Skip to main content

Serve a Local File

Problem#

You want to create an HTTP endpoint that responds to GET requests with content from a local file, such a PNG image.

Solution#

Use the File In node to load the required content and set the Content-Type to the appropriate value for the file type being returned.

Example#

img

Flow JSON
[{"id":"c7e341a0.381cc","type":"http in","z":"3045204d.cfbae","name":"","url":"/hello-file","method":"get","swaggerDoc":"","x":110,"y":720,"wires":[["2fb1c354.d04e3c"]]},{"id":"2fb1c354.d04e3c","type":"file in","z":"3045204d.cfbae","name":"","filename":"/tmp/Ignite.png","format":"","x":290,"y":720,"wires":[["c9e28681.361d78"]]},{"id":"c9e28681.361d78","type":"change","z":"3045204d.cfbae","name":"Set Headers","rules":[{"t":"set","p":"headers","pt":"msg","to":"{}","tot":"json"},{"t":"set","p":"headers.content-type","pt":"msg","to":"image/png","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":470,"y":720,"wires":[["88974243.7768c"]]},{"id":"88974243.7768c","type":"http response","z":"3045204d.cfbae","name":"","x":610,"y":720,"wires":[]}]
[~]$ curl  https://app_name.herokuapp.com/hello-file > file.png

Discussion#

When loading a non-text file such as an image, the File In node must be configured to return a Buffer object.

So that the receiver knows how to handle the file, the Content-Type header must be set to the appropriate mime type. The example above, which returns a .png file sets the Content-Type header to image/png.