javascript

Access and Manipulate Messages with Javascript - Example

Javascript is a powerful tool to manipulate messages and to change the behaviour of an API. Using the javascript plugin you can use Javascript within API definitions.

Hint: These examples require Membrane version 5.1.0 or newer.

Running the example

1. Take a look at proxies.xml. There you'll find the APIs with the javascriptplugin.

2. Open a commandline session or a terminal.

3. Run service-proxy.bat or ./service-proxy.sh in this folder

4. Open a second terminal and run the commands:

   Create JSON with Javascript:

   curl localhost:2000
   {"id":7,"city":"Berlin"}

   Transform JSON to JSON:

   Have a look at the order.json file, then send it to the API to transform the JSON into a different JSON format:

   curl -d @order.json -H "Content-Type: application/json"  http://localhost:2010
   {
       "id": 731,
       "date": "2023-04-07",
       "client": 17,
       "total": 38.35,
       "positions": [
           {
               "pieces": 5,
               "price": 5.9,
               "article": "Oolong"
           },
           {
               "pieces": 2,
               "price": 2.95,
               "article": "Assam"
           },
           {
               "pieces": 1,
               "price": 2.95,
               "article": "Darjeeling"
           }
       ]
   }

   Access HTTP Headers and a Spring Bean:

   ❯ curl http://localhost:2020 -v
   > GET / HTTP/1.1
   > Host: localhost:2020
   
   < HTTP/1.1 200 Ok
   < Content-Length: 21
   < X-Groovy: 42
   
   Greatings from Spring       

   Then take a look at the output of the service-proxy.sh/bat script. You should see the output from the script, printing the request header fields.

   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