return first offer when no accept header set (#351)

This commit is contained in:
tobi 2021-12-20 11:08:54 +01:00 committed by GitHub
parent 635ad2a42f
commit 2582515b4d
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23

View file

@ -56,17 +56,18 @@ var HTMLAcceptHeaders = []Offer{
// slice of Offers, and performs content negotiation for the given request
// with the given content-type offers. It will return a string representation
// of the first suitable content-type, or an error if something goes wrong or
// a suiteable content-type cannot be matched.
// a suitable content-type cannot be matched.
//
// For example, if the request in the *gin.Context has Accept headers of value
// [application/json, text/html], and the provided offers are of value
// [application/json, application/xml], then the returned string will be
// 'application/json', which indicates the content-type that should be returned.
//
// If there are no Accept headers in the request, or the length of offers is 0,
// then an error will be returned, so this function should only be called in places
// where format negotiation is actually needed and headers are expected to be present
// on incoming requests.
// If the length of offers is 0, then an error will be returned, so this function
// should only be called in places where format negotiation is actually needed.
//
// If there are no Accept headers in the request, then the first offer will be returned,
// under the assumption that it's better to serve *something* than error out completely.
//
// Callers can use the offer slices exported in this package as shortcuts for
// often-used Accept types.
@ -77,16 +78,17 @@ func NegotiateAccept(c *gin.Context, offers ...Offer) (string, error) {
return "", errors.New("no format offered")
}
accepts := c.Request.Header.Values("Accept")
if len(accepts) == 0 {
return "", fmt.Errorf("no Accept header(s) set on incoming request; this endpoint offers %s", offers)
}
strings := []string{}
for _, o := range offers {
strings = append(strings, string(o))
}
accepts := c.Request.Header.Values("Accept")
if len(accepts) == 0 {
// there's no accept header set, just return the first offer
return strings[0], nil
}
format := c.NegotiateFormat(strings...)
if format == "" {
return "", fmt.Errorf("no format can be offered for requested Accept header(s) %s; this endpoint offers %s", accepts, offers)