External Data Source

Camouflage lets you condition your response for a specific set of data. Because we understand that random values don't always fulfill the requirements. Camouflage provides two helpers, pg and csv, which can be used to connect to a postgres db and csv data file respectively.

Danger

Both pg and csv helpers, rely on code injection for response generation. To use these helpers, the property injection needs to be set to true in config.yml. Injection can lead to security related issues and should be used judiciously.

pg

pg helper requires a postgres connection. To establish this connection between Camouflage and a postgres database, add following parameters in the config.yml file

ext_data_source:
  pg:
    host: localhost
    port: 5432
    user: root
    password: password
    database: postgres

Update the connection parameters with your database details.

In your mock files, use pg helper to run queries and fetch corresponding data. A sample mock file would look similar to the following content:

HTTP/1.1 200 OK
Content-Type: application/json

{{#pg query='SELECT * FROM emp WHERE id = \'1\''}}
(()=> {
    let response = []
    result.rows.forEach(row => {
        const adult = row.age > 18 ? 'adult' : 'minor'
        response.push({
            user: row.name,
            adult: adult
        })
    })
    return {
        status: 201,
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify(response)
    };
})();
{{/pg}}

Explanation

pg helper, similar to code or csv helper, is written as an IIFE (Immediately Invoked Function Expression). As shown above, IIFE is written as (()=> { ... })();
The helper requires a mandatory parameter, query as a string.
The pg block gets access to a result object which can be used to condition the response. More details on how to use the result object can be found on node-postgres API documentation
IIFE should return the generated response as a json object which contains body as a string. Optionally the response object can contain a status code and headers.

csv

To use csv helper, you would need a data source, which is a csv file. A sample file can be found in the github repo.

Usage:

CSV helper can be invoked in following manner, with three parameters, i.e.

src: The location of your csv file.
key: The column name in which you would like Camouflage to search for a specific value
value: The value you want to search

Camouflage then gives you access to a result array, which you can use inside an IIFE. It's your responsibility to decide how you want to use the result array. For example, in the snippet shown below, we are simply using the 1st element of the array i.e. result[0]. But you could also write a for loop to iterate over the array and generate your response body.

Please note that the value you return MUST be a json object which contains a body in a string format (required), you can optionally provide status and headers as well.

HTTP/1.1 200 OK
X-Requested-By: Shubhendu Madhukar
Content-Type: application/json

{{#csv src="./test.csv" key="City" value="Worcester"}}
(()=> {
    return {
        status: 201,
        headers: {
            'Content-Type': 'application/json'
        },
        body: `{
            "City": "${result[0].City}",
            "State": "${result[0].State}",
            "LatD": ${result[0].LatD},
            "LonD": ${result[0].LonD}
        }`
    };
})();
{{/csv}}

Camouflage provides you another alternative, in case you don't want to search for a specific value, instead you just want to pick one row at random and tailor your response to that specific row.

In that case you'd remove key and value from the snippet shown above, and simply put random=true instead.

To get entire data pass all=true.

Danger

Note that, though we are calling it a "c"sv, it's not really comma separated, Camouflage expects the values to be separated by a semicolon. i.e. ;
Keep in mind that if you use random=true, you don't get the result object as an array, you would get one single object. So in the example above, result[0].City will not work, you'd need to update it to simply result.City