Documentation
¶
Overview ¶
Package middleware provides a convenient way to chain http handlers.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( AuthHandler = constructHandler(checkAPI) UserHandler = constructHandler(checkLogin) AdminHandler = constructHandler(checkAdmin) )
var (
ScionSessionName = "scion-session" // key name in the session map
)
Functions ¶
func GetUserSession ¶
if the returned session is nil, it means the session did not exist if the return session is not nil, then session existed before if the function returns an error, then we need to stop because the session could not be deserialized
Types ¶
type Chain ¶
type Chain struct {
// contains filtered or unexported fields
}
Chain acts as a list of http.Handler constructors. Chain is effectively immutable: once created, it will always hold the same set of constructors in the same order.
func New ¶
func New(constructors ...Constructor) Chain
New creates a new chain, memorizing the given list of middleware constructors. New serves no other function, constructors are only called upon a call to Then().
func NewWithLogging ¶
func NewWithLogging(constructors ...Constructor) Chain
Creates a new chain including a LoggingHandler as first Handler
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 := alice.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 ¶
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 := alice.New(m1, m2) ext1Chain := alice.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 := alice.New(m2)
aHtml := alice.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 ¶
Then chains the middleware and returns the final http.Handler.
New(m1, m2, m3).Then(h)
is equivalent to:
m1(m2(m3(h)))
When the request comes in, it will be passed to m1, then m2, then m3 and finally, the given handler (assuming every middleware calls the following one).
A chain can be safely reused by calling Then() several times.
stdStack := alice.New(ratelimitHandler, csrfHandler) indexPipe = stdStack.Then(indexHandler) authPipe = stdStack.Then(authHandler)
Note that constructors are called on every call to Then() and thus several instances of the same middleware will be created when a chain is reused in this way. For proper middleware, this should cause no problems.
Then() treats nil as http.DefaultServeMux.
Source Files