Mock responses that return binary data

For some requests, you might want to respond with binary data like documents or images.

In Dev Proxy, you can define a binary response by setting the response.body to a string value that starts with @ followed by file path relative to the current working directory, for example:

JSON

{
  "$schema": "https://raw.githubusercontent.com/dotnet/dev-proxy/main/schemas/v0.24.0/mockresponseplugin.schema.json",
  "mocks": [
    {
      "request": {
        "url": "https://graph.microsoft.com/v1.0/users/*/photo/$value",
        "method":  "GET"
      },
      "response": {
        "body": "@picture.jpg",
        "headers": [
          {
            "name": "content-type",
            "value": "image/jpeg"
          }
        ]
      }
    }
  ]
}

When you call GET https://graph.microsoft.com/v1.0/users/ben@contoso.com/photo/$value, you get the image stored in the picture.jpg file in the current directory.

Ettevaatust!

If you're using the command line to execute the HTTP request, ensure that you have correctly escaped the dollar sign. See Why is proxy not mocking my binary response.

Next step

Learn more about the MockResponsePlugin.

MockResponsePlugin

Samples

See also the related Dev Proxy samples:

• Simulate errors on Microsoft Graph with HTTP Cats