First implementation of serve_thumb.py

resize_rich_link_images/.gitignore

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+# created by virtualenv automatically
+lib/
+bin/

resize_rich_link_images/config.yaml

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+region: us-east-1
+
+function_name: resize_rich_link_images
+handler: serve_thumb.lambda_handler
+description: Serve thumbnail for rich link. If thumbnail does not exist, create it
+runtime: python3.9
+# role: lambda_basic_execution
+
+# S3 upload requires appropriate role with s3:PutObject permission
+# (ex. basic_s3_upload), a destination bucket, and the key prefix
+# bucket_name: 'example-bucket'
+# s3_key_prefix: 'path/to/file/'
+
+# if access key and secret are left blank, boto will use the credentials
+# defined in the [default] section of ~/.aws/credentials.
+
+# In this project the aws access keys are injected via github actions
+# when deploying the lambda function
+aws_access_key_id: AWS_ACCESS_KEY_ID
+aws_secret_access_key: AWS_SECRET_ACCESS_KEY
+
+# dist_directory: dist
+# timeout: 15
+# memory_size: 512
+# concurrency: 500
+#
+
+# Experimental Environment variables
+# environment_variables:
+#     env_1: foo
+#     env_2: baz
+
+# If `tags` is uncommented then tags will be set at creation or update
+# time.  During an update all other tags will be removed except the tags
+# listed here.
+#tags:
+#    tag_1: foo
+#    tag_2: bar
+
+# Build options
+build:
+  source_directories: lib # a comma delimited list of directories in your project root that contains source to package.

resize_rich_link_images/event.json

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+{
+    "Records": [
+        {
+            "cf": {
+                "config": {
+                    "distributionId": "EXAMPLE"
+                },
+                "request": {
+                    "uri": "/api/rich_link",
+                    "method": "GET",
+                    "clientIp": "2001:cdba::3257:9652",
+                    "body": "<meta property=\"og:image\" content=\"https://cambiatus-uploads.s3.amazonaws.com/cambiatus-uploads/b214c106482a46ad89f3272761d3f5b5\">",
+                    "headers": {
+                        "host": [
+                            {
+                                "key": "Host",
+                                "value": "d123.cf.net"
+                            }
+                        ]
+                    }
+                }
+            }
+        }
+    ]
+}

resize_rich_link_images/inject_secrets.sh

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+#!/bin/bash
+
+echo "Injectig AWS keys"
+
+sed -i "s/AWS_ACCESS_KEY_ID/$1/g" config.yaml
+sed -i "s/AWS_SECRET_ACCESS_KEY/$2/g" config.yaml
+
+echo "Injection complete"

resize_rich_link_images/pyvenv.cfg

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+home = /usr
+implementation = CPython
+version_info = 3.9.13.final.0
+virtualenv = 20.16.3
+include-system-site-packages = false
+base-prefix = /usr
+base-exec-prefix = /usr
+base-executable = /usr/bin/python3.9

resize_rich_link_images/serve_thumb.py

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+import json
+import boto3
+from bs4 import BeautifulSoup
+from PIL import Image
+from io import BytesIO
+
+
+def get_image_name(html_body):
+    body = BeautifulSoup(html_body, "html.parser")
+    image_tag = body.find("meta", property="og:image")
+    image_name = image_tag["content"].split("/")[-1]
+    return image_name
+
+
+def resize_image(image):
+    sizeX = image.size[0]
+    sizeY = image.size[1]
+    if sizeX > 300:
+        image.thumbnail((299, sizeY))
+
+
+def create_thumbnail(s3_client, s3_bucket, original_image, path):
+    image_object = s3_client.get_object(Bucket=s3_bucket, Key=original_image)
+    image = Image.open(BytesIO(image_object["Body"].read()))
+    resize_image(image)
+    file_object = BytesIO()
+    image.save(file_object, "png")
+    file_object.seek(0)
+    s3_client.put_object(
+        Body=file_object,
+        Bucket=s3_bucket,
+        Key=path,
+        ContentType=image_object["ContentType"],
+    )
+
+
+def object_exists(s3_client, s3_bucket, path):
+    try:
+        s3_client.head_object(Bucket=s3_bucket, Key=path)
+        return True
+    except:
+        return False
+
+
+def lambda_handler(event, context):
+
+    request = event["Records"][0]["cf"]["request"]
+
+    if "api/rich_link" in request["uri"]:
+        s3_bucket = "cambiatus-uploads"
+        s3_image_path = "cambiatus-uploads/"
+        s3_thumb_path = "cambiatus-uploads/thumbnails/"
+        s3_client = boto3.client("s3")
+
+        image_name = get_image_name(request["body"])
+
+        if not object_exists(s3_client, s3_bucket, s3_thumb_path + image_name):
+            create_thumbnail(
+                s3_client,
+                s3_bucket,
+                s3_image_path + image_name,
+                s3_thumb_path + image_name,
+            )
+
+        request["body"] = request["body"].replace(s3_image_path, s3_thumb_path)
+
+    return {"statusCode": 200, "body": json.dumps(request["body"])}