Explore your understanding of advanced API gateway patterns, including routing strategies, filtering techniques, and rate limiting approaches. Assess your knowledge of practical gateway scenarios, best practices, and key concepts to effectively manage and secure API traffic.
Which routing strategy directs incoming requests to different backend services based on the request URL's path, such as '/users' or '/orders'?
Explanation: Path-based routing inspects the path portion of the request URL to determine which backend service should handle the traffic. Host-based routing is based on the domain part rather than the path. Method-based routing uses HTTP verbs like GET or POST, and header-based routing relies on specific headers. Each strategy serves different routing needs, but only path-based routing uses the URL path for service selection.
When an API gateway uses a filter to remove or obfuscate sensitive information from requests or responses, what is this technique commonly called?
Explanation: Data masking is the process of hiding or altering sensitive data, ensuring that private information does not reach logs or clients unnecessarily. Data splitting refers to breaking data into parts, which is not related to confidentiality. Data shuffling reorders data, and data clustering groups data points, neither of which serve the masking purpose in API gateways.
Which concept in API gateways involves restricting how many requests a client can make in a set period, for example, 100 requests per minute?
Explanation: Rate limiting controls traffic by specifying how many requests are accepted from a client within a defined timeframe. Load shedding drops excess load but is not user-based. Auto scaling deals with infrastructure resizing, not request limitations. Latency injection adds artificial delays, but does not restrict request counts.
If an API gateway directs all GET requests to Service A and all POST requests to Service B, what type of routing is being used?
Explanation: Method-based routing uses the HTTP method (such as GET or POST) to decide which backend service should process the request. Time-based routing is not commonly used for this purpose. Domain-based routing makes decisions based on domain names, while protocol-based routing considers network protocols, not HTTP methods.
An API gateway sends users with a request header 'Region: EU' to a different backend service. What is this pattern called?
Explanation: Header-based routing inspects HTTP headers, such as 'Region', to route requests. Token-based and session-based routing involve authentication, and cookie-based routing checks for specific cookies, not headers. Only header-based routing uses the value of HTTP headers as the basis for decision-making.
In which way does an API gateway act as a reverse proxy?
Explanation: A reverse proxy accepts requests from clients and distributes them to backend servers, which is a key role of an API gateway. It does not handle user interfaces directly, nor is it responsible for storing passwords or managing firewalls. The reverse proxy pattern focuses on request forwarding between clients and services.
What distinguishes request throttling from a quota in API gateways?
Explanation: Throttling provides immediate control by limiting request rates in real time, while quotas enforce limits over a span, like per day or per month. Encryption and decryption are not related to these features. Business hours and logging are unrelated to the primary distinction between throttling and quotas.
How can caching at the API gateway improve backend performance in handling repeated identical requests?
Explanation: Caching allows the gateway to serve identical requests with stored responses, reducing load and latency for backend services. Blocking all repeated requests would harm usability. Randomizing request order and delaying responses do not enhance performance or efficiency and are not conventional uses of caching.
What role does request filtering play in an API gateway when it intercepts and rejects malformed or unauthorized requests?
Explanation: Filtering at the gateway level helps secure backend services by blocking malformed or unauthorized requests before they reach sensitive systems. Processing speed is not necessarily increased by filtering. Encryption is outside the scope of basic filtering, and sending spam is not an intended security function.
During a blue-green deployment, how does an API gateway route traffic to support both the old and new version of a service?
Explanation: In blue-green deployments, routing rules enable the gateway to control which percentage of traffic hits each version, allowing smooth rollout or rollback. Blocking the old version immediately defeats the purpose of phased deployment. Merging different versions' responses is not part of this pattern, and deleting requests is incorrect and would disrupt service.