Merge pull request #10 from jeroenjanssens/master

Add ability to show inline images

bash_kernel.py

@@ -1,24 +1,34 @@
 from IPython.kernel.zmq.kernelbase import Kernel
 from pexpect import replwrap, EOF
 
-import signal
 from subprocess import check_output
+from os import unlink
+
+import base64
+import imghdr
 import re
+import signal
+import urllib
 
 __version__ = '0.2'
 
 version_pat = re.compile(r'version (\d+(\.\d+)+)')
 
+_TEXT_SAVED_IMAGE = "bash_kernel: saved image data to:"
+
+
 class BashKernel(Kernel):
     implementation = 'bash_kernel'
     implementation_version = __version__
     language = 'bash'
+
     @property
     def language_version(self):
         m = version_pat.search(self.banner)
         return m.group(1)
 
     _banner = None
+
     @property
     def banner(self):
         if self._banner is None:
@@ -27,9 +37,8 @@ class BashKernel(Kernel):
 
     language_info = {'codemirror_mode': 'shell',
                      'mimetype': 'text/x-sh',
-                     'file_extension': 'sh'
-                    }
-    
+                     'file_extension': 'sh'}
+
     def __init__(self, **kwargs):
         Kernel.__init__(self, **kwargs)
         self._start_bash()
@@ -45,8 +54,18 @@ class BashKernel(Kernel):
         finally:
             signal.signal(signal.SIGINT, sig)
 
-    def do_execute(self, code, silent, store_history=True, user_expressions=None,
-                   allow_stdin=False):
+        # Register Bash function to write image data to temporary file
+        bash_rc = """
+        display () {
+            TMPFILE=$(mktemp ${TMPDIR-/tmp}/bash_kernel.XXXXXXXXXX)
+            cat > $TMPFILE
+            echo "%s $TMPFILE" >&2
+        }
+        """ % _TEXT_SAVED_IMAGE
+        self.bashwrapper.run_command(bash_rc)
+
+    def do_execute(self, code, silent, store_history=True,
+                   user_expressions=None, allow_stdin=False):
         if not code.strip():
             return {'status': 'ok', 'execution_count': self.execution_count,
                     'payload': [], 'user_expressions': {}}
@@ -64,12 +83,25 @@ class BashKernel(Kernel):
             self._start_bash()
 
         if not silent:
+            image_filenames, output = extract_image_filenames(output)
+
+            # Send standard output
             stream_content = {'name': 'stdout', 'text': output}
             self.send_response(self.iopub_socket, 'stream', stream_content)
-        
+
+            # Send images, if any
+            for filename in image_filenames:
+                try:
+                    data = display_data(filename)
+                except ValueError as e:
+                    message = {'name': 'stdout', 'text': str(e)}
+                    self.send_response(self.iopub_socket, 'stream', message)
+                else:
+                    self.send_response(self.iopub_socket, 'display_data', data)
+
         if interrupted:
             return {'status': 'abort', 'execution_count': self.execution_count}
-        
+
         try:
             exitcode = int(self.bashwrapper.run_command('echo $?').rstrip())
         except Exception:
@@ -109,6 +141,40 @@ class BashKernel(Kernel):
                 'cursor_end': cursor_pos, 'metadata': dict(),
                 'status': 'ok'}
 
+
+def display_data(filename):
+    with open(filename, 'rb') as f:
+        image = f.read()
+    unlink(filename)
+
+    image_type = imghdr.what(None, image)
+    if image_type is None:
+        raise ValueError("Not a valid image: %s" % image)
+
+    image_data = urllib.parse.quote(base64.b64encode(image))
+    content = {
+        'source': 'kernel',
+        'data': {
+            'image/' + image_type: image_data
+        }
+    }
+    return content
+
+
+def extract_image_filenames(output):
+    output_lines = []
+    image_filenames = []
+
+    for line in output.split("\n"):
+        if line.startswith(_TEXT_SAVED_IMAGE):
+            filename = line.rstrip().split(": ")[-1]
+            image_filenames.append(filename)
+        else:
+            output_lines.append(line)
+
+    output = "\n".join(output_lines)
+    return image_filenames, output
+
 if __name__ == '__main__':
     from IPython.kernel.zmq.kernelapp import IPKernelApp
     IPKernelApp.launch_instance(kernel_class=BashKernel)