middleware

func (Chain) Append ¶

func (c Chain) Append(constructors ...Constructor) Chain

Append extends a chain, adding the specified constructors as the last ones in the request flow.

Append returns a new chain, leaving the original one untouched.

stdChain := middleware.New(m1, m2)
extChain := stdChain.Append(m3, m4)
// requests in stdChain go m1 -> m2
// requests in extChain go m1 -> m2 -> m3 -> m4

func (Chain) Extend ¶

func (c Chain) Extend(chain Chain) Chain

Extend extends a chain by adding the specified chain as the last one in the request flow.

Extend returns a new chain, leaving the original one untouched.

stdChain := middleware.New(m1, m2)
ext1Chain := middleware.New(m3, m4)
ext2Chain := stdChain.Extend(ext1Chain)
// requests in stdChain go  m1 -> m2
// requests in ext1Chain go m3 -> m4
// requests in ext2Chain go m1 -> m2 -> m3 -> m4

Another example:

 aHtmlAfterNosurf := middleware.New(m2)
	aHtml := middleware.New(m1, func(h http.Handler) http.Handler {
		csrf := nosurf.New(h)
		csrf.SetFailureHandler(aHtmlAfterNosurf.ThenFunc(csrfFail))
		return csrf
	}).Extend(aHtmlAfterNosurf)
		// requests to aHtml hitting nosurfs success handler go m1 -> nosurf -> m2 -> target-handler
		// requests to aHtml hitting nosurfs failure handler go m1 -> nosurf -> m2 -> csrfFail

func (Chain) Then ¶

func (c Chain) Then(h http.Handler) http.Handler

Then chains the middleware and returns the final http.Handler.

New(m1, m2, m3).Then(h)

is equivalent to:

m1(m2(m3(h)))

Then() treats nil as http.DefaultServeMux.

func (Chain) ThenFunc ¶

func (c Chain) ThenFunc(fn http.HandlerFunc) http.Handler

ThenFunc works identically to Then, but takes a HandlerFunc instead of a Handler.

The following two statements are equivalent:

c.Then(http.HandlerFunc(fn))
c.ThenFunc(fn)

ThenFunc provides all the guarantees of Then.