Upload file with Azure Storage using SAS (Shared Access Signature)

Question

I know that there is library available for uploading the file using Azure Storage. I have refer this for same.

But, they have not give information for how to use SAS

Answer 1

Uploading a pic to BLOB storage . I got it after searching for hours .Take a look :-

Uploading the photo image is a multistep process:

First you take a photo, and insert a TodoItem row into the SQL database that contains new meta-data fields used by Azure Storage. A new mobile service SQL insert script asks Azure Storage for a Shared Access Signature (SAS). That script returns the SAS and a URI for the blob to the client. The client uploads the photo, using the SAS and blob URI.

So what is a SAS?

It's not safe to store the credentials needed to upload data to the Azure Storage service inside your client app. Instead, you store these credentials in your mobile service and use them to generate a Shared Access Signature (SAS) that grants permission to upload a new image. The SAS, a credential with a 5 minute expiration, is returned securely by Mobile Services to the client app. The app then uses this temporary credential to upload the image.

for further queries and detail analysis. Visit this official documentation https://azure.microsoft.com/en-us/documentation/articles/mobile-services-android-upload-data-blob-storage/

Answer 2

@kumar kundal The mechanism that you have explain is completely right. Below is the more detail answer about uploading profile image to the Azure Server.

First create SAS url to upload Image(or any file) to blob storage:

String sasUrl = "";
// mClient is the MobileServiceClient
ListenableFuture<JsonElement> result = mClient.invokeApi(SOME_URL_CREATED_TO_MAKE_SAS, null, "GET", null);
Futures.addCallback(result, new FutureCallback<JsonElement>() {
        @Override
        public void onSuccess(JsonElement result) {
            // here you will get SAS url from server
            sasUrl = result; // You need to parse it as per your response
        }

        @Override
        public void onFailure(Throwable t) {
        }
    });

Now, you have sasURL with you. That will be something like below string:

sv=2015-04-05&ss=bf&srt=s&st=2015-04-29T22%3A18%3A26Z&se=2015-04-30T02%3A23%3A26Z&sr=b&sp=rw&sip=168.1.5.60-168.1.5.70&spr=https&sig=F%6GRVAZ5Cdj2Pw4tgU7IlSTkWgn7bUkkAg8P6HESXwmf%4B

Now, you need to upend the sas url with your uploading url. See below code in which I have upend the SAS url with my uploading request.

try {
        File source = new File(filePath); // File path
        String extantion = source.getAbsolutePath().substring(source.getAbsolutePath().lastIndexOf("."));
        // create unique number to identify the image/file.
        // you can also specify some name to image/file
        String uniqueID = "image_"+ UUID.randomUUID().toString().replace("-", "")+extantion; 
        String blobUri = MY_URL_TO_UPLOAD_PROFILE_IMAGE + sas.replaceAll("\"","");
        StorageUri storage = new StorageUri(URI.create(blobUri));
        CloudBlobClient blobCLient = new CloudBlobClient(storage);
        CloudBlobContainer container = blobCLient.getContainerReference("");
        CloudBlockBlob blob = container.getBlockBlobReference(uniqueID);
        BlobOutputStream blobOutputStream = blob.openOutputStream();
        byte[] buffer = fileToByteConverter(source);
        ByteArrayInputStream inputStream = new ByteArrayInputStream(buffer);
        int next = inputStream.read();
        while (next != -1) {
            blobOutputStream.write(next);
            next = inputStream.read();
        }
        blobOutputStream.close();
        // YOUR IMAGE/FILE GET UPLOADED HERE
        // IF YOU HAVE FOLLOW DOCUMENT, YOU WILL RECEIVE IMAGE/FILE URL HERE 
    } catch (StorageException e) {
        e.printStackTrace();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (Exception e){
        e.printStackTrace();
    }

I hope this information help you lot for uploading the file using blob storage. Please let me know if you have any doubt apart from this. I can help in that.