Byte array versus Base 64 string in RESTful web service

Question

My REST web service has to send an image file to the client. I am confused between 2 options : send the image as a byte array, or should I encode it as a base 64 string ? What are the pros and cons of each ? I may have to compress the image using gzip...should it create problem with any one of methods ? I may even need to expose my method as a SOAP service, which method should I prefer in that case ?

Thanks !!

Answer 1

The wonderful thing about a RESTful interface is that it's just HTTP. So if you expose the "byte array" version via REST, any browser can do an HTTP GET on your REST URL and receive and directly render your image. Returning the payload verbatim is far more RESTful than placing an encoding on it. There is not much to recommend an extra base64 encoding layer via REST.

If you're returning SOAP, you absolutely want to return a base64 string. Raw binary data is not compatible with XML, upon which SOAP is built. You can try to work around it via MTOM, but for general-purpose compatibility with SOAP clients you probably want inlined base64-encoded data.

In general, there's no benefit to be gained by compressing an image file. The image formats themselves internally involve compression, and a second compression pass will not gain any more space savings.