Writing drakma http-request array to file

Question

What I want to do: take the output of (drakma:http-request "someURL.jpg") and write it to a file. The output consists of a byte array.

What I came up with:

(with-open-file (my-stream "thing.jpg" 
                           :direction :output
                           :element-type 'binary 
                           :if-does-not-exist :create
                           :if-exists :supersede)
  (let ((content (drakma:http-request "someURL.jpg")))
    (loop for i across content do
      (write-byte i my-stream))))

The error I get:

debugger invoked on a SIMPLE-ERROR in thread #<THREAD "initial thread" RUNNING
                                                {1002978FB1}>:
  could not find any output routine for :FULL buffered BINARY

I use SBCL 1.0.49. If you want any other info or find my question unclear then please, ask away :).

EDIT: The problem is the :element-type, it's supposed to be 'unsigned-byte. You can find information on the different possibilities of :element-type over at the Common Lisp Hyper Spec under open . Other than that everything is correct.

PS. I couldn't respond as an answer because my reputation is too low.

Answer 1

As Xach said, you're better off using '(unsigned-byte 8) (or make a type-definition , e.g. (deftype binary () '(unsigned-byte 8))).

In addition, you can probably replace your loop over the array and writing byte by byte with a call to write-sequence