def update_item(user_id, item):
"""
Update an item in the database, adding the quantity of the passed in item to the quantity of any products already
existing in the cart.
"""
table.update_item(
Key={"pk": f"user#{user_id}", "sk": item["sk"]},
ExpressionAttributeNames={
"#quantity": "quantity",
"#expirationTime": "expirationTime",
"#productDetail": "productDetail",
},
ExpressionAttributeValues={
":val": item["quantity"],
":ttl": generate_ttl(days=30),
":productDetail": item["productDetail"],
},
UpdateExpression="ADD #quantity :val SET #expirationTime = :ttl, #productDetail = :productDetail",
)
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 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)