Raise error nil

docs/middleware/response/raise_error.md

@@ -9,26 +9,9 @@ top_name: Back to Middleware
 top_link: ./list
 ---
 
-The `RaiseError` middleware checks the response HTTP code and raises an exception if it is a 4xx or 5xx code.
-Specific exceptions are raised based on the HTTP Status code, according to the list below:
-
-```
-## 4xx HTTP codes
-400 => Faraday::BadRequestError
-401 => Faraday::UnauthorizedError
-403 => Faraday::ForbiddenError
-404 => Faraday::ResourceNotFound
-407 => Faraday::ProxyAuthError
-409 => Faraday::ConflictError
-422 => Faraday::UnprocessableEntityError
-4xx => Faraday::ClientError (all exceptions above inherit from this one.
-
-## 5xx HTTP codes
-5xx => Faraday::ServerError
-```
-
-All exceptions classes listed above inherit from `Faraday::Error`, and are initialized providing
-the response `status`, `headers` and `body`, available for you to access on rescue:
+The `RaiseError` middleware raises a `Faraday::Error` exception if an HTTP
+response returns with a 4xx or 5xx status code. All exceptions are initialized
+providing the response `status`, `headers`, and `body`.
 
 ```ruby
 begin
@@ -37,5 +20,30 @@ rescue Faraday::ResourceNotFound => e
   e.response[:status]   #=> 404
   e.response[:headers]  #=> { ... }
   e.response[:body]     #=> "..."  
-end 
+end
 ```
+
+Specific exceptions are raised based on the HTTP Status code, according to the list below:
+
+An HTTP status in the 400-499 range typically represents an error
+by the client. They raise error classes inheriting from `Faraday::ClientError`.
+
+* 400 => `Faraday::BadRequestError`
+* 401 => `Faraday::UnauthorizedError`
+* 403 => `Faraday::ForbiddenError`
+* 404 => `Faraday::ResourceNotFound`
+* 407 => `Faraday::ProxyAuthError`
+* 409 => `Faraday::ConflictError`
+* 422 => `Faraday::UnprocessableEntityError`
+* 4xx => `Faraday::ClientError`
+
+An HTTP status in the 500-599 range represents a server error, and raises a
+`Faraday::ServerError` exception.
+
+* 5xx => `Faraday::ServerError`
+
+The HTTP response status may be nil due to a malformed HTTP response from the
+server, or a bug in the underlying HTTP library. It inherits from
+`Faraday::ServerError`.
+
+* nil => `Faraday::NilStatusError`

lib/faraday/error.rb

@@ -80,6 +80,14 @@ def initialize(exc = 'timeout', response = nil)
     end
   end
 
+  # Raised by Faraday::Response::RaiseError in case of a nil status in response.
+  class NilStatusError < ServerError
+    def initialize(_exc, response: nil)
+      message = 'http status could not be derived from the server response'
+      super(message, response)
+    end
+  end
+
   # A unified error for failed connections.
   class ConnectionFailed < Error
   end

lib/faraday/response/raise_error.rb

@@ -32,6 +32,8 @@ def on_complete(env)
           raise Faraday::ClientError, response_values(env)
         when ServerErrorStatuses
           raise Faraday::ServerError, response_values(env)
+        when nil
+          raise Faraday::NilStatusError, response: response_values(env)
         end
       end
 

spec/faraday/response/raise_error_spec.rb

@@ -14,6 +14,7 @@
         stub.get('conflict') { [409, { 'X-Reason' => 'because' }, 'keep looking'] }
         stub.get('unprocessable-entity') { [422, { 'X-Reason' => 'because' }, 'keep looking'] }
         stub.get('4xx') { [499, { 'X-Reason' => 'because' }, 'keep looking'] }
+        stub.get('nil-status') { [nil, { 'X-Reason' => 'bailout' }, 'fail'] }
         stub.get('server-error') { [500, { 'X-Error' => 'bailout' }, 'fail'] }
       end
     end
@@ -72,6 +73,12 @@
     end
   end
 
+  it 'raises Faraday::NilStatusError for nil status in response' do
+    expect { conn.get('nil-status') }.to raise_error(Faraday::NilStatusError) do |ex|
+      expect(ex.message).to eq('http status could not be derived from the server response')
+    end
+  end
+
   it 'raises Faraday::ClientError for other 4xx responses' do
     expect { conn.get('4xx') }.to raise_error(Faraday::ClientError) do |ex|
       expect(ex.message).to eq('the server responded with status 499')