Initial commit

.gitignore

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+venv
+urlshorten.zip

README.md

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+# URL Shortener
+There are many; this is mine.
+
+## Bundling for upload
+Create a virtual environment
+    python -m venv venv
+    source venv/bin/activate
+
+Install dependencies
+    python -m pip install -r requirements.txt   
+
+Zip it all up
+    cd venv/lib/python3.10/site-packages
+    zip -r ../../../../urlshorten.zip .
+    cd ../../../../
+    zip -g urlshorten.zip urlshorten.py

requirements.txt

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+certifi==2023.5.7
+charset-normalizer==3.1.0
+idna==3.4
+requests==2.29.0
+urllib3==1.26.15

urlshorten.py

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+import boto3
+import os
+import requests
+
+from base64 import b64decode
+from botocore.exceptions import ClientError
+
+dynamodb = boto3.resource('dynamodb', region_name='us-west-2')
+
+ENCRYPTED = os.environ['RECAPTCHA_SECRET']
+# Decrypt code should run once and variables stored outside of the function
+# handler so that these are decrypted once per container
+RECAPTCHA_SECRET = boto3.client('kms').decrypt(CiphertextBlob=b64decode(ENCRYPTED))['Plaintext']
+
+def lambda_handler(event, context):
+    table = dynamodb.Table('urlshorten')
+
+    if 'from' in event and 'to' in event:
+        captcha_data = {
+            'secret': RECAPTCHA_SECRET,
+            'response': event['g-recaptcha-response'],
+            'remoteip': event['remoteip']
+        }
+
+        verify = requests.get('https://www.google.com/recaptcha/api/siteverify',
+                              params=captcha_data)
+        if not (verify.status_code == 200 and verify.json()['success']):
+            return {
+                'status': 'error',
+                'error': verify.json()
+            }
+
+        ssl = event['to'][:5].lower() == 'https'
+
+        url = ('https://' if ssl else 'http://') + event['to'].split('://')[-1]
+
+        try:
+            table.put_item(
+                Item={
+                    'key': event['from'],
+                    'value': url
+                },
+                ConditionExpression='attribute_not_exists(#key)',
+                ExpressionAttributeNames={
+                    '#key': 'key'
+                }
+            )
+        except ClientError as e:
+            return {
+                'status': 'error',
+                'error': e.response['Error']
+            }
+        except KeyError:
+            return {
+                'status': 'error',
+                'error': 'Invalid Request',
+                'location': '/'
+            }
+        else:
+            return {
+                'status': 'ok'
+            }
+
+    try:
+        response = table.get_item(Key={ 'key': event['shortUrl'] })
+        location = response['Item']['value']
+    except ClientError as e:
+        return e.response['Error']
+    except KeyError:
+        return {
+            'location': '/'
+        }
+    else:
+        return {
+            'location': response['Item']['value']
+        }