Set the query string parameters in a URL

Problem

You want to set the query string parameters of a URL for an HTTP request.

Solution

Use the HTTP Request node's support for mustache to substitute query parameter strings in URLs directly.

Example

Flow JSON

[{"id":"e95c6faa.ab2e1","type":"http request","z":"c9a81b70.8abed8","name":"","method":"GET","ret":"txt","url":"https://query.yahooapis.com/v1/public/yql?q={{{query}}}&format=json","tls":"","x":470,"y":420,"wires":[["7cf30700.5bc978"]]},{"id":"7cf30700.5bc978","type":"debug","z":"c9a81b70.8abed8","name":"","active":true,"console":"false","complete":"payload","x":630,"y":420,"wires":[]},{"id":"637d3c55.eb3084","type":"inject","z":"c9a81b70.8abed8","name":"query parameter","topic":"","payload":"select astronomy.sunset from weather.forecast where woeid in (select woeid from geo.places(1) where text=\"maui, hi\")","payloadType":"str","repeat":"","crontab":"","once":false,"x":120,"y":420,"wires":[["b001d489.d8f818"]]},{"id":"b001d489.d8f818","type":"change","z":"c9a81b70.8abed8","name":"","rules":[{"t":"set","p":"query","pt":"msg","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":300,"y":420,"wires":[["e95c6faa.ab2e1"]]}]

The Inject node generates a query string that is to be sent in the URL. The Change node changes this to msg.query which is substituted in the mustache template in the HTTP Request node URL property configured as shown:

https://query.yahooapis.com/v1/public/yql?q={{{query}}}&format=json

The returned JSON content is the sunset in Hawaii:

"{"query":{"count":1,"created":"2017-01-22T01:31:07Z","lang":"en-US","results":{"channel":{"astronomy":{"sunset":"6:9 pm"}}}}}"

Discussion

By default, mustache will escape any HTML entities in the values it substitutes. To ensure HTML escaping is not used in your URL use <b>Flow JSON</b>{{{triple}}} braces.