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Testing your Alias or Redirect plugin

How to quickly check on proxied graphics and JSON.

Ryan avatar
Written by Ryan
Updated over 3 weeks ago

Since TRMNL forwards your Alias (Image URL) and Redirect (JSON URL) to your device, it is not possible to "preview" resulting content inside the TRMNL web application.

Alias plugin testing

  1. Set your Image URL, e.g. https://my-blog.com/img.png or http://192.168.0.1/img.png

  2. Navigate to Playlists, then find or add the Alias instance you just created via the Add a Plugin dropdown

  3. Drag and drop the Alias instance to be directly below whatever item is now being shown, indicated by a green badge with "Displayed now"
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  4. Click the button on the back of your TRMNL device to force-skip to the next item, your Alias instance

  5. If you see your image, great. If you just see the TRMNL logo, your image formatting may not be exactly to spec. See here.

Redirect plugin testing

  1. Set your JSON endpoint Web Address, noting that this must be publicly accessible on the web. A 192.168 style address won't work because our web server needs to GET this endpoint and share its response parameters to your physical device. The response's url parameter can* be a local network destination however.

  2. Navigate to Playlists, then find or add the Redirect instance you just created via the Add a Plugin dropdown

  3. Drag and drop the Redirect instance to be directly below whatever item is now being shown, indicated by a green badge with "Displayed now"
    ​

  4. Click the button on the back of your TRMNL device to force-skip to the next item, your Redirect instance

  5. If you see your image, great. If you just see the TRMNL logo, your JSON response body or image formatting may not be exactly to spec.

To confirm your JSON is returning and formatted correctly:

  1. Create a Private Plugin and input your Redirect instance's Web Address into the Polling URL field. Click Save, then click "Force Refresh" on the right side.

  2. Open the Markup Editor and click to expand the Your Variables accordion.

  3. Check if your 3x parameters are present. If not, double check that your JSON content is returned with header content-type set to application/json . TRMNL does not explicitly request a content-type.

To confirm your image formatting is correct, see here.

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