implement cursory api

apps/api/cloudformation.yml

@@ -12,31 +12,6 @@ Resources:
       ProtocolType: HTTP
       Target: !GetAtt Lambda.Arn
       CredentialsArn: !GetAtt ApiRole.Arn
-      Body:
-        openapi: 3.1.0
-        info:
-          title: Sample API
-          description: Optional multiline or single-line description in [CommonMark](http://commonmark.org/help/) or HTML.
-          version: 0.1.9
-        servers:
-          - url: http://api.example.com/v1
-            description: Optional server description, e.g. Main (production) server
-          - url: http://staging-api.example.com
-            description: Optional server description, e.g. Internal staging server for testing
-        paths:
-          /users:
-            get:
-              summary: Returns a list of users.
-              description: Optional extended description in CommonMark or HTML.
-              responses:
-                '200': # status code
-                  description: A JSON array of user names
-                  content:
-                    application/json:
-                      schema:
-                        type: array
-                        items:
-                          type: string
 
   ApiOverrides:
     Type: AWS::ApiGatewayV2::ApiGatewayManagedOverrides

apps/api/src/api.py

@@ -1,7 +1,55 @@
+import os
+
 import boto3
 
 s3 = boto3.client('s3')
 
+def get_orbit_for_granule(granule: str, bucket: str, orbit_type: str):
+    platform = granule[0:3]
+    start_date = granule[17:32]
+    end_date = granule[33:48]
+
+    paginator = s3.get_paginator('list_objects_v2')
+    page_iterator = paginator.paginate(
+        Bucket=bucket,
+        Prefix=f'{orbit_type}/{platform}',
+    )
+    for page in page_iterator:
+        for item in page['Contents']:
+            filename = os.path.basename(item['Key'])
+            start = filename[42:57]
+            end = filename[58:73]
+            if start <= start_date <= end_date <= end:
+                return item['Key']
+    return None
+
+
+def get_url(granule, bucket):
+    for orbit_type in ['AUX_POEORB', 'AUX_RESORB', 'AUX_PREORB']:
+        key = get_orbit_for_granule(granule, bucket, orbit_type)
+        if key:
+            return f'https://{bucket}.s3.amazonaws.com/{key}'
+    return None
+
 
 def lambda_handler(event, context):
-    print(event)
+    bucket = os.environ['BUCKET_NAME']
+    granule = os.path.basename(event['rawpath'])
+    url = get_url(granule, bucket)
+
+    if url:
+        response = {
+            'isBase64Encoded': False,
+            'statusCode': 302,
+            'headers': {
+                'location': url,
+            }
+        }
+    else:
+        response = {
+            'isBase64Encoded': False,
+            'statusCode': 404,
+            'body': f'No orbit file found for {granule}'
+        }
+
+    return response