Introducing and Open Sourcing Flashback, an Internet Mocking Tool

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LinkedIn
•
Shangshang Feng
•11 min read•intermediate•
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•View Original
HTTPSJavaJSONOAuthPython

Overview

The article introduces Flashback, an open-source internet mocking tool developed at LinkedIn to facilitate reliable testing of web applications that interact with third-party websites. It addresses challenges faced with existing tools like Betamax and outlines how Flashback allows for HTTP and HTTPS request mocking without requiring an internet connection.

What You'll Learn

1

How to record and replay HTTP transactions using Flashback

2

Why mocking external HTTP dependencies is crucial for reliable testing

3

How to implement match rules for dynamic request validation

Prerequisites & Requirements

  • Understanding of HTTP and HTTPS protocols
  • Familiarity with Git for cloning repositories(optional)

Key Questions Answered

What is Flashback and how does it work?
Flashback is an internet mocking tool that records HTTP and HTTPS requests and replays them for testing purposes. It eliminates the need for external internet connections, allowing developers to test applications reliably by using previously recorded transactions, referred to as 'scenes'.
How can Flashback handle dynamic changes in request parameters?
Flashback allows users to define match rules that can accommodate dynamic request parameters, such as those used in OAuth flows. This flexibility enables testing of requests with varying signatures and tokens without needing changes on the client side.
What are the steps to record an HTTP transaction using Flashback?
To record an HTTP transaction, start by setting up Flashback as a proxy, then make a real request to the desired URL. Flashback captures the request and response, storing them as a scene that can later be replayed, ensuring no external internet connection is needed.
What security considerations are there when using Flashback for HTTPS?
When using Flashback for HTTPS, a Certificate Authority (CA) certificate must be created to allow Flashback to act as a Man-in-the-Middle (MITM) proxy. This certificate must be trusted by the client to ensure secure communication during testing.

Technologies & Tools

Testing Tool
Flashback
Used for mocking HTTP and HTTPS requests in testing environments.
Version Control
Git
Used for cloning the Flashback repository from GitHub.

Key Actionable Insights

1
Implement Flashback in your testing environment to eliminate external dependencies that can lead to unreliable test results.
Using Flashback allows for consistent testing outcomes by replaying recorded HTTP transactions, which is particularly useful when dealing with third-party services that may change or become temporarily unavailable.
2
Utilize match rules in Flashback to handle dynamic request parameters effectively.
This feature is essential for testing APIs that require authentication or have varying parameters, enabling developers to validate requests without modifying client-side code.
3
Ensure that your team understands the security implications of using Flashback with HTTPS.
Properly managing CA certificates is crucial to avoid inadvertently exposing sensitive data during testing, especially when dealing with production-like environments.

Common Pitfalls

1
Failing to set up the CA certificate properly when using Flashback for HTTPS can lead to security vulnerabilities.
Without a trusted CA certificate, the client may reject connections to Flashback, preventing successful testing of HTTPS requests.

Related Concepts

Mocking Tools
HTTP/HTTPS Protocols
Testing Best Practices