How to develop API Proxy on APIGEE

Considerations:
1. Develop Flow
2. Develop Policy
3. Develop Fault Handling
4. Manage revision in Git
5. Deploy API Proxy

Knowledge Sharing:
1. Flow variable are used in policies and conditional flows. Policies can retrieve state from flow variables and use them to do their work.
2. The key to remember is that JavaScript executed by the JavaScript policy has access to all the flow variables that are exist and are in scope within the API proxy flow.
3. Variable scope is related to the flow or overall "life cycle" of an API proxy call.
4. To understand flow variable scope, it's important to understand or visualize the way messages flow through an API proxy. An API proxy consists of a series or message processing steps organized as a flow. At every step in a proxy flow, the proxy evaluates information available to it and decides what to do next. Along the way, the proxy may execute policy code or perform conditional branching.
5. the flows are composed of four main segments: ProxyEndpoint request, TargetEndpoint request, TargetEndpoint response, and ProxyEndpoint response.
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About how to debug API Proxy in APIGEE:
1. Develop API Proxy
2. Deploy API Proxy
3. Find out right URL
4. Invoke API
5. In the trace section, see how the message flows in the API Proxy from end to end, and see the contents inside the Flow.