Question

I am trying to send a blob data from oracle db to objective c via webservices.
The blob data is a word document stored in oracle db.

Following is what I did so far:

1. Obtain the blob object through java jdbc
2. Convert the blob object into java byte array
3. Setting this byte array in a plain java object (serialized) and sending it to the web service
4. Webservice sends the plain java object to objective-c with Media-type as application/json
5. The json object is retrieved in the objective-c and the byte array is assigned to NSData
6. NSData is then written to a file and the file is opened

Problem: I am unable to open the file through objective-c and when I open the file physically in the mac it contains some junk characters. Can anyone please let me know if there is anyway that a java byte array which represents a word document could be converted to a objective-c recognized data type and finally open the word document in the objective-c app.

Following is the code for your perusal on the objective-c end:

Note: “sourceDoc” in the code is the key for byte array.

NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

if ([data length] >0  && error == nil){

    NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
    NSData *returnData = nil;

    for(NSDictionary *billDict in jsonArray){
        returnData = [NSData dataWithBytes:(__bridge const void *)([billDict objectForKey:@"sourceDoc"]) length:[[billDict objectForKey:@"sourceDoc"] length]];
        break;
    }
}

Answer 1

The problem is that -[NSData dataWithBytes:length:] expects a pointer to the actual data but you are passing it an object from the dictionary. You should inspect the contents returned using NSLog(@"%@", [billDict objectForKey:@"sourceDoc"]); but I expect it will be a base64 string. If it is a base64 string you can use one the base64 decoding options from this question: How do I do base64 encoding on iphone-sdk?. If you use Alex Reynolds answer from that question then you would include the base64 decoding file header you created and set returnData in your above code like this:

returnData = [NSData base64DataFromString:[billDict objectForKey:@"sourceDoc"]];