Http Mandatory Headers - 5G

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Request Headers

Header Name	Description
Accept	This header is used to specify response media types that are acceptable.
Accept-Encoding	This header may be used to indicate what response content-encodings (e.g gzip) are acceptable in the response.
Authorization	This header shall be used if OAuth 2.0 based access authorization with "Client Credentials" grant type is used as specified in subclause 13.4.1 of 3GPP TS 33.501 [17], clause 7 of IETF RFC 6749 [22] and IETF RFC 6750 [23].
Cache-Control	This header may be used in some HTTP/2 requests to provide the HTTP cache-control directives that the client is willing to accept from the server.
Content-Length	This header is used to provide the anticipated size, as a decimal number of octets, for a potential payload body.
Content-Type	This header is used to indicate the media type of the associated representation.
If-Match	This header may be used in a conditional POST or PUT or DELETE or PATCH request. This is used in conjunction with the ETag server response header, to update / delete content only if the tag value of the resource on the server matches the tag value in the If-Match header.
If-Modified-Since	This header may be used in a conditional GET request, for server revalidation. This is used in conjunction with the Last-Modified server response header, to fetch content only if the content has been modified from the cached version.
If-None-Match	This header may be used in a conditional GET request. This is used in conjunction with the ETag server response header, to fetch content only if the tag value of the resource on the server differs from the tag value in the If-None-Match header.
User-Agent	This header shall be mainly used to identify the NF type of the HTTP/2 client.
Via	This header shall be inserted by HTTP proxies.

Response Headers

Header Name	Description
Age	This header may be inserted by HTTP proxies when returning a cached response. The "Age" header field conveys the sender's estimate of the amount of time since the response was generated or successfully validated at the origin server. The presence of an Age header field implies that the response was not generated or validated by the origin server for this request.
Allow	This header field shall be used to indicate methods supported by the target resource.
Cache-Control	This header may be used in some responses (e.g. NRF responses to queries) to provide HTTP response cache control directives. The cache directives "no-cache", "no-store", "max-age" and "must-revalidate" values shall be supported.
Content-Encoding	This header may be used in some responses to indicate to the HTTP/2 client the content encodings (e.g gzip) applied to the resource representation beyond those inherent in the media type.
Content-Length	This header may be used to provide the anticipated size, as a decimal number of octets, for a potential payload body.
Content-Type	This header shall be used to indicate the media type of the associated representation.
ETag	This header may be sent to allow for conditional GET with the If-If-None-Match header or a conditional POST / PUT / PATCH / DELETE with the If-Match header.
Last-Modified	This header may be sent to allow for conditional GET with the If-Modified-Since header.
Location	This header may be used in some responses to refer to a specific resource in relation to the response.
Retry-After	This header may be used in some responses to indicate how long the user agent ought to wait before making a follow-up request.
Via	This header shall be inserted by HTTP proxies.
WWW-Authenticate	This header field shall be included when an NF service producer rejects a request with a "401 Unauthorized" status code (e.g when a request is sent without an OAuth 2.0 access token or with an invalid OAuth 2.0 access token).