded and added to the message body if the properties mentioned are correct. We don’t need any particular adapter for this iFlow as this script takes care of downloading file.

Conclusion:

Using this concept you can download a file from AzureBlob using CPI without any adapter, using jar provided in Maven repository.

Cheers,

Suman Saha