feat: adds download blob from azure helper

README.md

@@ -5,3 +5,22 @@ This is a set of helpers for node. They're written for quick reuse rather than r
 My use is primarily in quicker one off scripts that sometime morph into something long lasting...
 
 
+## Azure Storage
+
+Get blob from Azure example, downloads `bar.jpg` from `foo` container to `baz.jgp`
+
+```javascript
+const AzureStorage  = require('./src/azure.js')
+
+
+let storageAccountName = 'devstoreaccount1'
+let storageAccountKey = 'Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw=='
+let options = {cloudName: 'Azurite'}
+
+let azure = new AzureStorage(storageAccountName,storageAccountKey,options)
+
+let containerName = 'foo'
+let blob = 'bar.jpg'
+let file = 'baz.jpg'
+await azure.downloadBlobToFile(containerName,blob,file)
+```

src/azure.js

@@ -163,6 +163,29 @@ getStorageQueueSignedURL(queueUrl,options) {
     });
   }
 
+  /**
+   * Downloads a blob to a local file
+   * 
+   * @param {string} containerName the name of the container to download the blob from
+   * @param {string} blob The blob to download
+   * @param {string} file The path to the location to write the file
+   */
+  async downloadBlobToFile(containerName,blob,file) {
+    const blobService = azure.createBlobService(this.storageAccountName, this.storageAccountKey, this.host('blob',this.cloudName));
+    const options = {
+        access: 'container'
+    };
+
+    blobService.getBlobToLocalFile(containerName,blob,file,options,function(error,response){
+      if( error) {
+        console.error(error.message)
+      } else {
+        // console.log(response)
+        console.log(`${response.name} downloaded to ${file}`)
+      }
+    });
+  }
+
 }
 
 module.exports = AzureStorage