Sometimes your web application just needs to reach out, and get something over the web. Sometimes that need involves an 'inside' connection, such as an API key or secure login.
This can be difficut in a client-side application, as there is no way to hide that privileged information in web browser source code.
The Rdbhost proxy mode is here to help you with that. Like the 'charge' and 'email' modes, the 'proxy' mode will take database query results, send them to a web service, and relay the web service response to the client. Unlike the 'charge' and 'email' modes, you can access arbitrary websites and web services. Unlike those modes, filtering the response, if necessary, is up to you. You can specify 'callback' and 'errback' functions (in SQL, pl/pgSQL or pl/V8) to process the response, in the event that the response contains content that needs to be hidden from the user.