javascript

Access and Manipulate Messages with Javascript - Example

JavaScript is a powerful tool for manipulating messages and customizing the behavior of an API. With the javascript plugin, you can embed JavaScript directly into API definitions to achieve flexible transformations and logic.

Note: These examples require Membrane version 5.1.0 or newer.

Running the Example

1. Review the proxies.xml file to see how the APIs are configured with the javascript plugin.
2. Open a command-line session or terminal.
3. Run service-proxy.ps1 (Windows) or ./service-proxy.sh (Linux/Mac) in this folder.
4. Open a second terminal and execute the following commands:

Create JSON with JavaScript

The query parameter from:

curl "http://localhost:2000?id=7&city=Berlin" 

will be filled in a JSON document.

{"id":"7","city":"Berlin"}

See API at port 2000 in 'proxies.xml' for details.

Transform JSON to JSON

Examine the order.json file to understand the input format. Then, send it to the API to transform it into a different JSON structure:

cat order.json

curl -d @order.json -H "Content-Type: application/json" http://localhost:2010

Access HTTP Headers and a Spring Bean

Send a request to the API and inspect the response:

curl http://localhost:2020 -v
> GET / HTTP/1.1
> Host: localhost:2020

< HTTP/1.1 200 Ok
< Content-Length: 21
< X-Javascript: 42

Greatings from Javascript       

The response should include an X-Javascript header. Additionally, the console output of service-proxy.sh or service-proxy.ps1 will display the request header fields logged by the script:

Request headers:
Host: localhost:2000
User-Agent: curl/7.79.1
Accept: */*
X-Forwarded-For: 127.0.0.1
X-Forwarded-Proto: http
X-Forwarded-Host: localhost:2000

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See:

• javascript plugin reference