[hunchentoot-devel] send-headers and SBCL's run-program

[Alexey Martynov]

Hi

I have following problem: I need to run external script which outputs
image to standard output. To deliver it to client I use
hunchentoot:send-headers call.

Following code works fine:
              (setf (hunchentoot:content-type*) "image/png")
              (setf (hunchentoot:header-out "Pragma") "no-cache")
              (let ((out (hunchentoot:send-headers)))
                (let ((process (sb-ext:run-program "generate-image" '()
                                    :output :stream
                                    :wait nil
                                    :error nil)))
                (let ((file (sb-ext:process-output process)))
                 (loop with buf = (make-array 10240 :element-type
'(unsigned-byte 8))
                    for pos = (read-sequence buf file)
                    until (zerop pos)
                    do (write-sequence buf out :end pos)))))

But when I want to use stream from "send-headers" as stream for
standard output for external program then status line and headers
received after image content. I use following code:
              (setf (hunchentoot:content-type*) "image/png")
              (setf (hunchentoot:header-out "Pragma") "no-cache")
              (let ((out (hunchentoot:send-headers)))
                (let ((process (sb-ext:run-program "generate-image" '()
                                    :output out
                                    :wait nil
                                    :error nil)))
                  (sb-ext:process-wait process)))

So I have following question: is it possible to use stream received
from "send-headers" as output stream for spawned process or not? If
yes how correct code must look?

Thanks in advance

-- 
Alexey Martynov