First commit: create mvp project

- create an orchestrator to orchestrate signature of pdf;
- create a worker to get request from amqp and resend it to amqp

pythonProject/worker.py

@@ -0,0 +1,75 @@
+import base64
+import io
+import json
+import logging
+import pika
+import sign
+
+dsn = 'amqp://guest:guest@localhost:32773/%2f/to_python_sign'
+
+LOG_FORMAT = ('%(levelname) -10s %(asctime)s %(name) -30s %(funcName) '
+              '-35s %(lineno) -5d: %(message)s')
+logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)
+LOGGER = logging.getLogger(__name__)
+LOGGER.setLevel(logging.DEBUG)
+
+orchestrator = sign.SignOrchestrator('./assets/dummy.p12',
+                                     'http://freetsa.org/tsr', pkcs12_password=None)
+
+parameters = pika.URLParameters(dsn)
+connection = pika.BlockingConnection(parameters)
+channel = connection.channel()
+channel.confirm_delivery()
+
+
+def on_message(channel, method_frame, header_frame, body):
+    LOGGER.debug("receiving a message")
+    body_content = json.loads(body)
+    LOGGER.info(f"request to add a signature, signatureId: {body_content['signatureId']}")
+
+    try:
+        box_place = (body_content['signatureZone']['x'], body_content['signatureZone']['y'],
+                     body_content['signatureZone']['x'] + body_content['signatureZone']['width'],
+                     body_content['signatureZone']['y'] + body_content['signatureZone']['height'])
+        LOGGER.debug("will try signature")
+        signed = orchestrator.sign(reason=body_content['reason'], signature_index=body_content['signatureZoneIndex'],
+                                   box_place=box_place, on_page=body_content['signatureZone']['PDFPage']['index'],
+                                   signer_text=body_content['signerText'],
+                                   input_content=base64.b64decode(body_content['content']))
+        LOGGER.info(f"signature obtained, signatureId: {body_content['signatureId']}")
+
+        with open(f"./assets/new.{method_frame.consumer_tag}.{method_frame.delivery_tag}.pdf", 'wb') as f:
+            f.write(signed.read())
+            LOGGER.debug("signed file saved")
+            # because we consumed the buffer to write a file, we have to rewind it
+            signed.seek(0)
+            channel.basic_publish(exchange='signed_docs',
+                                  body=json.dumps({'signatureId': body_content['signatureId'],
+                                                   'content': base64.b64encode(signed.read()).decode('utf-8')}),
+                                  properties=pika.BasicProperties(content_type='application/json',
+                                                                  delivery_mode=pika.DeliveryMode.Transient),
+                                  routing_key='signed_doc')
+            LOGGER.debug("signed file resend to amqp")
+        channel.basic_ack(delivery_tag=method_frame.delivery_tag)
+
+    except Exception as e:
+        LOGGER.warning(f"error encountered while signing: {e}")
+        if method_frame.redelivered:
+            LOGGER.warning(
+                f"stopping handling this message, because the message is already redelivered, signatureId: {body_content['signatureId']}")
+            channel.basic_reject(delivery_tag=method_frame.delivery_tag, requeue=True)
+        else:
+            LOGGER.warning(f"first try failed, signatureId: {body_content['signatureId']}")
+            channel.basic_ack(delivery_tag=method_frame.delivery_tag)
+
+
+if __name__ == '__main__':
+    LOGGER.info('starting worker')
+    channel.basic_consume('to_python_sign', on_message)
+    try:
+        LOGGER.info("start consuming")
+        channel.start_consuming()
+    except KeyboardInterrupt:
+        LOGGER.info("keyboard interrupt")
+        channel.stop_consuming()
+    connection.close()