def lambda_handler(event, context):
"""
Update cart table to use user identifier instead of anonymous cookie value as a key. This will be called when a user
is logged in.
"""
cart_id, _ = get_cart_id(event["headers"])
try:
# Because this method is authorized at API gateway layer, we don't need to validate the JWT claims here
user_id = event["requestContext"]["authorizer"]["claims"]["sub"]
except KeyError:
return {
"statusCode": 400,
"headers": get_headers(cart_id),
"body": json.dumps({"message": "Invalid user"}),
}
# Get all cart items belonging to the user's identity
response = table.query(
KeyConditionExpression=Key("pk").eq(f"user#{user_id}")
& Key("sk").begins_with("product#"),
ConsistentRead=
True, # Perform a strongly consistent read here to ensure we get correct and up to date cart
)
cart_items = response.get("Items")
# batch_writer will be used to update status for cart entries belonging to the user
with table.batch_writer() as batch:
for item in cart_items:
# Delete ordered items
batch.delete_item(Key={"pk": item["pk"], "sk": item["sk"]})
metrics.add_metric(name="CartCheckedOut", unit="Count", value=1)
logger.info({"action": "CartCheckedOut", "cartItems": cart_items})
return {
"statusCode":
200,
"headers":
get_headers(cart_id),
"body":
json.dumps({"products": response.get("Items")},
default=handle_decimal_type),
}
def lambda_handler(event, context):
"""
List items in shopping cart.
"""
cart_id, generated = get_cart_id(event["headers"])
# Because this method can be called anonymously, we need to check there's a logged in user
jwt_token = event["headers"].get("Authorization")
if jwt_token:
user_sub = get_user_sub(jwt_token)
key_string = f"user#{user_sub}"
logger.structure_logs(append=True, cart_id=f"user#{user_sub}")
else:
key_string = f"cart#{cart_id}"
logger.structure_logs(append=True, cart_id=f"cart#{cart_id}")
# No need to query database if the cart_id was generated rather than passed into the function
if generated:
logger.info(
"cart ID was generated in this request, not fetching cart from DB")
product_list = []
else:
logger.info("Fetching cart from DB")
response = table.query(
KeyConditionExpression=Key("pk").eq(key_string)
& Key("sk").begins_with("product#"),
ProjectionExpression="sk,quantity,productDetail",
FilterExpression=
"quantity > :val", # Only return items with more than 0 quantity
ExpressionAttributeValues={":val": 0},
)
product_list = response.get("Items", [])
for product in product_list:
product.update((k, v.replace("product#", ""))
for k, v in product.items() if k == "sk")
return {
"statusCode":
200,
"headers":
get_headers(cart_id),
"body":
json.dumps({"products": product_list}, default=handle_decimal_type),
}
def lambda_handler(event, context):
"""
Update cart table to use user identifier instead of anonymous cookie value as a key. This will be called when a user
is logged in.
"""
logger.debug(event)
cart_id, _ = get_cart_id(event["headers"])
try:
# Because this method is authorized at API gateway layer, we don't need to validate the JWT claims here
user_id = event["requestContext"]["authorizer"]["claims"]["sub"]
except KeyError:
return {
"statusCode": 400,
"headers": get_headers(cart_id),
"body": json.dumps({"message": "Invalid user"}),
}
# Get all cart items belonging to the user's anonymous identity
response = table.query(
KeyConditionExpression=Key("pk").eq(f"cart#{cart_id}")
& Key("sk").begins_with("product#"))
unauth_cart = response["Items"]
# Since there's no batch operation available for updating items, and there's no dependency between them, we can
# run them in parallel threads.
thread_list = []
for item in unauth_cart:
# Store items with user identifier as pk instead of "unauthenticated" cart ID
# Using threading library to perform updates in parallel
ddb_updateitem_thread = threading.Thread(target=update_item,
args=(user_id, item))
thread_list.append(ddb_updateitem_thread)
ddb_updateitem_thread.start()
# Delete items with unauthenticated cart ID
# Rather than deleting directly, push to SQS queue to handle asynchronously
queue.send_message(
MessageBody=json.dumps(item, default=handle_decimal_type))
for ddb_thread in thread_list:
ddb_thread.join() # Block main thread until all updates finished
response = table.query(
KeyConditionExpression=Key("pk").eq(f"user#{user_id}")
& Key("sk").begins_with("product#"),
ProjectionExpression="sk,quantity,productDetail",
ConsistentRead=
True, # Perform a strongly consistent read here to ensure we get correct values after updates
)
product_list = response.get("Items", [])
for product in product_list:
product.update((k, v.replace("product#", ""))
for k, v in product.items() if k == "sk")
return {
"statusCode":
200,
"headers":
get_headers(cart_id),
"body":
json.dumps({"products": product_list}, default=handle_decimal_type),
}
def lambda_handler(event, context):
"""
Idempotent update quantity of products in a cart. Quantity provided will overwrite existing quantity for a
specific product in cart, rather than adding to it.
"""
try:
request_payload = json.loads(event["body"])
except KeyError:
return {
"statusCode": 400,
"headers": get_headers(),
"body": json.dumps({"message": "No Request payload"}),
}
# retrieve the product_id that was specified in the url
product_id = event["pathParameters"]["product_id"]
quantity = int(request_payload["quantity"])
cart_id, _ = get_cart_id(event["headers"])
# Because this method can be called anonymously, we need to check if there's a logged in user
user_sub = None
jwt_token = event["headers"].get("Authorization")
if jwt_token:
user_sub = get_user_sub(jwt_token)
try:
product = get_product_from_external_service(product_id)
except NotFoundException:
logger.info("No product found with product_id: %s", product_id)
return {
"statusCode": 404,
"headers": get_headers(cart_id=cart_id),
"body": json.dumps({"message": "product not found"}),
}
# Prevent storing negative quantities of things
if quantity < 0:
return {
"statusCode": 400,
"headers": get_headers(cart_id),
"body": json.dumps(
{
"productId": product_id,
"message": "Quantity must not be lower than 0",
}
),
}
# Use logged in user's identifier if it exists, otherwise use the anonymous identifier
if user_sub:
pk = f"user#{user_sub}"
ttl = generate_ttl(
7
) # Set a longer ttl for logged in users - we want to keep their cart for longer.
else:
pk = f"cart#{cart_id}"
ttl = generate_ttl()
table.put_item(
Item={
"pk": pk,
"sk": f"product#{product_id}",
"quantity": quantity,
"expirationTime": ttl,
"productDetail": product,
}
)
logger.info("about to add metrics...")
metrics.add_metric(name="CartUpdated", unit="Count", value=1)
return {
"statusCode": 200,
"headers": get_headers(cart_id),
"body": json.dumps(
{"productId": product_id, "quantity": quantity, "message": "cart updated"}
),
}
def lambda_handler(event, context):
"""
Add a the provided quantity of a product to a cart. Where an item already exists in the cart, the quantities will
be summed.
"""
logger.debug(event)
try:
request_payload = json.loads(event["body"])
except KeyError:
return {
"statusCode": 400,
"headers": get_headers(),
"body": json.dumps({"message": "No Request payload"}),
}
product_id = request_payload["productId"]
quantity = request_payload.get("quantity", 1)
cart_id, _ = get_cart_id(event["headers"])
# Because this method can be called anonymously, we need to check there's a logged in user
user_sub = None
jwt_token = event["headers"].get("Authorization")
if jwt_token:
user_sub = get_user_sub(jwt_token)
try:
product = get_product_from_external_service(product_id)
except NotFoundException:
return {
"statusCode": 404,
"headers": get_headers(cart_id=cart_id),
"body": json.dumps({"message": "product not found"}),
}
if user_sub:
pk = f"user#{user_sub}"
ttl = generate_ttl(
7
) # Set a longer ttl for logged in users - we want to keep their cart for longer.
else:
pk = f"cart#{cart_id}"
ttl = generate_ttl()
if int(quantity) < 0:
table.update_item(
Key={
"pk": pk,
"sk": f"product#{product_id}"
},
ExpressionAttributeNames={
"#quantity": "quantity",
"#expirationTime": "expirationTime",
"#productDetail": "productDetail",
},
ExpressionAttributeValues={
":val": quantity,
":ttl": ttl,
":productDetail": product,
":limit": abs(quantity),
},
UpdateExpression=
"ADD #quantity :val SET #expirationTime = :ttl, #productDetail = :productDetail",
# Prevent quantity less than 0
ConditionExpression="quantity >= :limit",
)
else:
table.update_item(
Key={
"pk": pk,
"sk": f"product#{product_id}"
},
ExpressionAttributeNames={
"#quantity": "quantity",
"#expirationTime": "expirationTime",
"#productDetail": "productDetail",
},
ExpressionAttributeValues={
":val": quantity,
":ttl": generate_ttl(),
":productDetail": product,
},
UpdateExpression=
"ADD #quantity :val SET #expirationTime = :ttl, #productDetail = :productDetail",
)
return {
"statusCode":
200,
"headers":
get_headers(cart_id),
"body":
json.dumps({
"productId": product_id,
"message": "product added to cart"
}),
}
def lambda_handler(event, context):
"""
API Handler
The API catch the request and builds a record in dynamodb
for each request with sender's IP, build and id and timestamp
"""
logger.info(event)
logger.info(f"Table is {tableName}")
# Controls body
try:
request_payload = json.loads(event["body"])
except:
return {
"statusCode": 400,
"body": json.dumps({"message": "No Request payload"}),
}
# Controls payload : clientId is mandatory`
client_id = ""
try:
client_id = request_payload["client_id"]
except KeyError:
return {
"statusCode": 400,
"headers": get_headers(client_id),
"body": json.dumps({"message": "No client_id in payload ?"}),
}
# Build the record
ip = requests.get("http://checkip.amazonaws.com/").text.replace("\n", "")
pk = str(uuid.uuid4())
timestamp = time.strftime('%Y-%m-%d %H:%M:%S')
week = datetime.datetime.today() + datetime.timedelta(days=7)
expiry_date_time = int(time.mktime(week.timetuple()))
try:
result = dynamodb.put_item(
TableName=tableName,
Item={
'pk': {'S': pk},
'sk': {'S': ip},
'client_id': {'S': client_id},
'timestamp': {'S': timestamp},
'ttl': {'N': str(expiry_date_time)}
})
print(result)
except Exception as e:
logger.error(e)
# result = table.update_item(
# Key={
# "pk": {"S": pk}
# },
# ExpressionAttributeValues={
# ":ip": {"S": ip},
# ":ttl": {"N": ttl},
# ":client_id": {"S": client_id},
# ":timestamp": {"S": timestamp}
# },
# UpdateExpression="SET sk=:ip, ttl=:ttl, client_id=:client_id, timestamp=:timestamp",
# ReturnValues="ALL_NEW"
# )
# metrics.add_metric(name="GreetingAdded", unit="Count", value=1)
return {
"statusCode": 200,
"headers": get_headers(pk),
"body": json.dumps(
{"client_id": client_id, "ip": ip, "message": "Greetings added !"}
),
}
def test_lambda_handler(self):
"""
API Handler tester
The API catch the request and builds a record in dynamodb
for each request with sender's IP, build and id and timestamp
"""
# Controls body
try:
request_payload = json.loads(self.event["body"])
except KeyError or ValueError:
return {
"statusCode": 400,
"body": json.dumps({"message": "No Request payload"}),
}
# Controls payload : clientId is mandatory`
client_id = ""
try:
client_id = request_payload["client_id"]
except KeyError:
return {
"statusCode": 400,
"headers": get_headers(client_id),
"body": json.dumps({"message": "No client_id in payload ?"}),
}
# Build the record
ip = requests.get("http://checkip.amazonaws.com/").text.replace("\n", "")
pk = str(uuid.uuid4())
timestamp = time.strftime('%Y-%m-%d %H:%M:%S')
ttl = str(generate_ttl(7))
result = self.dynamodb.update_item(
TableName=self.tableName,
Key={
"pk": {"S": pk},
"sk": {"S": f"ip#{ip}"}
},
ExpressionAttributeNames={
"#ip": "ip",
"#ttl": "ttl",
"#client_id": "client_id",
"#timestamp": "timestamp"
},
ExpressionAttributeValues={
":ip": {"S": ip},
":ttl": {"N": ttl},
":client_id": {"S": client_id},
":timestamp": {"S": timestamp}
},
UpdateExpression="SET #ttl=:ttl, #client_id=:client_id, #timestamp=:timestamp",
ReturnValues="ALL_NEW"
)
pprint(result)
# metrics.add_metric(name="GreetingAdded", unit="Count", value=1)
response = {
"statusCode": 200,
"headers": get_headers(pk),
"body": json.dumps(
{"client_id": client_id, "ip": ip, "message": "Greetings added !"}
),
}
pprint(response)
self.assertEqual(response['statusCode'], 200)
