SeleniumHQ/selenium · error · Error::WebDriverError

expected HTTP proxy, got #{proxy.inspect}

Error message

expected HTTP proxy, got #{proxy.inspect}

What it means

Raised as Error::WebDriverError by Http::Default#new_http_client when a proxy is configured for use (use_proxy? is true) but the proxy object does not respond to #http or its #http method returns a falsy value. The adapter needs a valid proxy URL string to construct the Net::HTTP proxy connection; without it, it cannot route traffic through the proxy.

Source

Thrown at rb/lib/selenium/webdriver/remote/http/default.rb:151

          def new_request_for(verb, url, headers, payload)
            req = Net::HTTP.const_get(verb.to_s.capitalize).new(url.path, headers)

            req.basic_auth server_url.user, server_url.password if server_url.userinfo

            req.body = payload if payload

            req
          end

          def response_for(request)
            http.request request
          end

          def new_http_client
            if use_proxy?
              url = proxy.http
              unless proxy.respond_to?(:http) && url
                raise Error::WebDriverError,
                      "expected HTTP proxy, got #{proxy.inspect}"
              end

              proxy_uri = URI.parse(url)

              Net::HTTP.new(server_url.host, server_url.port,
                            proxy_uri.host, proxy_uri.port, proxy_uri.user, proxy_uri.password)
            else
              Net::HTTP.new server_url.host, server_url.port
            end
          end

          def proxy
            client_config.proxy
          end

          def use_proxy?
            return false if proxy.nil?

View on GitHub (pinned to aa36b38e69)

Solutions

1. Ensure the proxy object responds to #http and returns a valid URL string: Selenium::WebDriver::Proxy.new(http: 'host:8080', ssl: 'host:8080').
2. If using a custom proxy object, implement #http returning a non-nil URL string.
3. Verify both :http and :ssl proxy entries are set when the remote endpoint uses HTTPS.
4. If you don't actually need an HTTP-client-level proxy, clear it rather than leaving a partial/broken proxy config.

Example fix

# before
client.proxy = Selenium::WebDriver::Proxy.new(ssl: 'proxyhost:8080')  # :http is nil

# after
client.proxy = Selenium::WebDriver::Proxy.new(http: 'proxyhost:8080', ssl: 'proxyhost:8080')

# Validate the proxy object before assignment:
if use_proxy && !(proxy.respond_to?(:http) && proxy.http)
  raise ArgumentError, 'proxy must respond to #http with a non-nil URL'
end

def valid_http_proxy?(proxy)
  proxy.respond_to?(:http) && !proxy.http.nil?
end

begin
  client.request(verb, url)
rescue Selenium::WebDriver::Error::WebDriverError => e
  raise unless e.message.include?('expected HTTP proxy')
  raise 'Configure proxy with both :http and :ssl entries'
end

When it happens

Trigger: Setting a proxy via the HTTP client that is not a valid Selenium::WebDriver::Proxy with an :http or :ssl entry. Passing a custom proxy object missing the #http method. Configuring proxy= with a Proxy whose http and ssl are both nil. Passing a string URL to proxy= (the setter may accept it but #http won't resolve).

Common situations: Configuring an HTTP transport-level proxy (distinct from browser-level proxy capabilities) incorrectly. Passing a SOCKS proxy specification when only HTTP proxy is supported. Partial proxy config (setting only :ftp or :ssl in a way that leaves :http nil). Version changes to the Proxy API.

Related errors

• too many redirects
• Cannot use both :http_client and :client_config
• unexpected response, code=#{code}, content-type=#{content_ty
• Cannot use both :client_config and :open_timeout/:read_timeo
• Pattern must be an instance of UrlPattern. Received: '${patt

AI-assisted analysis of SeleniumHQ/selenium@aa36b38e69 (2026-08-14). Data as JSON: /api/errors/a93e9b5760f823bf. Report an issue: GitHub.