bract.ring.wrapper — bract/bract.ring 0.6.2-0.2.0-alpha2

A bract.ring wrapper is a function (fn [ring-handler context & args]) -> ring-handler to wrap the handler (like a middleware) using information in the context. This namespace includes such wrappers and some helper functions.

add-uri-trailing-slash clj

(add-uri-trailing-slash request)

Given a request map, add any missing trailing slash to the URI and return updated request map.

distributed-trace-wrapper clj

(distributed-trace-wrapper handler context)

(distributed-trace-wrapper handler context options)

Parse distributed trace HTTP headers and populate request with well configured attributes.

Option	Config key	Default config value
:trace-id-header	"bract.ring.trace.trace.id.header"	"x-trace-id"
:parent-id-header	"bract.ring.trace.parent.id.header"	"x-trace-parent-id"
:trace-id-required?	"bract.ring.trace.trace.id.req.flag"	false
:trace-id-validator	"bract.ring.trace.trace.id.valid.fn"	(constantly nil)
:trace-id-request-key	"bract.ring.trace.trace.id.req.key"	:trace-id
:span-id-request-key	"bract.ring.trace.span.id.req.key"	:span-id
:parent-id-request-key	"bract.ring.trace.parent.id.req.key"	:parent-id

health-check-response clj

(health-check-response health-check-fns
                       health-http-codes
                       body-encoder
                       content-type)

Return health-check response.

health-check-wrapper clj

(health-check-wrapper handler context)

(health-check-wrapper handler context options)

Given optional URIs (default: /health), body encoder (default: EDN) and content type (default: application/edn), wrap specified Ring handler such that it responds to application health query when health endpoint is requested.

Option	Config key	Default config value
:uris	"bract.ring.health.check.uris"	["/health" "/health/"]
:body-encoder	"bract.ring.health.body.encoder"	[[clojure.core/pr-str]]
:content-type	"bract.ring.health.content.type"	"application/edn"
:http-codes	"bract.ring.health.http.codes"	{:critical 503 :degraded 500 :healthy 200}

info-endpoint-wrapper clj

(info-endpoint-wrapper handler context)

(info-endpoint-wrapper handler context options)

Given Ring handler and Bract context, wrap the handler such that info (default: /info and /info/) URIs lead to returning a runtime info response.

Option	Config key	Default config value
:uris	"bract.ring.info.endpoint.uris"	["/info" "/info/"]
:body-encoder	"bract.ring.info.body.encoder"	[[clojure.core/pr-str]]
:content-type	"bract.ring.info.body.content.type"	"application/edn"

info-response clj

(info-response info-gen-fns body-encoder content-type)

Return /info response.

make-uri-prefix-matcher clj

(make-uri-prefix-matcher uri-prefix strip-prefix? uri-backup? backup-key)

Given a URI prefix, a flag to decide whether to strip the prefix and a key (nil=disabled) to backup the old URI to, return a function (fn [request]) -> request? returning updated request on successful prefix match, nil otherwise.

See: uri-prefix-match-wrapper

opt-or-config clj macro

(opt-or-config opt-key config-f)

Assuming 'options and 'context symbols are bound to respective arguments, extract the value of specified option falling back to config.

params-normalize-wrapper clj

(params-normalize-wrapper handler context)

(params-normalize-wrapper handler context options)

Normalize the result of ring.middleware.params/wrap-params middleware (that is, the request map with :params) by transforming each request params value. The wrap-params middleware extracts params as string, but multiple values for same param are turned into a vector of string - this middleware turns all param values into vectors of string and applies normalizer to that vector.

Option	Config key	Default config value
:normalizer	"bract.ring.params.normalize.function"	[[clojure.core/identity]]

Without this middleware/wrapper:

{"foo" "bar"
 "baz" ["quux" "corge"]}

After using this middleware, where normalizer is clojure.core/first:

{"foo" "bar"
 "baz" "quux"}

ping-endpoint-wrapper clj

(ping-endpoint-wrapper handler context)

(ping-endpoint-wrapper handler context options)

Given Ring handler and Bract context, wrap the handler such that ping (default: /ping and /ping/) URIs lead to returning a ping response.

Option	Config key	Default config value
:uris	"bract.ring.ping.endpoint.uris"	["/ping" "/ping/"]
:body	"bract.ring.ping.endpoint.body"	"pong"
:content-type	"bract.ring.ping.content.type"	"text/plain"

remove-uri-trailing-slash clj

(remove-uri-trailing-slash request)

Given a request map, remove any trailing slash from the URI and return updated request map.

request-update-wrapper clj

(request-update-wrapper handler context request-updater)

Given Ring handler, Bract context and request-updater function (fn [request]) -> request, wrap the handler such that the request is updated before the Ring handler is applied to it.

traffic-drain-wrapper clj

(traffic-drain-wrapper handler context)

(traffic-drain-wrapper handler context options)

Given a deref'able shutdown state and a boolean flag to respond with connection-close HTTP header, wrap specified Ring handler to respond with HTTP 503 (in order to drain current traffic) when the system is shutting down.

Option	Config key	Default config value
:conn-close?	"bract.ring.traffic.conn.close.flag"	true

traffic-log-wrapper clj

(traffic-log-wrapper handler context)

(traffic-log-wrapper handler context options)

Log traffic to the Ring handler.

Option	Value type	Description	Default
:request-logger	(fn [request])	Request logger function	No-op
:response-logger	(fn [request response ^double duration-millis])	Response logger function	No-op
:exception-logger	(fn [request exception ^double duration-millis])	Exception logger function	No-op

See: [[ring-mware/traffic-log-middleware]]

unexpected->500-wrapper clj

(unexpected->500-wrapper handler context)

(unexpected->500-wrapper handler context options)

Wrap given Ring handler such that if it returns unexpected Ring response (invalid/malformed response or exception) then return HTTP 500 Ring response.

Option	Config key	Default config value
:on-bad-response	"bract.ring.unexpected.response.fn"	bract.ring.util/bad-response->500
:on-exception	"bract.ring.unexpected.exception.fn"	bract.ring.util/exception->500

uri-prefix-match-wrapper clj

(uri-prefix-match-wrapper handler context)

(uri-prefix-match-wrapper handler context options)

Given a Ring handler, a Bract context, a URI prefix, a flag to decide whether to strip the prefix and a key (nil implies no-backup) to backup the old URI to, return updated Ring handler that matches prefix and proceeds on success or returns HTTP 400 on no match.

Option	Config key	Default config value
:uri-prefix	"bract.ring.uri.prefix.match.token"	(required config)
:strip-prefix?	"bract.ring.uri.prefix.strip.flag"	true
:backup-uri?	"bract.ring.uri.prefix.backup.flag"	true
:backup-key	"bract.ring.uri.prefix.backup.key"	:original-uri

See: make-uri-prefix-matcher

uri-trailing-slash-wrapper clj

(uri-trailing-slash-wrapper handler context)

(uri-trailing-slash-wrapper handler context options)

Wrap handler such that the trailing slash is either added (if missing) or removed (if present) depending upon the specified optional action (:add/:remove).

Option	Config key	Default config value
:action	"bract.ring.uri.trailing.slash.action"	:remove

when-wrapper-enabled clj macro

(when-wrapper-enabled pred handler context & body)

Given a predicate function, handler and context, evaluate body of code only when (pred config) returns truthy, return the handler otherwise. The config is extracted from context before applying the predicate to it.