From 6004d3f779b8175d92d8eb7819ed800e8eddbff6 Mon Sep 17 00:00:00 2001 From: Mark Sargent <99003+sarge@users.noreply.github.com> Date: Sat, 27 Jun 2020 09:12:37 +1200 Subject: caddyhttp: Add 'map' handler (#3199) * inital map implementation * resolve the value during middleware execution * use regex instead * pr feedback * renamed mmap to maphandler * refactored GetString implementation * fixed mispelling * additional feedback --- modules/caddyhttp/map/caddyfile.go | 71 +++++++++++++++++++++++++ modules/caddyhttp/map/map.go | 105 +++++++++++++++++++++++++++++++++++++ 2 files changed, 176 insertions(+) create mode 100644 modules/caddyhttp/map/caddyfile.go create mode 100644 modules/caddyhttp/map/map.go (limited to 'modules/caddyhttp/map') diff --git a/modules/caddyhttp/map/caddyfile.go b/modules/caddyhttp/map/caddyfile.go new file mode 100644 index 0000000..5737971 --- /dev/null +++ b/modules/caddyhttp/map/caddyfile.go @@ -0,0 +1,71 @@ +// Copyright 2015 Matthew Holt and The Caddy Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package maphandler + +import ( + "github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile" + "github.com/caddyserver/caddy/v2/modules/caddyhttp" +) + +func init() { + httpcaddyfile.RegisterHandlerDirective("map", parseCaddyfile) +} + +// parseCaddyfile sets up the handler for a map from Caddyfile tokens. Syntax: +// +// map { +// [default ] - used if not match is found +// [ ] - regular expression to match against the source find and the matching replacement value +// ... +// } +// +// The map takes a source variable and maps it into the dest variable. The mapping process +// will check the source variable for the first successful match against a list of regular expressions. +// If a successful match is found the dest variable will contain the replacement value. +// If no successful match is found and the default is specified then the dest will contain the default value. +// +func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) { + m := new(Handler) + + for h.Next() { + // first see if source and dest are configured + if h.NextArg() { + m.Source = h.Val() + if h.NextArg() { + m.Destination = h.Val() + } + } + + // load the rules + for h.NextBlock(0) { + expression := h.Val() + if expression == "default" { + args := h.RemainingArgs() + if len(args) != 1 { + return m, h.ArgErr() + } + m.Default = args[0] + } else { + args := h.RemainingArgs() + if len(args) != 1 { + return m, h.ArgErr() + } + m.Items = append(m.Items, Item{Expression: expression, Value: args[0]}) + } + } + } + + return m, nil +} diff --git a/modules/caddyhttp/map/map.go b/modules/caddyhttp/map/map.go new file mode 100644 index 0000000..d2a0a0a --- /dev/null +++ b/modules/caddyhttp/map/map.go @@ -0,0 +1,105 @@ +// Copyright 2015 Matthew Holt and The Caddy Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package maphandler + +import ( + "net/http" + "regexp" + + "github.com/caddyserver/caddy/v2" + "github.com/caddyserver/caddy/v2/modules/caddyhttp" +) + +func init() { + caddy.RegisterModule(Handler{}) +} + +// Handler is a middleware that maps a source placeholder to a destination +// placeholder. +// +// The mapping process happens early in the request handling lifecycle so that +// the Destination placeholder is calculated and available for substitution. +// The Items array contains pairs of regex expressions and values, the +// Source is matched against the expression, if they match then the destination +// placeholder is set to the value. +// +// The Default is optional, if no Item expression is matched then the value of +// the Default will be used. +// +type Handler struct { + // Source is a placeholder + Source string `json:"source,omitempty"` + // Destination is a new placeholder + Destination string `json:"destination,omitempty"` + // Default is an optional value to use if no other was found + Default string `json:"default,omitempty"` + // Items is an array of regex expressions and values + Items []Item `json:"items,omitempty"` +} + +// CaddyModule returns the Caddy module information. +func (Handler) CaddyModule() caddy.ModuleInfo { + return caddy.ModuleInfo{ + ID: "http.handlers.map", + New: func() caddy.Module { return new(Handler) }, + } +} + +// Provision will compile all regular expressions +func (h *Handler) Provision(_ caddy.Context) error { + for i := 0; i < len(h.Items); i++ { + h.Items[i].compiled = regexp.MustCompile(h.Items[i].Expression) + } + return nil +} + +func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error { + repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer) + + // get the source value, if the source value was not found do no + // replacement. + val, ok := repl.GetString(h.Source) + if ok { + found := false + for i := 0; i < len(h.Items); i++ { + if h.Items[i].compiled.MatchString(val) { + found = true + repl.Set(h.Destination, h.Items[i].Value) + break + } + } + + if !found && h.Default != "" { + repl.Set(h.Destination, h.Default) + } + } + return next.ServeHTTP(w, r) +} + +// Item defines each entry in the map +type Item struct { + // Expression is the regular expression searched for + Expression string `json:"expression,omitempty"` + // Value to use once the expression has been found + Value string `json:"value,omitempty"` + // compiled expression, internal use + compiled *regexp.Regexp +} + +// Interface guards +var ( + _ caddy.Provisioner = (*Handler)(nil) + _ caddyhttp.MiddlewareHandler = (*Handler)(nil) +) -- cgit v1.2.3