Improves 5xx status codes with referencing

contents/codes/500.md

@@ -6,10 +6,11 @@ references:
     "Rails HTTP Status Symbol": ":internal_server_error"
 ---
 
-The 500 Internal Server Error status code indicates that the server
+The server encountered an unexpected condition that prevented it from fulfilling
-encountered an unexpected condition that prevented it from fulfilling the
+the request.
-request.
 
-Source: [RFC7231 Section 6.6.1][1]
+---
+
+* Source: [RFC7231 Section 6.6.1][1]
 
 [1]: <http://tools.ietf.org/html/rfc7231#section-6.6.1>

contents/codes/501.md

@@ -6,17 +6,19 @@ references:
     "Rails HTTP Status Symbol": ":not_implemented"
 ---
 
-The 501 Not Implemented status code indicates that the server does not support
+The server does not support the functionality required to fulfill the request.
-the functionality required to fulfill the request.
 
 This is the appropriate response when the server does not recognize the request
 method and is not capable of supporting it for any resource.
 
 A 501 response is cacheable by default; i.e., unless otherwise indicated by the
-method definition or explicit cache controls
+method definition or explicit cache controls<sup>[1](#ref-1)</sup>.
-(see [Section 4.2.2 of RFC7234][1]).
 
-Source: [RFC7231 Section 6.6.2][1]
+---
+
+* <span id="ref-1"><sup>1</sup> Calculating Heuristic Freshness
+[RFC7234 Section 4.2.2][2]</span>
+* Source: [RFC7231 Section 6.6.2][1]
 
 [1]: <http://tools.ietf.org/html/rfc7231#section-6.6.2>
 [2]: <http://tools.ietf.org/html/rfc7234#section-4.2.2>

contents/codes/502.md

@@ -6,10 +6,11 @@ references:
     "Rails HTTP Status Symbol": ":bad_gateway"
 ---
 
-The 502 Bad Gateway status code indicates that the server, while acting as a
+The server, while acting as a gateway or proxy, received an invalid response
-gateway or proxy, received an invalid response from an inbound server it
+from an inbound server it accessed while attempting to fulfill the request.
-accessed while attempting to fulfill the request.
 
-Source: [RFC7231 Section 6.6.3][1]
+---
+
+* Source: [RFC7231 Section 6.6.3][1]
 
 [1]: <http://tools.ietf.org/html/rfc7231#section-6.6.3>

contents/codes/503.md

@@ -6,19 +6,21 @@ references:
     "Rails HTTP Status Symbol": ":service_unavailable"
 ---
 
-The 503 Service Unavailable status code indicates that the server is currently
+The server is currently unable to handle the request due to a temporary overload
-unable to handle the request due to a temporary overload or scheduled
+or scheduled maintenance, which will likely be alleviated after some delay.
-maintenance, which will likely be alleviated after some delay.
 
-The server MAY send a Retry-After header field ([RFC7231 Section 7.1.3][2]) to
+The server MAY send a Retry-After header field<sup>[1](#ref-1)</sup> to suggest
-suggest an appropriate amount of time for the client to wait before retrying the
+an appropriate amount of time for the client to wait before retrying the
 request.
 
 Note: The existence of the 503 status code does not imply that a server has to
 use it when becoming overloaded. Some servers might simply refuse the
 connection.
 
-Source: [RFC7231 Section 6.6.4][1]
+---
+
+* <span id="ref-1"><sup>1</sup> Retry-After [RFC7231 Section 7.1.3][2]</span>
+* Source: [RFC7231 Section 6.6.4][1]
 
 [1]: <http://tools.ietf.org/html/rfc7231#section-6.6.4>
 [2]: <http://tools.ietf.org/html/rfc7231#section-7.1.3>

contents/codes/504.md

@@ -6,10 +6,12 @@ references:
     "Rails HTTP Status Symbol": ":gateway_timeout"
 ---
 
-The 504 Gateway Timeout status code indicates that the server, while acting as
+The server, while acting as a gateway or proxy, did not receive a timely
-a gateway or proxy, did not receive a timely response from an upstream server it
+response from an upstream server it needed to access in order to complete the
-needed to access in order to complete the request.
+request.
 
-Source: [RFC7231 Section 6.6.5][1]
+---
+
+* Source: [RFC7231 Section 6.6.5][1]
 
 [1]: <http://tools.ietf.org/html/rfc7231#section-6.6.5>

contents/codes/505.md

@@ -6,9 +6,8 @@ references:
     "Rails HTTP Status Symbol": ":http_version_not_supported"
 ---
 
-The 505 HTTP Version Not Supported status code indicates that the server does
+The server does not support, or refuses to support, the major version of HTTP
-not support, or refuses to support, the major version of HTTP that was used in
+that was used in the request message.
-the request message.
 
 The server is indicating that it is unable or unwilling to complete the request
 using the same major version as the client, as described in
@@ -16,7 +15,9 @@ using the same major version as the client, as described in
 SHOULD generate a representation for the 505 response that describes why that
 version is not supported and what other protocols are supported by that server.
 
-Source: [RFC7231 Section 6.6.6][1]
+---
+
+* Source: [RFC7231 Section 6.6.6][1]
 
 [1]: <http://tools.ietf.org/html/rfc7231#section-6.6.6>
 [2]: <http://tools.ietf.org/html/rfc7230#section-2.6>

contents/codes/506.md

@@ -4,11 +4,12 @@ code: 506
 title: Variant Also Negotiates
 ---
 
-The 506 status code indicates that the server has an internal configuration
+The server has an internal configuration error: the chosen variant resource is
-error: the chosen variant resource is configured to engage in transparent
+configured to engage in transparent content negotiation itself, and is therefore
-content negotiation itself, and is therefore not a proper end point in the
+not a proper end point in the negotiation process.
-negotiation process.
 
-Source: [RFC2295 Section 8.1][1]
+---
+
+* Source: [RFC2295 Section 8.1][1]
 
 [1]: <http://tools.ietf.org/html/rfc2295#section-8.1>

contents/codes/507.md

@@ -6,12 +6,15 @@ references:
     "Rails HTTP Status Symbol": ":insufficient_storage"
 ---
 
-The 507 Insufficient Storage status code means the method could not be
+The method could not be performed on the resource because the server is unable
-performed on the resource because the server is unable to store the
+to store the representation needed to successfully complete the request.
-representation needed to successfully complete the request.
 
 This condition is considered to be temporary. If the request that received this
 status code was the result of a user action, the request MUST NOT be repeated
 until it is requested by a separate user action.
 
+---
+
+* Source: [RFC4918 Section 11.5][1]
+
 [1]: <http://tools.ietf.org/html/rfc4918#section-11.5>

contents/codes/508.md

@@ -4,10 +4,12 @@ code: 508
 title: Loop Detected
 ---
 
-The 508 Loop Detected status code indicates that the server terminated an
+The server terminated an operation because it encountered an infinite loop while
-operation because it encountered an infinite loop while processing a request
+processing a request with "Depth: infinity". This status indicates that the
-with "Depth: infinity".  This status indicates that the entire operation failed.
+entire operation failed.
 
-Source: [RFC5842 Section 7.2][1]
+---
+
+* Source: [RFC5842 Section 7.2][1]
 
 [1]: <http://tools.ietf.org/html/rfc5842#section-7.2>

contents/codes/510.md

@@ -20,6 +20,8 @@ according to the information provided in the 510 response. Otherwise the client
 MAY present any entity included in the 510 response to the user, since that
 entity may include relevant diagnostic information.
 
-Source: [RFC2774 Section 7][1]
+---
+
+* Source: [RFC2774 Section 7][1]
 
 [1]: <http://tools.ietf.org/html/rfc2774#section-7>

contents/codes/511.md

@@ -4,8 +4,7 @@ code: 511
 title: Network Authentication Required
 ---
 
-The 511 status code indicates that the client needs to authenticate to gain
+The client needs to authenticate to gain network access.
-network access.
 
 The response representation SHOULD contain a link to a resource that allows the
 user to submit credentials (e.g., with an HTML form).
@@ -67,6 +66,8 @@ Here, the 511 status code assures that non-browser clients will not interpret
 the response as being from the origin server, and the META HTML element
 redirects the user agent to the login server.
 
-Source: [RFC6585 Section 6][1]
+---
+
+* Source: [RFC6585 Section 6][1]
 
 [1]: <http://tools.ietf.org/html/rfc6585#section-6>

contents/codes/599.md

@@ -10,6 +10,8 @@ This status code is not specified in any RFCs, but is used by some HTTP proxies
 to signal a network connect timeout behind the proxy to a client in front of the
 proxy.
 
-Source: [unknown?][1]
+---
+
+* Source: [unknown?][1]
 
 [1]: <https://github.com/citricsquid/httpstatuses/issues/22>