Initial commit

caff_previewer_wrapper/app.py

@@ -0,0 +1,76 @@
+import tempfile
+import os
+import os.path
+import shutil
+from flask import Flask, current_app
+
+from config import Config
+
+from utils import write_file_to_fd_while_calculating_md5, create_md5_sum_for_file
+from converter import convert_caff_to_tga, convert_tga_to_png
+
+app = Flask(__name__)
+app.config.from_object(Config)
+
+
+def do_everything(workdir: str):
+    # Recieve file
+    uploaded_caff_fd, uploaded_caff_path = tempfile.mkstemp(suffix='.caff', dir=workdir)
+
+    uploaded_caff_md5sum = write_file_to_fd_while_calculating_md5(uploaded_caff_fd)  # Throws overflow error
+
+    # Convert CAFF to TGA
+    converted_tga_fd, converted_tga_path = tempfile.mkstemp(suffix='.tga', dir=workdir)
+    os.close(converted_tga_fd)
+
+    convert_caff_to_tga(uploaded_caff_path, converted_tga_path)
+
+    if not os.path.isfile(converted_tga_path):
+        raise FileNotFoundError("Conversion output is missing")
+
+    # Convert TGA to PNG
+    converted_png_fd, converted_png_path = tempfile.mkstemp(suffix='.png', dir=workdir)
+    os.close(converted_png_fd)
+
+    convert_tga_to_png(converted_tga_path, converted_png_path)
+
+    if not os.path.isfile(converted_tga_path):
+        raise FileNotFoundError("Conversion output is missing")
+
+    converted_png_md5sum = create_md5_sum_for_file(converted_png_path)
+
+    # Send back converted file
+    converted_png_handle = open(converted_png_path, 'rb')
+
+    def stream_and_remove_file():
+        # This really is some black magic here
+        # When flask transmits the file ...
+        yield from converted_png_handle  # <- It transmits from file handle
+        # After it's done the rest of this function will be called, so it cleans up after itself
+        converted_png_handle.close()
+        shutil.rmtree(workdir)
+
+    return current_app.response_class(
+        stream_and_remove_file(),
+        headers={
+            'X-request-checksum': uploaded_caff_md5sum,
+            'X-response-checksum': converted_png_md5sum,
+            'Content-type': 'image/png'
+        }
+    )
+
+
+@app.route('/preview', methods=['POST'])
+def perform_conversion():
+    workdir = tempfile.mkdtemp(prefix='caff')
+    try:
+        response = do_everything(workdir)  # normally this would clean up workdir
+    except:
+        shutil.rmtree(workdir)  # but sometimes it must be done externally
+        raise
+
+    return response
+
+
+if __name__ == '__main__':
+    app.run(debug=True)