Error: Cannot obtain Metadata from http://example.com/api/service.svc?wsdl

Setup

• WCF Service with SOAP, JSON and XML endpoints where the SOAP endpoint is a basicHttpBinding rather than a wsHttpBinding
• All service endpoints behind SSL
• SecuritySwitch installed and rewrite rules enabled to force all requests through to SSL where available
• AspNetCompatibilityEnabled = true, MultipleSiteBindingsEnabled = true
• <useRequestHeadersForMetadataAddress> element added to service behaviour with default ports http -> 80 and https -> 443
• Trying to add a service reference in Visual Studio yields a number of errors:

HTTP GET Error
    URI: http://example.com/api/Service.svc?wsdl

    The document at the url https://example.com/api/Service.svc?wsdl
was not recognized as a known document type.
The error message from each known type may help you fix the problem:
- Report from 'XML Schema' is 'The document format is not recognized 
(the content type is 'text/html; charset=UTF-8').'.
- Report from 'https://example.com/api/Service.svc?wsdl' is 
'The document format is not recognized (the content type is 
'text/html; charset=UTF-8').'.
- Report from 'DISCO Document' is 'Discovery document at the URL 
https://example.com/api/Service.svc?disco could not be found.'.
  - The document format is not recognized.
- Report from 'WSDL Document' is 'The document format is 
not recognized (the content type is 'text/html; charset=UTF-8').'.

Bugger. However, notice that the initial request URL is http, and the WSDL endpoint is https. Trying to navigate manually to the ?wsdl URL failed and just re-rendered the ‘You have created a service’ welcome page.

Solution

In my case the solution was to set httpsGetEnabled = true (in addition to httpGetEnabled=true) on the serviceMetadata tag for the service behaviour in question.

Hopefully Google’ll find this for me the next time I do it!